SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  Schedule 13G


   INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1 (b),
         (c) AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO 13d-2 (b)
                           (Amendment No.___________)*


                                 AtriCure, Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)


                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)


                                    04963C209
--------------------------------------------------------------------------------
                                 (CUSIP Number)


                                December 31, 2005
--------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)

Check the  appropriate box to designate the rule pursuant to which this Schedule
is filed:

           [ ]    Rule 13d-1(b)

           [ ]    Rule 13d-1(c)

           [X]    Rule 13d-1(d)

*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for  any  subsequent   amendment   containing   information  which  would  alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the
Notes).

                         (Continued on following pages)


                               Page 1 of 22 Pages
                       Exhibit Index Contained on Page 20





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 2 of 22
----------------------------------------                                        -------------------------------------

------------ ---------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING
             SS OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
                      U.S. Venture Partners VIII, L.P. ("USVP VIII")
                      Tax ID Number:
------------ ---------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ ---------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ ---------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             Delaware
------------ ---------------------------------------------------------------------------------------------------------

                                     5        SOLE VOTING POWER
             NUMBER OF                        2,286,924 shares, of which 2,194,151 are outstanding shares and 92,773
              SHARES                          are issuable upon the conversion of  warrants; except that Presidio
           BENEFICIALLY                       Management Group VIII, L.L.C. ("PMG VIII"), the general partner of
      OWNED BY EACH REPORTING                 USVP VIII, may be deemed to have sole power to vote these shares, and
              PERSON                          Timothy Connors ("Connors"), Irwin Federman ("Federman"), Winston Fu
               WITH                           ("Fu"), Steven M. Krausz  ("Krausz"), David Liddle ("Liddle"),
                                              Jonathan D. Root ("Root"), Christopher Rust ("Rust") and Philip M.
                                              Young ("Young") the managing members of PMG VIII, may be deemed to
                                              have shared power to vote these shares.
                                     -------- ------------------------------------------------------------------------
                                     6        SHARED VOTING POWER
                                              See response to row 5.
                                     -------- ------------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              2,286,924 shares, of which 2,194,151 are outstanding shares and 92,773
                                              are issuable upon the conversion of  warrants; except that PMG VIII,
                                              the general partner of USVP VIII, may be deemed to have the sole power
                                              to dispose of these shares, and Connors, Federman, Fu, Krausz, Liddle,
                                              Root, Rust and Young, the managing members of PMG VIII, may be deemed
                                              to have shared power to dispose of these shares.
                                     -------- ------------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              See response to row 7.
------------------------------------ -------- ------------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       2,286,924
------------ ---------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ ---------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                          19.0%
------------ ---------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                 PN
------------ ---------------------------------------------------------------------------------------------------------







----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 3 of 22
----------------------------------------                                        -------------------------------------

------------ ---------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING
             SS OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
                      USVP VIII Affiliates Fund, L.P. ("USVP VIII AF")
                      Tax ID Number:
------------ ---------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ ---------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ ---------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             Delaware
------------ ---------------------------------------------------------------------------------------------------------

                                     5        SOLE VOTING POWER
             NUMBER OF                        17,653 shares, of which 16,970 are outstanding and 683 are issuable
              SHARES                          upon the conversion of warrants; except that PMG VIII, the general
           BENEFICIALLY                       partner of USVP VIII AF, may be deemed to have sole power to vote
      OWNED BY EACH REPORTING                 these shares, and Connors, Federman, Fu, Krausz, Liddle, Root, Rust
              PERSON                          and Young, the managing members of PMG VIII, may be deemed to have
               WITH                           shared power to vote these shares.
                                     -------- ------------------------------------------------------------------------
                                     6        SHARED VOTING POWER
                                              See response to row 5.
                                     -------- ------------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              17,653 shares, of which 16,970 are outstanding and 683 are issuable
                                              upon the conversion of warrants; except that PMG VIII, the general
                                              partner of USVP VIII AF, may be deemed to have sole power to dispose
                                              of these shares, and Connors, Federman, Fu, Krausz, Liddle, Root, Rust
                                              and Young, the managing members of PMG VIII, may be deemed to have
                                              shared power to dispose of these shares.
                                     -------- ------------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              See response to row 7.
------------------------------------ -------- ------------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       17,653
------------ ---------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ ---------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                         0.1%
------------ ---------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                PN
------------ ---------------------------------------------------------------------------------------------------------





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 4 of 22
----------------------------------------                                        -------------------------------------

------------ ---------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING
             SS OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
                      USVP Entrepreneur Partners VIII-A, L.P. ("USVP EP VIII-A")
                      Tax ID Number:
------------ ---------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ ---------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ ---------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             Delaware
------------ ---------------------------------------------------------------------------------------------------------

                                     5        SOLE VOTING POWER
             NUMBER OF                        22,444 shares, of which 21,575 are outstanding and 869 are issuable
              SHARES                          upon conversion of  warrants; except that PMG VIII, the general
           BENEFICIALLY                       partner of USVP EP VIII-A,  may be deemed to have sole power to vote
      OWNED BY EACH REPORTING                 these shares, and Connors, Federman, Fu, Krausz, Liddle, Root, Rust
              PERSON                          and Young, the managing members of PMG VIII, may be deemed to have
               WITH                           shared power to vote these shares.
                                     -------- ------------------------------------------------------------------------
                                     6        SHARED VOTING POWER
                                              See response to row 5.
                                     -------- ------------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              22,444 shares, of which 21,575 are outstanding and 869 are issuable
                                              upon conversion of  warrants; except that PMG VIII, the general
                                              partner of USVP EP VIII-A,  may be deemed to have sole power to
                                              dispose of these shares, and Connors, Federman, Fu, Krausz, Liddle,
                                              Root, Rust and Young, the managing members of PMG VIII, may be deemed
                                              to have shared power to dispose of these shares.
                                     -------- ------------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              See response to row 7.
------------------------------------ -------- ------------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       22,444
------------ ---------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ ---------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                         0.2%
------------ ---------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                PN
------------ ---------------------------------------------------------------------------------------------------------





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 5 of 22
----------------------------------------                                        -------------------------------------

------------ ---------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING
             SS OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
                      USVP Entrepreneur Partners VIII-B, L.P. ("USVP EP VIII-B")
                      Tax ID Number:
------------ ---------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ ---------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ ---------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             Delaware
------------ ---------------------------------------------------------------------------------------------------------

                                     5        SOLE VOTING POWER
             NUMBER OF                        12,041 shares, of which 11,575 are outstanding and 466 are issuable
              SHARES                          upon conversion of warrants; except that PMG VIII, the general partner
           BENEFICIALLY                       of USVP EP VIII-B, may be deemed to have sole power to vote these
      OWNED BY EACH REPORTING                 shares, and Connors, Federman, Fu, Krausz, Liddle, Root, Rust and
              PERSON                          Young, the managing members of PMG VIII, may be deemed to have shared
               WITH                           power to vote these shares.
                                     -------- ------------------------------------------------------------------------
                                     6        SHARED VOTING POWER
                                              See response to row 5.
                                     -------- ------------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              12,041 shares, of which 11,575 are outstanding and 466 are issuable
                                              upon conversion of warrants; except that PMG VIII, the general partner
                                              of USVP EP VIII-B, may be deemed to have sole power to dispose of
                                              these shares, and Connors, Federman, Fu, Krausz, Liddle, Root, Rust
                                              and Young, the managing members of PMG VIII, may be deemed to have
                                              shared power to dispose of these shares.
                                     -------- ------------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              See response to row 7.
------------------------------------ -------- ------------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       12,041
------------ ---------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ ---------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                         0.1%
------------ ---------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                PN
------------ ---------------------------------------------------------------------------------------------------------





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 6 of 22
----------------------------------------                                        -------------------------------------

------------ ---------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING
             SS OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
                      Presidio Management Group VIII, L.L.C.
                      Tax ID Number:
------------ ---------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ ---------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ ---------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             Delaware
------------ ---------------------------------------------------------------------------------------------------------

                                     5       SOLE VOTING POWER
             NUMBER OF                       2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
              SHARES                         17,653 are directly owned by USVP VIII AF, 22,444 are directly owned by
           BENEFICIALLY                      USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.  PMG
      OWNED BY EACH REPORTING                VIII, the general partner of USVP VIII, USVP VIII AF, USVP EP VIII-A
              PERSON                         and USVP EP VIII-B, may be deemed to have sole power to vote these
               WITH                          shares, and Connors, Federman, Fu, Krausz, Liddle, Root, Rust and
                                             Young, the managing members of PMG VIII, may be deemed to have shared
                                             power to vote these shares.
                                     ------- -------------------------------------------------------------------------
                                     6       SHARED VOTING POWER
                                             See response to row 5.
                                     ------- -------------------------------------------------------------------------
                                     7       SOLE DISPOSITIVE POWER
                                             2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
                                             17,653 are directly owned by USVP VIII AF, 22,444 are directly owned by
                                             USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.  PMG
                                             VIII, the general partner of USVP VIII, USVP VIII AF, USVP EP VIII-A
                                             and USVP EP VIII-B, may be deemed to have sole power to dispose of
                                             these shares, and Connors, Federman, Fu, Krausz, Liddle, Root, Rust and
                                             Young, the managing members of PMG VIII, may be deemed to have shared
                                             power to dispose of these shares.
                                     ------- -------------------------------------------------------------------------
                                     8       SHARED DISPOSITIVE POWER
                                             See response to row 7.
------------------------------------ ------- -------------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       2,339,062
------------ ---------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ ---------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                          19.4%
------------ ---------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                 OO
------------ ---------------------------------------------------------------------------------------------------------





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 7 of 22
----------------------------------------                                        -------------------------------------

------------ ---------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING PERSON

                Timothy Connors
------------ ---------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ ---------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ ---------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             U.S. Citizen
------------ ---------------------------------------------------------------------------------------------------------

                                     5        SOLE VOTING POWER
             NUMBER OF                        0 Shares
              SHARES
           BENEFICIALLY
      OWNED BY EACH REPORTING
              PERSON
               WITH
                                     -------- ------------------------------------------------------------------------
                                     6        SHARED VOTING POWER
                                              2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
                                              17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
                                              by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Connors, a managing member of PMG VIII, may
                                              be deemed to have shared power to vote these shares.
                                     -------- ------------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              0 Shares
                                     -------- ------------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
                                              17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
                                              by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Connors, a managing member of PMG VIII, may
                                              be deemed to have shared power to dispose of these shares.
------------------------------------ -------- ------------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       2,339,062
------------ ---------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ ---------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                          19.4%
------------ ---------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                 IN
------------ ---------------------------------------------------------------------------------------------------------





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 8 of 22
----------------------------------------                                        -------------------------------------

------------ ---------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING PERSON

                Irwin Federman
------------ ---------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ ---------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ ---------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             U.S. Citizen
------------ ---------------------------------------------------------------------------------------------------------

             NUMBER OF
              SHARES                 5        SOLE VOTING POWER
           BENEFICIALLY                       0 Shares
           OWNED BY EACH
             REPORTING
              PERSON
               WITH
                                     -------- ------------------------------------------------------------------------
                                     6        SHARED VOTING POWER
                                              2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
                                              17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
                                              by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Federman, a managing member of PMG VIII,
                                              may be deemed to have shared power to vote these shares.
                                     -------- ------------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              0 Shares
                                     -------- ------------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
                                              17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
                                              by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Federman, a managing member of PMG VIII,
                                              may be deemed to have shared power to dispose of these shares.
------------------------------------ -------- ------------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       2,339,062
------------ ---------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ ---------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                        19.4%
------------ ---------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                              IN
------------ ---------------------------------------------------------------------------------------------------------





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 9 of 22
----------------------------------------                                        -------------------------------------

------------ --------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING PERSON

                Winston Fu
------------ --------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ --------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ --------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             U.S. Citizen
------------ --------------------------------------------------------------------------------------------------------

                                     5        SOLE VOTING POWER
                                              0 Shares
             NUMBER OF
              SHARES                 -------- -----------------------------------------------------------------------
           BENEFICIALLY              6        SHARED VOTING POWER
      OWNED BY EACH REPORTING                 2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
              PERSON                          17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
               WITH                           by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Fu, a managing member of PMG VIII, may be
                                              deemed to have shared power to vote these shares.
                                     -------- -----------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              0 Shares
                                     -------- -----------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
                                              17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
                                              by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Fu, a managing member of PMG VIII, may be
                                              deemed to have shared power to dispose of these shares.
------------------------------------ -------- -----------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       2,339,062
------------ --------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ --------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                          19.4%
------------ --------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                 IN
------------ --------------------------------------------------------------------------------------------------------





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 10 of 22
----------------------------------------                                        -------------------------------------

------------ --------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING PERSON

                Steven M. Krausz
------------ --------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ --------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ --------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             U.S. Citizen
------------ --------------------------------------------------------------------------------------------------------

                                     5        SOLE VOTING POWER
                                              0 Shares
             NUMBER OF
              SHARES                 -------- -----------------------------------------------------------------------
           BENEFICIALLY              6        SHARED VOTING POWER
      OWNED BY EACH REPORTING                 2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
              PERSON                          17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
               WITH                           by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Krausz, a managing member of PMG VIII, may
                                              be deemed to have shared power to vote these shares.
                                     -------- -----------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              0 Shares
                                     -------- -----------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
                                              17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
                                              by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Krausz, a managing member of PMG VIII, may
                                              be deemed to have shared power to dispose of these shares.
------------------------------------ -------- -----------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       2,339,062
------------ --------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ --------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                          19.4%
------------ --------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                 IN
------------ --------------------------------------------------------------------------------------------------------





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 11 of 22
----------------------------------------                                        -------------------------------------

------------ --------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING PERSON

                David Liddle
------------ --------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ --------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ --------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             U.S. Citizen
------------ --------------------------------------------------------------------------------------------------------

                                     5        SOLE VOTING POWER
                                              0 Shares
             NUMBER OF
              SHARES                 -------- -----------------------------------------------------------------------
           BENEFICIALLY              6        SHARED VOTING POWER
      OWNED BY EACH REPORTING                 2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
              PERSON                          17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
               WITH                           by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Liddle, a managing member of PMG VIII, may
                                              be deemed to have shared power to vote these shares.
                                     -------- -----------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              0 Shares
                                     -------- -----------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
                                              17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
                                              by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Liddle, a managing member of PMG VIII, may
                                              be deemed to have shared power to dispose of these shares.
------------------------------------ -------- -----------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       2,339,062
------------ --------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ --------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                          19.4%
------------ --------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                  IN
------------ --------------------------------------------------------------------------------------------------------





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 12 of 22
----------------------------------------                                        -------------------------------------

------------ --------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING PERSON

                Jonathan D. Root
------------ --------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ --------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ --------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             U.S. Citizen
------------ --------------------------------------------------------------------------------------------------------

                                     5        SOLE VOTING POWER
                                              0 Shares
             NUMBER OF
              SHARES                 -------- -----------------------------------------------------------------------
           BENEFICIALLY              6        SHARED VOTING POWER
      OWNED BY EACH REPORTING                 2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
              PERSON                          17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
               WITH                           by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Root, a managing member of PMG VIII, may
                                              be deemed to have shared power to vote these shares.
                                     -------- -----------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              0 Shares
                                     -------- -----------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
                                              17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
                                              by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Root, a managing member of PMG VIII, may
                                              be deemed to have shared power to dispose of these shares.
------------------------------------ -------- -----------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       2,339,062
------------ --------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ --------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                          19.4%
------------ --------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                  IN
------------ --------------------------------------------------------------------------------------------------------





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 13 of 22
----------------------------------------                                        -------------------------------------

------------ --------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING PERSON

                Christopher Rust
------------ --------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ --------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ --------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             U.S. Citizen
------------ --------------------------------------------------------------------------------------------------------

                                     5        SOLE VOTING POWER
                                              0 Shares
             NUMBER OF
              SHARES                 -------- -----------------------------------------------------------------------
           BENEFICIALLY              6        SHARED VOTING POWER
      OWNED BY EACH REPORTING                 2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
              PERSON                          17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
               WITH                           by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Rust, a managing member of PMG VIII, may
                                              be deemed to have shared power to vote these shares.
                                     -------- -----------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              0 Shares
                                     -------- -----------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
                                              17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
                                              by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Rust, a managing member of PMG VIII, may
                                              be deemed to have shared power to dispose of these shares.
------------------------------------ -------- -----------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       2,339,062
------------ --------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ --------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                          19.4%
------------ --------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                 IN
------------ --------------------------------------------------------------------------------------------------------





----------------------------------------                                        -------------------------------------
          CUSIP NO. 04963C209                            13 G                                          Page 14 of 22
----------------------------------------                                        -------------------------------------

------------ --------------------------------------------------------------------------------------------------------
                              
1            NAME OF REPORTING PERSON

                Philip M. Young
------------ --------------------------------------------------------------------------------------------------------
2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                    (a)              (b) X
------------ --------------------------------------------------------------------------------------------------------
3            SEC USE ONLY

------------ --------------------------------------------------------------------------------------------------------
4            CITIZENSHIP OR PLACE OF ORGANIZATION

             U.S. Citizen
------------ --------------------------------------------------------------------------------------------------------

                                     5        SOLE VOTING POWER
                                              0 Shares
             NUMBER OF
              SHARES                 -------- -----------------------------------------------------------------------
           BENEFICIALLY              6        SHARED VOTING POWER
      OWNED BY EACH REPORTING                 2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
              PERSON                          17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
               WITH                           by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Young, a managing member of PMG VIII, may
                                              be deemed to have shared power to vote these shares.
                                     -------- -----------------------------------------------------------------------
                                     7        SOLE DISPOSITIVE POWER
                                              0 Shares
                                     -------- -----------------------------------------------------------------------
                                     8        SHARED DISPOSITIVE POWER
                                              2,339,062 shares, of which 2,286,924 are directly owned by USVP VIII,
                                              17,653 are directly owned by USVP VIII AF, 22,444 are directly owned
                                              by USVP EP VIII-A and 12,041 are directly owned by USVP EP VIII-B.
                                              PMG VIII is the general partner of USVP VIII, USVP VIII AF, USVP EP
                                              VIII-A and USVP EP VIII-B. Young, a managing member of PMG VIII, may
                                              be deemed to have shared power to dispose of these shares.
------------------------------------ -------- -----------------------------------------------------------------------
9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
             REPORTING PERSON                                                                       2,339,062
------------ --------------------------------------------------------------------------------------------------------
10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
             EXCLUDES CERTAIN SHARES*
------------ --------------------------------------------------------------------------------------------------------
11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9                                          19.4%
------------ --------------------------------------------------------------------------------------------------------
12           TYPE OF REPORTING PERSON*                                                                 IN
------------ --------------------------------------------------------------------------------------------------------




-------------------------------------                 --------------------------
     CUSIP NO. 04963C209                13 G                  Page 15 of 22
-------------------------------------                 --------------------------


ITEM 1(A).        NAME OF ISSUER
                  --------------

                  AtriCure, Inc.

                  ITEM 1(B).   ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES
                               -----------------------------------------------

                  6033 Schumacher Park Drive
                  Cincinnati, OH 45069

ITEM 2(A).        NAME OF PERSONS FILING
                  ----------------------

                  This  Statement  is filed by Presidio  Management  Group VIII,
                  L.L.C.,  a Delaware  limited  liability  company ("PMG VIII"),
                  U.S.   Venture   Partners  VIII,   L.P.,  a  Delaware  limited
                  partnership ("USVP VIII"),  USVP VIII Affiliates Fund, L.P., a
                  Delaware   limited   partnership   ("USVP   VIII  AF"),   USVP
                  Entrepreneur   Partners  VIII-A,   L.P.,  a  Delaware  limited
                  partnership  ("USVP EP VIII-A"),  U.S.  Entrepreneur  Partners
                  VIII-B,  a Delaware  limited  partnership  ("USVP EP VIII-B"),
                  Timothy  Connors  ("Connors"),  Irwin  Federman  ("Federman"),
                  Winston Fu ("Fu"),  Steven M. Krausz ("Krausz"),  David Liddle
                  ("Liddle"),   Jonathan  D.  Root  ("Root")   Christopher  Rust
                  ("Rust") and Philip M. Young ("Young"). The foregoing entities
                  and individuals are collectively referred to as the "Reporting
                  Persons."

                  PMG VIII, the general partner of USVP VIII, USVP VIII AF, USVP
                  EP VIII-A and USVP EP VIII-B, may be deemed to have sole power
                  to vote and sole  power to  dispose  of shares  of the  issuer
                  directly owned by USVP VIII,  USVP VIII AF, USVP EP VIII-A and
                  USVP EP VIII-B.  Connors,  Federman, Fu, Krausz, Liddle, Root,
                  Rust and Young  are  managing  members  of PMG VIII and may be
                  deemed  to have  shared  power  to vote  and  shared  power to
                  dispose of shares of the issuer  directly  owned by USVP VIII,
                  USVP VIII AF, USVP EP VIII-A and USVP EP VIII-B.

ITEM 2(B).        ADDRESS OF PRINCIPAL OFFICE
                  ---------------------------

                  The address for each of the Reporting Persons is:

                  U.S. Venture Partners
                  2735 Sand Hill Road
                  Menlo Park, California  94025

ITEM 2(C)         CITIZENSHIP
                  -----------

                  USVP VIII, USVP VIII AF, USVP EP VIII-A and USVP EP VIII-B are
                  Delaware limited partnerships.  PMG VIII is a Delaware limited
                  liability  company.  Connors,  Federman,  Fu, Krausz,  Liddle,
                  Root, Rust and Young are United States citizens.

ITEM 2(D) AND (E).   TITLE OF CLASS OF SECURITIES AND CUSIP NUMBER
                     ---------------------------------------------

                  Common Stock
                  CUSIP # 04963C209

ITEM 3.           Not Applicable.
                  ---------------



-------------------------------------                 --------------------------
     CUSIP NO. 04963C209                13 G                  Page 16 of 22
-------------------------------------                 --------------------------


ITEM 4.           OWNERSHIP
                  ---------

                  Provide the  following  information  regarding  the  aggregate
                  number and percentage of the class of securities of the issuer
                  identified in Item 1.

                      (a)   Amount beneficially owned:
                            --------------------------

                            See Row 9 of cover page for each Reporting Person.

                      (b)   Percent of Class:
                            -----------------

                            See Row 11 of cover page for each Reporting Person.

                      (c)   Number of shares as to which such person has:
                            ---------------------------------------------

                            (i)   Sole power to vote or to direct the vote:
                                  -----------------------------------------

                                  See Row 5 of cover  page  for  each  Reporting
                                  Person.

                            (ii)  Shared power to vote or to direct the vote:
                                  -------------------------------------------

                                  See Row 6 of cover  page  for  each  Reporting
                                  Person.

                            (iii) Sole   power  to  dispose  or  to  direct  the
                                  disposition of:
                                  ----------------------------------------------

                                  See Row 7 of cover  page  for  each  Reporting
                                  Person.

                            (iv)  Shared  power  to  dispose  or to  direct  the
                                  disposition of:
                                  ----------------------------------------------

                                  See Row 8 of cover  page  for  each  Reporting
                                  Person.


ITEM 5.           OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS
                  --------------------------------------------

                  Not applicable.

ITEM 6.           OWNERSHIP  OF MORE THAN  FIVE  PERCENT  ON  BEHALF OF  ANOTHER
                  --------------------------------------------------------------
                  PERSON.
                  -------

                  Under   certain   circumstances   set  forth  in  the  limited
                  partnership  agreements  of USVP VIII,  USVP VIII AF,  USVP EP
                  VIII-A and USVP EP VIII-B,  and the limited  liability company
                  agreement  of PMG VIII,  the general  and limited  partners or
                  members,  as the case may be, of each of such  entities may be
                  deemed to have the right to  receive  dividends  from,  or the
                  proceeds  from, the sale of shares of the issuer owned by each
                  such entity of which they are a partner or member, as the case
                  may be.

ITEM 7.           IDENTIFICATION  AND  CLASSIFICATION  OF THE  SUBSIDIARY  WHICH
                  --------------------------------------------------------------
                  ACQUIRED THE SECURITY  BEING REPORTED ON BY THE PARENT HOLDING
                  --------------------------------------------------------------
                  COMPANY
                  -------

                  Not applicable.



-------------------------------------                 --------------------------
     CUSIP NO. 04963C209                13 G                  Page 17 of 22
-------------------------------------                 --------------------------


ITEM 8.           IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.
                  ----------------------------------------------------------

                  Not applicable.

ITEM 9.           NOTICE OF DISSOLUTION OF GROUP.
                  -------------------------------

                  Not applicable.

ITEM 10.          CERTIFICATION.
                  --------------

                  Not applicable.



-------------------------------------                 --------------------------
     CUSIP NO. 04963C209                13 G                  Page 18 of 22
-------------------------------------                 --------------------------


                                   SIGNATURES
                                   ----------

     After  reasonable  inquiry and to the best of my  knowledge  and belief,  I
certify that the information  set forth in this statement is true,  complete and
correct.


Dated:  February 10, 2006


U.S. VENTURE PARTNERS VIII, L.P.                 /s/ Michael Maher
By Presidio Management Group VIII, L.L.C.        -----------------------------
Its General Partner                              Signature


                                                 Michael Maher
                                                 -------------------------------
                                                 Chief Financial Officer/
                                                 Attorney-In-Fact*


USVP VIII Affiliates Fund, L.P.                  /s/ Michael Maher
By Presidio Management Group VIII, L.L.C.        -------------------------------
Its General Partner                              Signature



                                                 Michael Maher
                                                 -------------------------------
                                                 Chief Financial Officer/
                                                 Attorney-In-Fact*


USVP Entrepreneur Partners VIII-A, L.P.,         /s/ Michael Maher
By Presidio Management Group VIII, L.L.C.        -------------------------------
Its General Partner                              Signature


                                                 Michael Maher
                                                 -------------------------------
                                                 Chief Financial Officer/
                                                 Attorney-In-Fact*


USVP Entrepreneur Partners VIII-B- L.P.,         /s/ Michael Maher
By Presidio Management Group VIII, L.L.C.        -------------------------------
Its General Partner                              Signature


                                                 Michael Maher
                                                 -------------------------------
                                                 Chief Financial Officer/
                                                 Attorney-In-Fact*


PRESIDIO MANAGEMENT GROUP VIII, L.L.C.           /s/ Michael Maher
A Delaware Limited Liability Company             -------------------------------
                                                 Signature

                                                 Michael Maher
                                                 -------------------------------
                                                 Chief Financial Officer/
                                                 Attorney-In-Fact*


Timothy Connors                                  /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


Irwin Federman                                   /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*



-------------------------------------                 --------------------------
     CUSIP NO. 04963C209                13 G                  Page 19 of 22
-------------------------------------                 --------------------------


Winston Fu                                       /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


Steven M. Krausz                                 /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


David Liddle                                     /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


Jonathan D. Root                                 /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


Christopher Rust                                 /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


Philip M. Young                                  /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


*Signed  pursuant  to a Power of Attorney  already on file with the  appropriate
agencies.

The  original  statement  shall be signed by each  person  on whose  behalf  the
statement is filed or his authorized representative.  If the statement is signed
on behalf of a person by his authorized  representative  other than an executive
officer  or   general   partner  of  the   filing   person,   evidence   of  the
representative's  authority to sign on behalf of such person shall be filed with
the  statement,  provided,  however,  that a power of attorney  for this purpose
which is already on file with the Commission may be  incorporated  by reference.
The name and any title of each person who signs the statement  shall be typed or
printed beneath his signature.

NOTE:  Schedules  filed in paper format shall include a signed original and five
copies of the  schedule,  including  all exhibits.  See  ss.240.13d-7  for other
parties for whom copies are to be sent.

Attention:  Intentional  misstatements  or omissions of fact constitute  Federal
criminal violations (See 18 U.S.C. 1001)



-------------------------------------                 --------------------------
     CUSIP NO. 04963C209                13 G                  Page 20 of 22
-------------------------------------                 --------------------------


                                  EXHIBIT INDEX
                                  -------------


                                                              Found on
                                                            Sequentially
Exhibit                                                     Numbered Page
-------                                                     -------------

Exhibit A:  Agreement of Joint Filing                            22




-------------------------------------                 --------------------------
     CUSIP NO. 04963C209                13 G                  Page 21 of 22
-------------------------------------                 --------------------------


                                    EXHIBIT A
                                    ---------



                            Agreement of Joint Filing
                            -------------------------

     The  undersigned  hereby agree that a single Schedule 13G (or any amendment
thereto) relating to the Common Stock of Atricure, Inc. shall be filed on behalf
of each of the  undersigned and that this Agreement shall be filed as an exhibit
to such Schedule 13G.


Dated:  February 10, 2006


U.S. VENTURE PARTNERS VIII, L.P.                 /s/ Michael Maher
By Presidio Management Group VIII, L.L.C.        -----------------------------
Its General Partner                              Signature


                                                 Michael Maher
                                                 -------------------------------
                                                 Chief Financial Officer/
                                                 Attorney-In-Fact*


USVP VIII Affiliates Fund, L.P.                  /s/ Michael Maher
By Presidio Management Group VIII, L.L.C.        -------------------------------
Its General Partner                              Signature



                                                 Michael Maher
                                                 -------------------------------
                                                 Chief Financial Officer/
                                                 Attorney-In-Fact*


USVP Entrepreneur Partners VIII-A, L.P.,         /s/ Michael Maher
By Presidio Management Group VIII, L.L.C.        -------------------------------
Its General Partner                              Signature


                                                 Michael Maher
                                                 -------------------------------
                                                 Chief Financial Officer/
                                                 Attorney-In-Fact*


USVP Entrepreneur Partners VIII-B- L.P.,         /s/ Michael Maher
By Presidio Management Group VIII, L.L.C.        -------------------------------
Its General Partner                              Signature


                                                 Michael Maher
                                                 -------------------------------
                                                 Chief Financial Officer/
                                                 Attorney-In-Fact*


PRESIDIO MANAGEMENT GROUP VIII, L.L.C.           /s/ Michael Maher
A Delaware Limited Liability Company             -------------------------------
                                                 Signature

                                                 Michael Maher
                                                 -------------------------------
                                                 Chief Financial Officer/
                                                 Attorney-In-Fact*


Timothy Connors                                  /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


Irwin Federman                                   /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*



-------------------------------------                 --------------------------
     CUSIP NO. 04963C209                13 G                  Page 22 of 22
-------------------------------------                 --------------------------


Winston Fu                                       /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


Steven M. Krausz                                 /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


David Liddle                                     /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


Jonathan D. Root                                 /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


Christopher Rust                                 /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


Philip M. Young                                  /s/ Michael Maher
                                                 -------------------------------
                                                 Michael Maher
                                                 Attorney-In-Fact*


*Signed  pursuant  to a Power of Attorney  already on file with the  appropriate
agencies.