EXHIBIT 2.1

                                                               EXECUTION VERSION

                               AMENDMENT NO. 1 TO
                          AGREEMENT AND PLAN OF MERGER

     THIS AMENDMENT NO. 1 TO AGREEMENT AND PLAN OF MERGER (this "Amendment") is
entered into as of June 13, 2006, by and among ATS Medical, Inc., a Minnesota
corporation ("Parent"), Seabiscuit Acquisition Corp., a Delaware corporation and
a wholly-owned subsidiary of Parent ("Merger Subsidiary"), 3F Therapeutics,
Inc., a Delaware corporation (the "Company"), and Boyd D. Cox, as Stockholder
Representative (the "Stockholder Representative" and, together with Parent,
Merger Subsidiary and the Company, the "Parties").

                                    RECITALS

     WHEREAS, the Parties entered into that certain Agreement and Plan of Merger
dated January 23, 2006 (the "Merger Agreement");

     WHEREAS, the Merger Agreement provides that, on or after June 15, 2006 (the
"Termination Date"), and provided that certain conditions are met, any of
Parent, Merger Subsidiary or the Company may terminate the Merger Agreement and
abandon the transactions contemplated therein;

     WHEREAS, the Parties desire to amend the Merger Agreement in order to,
among other things, extend the Termination Date as provided herein;

     WHEREAS, if (a) by 11:59 p.m. Pacific time on June 13, 2006 this Amendment
is not fully executed by the Parties hereto, and (b) by 11:59 a.m. Pacific time
on June 14, 2006, evidence of the approval, by the Principal Stockholders and
each director of the Company who is also a Stockholder, of this Amendment is not
received by Parent, this Amendment will terminate without further action by any
party hereto;

     WHEREAS, Section 5.26 of the Merger Agreement provides that the Company
will cause all holders of Company Stock Options to agree in writing that any
such options that remain outstanding as of the Effective Time shall terminate
and be cancelled at such time, and if this covenant is not satisfied, the
Stockholders agreed to fully indemnify Parent, pursuant to Sections 9.2(e) and
9.5(b), for all costs and Losses arising in connection with the failure by the
Company to satisfy such covenant;

     WHEREAS, the Parties desire to amend the Merger Agreement to provide that,
in the event that any of the current holders of options to purchase shares of
the Company's common stock fail to fully exercise or agree to terminate such
options prior to ten (10) days before the Effective Time (which amends Section
5.26 of the Merger Agreement previously providing for fifteen (15) days), and if
Parent agrees to waive the failure of the relevant closing condition, Parent
shall reserve and continue to keep available for issuance that number of shares
of Parent Common Stock equal to the number of such shares that such
non-exercising and non-terminating option holders would have been entitled to
had they fully exercised such options; and



     WHEREAS, the boards of directors of Parent, Merger Subsidiary and the
Company, as well as the stockholders of the Company, have approved this
Amendment.

     NOW, THEREFORE, in consideration of the foregoing, and for other good and
valuable consideration, the receipt and adequacy of which are hereby
acknowledged, the Parties agree as follows:

                                    AGREEMENT

1.   DEFINITIONS. Capitalized terms used herein and not otherwise defined herein
     shall have the meanings ascribed to such terms in the Merger Agreement.

2.   AMENDMENTS.

     (a)  The final sentence of Section 2.1(b)(ii) is hereby amended by adding
          the following to the end thereof:

               "; provided, however, that, no payment of Milestone Consideration
               shall be made to holders of Outstanding Options until, and only
               to the extent that, such options have been exercised in
               accordance with their terms and, prior to such exercise, all
               Milestone Consideration that would otherwise have been issuable
               to such holders shall be reserved for issuance and available for
               distribution thereunder when and if the Outstanding Options are
               exercised and Milestones are achieved. If, following the
               achievement of the final Milestone, not all of the Milestone
               Consideration is paid in connection with such achievement (due to
               the fact that Outstanding Options remain outstanding as of such
               date), then, following the expiration, termination or exercise of
               the last to expire, terminate or be exercised of the Outstanding
               Options, all Milestone Consideration remaining as of such time
               shall be deposited by Parent with the Exchange Agent for
               distribution in accordance with the terms of the Exchange
               Agreement."

     (b)  The first sentence of Section 2.2 is hereby amended and restated in
          its entirety as follows:

               "At the Closing, Parent shall deposit, or cause to be deposited,
               with the escrow agent (the "Escrow Agent"), for the benefit of
               the Stockholders, a certificate (issued in the name of the Escrow
               Agent or its nominee) representing the Escrow Shares and Parent
               shall reserve and continue to keep available for issuance a
               number of shares of Parent Common Stock equal to the Reserved
               Shares."

     (c)  The second sentence of Section 2.2 is hereby amended by adding the
          following to the end thereof:

               "; provided, however, that Reserved Shares may only be issued to
               a holder of Outstanding Options following the later of (i) the
               Effective Time and


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               (ii) the date on which the Outstanding Options are exercised in
               accordance with its terms by such holder in accordance with
               Section 2.5 of this Agreement, and such Reserved Shares shall not
               be subject to set-off rights to satisfy any indemnification
               obligation of the Stockholders (except to the extent provided for
               in the Escrow Agreement); provided, further, that at the time
               when the last Outstanding Option is exercised, expires, or is
               terminated in accordance with its terms, Parent shall issue and
               deposit the remaining Reserved Shares, if any, with the Exchange
               Agent for distribution in accordance with the terms and
               conditions of the Exchange Agreement."

     (d)  The parties acknowledge that summons and complaints were filed by
          Arthur Abbey (x) on January 19, 2006 against, among others, Theodore
          C. Skokos ("Skokos") and the Company (the "First Complaint"), and (y)
          on June 7, 2006 against Skokos and the Company (the "Second Complaint"
          and, together with the First Complaint, the "Complaints"); and further
          that in recognition of the additional risk presented by the
          Complaints, the Parties agree and hereby amend the Merger Agreement to
          provide that any Damages (as defined in the Merger Agreement) incurred
          by the Company prior to the Closing that arise out of or in connection
          with the Complaints (the "Abbey Damages") will result in a
          dollar-for-dollar adjustment to the calculation of the Actual Net
          Operating Assets, provided that no such adjustment to the Initial
          Merger Consideration will be made to the extent that the Abbey
          Damages, if any, are offset by positive adjustments, if any, to the
          calculation of the Actual Net Operating Assets. Accordingly, the
          parties agree that Section 9.2 of the Merger Agreement is hereby
          amended as follows:

          (i)  Delete the word "and" currently placed between the comma at the
               end of subsection (f) and "(g)".

          (ii) The following is inserted immediately before the period at the
               end of this section:

                    ", and (h) the summons and complaints filed by Arthur Abbey
                    ("Plaintiff") (i) on January 19, 2006 against, among others,
                    Theodore C. Skokos ("Skokos") and the Company, alleging,
                    among other matters, the violation of federal securities
                    laws in connection with the purchase by Plaintiff of certain
                    securities of 3F Partners Limited Partnership II, and (ii)
                    on June 7, 2006 against Skokos and the Company, among other
                    matters, fraud and breach of fiduciary duties in connection
                    with the purchase by Plaintiff of certain securities of 3F
                    Partners Limited Partnership II (such allegations, the
                    "Abbey Claims")"


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     (e)  Section 9.5(b) of the Merger Agreement is hereby amended as follows:

          (i)  Delete the word "and" currently placed between "(c)" and "(e)" in
               the first sentence.

          (ii) Insert a comma immediately following "(c)" in the first sentence.

          (iii) Insert " and (h)" immediately following "(e)" in the first
               sentence.

     (f)  Section 9.6 of the Merger Agreement is hereby amended by replacing
          "(g)" with "(h)" in the first sentence.

     (g)  The final sentence of Section 9.6 is hereby amended as follows:

          (i)  In the fifth line from the end thereof, insert "or Set-Off
               Shares" after "Escrow Shares"; and

          (ii) In the third line from the end thereof, insert "Escrow Shares or"
               before "Set-Off Shares".

     (h)  Subsection (v) of Section 11.1 of the Merger Agreement is hereby
          amended and restated in its entirety as follows:

               "(v) "Closing Date Shares" shall mean that number of Parent
               Common Shares equal to (i) 9,000,000 (with appropriate
               adjustments thereto in the event of any stock splits, stock
               combinations, stock dividends, recapitalizations or other similar
               transaction in Parent Common Stock after the date hereof and
               prior to the Effective Time), minus (ii) the Escrow Shares, minus
               (iii) the Reserved Shares, minus (iv) the Reduction Shares, if
               any."

     (i)  Subsection (kkk) of Section 11.1 of the Merger Agreement is hereby
          amended and restated in its entirety as follows:

               "(kkk) "Escrow Shares" means 1,400,000 fully paid and
               nonassessable shares of Parent Common Stock."

     (j)  Subsection (ggggg) of Section 11.1 of the Merger Agreement is hereby
          amended and restated in its entirety as follows:

               "(ggggg) "Milestone Ratio" means a number, subject to adjustment
               as provided in this Agreement, calculated to five (5) decimal
               points, equal to the quotient obtained by dividing (i) Milestone
               Shares, by (ii) a sum equal to (A) the Fully-Diluted Outstanding
               Shares, plus (B) that number of shares of Company Common Stock
               issuable upon the exercise of all Outstanding Options."


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     (k)  The following definition is hereby inserted immediately prior to
          existing Subsection (ooooo) of Section 11.1, and the subsequent
          subsections are hereby renumbered accordingly:

               "(ooooo) "Outstanding Options" means that aggregate number of
               Company Stock Options that remain issued and outstanding, and
               whose holders have not otherwise agreed to terminate such
               options, as of the date that is ten (10) days before the
               Effective Time."

     (l)  To reflect the Parties' agreement that Reserved Shares shall be
          created and reserved out of the Initial Merger Consideration, the
          following definition is hereby inserted immediately prior to existing
          Subsection (nnnnnn) of Section 11.1, and the subsequent subsections
          are hereby renumbered accordingly:

               "(nnnnnn) "Reserved Shares" means that number of shares of
               Initial Merger Consideration to which all holders of Outstanding
               Options would have been entitled had such holders exercised such
               options prior to the date that is ten (10) days before the
               Effective Time."

     (m)  Subsection (bbbbbbb) of Section 11.1 of the Merger Agreement is hereby
          amended and restated in its entirety as follows:

               "(bbbbbbb) "Termination Date" shall mean August 31, 2006."

     (n)  Section 12.2(a) is hereby amended and restated in its entirety as
          follows:

               "(a) Subject to Applicable Law, any provision of this Agreement
                    may be (i) waived, if such waiver is in writing and signed
                    by the party against whom the waiver is to be effective, or
                    (ii) amended (A) if such amendment is in writing and signed
                    by all Parties hereto, or (B) if such amendment in writing,
                    is approved by the respective boards of directors of Parent
                    and the Company and is signed by authorized representatives
                    of both Parent and the Company."

     (o)  The following section is hereby added to the end of the Merger
          Agreement:

               "12.14 Additional Agreements. The Parties hereto acknowledge and
               agree that:

                    (a)  On the date that this Agreement was originally
                         executed, the First Complaint had been filed but had
                         not been disclosed to Parent or Merger Subsidiary prior
                         to such execution and therefore the existence of the
                         Abbey Claims constitutes a breach of certain of the
                         Company's representations and warranties under Article
                         3, including without limitation Section 3.20, thereby
                         entitling the Parent to indemnification rights under
                         Article 9 of this Agreement (without being subject to
                         the Basket Amount).


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     (p)  The Operating Budget attached to the Merger Agreement as Exhibit B,
          with respect to June, July and August 2006, is being amended to
          reflect an increase in anticipated operating expenses of the Company
          due to the change in the timing of the Closing and thus is being
          amended hereby in its entirety to read as Exhibit A attached to this
          Amendment.

3.   NO OTHER AMENDMENTS. Except as specifically set forth in Section 2 of this
     Amendment, the Merger Agreement shall remain unchanged and shall continue
     in full force and effect.

4.   RESERVATION OF RIGHTS; EXPRESS ACKNOWLEDGEMENT. Except to the extent
     explicitly waived by Parent or Merger Subsidiary in this Amendment, Parent
     and Merger Subsidiary reserve all rights of any nature whatsoever under the
     Merger Agreement with respect to the Complaint or the Outstanding Options.
     Solely for purposes of determining Parent's and Merger Subsidiary's rights
     to terminate the Merger Agreement pursuant to Article 8 thereof, and not
     for any other purpose (including without limitation not for the purpose of
     determining any of Parent's or Merger Subsidiary's indemnification rights
     under Article 9 of the Merger Agreement), Parent hereby expressly
     acknowledges that it does not have knowledge of any fact or circumstance
     which, to the actual knowledge of Parent as of the date hereof, constitutes
     a material breach of any representation or warranty of the Company set
     forth in Article 3 of the Merger Agreement, other than the litigation
     underlying the Complaints, both of which are addressed further in this
     Amendment; provided, however, that Parent reserves all its rights to
     evaluate and consider any such facts or circumstances (of which Parent has
     actual knowledge before executing this Amendment), together with any facts
     or circumstances of which it acquires actual knowledge after executing this
     Amendment, and to treat any one or all such facts and circumstances (of
     which Parent has actual knowledge before the execution of this Amendment)
     on a cumulative basis as a material breach of any representation or
     warranty of the Company. For purposes of this Section 4, "Parent's actual
     knowledge" means only the actual knowledge, without any implication of any
     inquiry, of Michael Dale, Jack Judd, Rick Curtis, Rachel Nachreiner, and Al
     Putnam of specific facts and circumstances related to a matter and
     appreciation of the significance thereof under the Merger Agreement.

5.   STOCKHOLDER APPROVALS. By 11:59 a.m. Pacific time on June 14, 2006 and
     following execution and delivery of this Amendment by the parties hereto,
     the Principal Stockholders, and each director of the Company who is also a
     Stockholder, shall have delivered to Parent executed written consents
     approving this Amendment. The failure to timely deliver any of the consents
     described in this Section 5 shall result in the immediate termination of
     this Amendment without further action by any party hereto.

6.   ESCROW AND EXCHANGE AGENT AGREEMENTS. In connection with the consummation
     of the Merger, and subject to any further comments from any third parties
     thereto, the relevant parties hereto will enter into the Escrow Agreement
     and the Exchange Agent


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     Agreement, substantially in the forms attached hereto as Exhibit B and
     Exhibit C, respectively.

7.   WAIVER REGARDING SECOND CLAIM. The Company hereby waives its right to
     receive notice from Parent under Section 5.17(a) of the Merger Agreement
     with respect to the existence of the Second Claim.

8.   MISCELLANEOUS.

     (a)  SUCCESSORS AND ASSIGNS. The terms and conditions of this Amendment
          shall inure to the benefit of and be binding upon and be enforceable
          by the respective heirs, successors and assigns of the parties hereto.
          Nothing in this Amendment, express or implied, is intended to confer
          upon any party, other than the parties hereto or their respective
          successors and assigns, any rights, remedies, obligations or
          liabilities under or by reason of this Amendment, except as expressly
          provided in this Amendment.

     (b)  GOVERNING LAW. This Amendment shall be governed by, construed and
          enforced in accordance with the internal laws of the State of Delaware
          (regardless of the laws that might otherwise govern under applicable
          principles of conflicts of law).

     (c)  COUNTERPARTS. This Amendment may be signed in any number of
          counterparts and the signatures delivered by facsimile, each of which
          shall be an original, with the same effect as if the signatures
          thereto and hereto were upon the same instrument. This Amendment shall
          become effective when each party hereto shall have received a
          counterpart hereof signed by the other parties hereto.

                  [Remainder of Page Intentionally Left Blank]


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     IN WITNESS WHEREOF, the Parties have caused this Amendment to be duly
executed by their respective authorized officers as of the day and year first
above written.

PARENT:                                 ATS MEDICAL, INC.


                                        By: /s/ Michael D. Dale
                                            ------------------------------------
                                            Michael D. Dale
                                            President and Chief Executive
                                            Officer


MERGER SUBSIDIARY:                      SEABISCUIT ACQUISITION CORP.


                                        By: /s/ Michael D. Dale
                                            ------------------------------------
                                            Michael D. Dale
                                            Chief Executive Officer


COMPANY:                                3F THERAPEUTICS, INC.


                                        By: /s/ Walter A. Cuevas
                                            ------------------------------------
                                            Walter A. Cuevas
                                            President and Chief Executive
                                            Officer


STOCKHOLDER REPRESENTATIVE:


                                        /s/ Boyd D. Cox
                                        ----------------------------------------
                                        Boyd D. Cox

                                 SIGNATURE PAGE
                 AMENDMENT NO. 1 TO AGREEMENT AND PLAN OF MERGER



AMENDMENT NO.1 TO AGREEMENT AND PLAN OF MERGER

EXHIBITS LIST

Exhibit A - Amended Operating Plan

Exhibit B - Form of Escrow Agreement

Exhibit C - Form of Exchange Agreement

                                 SIGNATURE PAGE
                      AMENDMENT NO. 1 TO MERGER AGREEMENT