Exhibit 99.1



                         [ATS Medical, Inc. Letterhead]




December ___, 2005


To the Undersigned Executive Officer
of ATS Medical, Inc. who holds a Stock Option
to acquire ATS Medical Common Stock

Dear Optionee:

         This letter agreement (this "Agreement") is being entered into by and
between you and ATS Medical, Inc. (the "Company"), a Minnesota corporation, in
connection with certain stock options granted to you, either as a free standing
option in connection with your initial employment by the Company or pursuant to
the Company's 2000 Stock Incentive Plan, which are "Underwater Options," as
defined below.

         The Compensation Committee of the Board of Directors of the Company has
determined to accelerate the vesting of each otherwise unvested stock option
held by an option holder employed by the Company as of December 22, 2005 if such
option has an exercise price that is equal to or greater than $3.00 (each an
"Underwater Option"), subject to the condition that the vesting of any such
stock options that are held by any executive officer of the Company shall not
accelerate until such officer executes an agreement pursuant to which he or she
agrees to refrain from selling, transferring, pledging, or otherwise disposing
of any shares acquired upon the exercise of options so accelerated until the
date on which the exercise would have been permitted under such options'
pre-acceleration vesting terms or, if earlier, his or her last day of
employment.

Lock-Up Agreement.
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         You agree to refrain from selling, transferring, pledging, or otherwise
disposing of any shares acquired upon the exercise of your accelerated
Underwater Options until the date on which the exercise would have been
permitted under such options' pre-acceleration vesting terms set forth in the
option agreement(s) between you and the Company relating to your Underwater
Options or, if earlier, your last day of employment with the Company.

                                     *  *  *

         This Agreement may be executed in one or more counterparts, each of
which shall be deemed to be an original but all of which together will
constitute one instrument.

         If this Agreement correctly sets forth our agreement on the subject
matter hereof, kindly sign and return to the Company the enclosed copy of this
Agreement which will then constitute our agreement on this subject.






                                                  Sincerely,

                                                  ATS Medical, Inc.



                                                  ------------------------------
                                                  Name:
                                                  Title:


I acknowledge receipt and agree with the foregoing terms and conditions.




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Signature & Date




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Print Name





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