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                                                                 Exhibit 10.29.1



                     FIRST AMENDMENT TO EMPLOYMENT AGREEMENT


        This First Amendment to Employment Agreement (the "Amendment") is made
as of December 10, 1999, between Radiance Medical Systems, Inc., a Delaware
corporation (the "Company"), and Jeffrey Thiel, an individual ("Executive").

                                    RECITALS

        WHEREAS, the Company currently employs Executive pursuant to that
certain Employment Agreement dated February 1, 1999 (the "Employment
Agreement"); and

        WHEREAS, the Company and Executive desire to amend the Employment
Agreement to extend the automatic renewal terms set forth in the Employment
Agreement, as provided in greater detail below;

        NOW THEREFORE, in consideration of the mutual agreements and covenants
hereinafter set forth and for other valuable consideration, the Company and
Executive hereby agree as follows:

                                    AGREEMENT

        1.     DEFINITIONS.

        Unless otherwise defined herein, capitalized terms used herein shall
have the meanings assigned to them in the Employment Agreement.

        2.     AMENDMENT TO SECTION 1 OF THE EMPLOYMENT AGREEMENT.

        Section 1 of the Employment Agreement is hereby amended to read in its
entirety as follows:

               "1. EMPLOYMENT. Effective October 1, 1999, the Company hereby
        agrees to employ the Executive as the President and Chief Operating
        Officer, reporting to the Chief Executive Officer ("CEO") of the
        Company, and the Executive accepts such employment and agrees to devote
        substantially all his business time and effort and skills on such
        reasonable duties as shall be assigned to him by the Company
        commensurate with such position."

        3.     AMENDMENT TO SECTION 2 OF THE EMPLOYMENT AGREEMENT.

        Section 2 of the Employment Agreement is hereby amended to read in its
entirety as follows:

               "2. TERM. The term of this Agreement will begin on February 1,
        1999 (the "Effective Date"), and shall continue thereafter for a two (2)
        year period, and commencing on the first anniversary of the Effective
        Date shall be extended on each day for one (1) day so that the remaining
        term hereof is always one (1) year unless either party elects to
        terminate this Agreement in accordance with its provisions. Executive's
        employment is subject to earlier termination as hereafter specified."

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        4.     AMENDMENT TO SECTION 3.1 OF THE EMPLOYMENT AGREEMENT.

        Section 3.1 of the Employment Agreement is hereby amended to read in its
entirety as follows:

               "3.1 SERVICE WITH THE COMPANY. Effective October 1, 1999, during
        the term of this Agreement, the Executive agrees to perform such
        reasonable duties and on such basis as shall be assigned to him from
        time to time by the CEO; such duties, however, to be commensurate with
        the Executive's position as President and Chief Operating Officer of the
        Company. In particular, and without limitation, such duties shall
        include, within the guidelines set by the CEO, setting up long-range
        strategic plans, guidance of day-to-day operations of the Company,
        preparing operating budgets for presentation to the CEO, and
        implementation of operating plans as approved by the CEO."

        5.     AMENDMENT TO SECTIONS 4.1. AND 4.3 OF THE EMPLOYMENT AGREEMENT.

        Sections 4.1 and 4.3 of the Employment Agreement are hereby amended as
follows:

               Effective October 1, 1999, Executive's Base Salary is $180,000
        and the bonus percentage is Thirty percent (30%).

        6.     AMENDMENT TO SECTION 5.5.

        Section 5.5 of the Employment Agreement is hereby amended to read in its
entirety as follows:

               "5.5 PAYMENTS UPON REMOVAL OR TERMINATION. If during the term of
        this Agreement, the Executive resigns for one of the reasons stated in
        Section 5.3, or the Company terminates the Executive's service, except
        as provided in Sections 5.1 or 5.2 hereof, the Executive shall be
        entitled to the following compensation: (i) the portion of his then
        current Base Salary which has accrued through his date of termination,
        (ii) any payments for unused vacation and reimbursement expenses, which
        are due, accrued or payable at the date of Executive's termination,
        (iii) severance payment in an amount (the "Severance Amount") equal to
        Executive's then-current Base Salary, payable for the remainder of the
        Term; and (iv) to the extent not already vested under Section 4.5 or
        otherwise all of Executive's options to purchase shares of the Company's
        common stock and restricted stock shall accelerate and automatically
        vest by one additional year, and such options shall otherwise be
        exercisable in accordance with their terms. In addition, in such event,
        Executive shall be entitled to (a) a prorated payment equal to the
        target bonus amount for which Executive would be eligible for the year
        in which such resignation or termination occurred, and (b) continuation
        of the insurance benefits set forth in Exhibit C and, to the extent
        permissible, participation in the Company's 401k plan, for the remainder
        of the Term."

        7.     MISCELLANEOUS.

               (a) Continuing Force and Effect. Except as herein expressly
amended, all terms, covenants and provisions of the Employment Agreement are and
shall remain in full force and effect



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and all references therein to such Employment Agreement shall henceforth refer
to the Employment Agreement as amended by this Amendment. This Amendment shall
be deemed incorporated into, and a part of, the Employment Agreement.

               (b) Counterparts. This Amendment may be executed in any number of
counterparts, each of which shall be deemed an original, but all such
counterparts together shall constitute but one and the same instrument.

        IN WITNESS WHEREOF, we have set our hands hereto as of the date first
above written.

RADIANCE MEDICAL SYSTEMS, INC.


        /s/ Michael R. Henson
------------------------------------------
Michael R. Henson, Chief Executive Officer
   and Chairman of the Board



EXECUTIVE


        /s/  Jeffrey Thiel
------------------------------------------
Jeffrey Thiel



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