EXHIBIT 10.3

                                                                       Exhibit A

                              AMENDED AND RESTATED
                              THORATEC CORPORATION
                        RESTRICTED STOCK GRANT AGREEMENT

This Amended and Restated Thoratec Corporation Restricted Stock Grant Agreement
("Agreement") amends and restates the Restricted Stock Grant Agreement (the
"Existing Agreement") between Thoratec Corporation (the "Company") and M. Wayne
Boylston ("Consultant").

WHEREAS, Consultant was previously an employee of the Company, and in accordance
with his employment, he was granted 50,000 shares of Common Stock of the Company
(the "Restricted Shares") pursuant to the Company's 1997 Employee Stock Option
Plan, as amended (the "Plan"), and the Thoratec Corporation Restricted Stock
Grant Agreement, effective as of August 13, 2002 (the "Existing Agreement"); and

WHEREAS, Consultant has resigned from the Company effective December 17, 2004
prior to any of the restrictions on the Restricted Shares having lapsed or
otherwise accelerated in accordance with the Existing Agreement; and

WHEREAS, in accordance with the terms of the Existing Agreement, Consultant has
forfeited all rights and interest in and to the Restricted Shares; and

WHEREAS, the Company and Consultant have entered into a Consulting Services
Agreement of even date herewith (the "Consulting Services Agreement") for the
provision of certain "Services" defined therein; and

WHEREAS, as consideration for Consultant's performance of Services as defined in
the Consulting Services Agreement, the Company desires to permit the continued
vesting by Consultant in certain of the Restricted Shares subject to the terms
and conditions set forth herein.

NOW THEREFORE, the Existing Agreement is hereby amended and restated to read in
its entirety as follows:

         1. FORFEITURE OF RESTRICTED SHARES AND GRANT OF SHARES. Consultant
         hereby agrees to his irrevocable forfeiture of 25,000 Restricted Shares
         granted pursuant to the Existing Agreement. Consultant shall retain
         25,000 Restricted Shares, subject to the vesting and other provisions
         of this Agreement. This Agreement supersedes, in all respects, the
         Existing Agreement, which shall no longer have any legal effect
         whatsoever.

         2. FORFEITURE AND TRANSFER RESTRICTIONS.

                  a. Restrictions.

                           (i) If the Consulting Agreement is terminated for the
         reasons set forth in Section 4(a)(i) or 4(a)(iv) thereof, or as the
         result of the death or disability of Consultant, all

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         Restricted Shares as to which restrictions set forth herein have not
         then lapsed pursuant to Section 2(b) or Section 3(a) hereof will be
         forfeited by Consultant and will return to the Company (the
         "Forfeiture"). Consultant will not be permitted to sell, assign, pledge
         or otherwise encumber any Restricted Shares until there is no longer a
         possibility of Forfeiture with respect thereto (such restriction,
         together with the potential Forfeiture, referred to as the
         "Restrictions").

                           (ii) If the Consulting Agreement is terminated for
         the reasons set forth in Section 4(a)(ii), 4(a)(iii) or 4(a)(v)
         thereof, the Restrictions will lapse with respect to all remaining
         Restricted Shares as to which restrictions set forth herein have not
         then lapsed.

                  b. Lapse of Restrictions. Except as otherwise provided in
         Section 2(a)(ii) or Section 3 hereof, the Restrictions will lapse with
         respect to 8,333 Restricted Shares on January 1, 2006, with respect to
         8,333 Restricted Shares on January 1, 2007 and with respect to 8,334
         Restricted Shares on January 1, 2008, provided that on each such
         lapsing date Consultant's services to the Company pursuant to the
         Consulting Agreement are continuing.

                  c. Rights to Surrendered Shares. If any Restricted Shares are
         Forfeited as provided herein, such shares will be immediately
         surrendered to the Company, and Consultant will have no further rights
         with respect to such shares.

         3. CHANGE OF CONTROL.

                  a. Change of Control. Upon a Change of Control Transaction in
         which shares of the Company's common stock are (or are deemed to be)
         converted into the capital stock of a third party entity (the
         "Converted Shares"), then all of the Restricted Shares shall be
         converted into the Converted Shares on the same basis as all other
         Company common stock; provided, however, that the Restrictions shall
         remain in effect and be applicable to the pro-rata number of Converted
         Shares on the same terms set forth herein. As used herein, a "Change of
         Control Transaction" shall mean a merger, consolidation, reorganization
         or similar transaction in which holders of the Company's stock hold,
         after the consummation thereof, less than a majority of the total
         outstanding voting shares of the other party to such transaction; or a
         sale by the Company of all or substantially all of its assets in any
         one or series of related transactions to a third party.

                  b. Reclassification, Merger, etc. This Agreement will not
         affect the right of the Company to engage in any Change of Control
         Transaction (as defined above), or to adjust, reclassify, reorganize or
         otherwise change its capital or business structure, dissolve, liquidate
         or sell or transfer all or any part of its business or assets.

         4. RIGHTS AS A SHAREHOLDER; CASH DIVIDENDS. Consultant will have full
         rights as a shareholder with respect to the Restricted Shares, whether
         or not the Restrictions have lapsed with respect to such shares, to the
         extent that the relevant Restricted Shares have not been Forfeited as
         provided herein, including without limitation the right to vote the
         Restricted Shares and to receive any dividends paid on the Restricted
         Shares.

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         5. STOCK DIVIDENDS AND RELATED MATTERS. Any new, substituted or
         additional securities or other property (including money paid other
         than as a regular cash dividend) which Consultant may have the right to
         receive, by reason of any stock dividend, stock split,
         recapitalization, combination of shares, exchange of shares or other
         change affecting the outstanding common stock, as a class, without the
         Company's receipt of consideration, with respect to any Restricted
         Shares which remain subject to the Restrictions, will be issued subject
         to the same Restrictions applicable to any Restricted Shares which
         remain subject to the Restrictions, with any securities of the Company
         ceasing to be Restricted Shares on a pro rata basis as to thirty three
         and one-third percent (33 1/3%) of such additional securities on each
         of January 1, 2006, January 1, 2007 and January 1, 2008, respectively,
         under the conditions set forth in Section 2(b) hereof.

         6. CERTIFICATE; LEGENDS.

                  a. Legend. All certificates representing the Restricted Shares
         will bear the following legend:

                           i.       "THE SECURITIES REPRESENTED HEREBY MAY BE
                                    SUBJECT TO FORFEITURE TO THE COMPANY
                                    PURSUANT TO THE PROVISIONS OF AN AGREEMENT
                                    BETWEEN THE COMPANY AND THE ORIGINAL
                                    PURCHASER OF SUCH SECURITIES, SHOULD THE
                                    PERSON INITIALLY ISSUED THESE SECURITIES
                                    CEASE TO BE INVOLVED WITH THE COMPANY OR ANY
                                    AFFILIATE THEREOF, AND SUCH SECURITIES MAY
                                    NOT BE SOLD OR OTHERWISE TRANSFERRED IF SUCH
                                    SECURITIES ARE SUBJECT TO SUCH RISK OF
                                    FORFEITURE.

                           ii.      THE HOLDER OF THESE SECURITIES MAY BE AN
                                    AFFILIATE OF THE ISSUER HEREOF WITHIN THE
                                    MEANING OF PARAGRAPH (A)(1) OF RULE 144
                                    PROMULGATED UNDER THE SECURITIES ACT OF
                                    1933, AS AMENDED."

                  b. Lapse of Restrictions. One or more certificates
         representing the Restricted Shares will be issued in Consultant's name
         and held by the Secretary of the Company until all restrictions on the
         Restricted Shares have lapsed. When restrictions have lapsed on the
         Restricted Shares, certificates for such Restricted Shares will be
         delivered to Consultant upon his request.

         7. TAX CONSEQUENCES.

                  a. Tax Advisor. Consultant acknowledges that the tax
         consequences associated with the Restricted Shares and this Agreement
         are complex and depend upon Consultant's particular circumstances and
         that the Company has urged Consultant to consult a tax advisor. By
         executing this Agreement, Consultant acknowledges that Consultant has
         retained, or has had the opportunity to retain, his own advisor(s) to
         provide tax advice to him as to such matters and as to this Agreement,
         and neither the Company nor any of its employees, representatives or
         advisors has given Consultant any tax advice regarding the Restricted
         Shares or this Agreement and Consultant has not relied on any
         representations of the Company or any of its employees, representatives
         or advisors on that subject.

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                  b. Withholding Tax. Consultant is an independent contractor
         and not an employee of the Company. Therefore, Consultant is
         responsible for the payment of any withholding or employment taxes
         which, in the good-faith judgment of the Company, result from the
         purchase of the Restricted Shares or the lapse of Restrictions thereon.

                  c. No Section 83(b) Election. Consultant represents and
         warrants to the Company that he has not made an election under Section
         83(b) of the Internal Revenue Code with respect to the Restricted
         Shares, and agrees that he will not make such an election with respect
         to the Restricted Shares.

         8.   SUCCESSORS AND ASSIGNS. Except to the extent otherwise provided
              herein, the provisions of this Agreement will inure to the benefit
              of, and be binding upon, the Company and its successors and
              assigns and Consultant, Consultant's assigns and the legal
              representatives, heirs, beneficiaries, executors and
              administrators and legatees of Consultant's estate.

         9.   NOTICES. Any notice required or permitted to be given or made
              under this Agreement by either of the parties to the other will be
              in writing, delivered personally or by facsimile (and promptly
              confirmed by personal delivery, first class mail or courier),
              first class mail or courier, postage prepaid (where applicable),
              addressed to such other party at its relevant address, which for
              the Company will be the address and facsimile number of its
              principal office, and for Consultant will be the address and
              facsimile number set forth below Consultant's signature on this
              Agreement, or to such other address as the addressee has last
              furnished in writing to the addressor and will be effective and
              deemed given under this Agreement on the earliest of: (a) the date
              of personal delivery; (b) the date of delivery by facsimile; or
              (c) the next business day after deposit with a
              nationally-recognized courier or overnight service, including
              FedEx or Express Mail.

         10.  NO COMMITMENT. Nothing in this Agreement constitutes an agreement
              that Consultant will be retained by the Company for any term.

         11.  GOVERNING LAW; VENUE. This Agreement will be deemed to have been
              entered into and will be construed and enforced in accordance with
              the laws of the State of California without regard to principles
              of conflicts of laws. The parties hereby agree to submit to the
              exclusive jurisdiction of the courts of the State of California
              and the Federal courts of the United States of America located
              within the County of Alameda in the State of California for any
              action to enforce this Agreement. If either party brings an action
              to enforce the terms of this Agreement, the prevailing party shall
              be entitled to reasonable attorneys' fees and costs.
              Interpretation, performance and enforcement of this Agreement will
              be governed by the laws of the State of California without regard
              to its conflict-of-laws rules.

         12.  COUNTERPARTS. This Agreement may be executed by facsimile and in
              two counterparts, each of which will be deemed an original, and
              both of which together will constitute one and the same
              instrument.

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                                 THORATEC CORPORATION

                                 By: /s/ D. Keith Grossman
                                    _______________________
                                 Name:  D. Keith Grossman
                                 Title: Chief Executive Officer and President

                                           /s/ M. Wayne Boylston
                                           ______________________
                                           M. WAYNE BOYLSTON

                                           Address:  *
                                                     *

                                           Telephone Number:________________

                                           Facsimile Number:________________

                           I, as the Consultant's spouse, also accept and agree
                         to be bound by the terms and conditions of this
                         Agreement.

                       i.____________________________________________
                                       Signature

                          Printed name:______________________________

                       ii. Date signed:___________, 200__


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