<PAGE>
                                    RESTATED

                           ARTICLES OF INCORPORATION

                                       OF

                       THORATEC LABORATORIES CORPORATION

               ROBERT J. HARVEY and PAUL J. MUNDIE hereby certify.

               1. That they are the President and Assistant Secretary,
respectively, of THORATEC LABORATORIES CORPORATION, a California corporation.

               2. The articles of incorporation of this corporation are amended
and restated to read as follows:

               FIRST: The name of this corporation is THORATEC LABORATORIES
CORPORATION.

               SECOND: The purpose of this corporation is to engage in any
lawful act or activity for which a corporation may be organized under the
General Corporation Law of California other than the banking business, the
trust company business or the practice of a profession permitted to be
incorporated by the California Corporations Code.

               THIRD: The corporation elects to be governed by all the
provisions of Division 1 of Title 1 of the California Corporation Code (as
amended by act of the California Legislature, 1975-1976 regular session,
effective January 1, 1977, as defined in Section 2300 of the California General
Corporation Law) not otherwise applicable to this corporation under Chapter 23
of said Division I.

               FOURTH: This Corporation is authorized to issue only one class of
shares, all of which shall be known as Common Stock. The total number of shares
which this corporation is authorized to issue is 20,000,000.



<PAGE>
     3.   The foregoing amendment and restatement of the Articles of
Incorporation has been duly approved by the Board of Directors of this
corporation.

     4.   The foregoing amendment and restatement of the Articles of
Incorporation has been duly approved by the required vote of shareholders in
accordance with Section 902 of the Corporation Code of the State of California.
The total number of outstanding shares of the corporation is 167,149. The
number of shares voting in favor of the amendment equaled or exceeded the vote
required. The percentage vote required was more than 50%.



                                   /s/ Robert J. Harvey
                                   ------------------------------------------
                                   Robert J. Harvey, President


                                   /s/ Paul J. Mundie
                                   ------------------------------------------
                                   Paul J. Mundie, Assistant Secretary


     The undersigned declare under penalty of perjury that the matters set
forth on the foregoing certificate are true of their knowledge.

     Executed at San Francisco, California on December 10, 1980.




                                   /s/ Robert J. Harvey
                                   ------------------------------------------
                                   Robert J. Harvey


                                   /s/ Paul J. Mundie
                                   ------------------------------------------
                                   Paul J. Mundie




                                      -2-
<PAGE>



                          CERTIFICATE OF AMENDMENT OF
                           ARTICLES OF INCORPORATION





     ROBERT J. HARVEY AND PAUL J. MUNDIE certify that:

     1.   They are the President and Assistant Secretary, respectively, of
Thoratec Laboratories Corporation, a California corporation.

     2.   Article Fourth of the Articles of Incorporation of this corporation
is amended to read as follows:

     "This corporation is authorized to issue
     only one class of shares, all of which
     shall be known as Common Stock. The total
     number of shares which this corporation is
     authorized to issue is 20,000,000. Upon
     amendment of this article, each outstanding
     share is split into 4.896 shares."

     3.   The foregoing amendment has been approved by unanimous written
consent of the directors of this corporation.

     4.   This corporation has only one class of shares outstanding.
Accordingly, as provided in Section 902(c) of the California Corporations Code,
no vote of shareholders is required to approve such amendment.



                                   /s/ Robert J. Harvey
                                   ------------------------------------------
                                       Robert J. Harvey


                                   /s/ Paul J. Mundie
                                   ------------------------------------------
                                       Paul J. Mundie


The undersigned declare under penalty of perjury that the matters set forth in
the foregoing certificate are true of their own knowledge. Executed at San
Francisco, California on December 22, 1980.



                                   /s/ Robert J. Harvey
                                   ------------------------------------------
                                       Robert J. Harvey


                                   /s/ Paul J. Mundie
                                   ------------------------------------------
                                       Paul J. Mundie


<PAGE>
                           CERTIFICATE OF AMENDMENT
                                      OF
                           ARTICLES OF INCORPORATION



          ROBERT J. HARVEY AND LOUIS A. McKELLAR certify that:

          1.  They are the President and Secretary, respectively, of THORATEC
LABORATORIES CORPORATION, a California corporation.

          2.  Article Fourth of the Articles of Incorporation of this
corporation is amended to read as follows:

              "This corporation is authorized to issue two classes of shares,
          which shall be known as Common Stock and Preferred Stock. The total
          number of shares of Common stock which this corporation is authorized
          to issue is 10,000,000, and the total number of shares of Preferred
          Stock which this corporation is authorized to issue is 2,500,000."

          3.  Article Five is added to the Articles of Incorporation of this
corporation as follows:

          "Shares of Preferred Stock may be issued from time to time in one or
          more series. The Board of Directors shall determine the designation of
          each series and the authorized number of shares of each series. The
          Board of Directors is authorized to determine and alter the rights,
          preferences, privileges and restrictions granted to or imposed upon
          any wholly unissued series of shares of Preferred Stock and to
          increase or decrease (but not below the number of shares of such
          series then outstanding) the number of shares of any such series
          subsequent to the issue of shares of that series. If the number of
          shares of any series of Preferred Stock shall be so decreased, the
          shares constituting such decrease shall resume that status which they
          had prior to the adoption of the resolution originally fixing the
          number of shares of such series."







<PAGE>
     4.   The foregoing amendment of and addition to the Articles of
Incorporation has been duly approved by the Board of Directors.

     5.   The foregoing amendment of and addition to the Articles of
Incorporation has been duly approved by the required vote of shareholders in
accordance with Section 902 of the Corporations Code. The total number of
outstanding shares of the corporation entitled to vote with respect to the
amendment was 2,403,777. The number of shares voting in favor of the amendment
equaled or exceeded the vote required. The percentage vote required was more
than 50%.

     IN WITNESS WHEREOF, the undersigned have executed this Certificate this
16th day of August, 1982.

                                        /s/ Robert J. Harvey
                                        -----------------------------------
                                        Robert J. Harvey, President



                                        /s/ Louis A. McKellar
                                        -----------------------------------
                                        Louis A. McKellar, Secretary


     The undersigned declare under penalty of perjury that the matters set forth
in the foregoing certificate are true of their own knowledge.

     Executed at Berkeley, California, on August 16, 1982.

                                        /s/ Robert J. Harvey
                                        ----------------------------------
                                        Robert J. Harvey

                                        /s/ Louis A. McKellar
                                        ----------------------------------
                                        Louis A. McKellar


                                      -2-



<PAGE>
                         CERTIFICATE OF DETERMINATION

                                       OF

                            SERIES A PREFERRED STOCK

                                       OF

                       THORATEC LABORATORIES CORPORATION



     Robert J. Harvey and Louis A. McKellar certify that:

     1.   They are the president and the secretary, respectively, of Thoratec
Laboratories Corporation, a California corporation.

     2.   The number of shares of Preferred Stock which this corporation is
authorized to issue is 2,500,000, none of which have previously been issued.

     3.   The Board of Directors has duly adopted the following resolutions:

     WHEREAS, the articles of incorporation authorize the Preferred Stock of the
corporation to be issued in series and authorize the Board of Directors to
determine the rights, preferences, privileges and restrictions granted to or
imposed upon any wholly unissued series of Preferred Stock and to fix the number
of shares and designation of any such series, and

     WHEREAS, the Board of Directors of this corporation desires to determine
the rights, preferences, privileges and restrictions of, and fix the number of
shares of, a series of Preferred Stock to be known as Series A Preferred Stock,
now, therefore, it is

     RESOLVED that:


<PAGE>
     (a)  The designations of such series of Preferred Stock is Series A
Preferred Stock and the number of shares of such series is 540,541 shares of
Series A Preferred Stock.

     (b)  The rights, preferences, privileges and restrictions granted to or
imposed upon the Series A Preferred Stock or the holders thereof are as follows:

     A.   Dividend Rights.

          1.   Series A Preferred Stock Cumulative Dividends. The holders of
Series A Preferred Stock shall be entitled to receive, out of funds legally
available therefor, dividends at the rate of $1.30 per annum payable in cash
quarterly on the 1st day of August, November, February and May each year when
and as declared by the Board of Directors. Such dividends shall accrue on each
share of Series A Preferred Stock from the date of its original issuance and
shall accrue from day to day whether or not declared or legally distributable.
Such dividends shall be cumulative so that if such dividends in respect of any
previous dividend period at the above specified rate shall not have been
declared and paid or set apart for payment, the deficiency shall be declared and
paid or set apart for payment, but without interest, before the payment of any
dividend or distribution of assets on the Common Stock.

          2.   Common Stock Dividends. At any time after all dividends on
Series A Preferred Stock shall have been declared and paid or set apart for
payment in accordance with the provisions of paragraph 1, dividends may be paid
on outstanding Common Stock out of any funds legally available therefor. The
holders of Series A


                                      -2-
<PAGE>
Preferred Stock shall not be entitled to participate in any dividends other
than as provided in paragraph A1.

     B.  Liquidation Preferences.  In the event of any liquidation, dissolution
and winding up of the corporation, whether voluntary or not, (1) the holders of
Series A Preferred Stock shall be entitled to receive an amount equal to $9.25
per share plus all dividends accrued but unpaid before any amount shall be paid
to holders of Common Stock and (2) the holders of Common Stock shall be entitled
to receive pro rata all remaining assets.

         A merger, consolidation or conveyance of assets within the meaning of
reorganization set forth at Section 181(c) of the California Corporations Code
shall not be deemed to be a liquidation, dissolution or winding up within the
meaning of the foregoing paragraph so long as the stockholders of this
corporation shall continue as the stockholders of the continuing or combined
corporation or the corporation to which assets are transferred.

     C.  Voting Rights.  Except as otherwise expressly provided by law, the
holders of Common Stock shall have the exclusive right to notice of
shareholders' meetings and the exclusive voting power in this corporation, each
holder to have one vote for each share of Common Stock held; provided, however,
the holders of Series A Preferred Stock shall be entitled to one vote for each
share of Series A Preferred Stock standing in their names on the books of this
corporation, with a vote of a majority of the issued and outstanding Series A
Preferred Stock voting as a series (as


                                      -3-

<PAGE>
distinguished from voting as part of a larger class) required for each of the
following matters:

          1.  Any matter which under California law requires the vote of
              Preferred Stock as a class or any series of Preferred stock as a
              series.

          2.  Issuance of any shares of Preferred Stock of this corporation.

          3.  Any reorganization, merger, consolidation by or with this
              corporation and any transfer of all or substantially all of the
              assets of this corporation.

          4.  The amendment of this Certificate of Determination.

     D. Redemption of Preferred Stock.  This corporation, at the option of the
Board of Directors, may redeem at any time the whole or any part of the Series
A Preferred Stock by paying $9.25 per share together with all accrued and
unpaid dividends thereon (the "redemption price") to and including the date
fixed for redemption (the "redemption date"). The corporation shall give notice
of the redemption of any or all such shares by causing a notice of redemption
to be mailed not earlier than 60 nor later than 30 days prior to the redemption
date to the holders of record of the Series A Preferred Stock to be redeemed
addressed to each such holder at the holder's post office address appearing on
the records of the corporation or, if no address is shown, at the place where
the principal executive office of the corporation is located. The notice of
redemption shall set forth: (i) the class or series of shares or part of any
class or series of shares to be redeemed;



                                     -4-



<PAGE>
(ii) the redemption date; (iii) the redemption price; and (iv) the place at
which the shareholders may obtain payment of the redemption price upon
surrender of their share certificates. In case of the partial redemption of
Series A Preferred Stock, such redemption shall be pro rata among the various
holders thereof or as determined by lot in the discretion of the Board of
Directors. On or before the redemption date, each holder of shares called for
redemption shall surrender the certificate representing such shares to the
corporation at the place designated in the redemption notice and shall
thereupon be entitled to receive payment of the redemption price on the
redemption date. If less than all of the shares represented by a surrendered
certificate are redeemed, the corporation shall issue a new certificate
representing the unredeemed shares.

     If, on or before the redemption date, the corporation has cash funds
available and has deposited for such purpose in trust with a bank or trust
company sufficient funds to pay the redemption price in full to the holders of
all shares called for redemption, the shares so called shall be deemed to be
redeemed as of the date of deposit, dividends on those shares shall cease to
accrue and no interest shall accrue on the redemption price from and after the
redemption date. The right to convert said shares shall terminate at the close
of business on the fifth day prior to the redemption date. Any amounts so
deposited on account of the redemption price of shares converted subsequent to
the date of deposit shall be


                                      -5-
<PAGE>
repaid to the corporation forthwith upon the conversion of such shares.

     E.   Conversion Rights. The holders of Series A Preferred Stock shall have
conversion rights as follows:

          1.   Each holder of Series A Preferred Stock may, on or after
September 1, 1989, upon surrender of the certificates therefor, convert any or
all Series A Preferred Stock held by such holder into a number of fully paid
and nonassessable shares of Common Stock equal to (a) $9.25 plus any accrued
and unpaid dividends with respect to such share divided by (b) $9.25 for each
share of Series A Preferred Stock. Such option to convert shall be exercised by
surrendering for such purposes to the corporation, at the office of the
corporation or of any transfer agent for the Common Stock or Series A Preferred
Stock, certificates representing the shares to be converted duly endorsed in
blank or accompanied by proper instruments of transfer. Such conversion shall
be deemed to have been made as of the date of such surrender of the Series A
Preferred Stock and the person entitled to receive the Common Stock therefor
shall be treated for all purposes as the record holder of such Common Stock on
such date. If any shares of Series A Preferred Stock have been called for
redemption, the right of conversion shall terminate as to such shares at the
close of business on the fifth day preceding the redemption date.

          2.   The number of shares of Common Stock into which shares of Series
A Preferred Stock may be converted shall be subject to adjustments as follows
with such adjustment to be

                                      -6-

<PAGE>
effected if any of the following events occur at any time after the date of
issuance of the Series A Preferred Stock and not from the date the Series A
Preferred Stock becomes convertible:

         (a) In case the corporation shall be recapitalized through the
subdivision or combination of its outstanding Common Stock into a larger or
smaller number of shares, then in each such case the number of shares of Common
Stock into which shares of Series A Preferred Stock may be converted shall be
increased or reduced in the same proportion.

         (b) In case the corporation declares a dividend on Common Stock
payable in Common Stock or securities convertible into Common Stock, then, as
of the record date for determining the holders entitled to receive such
dividend, the number of shares of Common Stock into which shares of Series A
Preferred Stock may be converted shall be increased in proportion to the
increase through such dividend of the number of outstanding shares of Common
Stock.

         (c) In case the corporation determines to offer rights to the holders
of Common Stock entitling them to subscribe to additional Common Stock or
securities convertible into Common Stock, the corporation shall give written
notice of such proposed rights offering to the holders of Series A Preferred
Stock at least 15 days prior to the proposed record date. There shall be no
adjustment in the conversion rate by virtue of such rights offering or by
virtue of any sale of any class of securities of the corporation.


                                      -7-
<PAGE>
         (d) In case of any capital reorganization, including any
reclassification of the capital stock of the corporation or any merger of the
corporation with another corporation or the sale or conveyance of all or
substantially all of the assets of the corporation to another corporation, each
share of Series A Preferred Stock shall thereafter be convertible into the
number of shares of stock or other securities or property to which a holder of
the number of shares of Common Stock otherwise deliverable hereunder upon
conversion of such share of Series A Preferred Stock would have been entitled
upon such reorganization; and in any such case, appropriate adjustments (as
determined by the Board of Directors) shall be made in the application of the
provisions herein set forth with respect to the rights and interests thereafter
of the holders of the Series A Preferred Stock to the end that the provisions
set forth herein (including provisions with respect to changes in, and other
adjustments of, the conversion rate) shall thereafter be applicable, as nearly
as reasonably may be, in relation to any securities or other property thereafter
deliverable upon the conversion of the Series A Preferred Stock.

         3. Whenever the amount of Common Stock or other securities deliverable
upon the conversion of Series A Preferred Stock shall be adjusted pursuant to
the provisions hereof, the corporation shall forthwith file, at its principal
executive office and with any transfer agent for its Common Stock and Series A
Preferred Stock, a statement signed by the Chief Executive Officer


                                      -8-
<PAGE>
and Chief Financial Officer of the corporation stating the adjusted amount of
its Common Stock or other securities deliverable per share of Series A Preferred
Stock calculated to the nearest one-hundredth and setting forth in reasonable
detail the method of calculation and the facts requiring such adjustment and
upon which such calculation is based. Each adjustment shall remain in effect
until a subsequent adjustment is required hereunder.

          4.  The corporation shall at all times reserve and keep available out
of its authorized but unissued Common Stock the full number of shares
deliverable upon conversion of all the then outstanding Series A Preferred Stock
and shall take all such action and obtain all such permits and orders as may be
necessary to enable the corporation lawfully to issue such Common Stock upon the
conversion of Series A Preferred Stock.

          5.  No fractions of shares of Common Stock shall be issued upon the
conversion of Series A Preferred Stock. In lieu of fractions, the corporation
shall pay to the persons otherwise entitled to such fractions, an amount in cash
equal to the fair market value of such fractional interests as determined by the
Board of Directors.

     F.   Status of Converted or Redeemed Stock.  In case any shares of Series
A Preferred Stock shall be converted pursuant to Section E hereof, or redeemed,
the shares so converted or redeemed shall resume the status of authorized but
unissued shares of Series A Preferred Stock but this corporation may not
reissue or vote any such Series A Preferred Stock until all of the Series A
Preferred

                                      -9-
<PAGE>
Stock designated by this Certificate have been redeemed and/or converted.

     G.   No Preemptive Rights. No holder of either Common Stock or Preferred
Stock shall have any preemptive right to purchase and/or subscribe to any
additional shares of any class of stock which may be issued at any time by this
corporation.

     IN WITNESS WHEREOF, the undersigned have executed this Certificate of
Determination on this 30th day of November, 1984.




                                   /s/ Robert J. Harvey
                                   ----------------------------
                                   Robert J. Harvey
                                   President



                                   /s/ Louis A. McKellar
                                   ----------------------------
                                   Louis A. McKellar
                                   Secretary


     Robert J. Harvey and Louis A. McKellar each declare under penalty of
perjury that he has read the foregoing certificate and knows the contents
thereof and that the same is true of his own knowledge.

     Executed at Berkeley, California, on November 30, 1984.



                                   /s/ Robert J. Harvey
                                   ----------------------------
                                   Robert J. Harvey



                                   /s/ Louis A. McKellar
                                   ----------------------------
                                   Louis A. McKellar


                                      -10-
<PAGE>











                            CERTIFICATE OF AMENDMENT
                                       OF
                           ARTICLES OF INCORPORATION



ROBERT J. HARVEY and KATHLEEN COZZETTA certify that:

     1.   They are the President and Secretary, respectively, of THORATEC
LABORATORIES CORPORATION, a California corporation.

     2.   Article Fourth of the Articles of Incorporation of this corporation is
amended to read as follows:

          "This corporation is authorized to issue two classes of shares, which
     shall be known as Common Stock and Preferred Stock. The total number of
     shares of Common Stock which this corporation is authorized to issue is
     50,000,000, and the total number of shares of Preferred Stock which this
     corporation is authorized to issue is 2,500,000."

     3.   The foregoing amendment of the addition to the Articles of
Incorporation has been duly approved by the Board of Directors.

     4.   The foregoing amendment of and addition to the Articles of
Incorporation has been duly approved by the required vote of shareholders in
accordance with Section 902 of the Corporations Code. The total number of
outstanding shares of the corporation entitled to vote with respect to the
amendment was 5,328,577.

<PAGE>
The number of shares voting in favor of the amendment equaled or exceeded the
vote required. The percentage vote required was more than 50%.

     IN WITNESS WHEREOF, the undersigned have executed this Certificate this
28th day of June, 1985.


                                              /s/ Robert J. Harvey
                                              ----------------------------------
                                              Robert J. Harvey, President



                                              /s/ Kathleen Cozzetta
                                              ----------------------------------
                                              Kathleen Cozzetta, Secretary

     The undersigned declare under penalty of perjury that the matters set forth
in the foregoing certificate are true of their own knowledge.

     Executed at Berkeley, California, on June 28, 1985.


                                              /s/ Robert J. Harvey
                                              ----------------------------------
                                              Robert J. Harvey



                                              /s/ Kathleen Cozzetta
                                              ----------------------------------
                                              Kathleen Cozzetta



                                      -2-
<PAGE>
                      AMENDED CERTIFICATE OF DETERMINATION

                                       OF

                     SERIES A AND SERIES B PREFERRED STOCK

                                       OF

                       THORATEC LABORATORIES CORPORATION


     Robert J. Harvey and Kathleen Cozzetta certify that:

     1.   They are the president and the secretary, respectively, of Thoratec
Laboratories Corporation, a California corporation.

     2.   The number of shares of Preferred Stock which this corporation is
authorized to issue is 2,500,000, of which 540,541 have previously been
designated Series A Preferred Stock pursuant to a Certificate of Determination
duly adopted by the Board of Directors and filed with the California Secretary
of State on December 3, 1984.

     3.   The corporation has issued and there are presently outstanding
540,541 shares of Series A Preferred Stock and 6,349,087 shares of Common Stock.

     4.   The Board of Directors and the holders of all of the outstanding
shares of Series A Preferred Stock have duly adopted the following resolutions:

     WHEREAS, the articles of incorporation authorize the Preferred Stock of
the corporation to be issued in series and authorize the Board of Directors to
determine the rights, preferences, privileges and restrictions granted to or
imposed upon any wholly unissued
<PAGE>
series of Preferred Stock and to fix the number of shares and designation of
any such series, and

     WHEREAS, the Board of Directors has established a series of Preferred
Stock designated as Series A Preferred Stock pursuant to a Certificate of
Determination filed December 3, 1984 with the California Secretary of State, and

     WHEREAS, this corporation has issued 540,541 shares of Series A Preferred
Stock, and

     WHEREAS, the Board of Directors and the holders of the outstanding Series
A Preferred Stock desire to amend the Certificate of Determination to authorize
the issuance of a new series of Preferred Stock to be known as Series B
Preferred Stock, and

     WHEREAS, the Board of Directors of this corporation desires to determine
the rights, preferences, privileges and restrictions of, and fix the number of
shares of, a series of Preferred Stock to be known as Series B Preferred Stock,

     NOW, THEREFORE, IT IS RESOLVED THAT:

     1.   The designations of such series of Preferred Stock are Series A and
Series B Preferred Stock and the number of shares of each such series is
540,541 shares of Series A Preferred Stock and 500,000 shares of Series B
Preferred Stock.

     2.   The rights, preferences, privileges and restrictions granted to or
imposed upon the Series A and Series B Preferred Stock or the holders thereof
are as follows:


                                      -2-

<PAGE>
     A.   Dividend Rights.

          1.   Series B Preferred Stock Cumulative Dividends. The holders of
Series B Preferred Stock shall be entitled to receive, out of funds legally
available therefor, dividends at the rate of $.96 per annum payable in cash
quarterly on the last day of March, June, September and December each year when
and as declared by the Board of Directors. Such dividends shall accrue on each
share of Series B Preferred Stock from the date of its original issuance and
shall accrue from day to day whether or not declared or legally distributable.
Such dividends shall be cumulative so that if such dividends in respect of any
previous dividend period at the above specified rate shall not have been
declared and paid or set apart for payment, the deficiency shall be declared and
paid or set apart for payment, but without interest, before the payment of any
dividend on the Series A Preferred Stock or Common Stock.

          2.   Series A Preferred Stock Cumulative Dividends. The holders of
Series A Preferred Stock shall be entitled to receive, out of funds legally
available therefor, dividends at the rate of $1.30 per annum payable in cash
quarterly on the 1st day of August, November, February and May each year when
and as declared by the Board of Directors. Such dividends shall accrue on each
share of Series A Preferred Stock from the date of its original issuance and
shall accrue from day to day whether or not declared or legally distributable.
Such dividends shall be cumulative so that if such dividends in respect of any
previous dividend period at the above specified rate shall not have been
declared and paid or set apart


                                      -3-
<PAGE>
for payment, the deficiency shall be declared and paid or set apart for payment,
but without interest, before the payment of any dividend or distribution of
assets on the Common Stock.

          3.   Common Stock Dividends.  At any time after all dividends on
Series A and Series B Preferred Stock shall have been declared and paid or set
apart for payment in accordance with the provisions of paragraphs A1 and A2,
dividends may be paid on outstanding Common Stock out of any funds legally
available therefor. The holders of Series B and Series A Preferred Stock shall
not be entitled to participate in any dividends other than as provided in
paragraph A1 and A2, respectively.

     B.   Liquidation Preferences.  In the event of any liquidation,
dissolution and winding up of the corporation, whether voluntary or not, (1)
the holders of Series B Preferred Stock shall be entitled to receive an amount
equal to $8.00 per share plus any accrued but unpaid dividends before any
amount shall be paid to holders of Series A Preferred Stock or Common Stock,
(2) thereafter, the holders of Series A Preferred Stock shall be entitled to
receive an amount equal to $9.25 per share plus any accrued but unpaid
dividends before any amount shall be paid to holders of Common Stock and (3)
thereafter, the holders of Common Stock shall be entitled to receive pro rata
all remaining assets.

          A merger, consolidation or conveyance of assets within the meaning of
the term "reorganization" set forth at Section 181(c) of the California
Corporations Code shall not be deemed to be a liquidation, dissolution or
winding up within the meaning of

                                      -4-




<PAGE>
the foregoing paragraph so long as the shareholders of the corporation shall
continue as the shareholders of the continuing or combined corporation or the
corporation to which such assets are transferred.

     C.   Voting Rights.  Except as otherwise expressly provided by law, the
holders of Series B Preferred Stock and Common Stock shall have the exclusive
right to notice of shareholders' meetings and the exclusive voting power in this
corporation and shall vote together as a single class (except where a separate
class vote is required by law or otherwise required by this paragraph C), each
holder to have one vote for each share of Common Stock held and that number of
votes for each share of Series B Preferred Stock held equal to the number of
shares of Common Stock into which such share is convertible; provided, however,
the holders of Series A Preferred Stock shall be entitled to one vote for each
share of Series A Preferred Stock standing in their names on the books of this
corporation, with a vote of a majority of the issued and outstanding Series A
Preferred Stock voting as a series (as distinguished from voting as part of a
larger class) required for each of the following matters:

          1.   Any matter which under California law requires the vote of
               Preferred Stock as a class or any series of Preferred Stock as a
               series;

          2.   Issuance of any shares of Preferred Stock of this corporation;

                                      -5-
<PAGE>
         3.  Any reorganization, merger, consolidation by or with this
             corporation and any transfer of all or substantially all of the
             assets of this corporation; and

         4.  The amendment of this Certificate of Determination;
provided further, that the holders of Series B Preferred Stock shall be entitled
to one vote for each share of Series B Preferred Stock standing in their names
on the books of this corporation, with a vote of a majority of the issued and
outstanding Series B Preferred Stock voting as a series (as distinguished from
voting as part of a larger class) required for each of the following matters:

         1.  Any matter which, under California law, requires the vote of
             Preferred Stock as a class or any series of Preferred Stock as a
             series;

         2.  Any reorganization, merger, consolidation by or with this
             corporation and any transfer of all or substantially all of the
             assets of this corporation; and

         3.  The amendment of this Certificate of Determination.

     D.  Redemption of Series A and Series B Preferred Stock. This corporation,
at the option of the Board of Directors, (i) may redeem at any time the whole
or any part of the Series A Preferred Stock by paying $9.25 per share together
with all accrued and unpaid dividends thereon (the "Series A redemption price")
to and including the date fixed for redemption (the "redemption date"), and
(ii) may redeem at any time after five years after the date of


                                      -6-









<PAGE>
issuance of each share by the corporation the whole or any part of the Series B
Preferred Stock by paying $8.00 per share together with all accrued and unpaid
dividends thereon (the "Series B redemption price") to and including the
redemption date. The corporation shall give notice of the redemption of any or
all such shares by causing a notice of redemption to be mailed not earlier than
60 nor later than 30 days prior to the redemption date to the holders of record
of the Series A or Series B Preferred Stock to be redeemed addressed to each
such holder at the holder's post office address appearing on the records of the
corporation or, if no address is shown, at the place where the principal
executive office of the corporation is located. The notice of redemption shall
set forth: (i) the class or series of shares or part of any class or series of
shares to be redeemed; (ii) the redemption date; (iii) the redemption price; and
(iv) the place at which the shareholders may obtain payment of the Series A or
Series B redemption price, as the case may be, upon surrender of their share
certificates. In case of the partial redemption of Series A or Series B
Preferred Stock, such redemption shall be pro rata among the various holders
thereof or as determined by lot in the discretion of the Board of Directors. On
or before the redemption date, each holder of shares called for redemption shall
surrender the certificate representing such shares to the corporation at the
place designated in the redemption notice and shall thereupon be entitled to
receive payment of the redemption price on the redemption date. If less than all
of the shares represented by a surrendered certificate are


                                      -7-
<PAGE>
redeemed, the corporation shall issue a new certificate representing the
unredeemed shares.

         If, on or before the redemption date, the corporation has cash funds
available and has deposited for such purpose in trust with a bank or trust
company sufficient funds to pay the Series A or Series B redemption price, as
the case may be, in full to the holders of all shares called for redemption, the
shares so called shall be deemed to be redeemed as of the date of deposit,
dividends on those shares shall cease to accrue and no interest shall accrue on
the redemption price from and after the redemption date. The right to convert
said shares shall terminate at the close of business on the fifth day prior to
the redemption date. Any amounts so deposited on account of the Series A or
Series B redemption price of shares converted subsequent to the date of deposit
shall be repaid to the corporation forthwith upon the conversion of such shares.

     E.  Conversion Rights.  The holders of Series A Preferred Stock shall have
conversion rights as follows:

         1.  Each holder of Series A Preferred Stock may, on or after September
1, 1989, upon surrender of the certificates therefor, convert any or all Series
A Preferred Stock held by such holder into a number of fully paid and
nonassessable shares of Common Stock equal to (a) $9.25 plus any accrued and
unpaid dividends with respect to such share dividend by (b) $9.25 for each share
of Series A Preferred Stock. Such option to convert shall be exercised by
surrendering for such purpose to the corporation, at


                                      -8-



<PAGE>
the office of the corporation or of any transfer agent for the Common Stock or
Series A Preferred Stock, certificates representing the shares to be converted
duly endorsed in blank or accompanied by proper instruments of transfer. Such
conversion shall be deemed to have been made as of the date of such surrender of
the Series A Preferred Stock and the person entitled to receive the Common Stock
therefor shall be treated for all purposes as the record holder of such Common
Stock on such date. If any shares of Series A Preferred Stock have been called
for redemption, the right of conversion shall terminate as to such shares at the
close of business on the fifth day preceding the redemption date.

     2.   Each holder of Series B Preferred Stock may, at any time, upon
surrender of the certificates therefor, convert any or all Series B Preferred
Stock in minimum denominations of 1,000 shares held by such holder into such
number of fully paid and nonassessable shares of Common Stock as is determined
by dividing (i) $8.00, multiplied by the number of shares to be converted by
(ii) the Conversion Price (as defined below) in effect at the time of
conversion. The initial Conversion Price shall be $.80. The initial Conversion
Price shall be subject to adjustment from time to time as provided below (as
adjusted the "Conversion Price"). Any right to receive dividends which may be
accrued and unpaid at the date of surrender for conversion shall terminate upon
surrender for conversion, and no adjustment in the Conversion Price shall be
made with respect to any dividends which may be accrued and unpaid at the date
of surrender for conversion. Such option to convert


                                      -9-
<PAGE>
shall be exercised by surrendering for such purpose to the corporation, at the
office of the corporation or of any transfer agent for the Common Stock or
Series B Preferred Stock, certificates representing the shares to be converted
duly endorsed in blank or accompanied by proper instruments of transfer. Such
conversion shall be deemed to have been made as of the date of such surrender
of the Series B Preferred Stock and the person entitled to receive the Common
Stock therefor shall be treated for all purposes as the record holder of such
Common Stock on such date.

     The Conversion Price shall be subject to adjustment from time to time as
follows:

     (i)(a)    If the corporation shall issue or sell any Additional Stock (as
defined below) subsequent to December 31, 1986 without consideration or for a
consideration per share less than the Conversion Price in effect immediately
prior to the issuance or sale of such Additional Stock, the Conversion Price in
effect immediately prior to the issuance or sale shall (except as otherwise
provided in this clause (i)) be adjusted, as of the opening of business on the
date of such issuance or sale, to a price calculated to the nearest cent, equal
to the consideration per share received for such Additional Stock.

        (b)    In the case of the issuance of Common Stock for cash, the
consideration shall be deemed to be the amount of cash paid therefor before
deducting discounts, commissions or other selling expenses allowed, paid or
incurred by the corporation


                                      -10-
<PAGE>
for any underwriting or otherwise in connection with the issuance and sale
thereof.

     (c)  In the case of the issuance of the Common Stock for a consideration
in whole or in part other than cash, the consideration other than cash shall be
deemed to be the fair value thereof as determined in good faith on any
reasonable basis by the Board of Directors.

     (d)  In the case of the issuance of options to purchase or rights to
subscribe for Common Stock, options to purchase or rights to subscribe for
securities by their terms convertible or exchangeable for Common Stock or
securities by their terms convertible into or exchangeable for Common Stock
(which are not excluded from the definition of Additional Stock), the following
provisions shall apply:

          (1)  The consideration shall be the consideration (determined in the
manner provided in paragraphs E.2(i)(b) and E.2(i)(c)), if any, received by the
corporation upon the issuance of such options, rights or convertible or
exchangeable securities plus the minimum purchase price provided in such
options, rights or convertible or exchangeable securities for the Common Stock
covered thereby.

          (2)  In the event of any change in the number of shares of Common
Stock deliverable upon exercise of such options or rights or upon conversion of
or in exchange for such convertible or exchangeable securities, including, but
not limited to, a change resulting from the antidilution provisions thereof,


                                      -11-
<PAGE>
the Conversion Price in effect at the time shall forthwith be readjusted to
such Conversion Price as would have obtained had the adjustment which was made
upon the issuance of such options, rights or convertible or exchangeable
securities not converted or exchanged prior to such change or the options or
rights related to such securities not converted or exchanged prior to such
change been made upon the basis of such change, but no further adjustment shall
be made for the actual issuance of Common Stock upon the exercise of any such
options or rights or the conversion or exchange of such securities.

                                  (3) Upon the expiration of any such options
or rights, the termination of any such rights to convert or exchange, the
Conversion Price shall forthwith be readjusted to such Conversion Price in
effect prior to the adjustment which was made upon the issuance of such options,
rights or securities.

                         (ii) "Additional Stock" shall mean any shares of
Common Stock issued (or deemed to have been pursuant to paragraph E.2(i)(d)) by
this corporation after December 31, 1986, other than

                              (a) shares of Common Stock and options and
warrants to issue shares of Common Stock aggregating 2,700,000 shares (as
presently constituted) issuable to employees, officers, directors or
consultants of the corporation directly or upon exercise of options; provided
that the 2,700,000 shares shall reduced on a share-for-share basis to the
extent the Company


                                        -12-
<PAGE>
reduces the exercise price of any options outstanding on December 31, 1986 to a
price less than $.80 per share;

                    (b)  shares of Common Stock issuable upon exercise of
warrants outstanding as of December 31, 1986;

                    (c)  shares of Common Stock issued upon conversion of the
Series B Preferred Stock; and

                    (d)  warrants issued to Wells Fargo Bank, N.A. for the
purchase of 1,000,000 shares of Common Stock at an exercise price of $.001 per
share.

          3.   The number of shares of Common Stock into which shares of Series
A or Series B Preferred Stock may be converted shall be subject to adjustments
as follows with such adjustment to be effected if any of the following events
occur at any time after December 31, 1986:

               (a)  In case the corporation shall be recapitalized through the
subdivision or combination of its outstanding Common Stock into a larger or
smaller number of shares, then in each such case the number of shares of Common
Stock into which shares of Series A and Series B Preferred Stock may be
converted shall be increased or reduced in the same proportion.

               (b)  In case the corporation declares a dividend on Common Stock
payable in Common Stock or securities convertible into Common Stock, then, as
of the record date for determining the holders entitled to receive such
dividend, the number of shares of Common Stock into which shares of Series A
and Series B Preferred Stock may be converted shall be increased in proportion
to the

                                      -13-
<PAGE>
increase through such dividend of the number of outstanding shares of Common
Stock.

               (c)  In case the corporation determines to offer rights to the
holders of Common Stock entitling them to subscribe to additional Common Stock
or securities convertible or exchangeable into Common Stock, the corporation
shall give written notice of such proposed rights offering to the holders of
Series A and Series B Preferred Stock at least 15 days prior to the proposed
record date. There shall be no adjustment in the conversion rate with respect to
the Series A Preferred Stock by virtue of such rights offering or by virtue of
any sale of any class of securities of the corporation. There shall, however, be
an adjustment in the conversion rate with respect to the Series B Preferred
Stock by virtue of such rights offering or by virtue of any class of securities
of the corporation, determined in accordance with paragraph E(2).

               (d)  In case of any capital reorganization, including any
reclassification of the capital stock of the corporation or any merger of the
corporation with another corporation or the sale or conveyance of all or
substantially all of the assets of the corporation to another corporation, each
share of Series A and Series B Preferred Stock shall thereafter be convertible
into the number of shares of stock or other securities or property to which a
holder of the number of shares of Common Stock otherwise deliverable hereunder
upon conversion of such share of Series A or Series B Preferred Stock would have
been entitled


                                      -14-
<PAGE>
upon such reorganization; and in any such case, appropriate adjustments (as
determined in good faith on any reasonable basis by the Board of Directors)
shall be made in the application of the provisions herein set forth with respect
to the rights and interests thereafter of the holders of the Series A and Series
B Preferred Stock to the end that the provisions set forth herein (including
provisions with respect to changes in, and other adjustments of, the conversion
rate) shall thereafter be applicable, as nearly as reasonably may be, in
relation to any securities or other property thereafter deliverable upon the
conversion of the Series A and Series B Preferred Stock.

          4.   Whenever the amount of Common Stock or other securities
deliverable upon the conversion of Series A or Series B Preferred Stock shall be
adjusted pursuant to the provisions hereof, the corporation shall forthwith
file, at its principal executive office and with any transfer agent for its
Common Stock and Series A and Series B Preferred Stock, a statement signed by
the Chief Executive Officer and Chief Financial Officer of the corporation
stating the adjusted amount of its Common Stock or other securities deliverable
per share of Series A or Series B Preferred Stock calculated to the nearest cent
and setting forth in reasonable detail the method of calculation and the facts
requiring such adjustment and upon which such calculation is based. Each
adjustment shall remain in effect until a subsequent adjustment is required
hereunder, as the case may be.



                                      -15-

<PAGE>
       5.   The corporation shall at all times reserve and keep available out of
its authorized but unissued Common Stock the full number of shares deliverable
upon conversion of all the then outstanding Series A and Series B Preferred
Stock and shall take all such action and obtain all such permits and orders as
may be necessary to enable the corporation lawfully to issue such Common Stock
upon the conversion of Series A and Series B Preferred Stock.

       6.   No fraction of shares of Common Stock shall be issued upon the
conversion of Series A or Series B Preferred Stock. In lieu of fractions, the
corporation shall pay to the persons otherwise entitled to such fractions, an
amount in cash equal to the fair market value of such fractional interests as
determined by the Board of Directors.

       7.   The issue of stock certificates on conversion of Series A or Series
B Preferred Stock shall be made without charge to the converting shareholder,
and the corporation shall pay any stock transfer tax with respect to the issue
thereof; provided that the Common Stock deliverable upon conversion is issued in
the name of the holder of the Series A or Series B Preferred Stock certificate
converted.

     F.   Status of Converted or Redeemed Stock.  In case any shares of Series
A or Series B Preferred Stock shall be converted pursuant to paragraph E
hereof, or redeemed, the shares so converted or redeemed shall resume the
status of authorized but unissued shares of Series A or Series B Preferred
Stock, as the case may be, but this corporation may not reissue or vote any such


                                      -16-


<PAGE>
Series A or Series B Preferred Stock until all of the Series A and Series B
Preferred Stock designated by this Certificate have been redeemed and/or
converted.

     G.   Notices of Record Date.  If this corporation establishes a record date
for the purpose of determining the holders of any class of securities who are
entitled to receive any dividend or other distribution, any right to subscribe
for, purchase or otherwise acquire any shares of stock of any class or any other
securities or property or to receive any other right, this corporation shall
mail at least 20 days prior to the record date to each holder of Series B
Preferred Stock, addressed to each such holder at the holder's post office
address appearing in the records of this corporation, a notice specifying such
record date and the amount and character of such dividend, distribution or
right.


     H.   No Preemptive Rights.  No holder of either Common Stock or Preferred
Stock shall have any preemptive right to purchase and/or subscribe to any
additional shares of any class of stock which may be issued at any time by this
corporation.

     IN WITNESS WHEREOF, the undersigned have executed this Certificate of
Determination on this 21 day of January, 1987.




                                             /s/ Robert J. Harvey
                                             ----------------------------
                                             Robert J. Harvey
                                             President



                                             /s/ Kathleen Cozzetta
                                             ----------------------------
                                             Kathleen Cozzetta
                                             Secretary


                                      -17-

<PAGE>
     Robert J. Harvey and Kathleen Cozzetta each declare under penalty of
perjury that he/she has read the foregoing certificate and knows the contents
thereof and that the same is true of his own knowledge.

     Executed at Berkeley, California, on January 21, 1987.

                                              /s/ Robert J. Harvey
                                              ----------------------------------
                                              Robert J. Harvey


                                              /s/ Kathleen Cozzetta
                                              ----------------------------------
                                              Kathleen Cozzetta



                                      -18-
<PAGE>


                                AMENDMENT TO THE
                      AMENDED CERTIFICATE OF DETERMINATION
                                       OF
                        THORATEC LABORATORIES CORPORATION


     Robert J. Harvey and Kathleen Cozzetta certify  that:

     1.   They are the president and the secretary, respectively, of Thoratec
Laboratories Corporation, a California corporation.

     2.   The number of shares of Preferred Stock which this corporation is
authorized to issue is 2,500,000, of which (1) 540,541 have previously been
designated Series A Preferred Stock pursuant to a Certificate of Determination
duly adopted by the Board of Directors and filed with the California Secretary
of State on December 3, 1984, and (2) 500,000 have previously been designated
Series B Preferred Stock pursuant to a Certificate of Determination duly
adopted by the Board of Directors and all of the holders of the Series A
Preferred Stock and filed with the California Secretary of State on January 23,
1987.

     3.   The corporation has issued and there are presently outstanding
502,518 shares of Series A Preferred Stock and 6,349,087 shares of Common
Stock. No shares of Series B Preferred Stock have been issued to date.

     4.   The Board of Directors has adopted the resolutions set forth below.
There are no shares of Series B Preferred Stock outstanding and entitled to
vote.
<PAGE>
     WHEREAS, the articles of incorporation authorize the Preferred Stock of
the corporation to be issued in series and authorize the Board of Directors to
determine the rights, preferences, privileges and restrictions granted to or
imposed upon any wholly unissued series of Preferred Stock and to fix the
number of shares and designation of any such series, and

     WHEREAS, the Board of Directors has established a series of Preferred Stock
designated as Series B Preferred Stock pursuant to an Amended Certificate of
Determination filed January 23, 1987 with the California Secretary of State, and

     WHEREAS, this corporation has not issued any shares of Series B Preferred
Stock to date, and

     WHEREAS, the Board of Directors desires to amend Section E.2 (ii) of the
Amended Certificate of Determination relating to the rights, preferences,
privileges and restrictions granted to the Series B Preferred Stock to exclude
additional securities from the definition of "Additional Stock."

     NOW, THEREFORE, IT IS

          RESOLVED, that Section E.2 (ii) of the Amended Certificate of
     Determination is hereby amended and restated in its entirety to read as
     follows:

     (ii)  "Additional Stock" shall mean any shares of Common Stock issued (or
     deemed to have been issued pursuant to paragraph E.2(i)(d)) by this
     corporation after December 31, 1986, other than:

               (a)  Shares of Common Stock and options and warrants to issue
               shares of Common Stock aggregating 2,700,000 shares (as presently
               constituted) issuable to employees, officers, directors or
               consultants of the corporation directly or upon exercise of such
               options and warrants; provided that the 2,700,000 shares shall be
               reduced on a share for share basis to the extent the company
               reduces the exercise price of any options outstanding on December
               31, 1986 to a price less than $0.80 per share (as presently
               constituted);

               (b)  30,000 shares of Common Stock (as presently constituted)
               issuable upon exercise of warrants outstanding as of December 31,
               1986;

                                      -2-


<PAGE>
(c) Up to 3,750,000 shares of Common Stock (as presently constituted) issuable
upon conversion of the Series B Preferred Stock;

(d) A convertible secured promissory note issued to Wells Fargo Bank, N.A. (the
"Bank") pursuant to the Amended and Restated Loan Agreement, dated as of
December 31, 1986, between the Bank and this corporation and its subsidiaries
and the 500,000 shares of Series B Preferred Stock (as presently constituted)
issuable upon conversion of such note;

(e) Warrants to purchase an aggregate of 1,900,000 shares of Common Stock (as
presently constituted) issued to Paul F. Glenn, Christy Bell and Bradley
Resources Company pursuant to the Interim Loan Agreement dated as of June 5,
1987, as amended by the First, Second and Third Amendment to such Interim Loan
Agreement (as so amended, the "Interim Loan Agreement"), and the shares of
Common Stock issuable upon the exercise of such warrants;

(f) Warrants to purchase an aggregate of 4,000,000 shares of Common Stock (as
presently constituted)issued to the Bank, and the shares of Common Stock
issuable upon the exercise of such warrants;

(g) Warrants to purchase an aggregate of 1,000,000 shares of Common Stock (as
presently constituted) issuable to the Bank pursuant to the terms of the Loan
Acquisition Agreement dated as of March 9, 1988 by and among this corporation,
the Bank and Paul F. Glenn, and the shares of Common Stock issuable upon the
exercise of such warrants;

(h) Convertible secured promissory notes issued or issuable to Paul F. Glenn,
Christy Bell and Bradley Resources Company pursuant to the Interim Loan
Agreement, and the shares of Common Stock (as presently constituted) issuable
upon the conversion of such notes;

(i) Convertible promissory notes (convertible as to interest only) in principal
amount of $250,000 and $100,000, respectively, issued to Ethicon, Inc. and J.
Donald Hill, M.D., respectively, and the shares of Common Stock (as presently
constituted) issuable upon the conversion of such notes;

(j) Options to purchase up to 1,000,000 shares of Common Stock (as presently
constituted) issued or issuable pursuant to the 1988 Non-Qualified Stock Option
Plan of this corporation, and the shares of Common Stock issuable upon the
exercise of such options.


                                      -3-
<PAGE>
     IN WITNESS WHEREOF, the undersigned have executed this Amendment to the
Amended Certificate of Determination on this 9th day of March, 1988.


                                        /s/ Robert J. Harvey
                                        ----------------------------------
                                        Robert J. Harvey
                                        President


                                        /s/ Kathleen Cozzetta
                                        ----------------------------------
                                        Kathleen Cozzetta
                                        Secretary



                                      -4-

<PAGE>
     Robert J. Harvey and Kathleen Cozzetta each declare under penalty of
perjury that he/she has read the foregoing certificate and knows the contents
thereof and that the same is true of his/her own knowledge.

     Executed at Berkeley, California, on March 9, 1988.



                                        /s/ Robert J. Harvey
                                        ----------------------------------
                                        Robert J. Harvey


                                        /s/ Kathleen Cozzetta
                                        ----------------------------------
                                        Kathleen Cozzetta



                                      -5-


<PAGE>

                            CERTIFICATE OF AMENDMENT

                                       OF

                           ARTICLES OF INCORPORATION

     ROBERT J. HARVEY and CHERYL D. HESS certify that:

     1. They are the President and Secretary, respectively, of THORATEC
LABORATORIES CORPORATION, a California corporation.

     2. Article Fourth of the Articles of Incorporation of this corporation is
amended to read as follows:

        This corporation is authorized to issue two classes of shares, which
        shall be known as Common Stock and Preferred Stock. The total number of
        shares of Common Stock which this corporation is authorized to issue is
        100,000,000, and the total number of shares of Preferred Stock which
        this corporation is authorized to issue is 2,500,000.

     3. The foregoing amendment to the Articles of Incorporation has been duly
approved by the Board of Directors.

     4. The foregoing amendment to the Articles of Incorporation has been duly
approved by the required vote of shareholders in accordance with Sections 902
and 903 of the Corporations Code. The total number of outstanding shares of the
corporation entitled to vote with respect to the amendment was 42,523,751. The
number of shares
<PAGE>
voting in favor of the amendment equaled or exceeded the vote required. The
percentage vote required was more than 50%.

     IN WITNESS WHEREOF, the undersigned have executed this Certificate this 24
day of June, 1994.


                                 /s/ Robert J. Harvey
                                 -----------------------------------------------
                                 Robert J. Harvey, President


                                 /s/ Cheryl D. Hess
                                 -----------------------------------------------
                                 Cheryl D. Hess, Secretary


     The undersigned declare under penalty of perjury that the matters set
forth in the foregoing certificate are true of their own knowledge.

     Executed at Berkeley, California on this 24 day of June, 1994.


                                 /s/ Robert J. Harvey
                                 -----------------------------------------------
                                 Robert J. Harvey


                                 /s/ Cheryl D. Hess
                                 -----------------------------------------------
                                 Cheryl D. Hess
<PAGE>









                          CERTIFICATE OF AMENDMENT OF
                          ARTICLES OF INCORPORATION OF
                       THORATEC LABORATORIES CORPORATION

     D. KEITH GROSSMAN and CHERYL D. HESS hereby certify as follows:

     1.  That they are the President and Secretary, respectively, of THORATEC
LABORATORIES CORPORATION, a California corporation (the "Corporation").

     2.  Article Fourth of the Articles of Incorporation of this Corporation is
hereby amended in full to read as follows:

          "This corporation is authorized to issue two classes of shares, which
          shall be known as Common Stock and Preferred Stock. The total number
          of shares of Common Stock which this corporation is authorized to
          issue is 100,000,000 and the total number of shares of Preferred Stock
          which this corporation is authorized to issue is 2,500,000. Effective
          at 2 p.m. Pacific daylight time on June 3, 1996 (the "Effective
          Date"), each three shares of Common Stock of the Corporation
          outstanding shall be reconstituted and converted into one share of
          Common Stock. No fractional shares will be issued upon the Reverse
          Split. In lieu thereof, the Company will pay each holder of a
          fractional interest an amount in cash equal to the value of such
          fractional interest on the Effective Date. The number of authorized
          shares of Common Stock will remain 100,000,000.

     3.  The foregoing amendment of the Articles of Incorporation of the
Corporation has been duly approved by the Board of Directors.

     4.  The foregoing amendment of the Articles of Incorporation of the
Corporation has been duly approved by the required vote of the shareholders in
accordance with Section 902 and 903 of the California Corporations Code. The
total number of outstanding shares of the Corporation entitled to vote with
respect to the amendment was 46,784,255 shares of Common Stock. The number of
shares voting in favor of the amendment equaled or exceeded the vote required.
The percentage vote required was more than 50%.
<PAGE>
     We further declare under penalty of perjury under the laws of the State of
California that the matters set forth in this Certificate are true and correct
of our knowledge. Executed at Berkeley, California, this 3rd day of June, 1996.



                                   /s/ D. Keith Grossman
                                   ------------------------------------------
                                   D. KEITH GROSSMAN,
                                   President















                                      -2-
<PAGE>
     We further declare under penalty of perjury under the laws of the State of
California that the matters set forth in this Certificate are true and correct
of our knowledge. Executed at Charleston, South Carolina, this 3rd day of
June, 1996.



                                   /s/ Cheryl D. Hess
                                   ------------------------------------------
                                   CHERYL D. HESS,
                                   Secretary















                                      -3-
<PAGE>



                            CERTIFICATE OF AMENDMENT
                                     OF THE
                 AMENDED AND RESTATED ARTICLES OF INCORPORATION
                                       OF
                       THORATEC LABORATORIES CORPORATION


     D. Keith Grossman and Cheryl D. Hess hereby certify as follows:

     1.   They are the President and Chief Executive Officer and Chief Financial
Officer and Secretary, respectively, of Thoratec Laboratories Corporation, a
California corporation (the "Corporation");

     2.   The Amended and Restated Articles of Incorporation are hereby amended
by deleting, in its entirety, Article FIRST thereof, and inserting in its place
a new Article FIRST that reads, in its entirety as follows:

          "FIRST: The name of this corporation is Thoratec Corporation."

     3.   The foregoing amendment to the Corporation's Articles of Incorporation
has been duly approved by the Corporation's Board of Directors.

     4.   The foregoing amendment to the Corporation's Articles of Incorporation
has been duly approved by the required vote of the Corporation's shareholders in
accordance with Sections 902 and 903 of the California Corporations Code. The
total number of outstanding shares of the Corporation entitled to vote with
respect to the amendment was 22,421,775 shares of Common Stock. There are no
shares of Preferred Stock outstanding. The number of shares voting in favor of
the amendment equaled or exceeded the vote required. The percentage vote
required was more than 50 percent.

     We further declare under penalty of perjury under the laws of the State of
California that the matters set forth in this certificate are true and correct
of our own knowledge.

     IN WITNESS WHEREOF, the undersigned have executed this certificate this
13 day of February 2001.



                                           /s/ D. Keith Grossman
                                           ---------------------
                                           D. Keith Grossman,
                                           President and Chief Executive Officer



                                            /s/ Cheryl D. Hess
                                           ---------------------
                                           Cheryl D. Hess,
                                           Chief Financial Officer and Secretary




<PAGE>

                          Certificate of Determination

                                       of

                            Series RP Preferred Stock

                                       of

                              Thoratec Corporation

          (Pursuant to Section 401 of the California Corporations Code)


      1. I, M. Wayne Boylston, Senior Vice President, Chief Financial Officer
and Secretary of Thoratec Corporation (the "CORPORATION"), a corporation
organized and existing under the Corporations Code of the State of California,
in accordance with Section 401 thereof, DO HEREBY CERTIFY:

      2. That pursuant to the authority conferred upon the Board of Directors of
the Corporation by the Amended and Restated Articles of Incorporation of the
Corporation, the Board of Directors on May 2, 2002, adopted the following
resolutions creating a series of 100,000 shares of Preferred Stock designated as
Series RP Preferred Stock, none of which have been issued.

      RESOLVED, that pursuant to the authority granted to and vested in the
Board of Directors of the Corporation under its Amended and Restated Articles of
Incorporation, the Board of Directors hereby creates a series of 100,000 shares
of Series RP Preferred Stock, without par value, of the Corporation and hereby
determines that the designation and number of shares that stock and their
rights, preferences and limitations (in addition to the provisions set forth in
the Amended and Restated Articles of Incorporation of the Corporation, which are
applicable to preferred stock of all classes and series), shall be as set forth
below:

                            Series RP Preferred Stock

      Section 1. DESIGNATION, PAR VALUE AND AMOUNT. The shares of such series
shall be designated as "Series RP Preferred Stock" (hereinafter referred to as
"SERIES RP PREFERRED STOCK"), the shares of such series shall be without par
value, and the number of shares constituting such series shall be 100,000;
provided, however, that, if more than a total of 100,000 shares of Series RP
Preferred Stock shall be issuable upon the exercise of Rights (the "RIGHTS")
issued pursuant to the Rights Agreement dated as of May 2, 2002 between the
Corporation and Computershare Trust Company, Inc., a Colorado corporation, as
Rights Agent (as amended from time to time, the "AGREEMENT"), the Board of
Directors of the Corporation shall direct by resolution or resolutions that a
certificate be properly executed, acknowledged and filed providing for the total
number of shares of Series RP Preferred Stock authorized to be issued to be
increased (to the extent that the Restated Certificate of Incorporation then
permits) to the largest number of whole shares of Series RP Preferred Stock
(rounded up to the nearest whole number) issuable upon exercise of the Rights.

      Section 2. DIVIDENDS AND DISTRIBUTIONS
<PAGE>
            2.1 Subject to the prior and superior rights of the holders of any
shares of any series of Preferred Stock ranking prior and superior to the shares
of Series RP Preferred Stock with respect to dividends, the holders of shares of
Series RP Preferred Stock shall be entitled to receive, when, as and if declared
by the Board of Directors out of assets legally available for that purpose,
quarterly dividends payable in cash on the first business day of March, June,
September and December in each year (each such date being referred to herein as
a "QUARTERLY DIVIDEND PAYMENT DATE"), commencing on the first Quarterly Dividend
Payment Date after the first issuance of a share or fraction of a share of
Series RP Preferred Stock, in an amount per share (rounded to the nearest cent)
equal to the greater of (A) $1.00 or (B) subject to the provision for adjustment
set forth in Section 6.1, 1,000 times the total per share amount of any and all
cash dividends, and 1,000 times the total per share amount (payable in kind) of
any and all non-cash dividends or other distributions other than a dividend
payable in shares of Common Stock, no par value, of the Corporation (the "COMMON
STOCK") or a subdivision of the outstanding shares of Common Stock (by
reclassification or otherwise), declared on the Common Stock since the
immediately preceding Quarterly Dividend Payment Date, or, with respect to the
first Quarterly Dividend Payment Date, since the first issuance of any share or
fraction of a share of Series RP Preferred Stock.

            2.2 The Corporation shall declare a dividend or distribution on the
Series RP Preferred Stock as provided in Section 2.1 above immediately after it
declares a dividend or distribution on the Common Stock (other than a dividend
payable in shares of Common Stock); provided that, if no dividend or
distribution shall have been declared on the Common Stock during the period
between any Quarterly Dividend Payment Date and the next subsequent Quarterly
Dividend Payment Date, a dividend of $1.00 per share on the Series RP Preferred
Stock shall nevertheless be payable on such subsequent Quarterly Dividend
Payment Date.

            2.3 Dividends shall begin to accrue and be cumulative on outstanding
shares of Series RP Preferred Stock from the Quarterly Dividend Payment Date
next preceding the date of issue of such shares of Series RP Preferred Stock,
unless the date of issue of such shares is before the record date for the first
Quarterly Dividend Payment Date, in which case dividends on such shares shall
begin to accrue from the date of issuance of such shares, or unless the date of
issuance is a Quarterly Dividend Payment Date or is a date after the record date
for the determination of holders of shares of Series RP Preferred Stock entitled
to receive a quarterly dividend and before such Quarterly Dividend Payment Date,
in either of which events such dividends shall begin to accrue and be cumulative
from such Quarterly Dividend Payment Date. Accrued but unpaid dividends shall
not bear interest. Dividends paid on the shares of Series RP Preferred Stock in
an amount less than the total amount of such dividends at the time accrued and
payable on such shares shall be allocated pro rata on a share-by-share basis
among all such shares at the time outstanding. The Board of Directors may fix a
record date for the determination of holders of shares of Series RP Preferred
Stock entitled to receive payment of a dividend or distribution declared
thereon, which record date shall be not more than 30 days before the date fixed
for the payment thereof.

      Section 3 VOTING RIGHTS. The holders of shares of Series RP Preferred
Stock shall have the following voting rights:



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<PAGE>
            3.1 Except as provided in Section 3.3 and subject to the provision
for adjustment hereinafter set forth, each share of Series RP Preferred Stock
shall entitle the holder thereof to 1,000 votes on all matters submitted to a
vote of the shareholders of the Corporation.

            3.2 Except as otherwise provided herein or by law, the holders of
shares of Series RP Preferred Stock and the holders of shares of Common Stock
shall vote together as one class on all matters submitted to a vote of
shareholders of the Corporation.

            3.3 The following additional provisions shall apply with respect to
the voting of shares of Series RP Preferred Stock: If, on the date used to
determine shareholders of record for any meeting of shareholders for the
election of directors, a default in preference dividends (as defined below) on
the Series RP Preferred Stock shall exist, the holders of the Series RP
Preferred Stock shall have the right, voting as a class as described in Section
3.3(B) below, to elect two directors (in addition to the directors elected by
holders of Common Stock of the Corporation). Such right may be exercised: (i) at
any meeting of shareholders for the election of directors or (ii) at a meeting
of the holders of shares of Voting Preferred Stock (as hereinafter defined),
called for the purpose in accordance with the Bylaws of the Corporation, until
all such cumulative dividends (referred to above) shall have been paid in full
or until non-cumulative dividends have been paid regularly for at least one
year. The right of the holders of Series RP Preferred Stock to elect two
directors, as described above, shall be exercised as a class concurrently with
the rights of holders of any other series of Preferred Stock upon which voting
rights to elect such directors have been conferred and are then exercisable. The
Series RP Preferred Stock and any additional series of Preferred Stock that the
Corporation may issue and that may provide for the right to vote with the
foregoing series of Preferred Stock are collectively referred to herein as
"VOTING PREFERRED STOCK." Each director elected by the holders of shares of
Voting Preferred Stock shall be referred to herein as a "PREFERRED DIRECTOR." A
Preferred Director shall continue to serve as such for a term of one year,
except that upon any termination of the right of all holders of Voting Preferred
Stock to vote as a class for Preferred Directors, the term of office of
Preferred Directors then serving shall terminate. Any Preferred Director may be
removed by, and shall not be removed except by, the vote of the holders of
record of the outstanding shares of Voting Preferred Stock then entitled to vote
for the election of directors, present (in person or by proxy) and voting
together as a single class: (i) at a meeting of the shareholders or (ii) at a
meeting of the holders of shares of such Voting Preferred Stock, called for the
purpose in accordance with the Bylaws of the Corporation. So long as a default
in any preference dividends of the Series RP Preferred Stock shall exist or the
holders of any other series of Voting Preferred Stock shall be entitled to elect
Preferred Directors: (i) any vacancy in the office of a Preferred Director may
be filled (except as provided in the following clause (ii)) by an instrument in
writing signed by the remaining Preferred Director and filed with the
Corporation and (ii) in the case of the removal of any Preferred Director, the
vacancy may be filled by the vote of the holders of the outstanding shares of
Voting Preferred Stock entitled to vote for the election of directors, present
(in person or by proxy) and voting together as a single class, at such time as
the removal shall be effected. Each director appointed as aforesaid by the
remaining Preferred Director shall be deemed, for all purposes hereof, to be a
Preferred Director. Whenever (1) no default in preference dividends on the
Series RP Preferred Stock shall exist and (2) the holders of other series of
Voting Preferred Stock shall no longer be entitled to elect such Preferred
Directors, then the number of directors constituting the Board of Directors of
the Corporation shall be reduced by two. For purposes hereof, a "DEFAULT IN
PREFERENCE DIVIDENDS"

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<PAGE>
on the Series RP Preferred Stock shall be deemed to have occurred whenever the
amount of cumulative and unpaid dividends on the Series RP Preferred Stock shall
be equivalent to six full quarterly dividends or more (whether or not
consecutive), and, having so occurred, such default shall be deemed to exist
thereafter until, but only until, all cumulative dividends on all shares of the
Series RP Preferred Stock then outstanding shall have been paid through the last
Quarterly Dividend Payment Date or until, but only until, non-cumulative
dividends have been paid regularly for at least one year.

      Section 4. CERTAIN RESTRICTIONS

            4.1 Whenever quarterly dividends or other dividends or distributions
payable on the Series RP Preferred Stock as provided in Section 2 are in
arrears, thereafter and until all accrued and unpaid dividends and
distributions, whether or not declared, on shares of Series RP Preferred Stock
outstanding shall have been paid in full, the Corporation shall not: (A) declare
or pay dividends, or make any other distributions, on any shares of stock
ranking junior (either as to dividends or upon liquidation, dissolution or
winding up) to the Series RP Preferred Stock, (B) declare or pay dividends, or
make any other distributions, on any shares of stock ranking on a parity (either
as to dividends or upon liquidation, dissolution or winding up) with the Series
RP Preferred Stock, except dividends paid ratably on the Series RP Preferred
Stock and all such parity stock on which dividends are payable or in arrears in
proportion to the total amounts to which the holders of all such shares are then
entitled, (C) purchase or otherwise acquire for consideration (except as
provided below) shares of any stock ranking junior (either as to dividends or
upon liquidation, dissolution or winding up) to the Series RP Preferred Stock,
provided that the Corporation may at any time purchase or otherwise acquire
shares of any such junior stock in exchange for shares of any stock of the
Corporation ranking junior (either as to dividends or upon dissolution,
liquidation or winding up) to the Series RP Preferred Stock, or (D) purchase or
otherwise acquire for consideration any shares of Series RP Preferred Stock, or
any shares of stock ranking on a parity (either as to dividends or upon
liquidation, dissolution or winding up) with the Series RP Preferred Stock,
except in accordance with a purchase offer made in writing or by publication (as
determined by the Board of Directors) to all holders of such shares upon such
terms as the Board of Directors, after consideration of the respective annual
dividend rates and other relative rights and preferences of the respective
series and classes, shall determine in good faith will result in fair and
equitable treatment among the respective series or classes.

            4.2 The Corporation shall not permit any subsidiary of the
Corporation to purchase or otherwise acquire for consideration any shares of
stock of the Corporation unless the Corporation could, under Section 4.1,
purchase or otherwise acquire such shares at such time and in such manner.

      Section 5. REACQUIRED SHARES. Any shares of Series RP Preferred Stock
purchased or otherwise acquired by the Corporation in any manner whatsoever
shall be retired and cancelled promptly after the acquisition thereof. All such
shares shall upon their cancellation become authorized but unissued shares of
Preferred Stock and may be reissued as part of a new series of Preferred Stock
subject to the conditions and restrictions on issuance set forth herein, in the
Articles of Incorporation, in any other certificate or amendment creating a
series of Preferred Stock or as otherwise required by law.



                                       4
<PAGE>
      Section 6. LIQUIDATION, DISSOLUTION OR WINDING UP

            6.1 Subject to the prior and superior rights of holders of any
shares of any series of Preferred Stock ranking prior and superior to the shares
of Series RP Preferred Stock with respect to rights upon liquidation,
dissolution or winding up (voluntary or otherwise), if the assets available to
permit payment to the holders of Series RP Preferred Stock and Common Stock
pursuant to this Section 6 are:

                  (a) less than or equal to the greater of (i) 1,000 times
$70.00 per share of Series RP Preferred Stock, or (ii) 1,000 times any payments
made pursuant to this Section 6 for each share of Common Stock plus an amount
equal to accrued and unpaid dividends and distributions thereon whether or not
declared (such greater amount is referred to as the "SERIES RP LIQUIDATION
PREFERENCE"), then all such assets shall be distributed ratably to the holders
of shares of Series RP Preferred Stock.

                  (b) greater than the Series RP Liquidation Preference but less
than or equal to the sum of (i) the Series RP Liquidation Preference plus (ii)
an amount in respect of each share of Common Stock (the "CAPITAL ADJUSTMENT")
equal to the quotient obtained by dividing (A) the Series RP Liquidation
Preference by (B) 1,000 (as appropriately adjusted as set forth in Section 6.3
to reflect such events as stock splits, stock dividends and recapitalizations
with respect to the Common Stock) (such number in clause (B) being hereafter
referred to as the "ADJUSTMENT NUMBER"), then no distribution shall be made to
the holders of shares of stock ranking junior (either as to dividends or upon
liquidation, dissolution or winding up) to the Series RP Preferred Stock unless,
prior thereto, the holders of shares of Series RP Preferred Stock shall have
received per share an amount equal to the Series RP Liquidation Preference.
Subject to the prior and superior rights of holders of any shares of any series
of Preferred Stock, the remaining assets available for distribution shall be
distributed ratably to the holders of shares of Common Stock.

                  (c) greater than the amount necessary to pay the Series RP
Liquidation Preference in full and the Capital Adjustment in full, then all such
assets shall be distributed to the holders of Series RP Preferred Stock and
holders of Common Stock in the ratio of the Adjustment Number to 1 with respect
to such Preferred Stock and Common Stock, on a per share basis, respectively.

            6.2 If, in applying Section 6.1, there are some, but not sufficient,
assets available to permit payment in full of the Series RP Liquidation
Preference and the liquidation preferences of all other series of preferred
stock, if any, which rank on a parity with the Series RP Preferred Stock, then
such remaining assets shall be distributed ratably to the holders of Series RP
Preferred Stock and the holders of such parity shares in proportion to their
respective liquidation preferences.

            6.3 If the Corporation shall (A) declare any dividend on Common
Stock payable in shares of Common Stock, (B) subdivide the outstanding Common
Stock, or (C) combine the outstanding Common Stock into a smaller number of
shares, then in each such case the Adjustment Number in effect immediately
before such event shall be adjusted by multiplying such Adjustment Number by a
fraction, the numerator of which is the number of shares of

                                       5
<PAGE>
Common Stock outstanding immediately after such event, and the denominator of
which is the number of shares of Common Stock outstanding immediately before
such event.

      Section 7. CONSOLIDATION, MERGER, ETC. If the Corporation is party to any
consolidation, merger, combination or other transaction in which the shares of
Common Stock are exchanged for or changed into other stock or securities, cash
and/or any other property, then, in any such case, the shares of Series RP
Preferred Stock shall at the same time be similarly exchanged or changed in an
amount per share equal to the Adjustment Number (as appropriately adjusted as
set forth in Section 6.3 to reflect such events as stock splits, stock dividends
and recapitalizations with respect to the Common Stock) times the total amount
of stock, securities, cash and/or any other property (payable in kind), as the
case may be, into which or for which each share of Common Stock is changed or
exchanged.

      Section 8. NO REDEMPTION. The shares of Series RP Preferred Stock shall
not be redeemable.

      Section 9. RANKING. The Series RP Preferred Stock shall rank junior to all
other series of the Corporation's Preferred Stock as to the payment of dividends
and the distribution of assets, unless the terms of any such other series shall
provide otherwise.

      Section 10. AMENDMENT. The Amended and Restated Articles of Incorporation
of the Corporation shall not be further amended in any manner that would
materially alter or change the powers, preferences or special rights of the
Series RP Preferred Stock so as to affect them adversely without the affirmative
vote of the holders of a majority or more of the outstanding shares of Series RP
Preferred Stock, voting separately as a class.

      Section 11. FRACTIONAL SHARES. Series RP Preferred Stock may be issued in
fractions of a share which shall entitle the holder, in proportion to such
holder's fractional shares, to exercise voting rights, receive dividends,
participate in distributions and have the benefit of all other rights of holders
of Series RP Preferred Stock.

      RESOLVED FURTHER, that each officer of the Corporation be, and each of
them hereby is, authorized to sign a Certificate of Determination with respect
to the Series RP Preferred Stock pursuant to Section 401 of the California
Corporations Code and to cause that certificate to be filed with the Secretary
of State of the State of California.

      3. There are no shares of the Corporation's Series A Preferred Stock or
Series B Preferred Stock issued and outstanding.




                                       6
<PAGE>
      IN WITNESS WHEREOF, I further declare under penalty of perjury under the
laws of the state of California that the matters set forth in the foregoing
certificate are true and correct of my own knowledge.

Dated  May 2, 2002




                                /s/ M. Wayne Boylston
                                ------------------------------------------------
                                Name:  M. Wayne Boylston
                                Title: Senior Vice President, Chief Financial
                                       Officer and Secretary



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