SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON, D.C. 20549


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                                      FORM 8-A/A


                  FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                       PURSUANT TO SECTION 12(b) OR (g) OF THE
                           SECURITIES EXCHANGE ACT OF 1934


                             CARDIOTHORACIC SYSTEMS, INC.
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               (Exact name of Registrant as specified in its charter)


              Delaware                                  94-3228757
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(State of incorporation or organization)       (IRS Employer Identification No.)


                             10600 North Tantau Avenue
                                Cupertino, CA 95014
                (Address of principal executive offices) (Zip Code)

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Securities to be registered pursuant to Section 12(b) of the Act:




     Title of each class                  Name of each exchange on which
     to be so registered                  each class is to be registered
     -------------------                  ------------------------------
           None                                       None


Securities to be registered pursuant to Section 12(g) of the Act:

                           Preferred Share Purchase Rights
                           -------------------------------
                                  (Title of Class)




ITEM 1.       DESCRIPTION OF SECURITIES TO BE REGISTERED.

           Pursuant to the Preferred Shares Rights Agreement (the "Rights
Agreement") dated as of February 14, 1997 between CardioThoracic Systems,
Inc. (the "Company") and Norwest Bank Minnesota, N.A., as Rights Agent (the
"Rights Agent"), as amended and restated as of August 30, 1999, the Company's
Board of Directors declared a dividend of one right (a "Right") to purchase
one one-thousandth share of the Company's Series A Participating Preferred
Stock ("Series A Preferred") for each outstanding share of Common Stock
("Common Shares") of the Company. The dividend was paid on February 14, 1997
(the "Record Date") to stockholders of record as of the close of business on
that date. Each Right entitles the registered holder to purchase from the
Company one one-thousandth of a share of Series A Preferred at an exercise
price of $150.00 (the "Purchase Price"), subject to adjustment. The following
summary of the principal terms of the Rights Agreement is a general
description only and is subject to the detailed terms and conditions of the
Rights Agreement. A copy of the Rights Agreement is attached as Exhibit 4 to
this Registration Statement and is incorporated herein by reference.

         RIGHTS EVIDENCED BY COMMON SHARE CERTIFICATES.  The Rights will not
be exercisable until the Distribution Date (defined below). Until the
Distribution Date, certificates for the Rights ("Rights Certificates") will
not be sent to stockholders; instead, the Rights will attach to and trade
only together with the Common Shares. Accordingly, Common Share certificates
outstanding on the Record Date will evidence the Rights related thereto, and
Common Share certificates issued after the Record Date will contain a
notation incorporating the Rights Agreement by reference. Until the
Distribution Date (or the earlier redemption or expiration of the Rights),
the surrender or transfer of any certificates for Common Shares outstanding
as of the Record Date, even without the notation or a copy of the Summary of
Rights being attached thereto, will also constitute the transfer of the
Rights associated with the Common Shares represented by such certificate.

        DISTRIBUTION DATE.  The Rights will separate from the Common Shares,
Rights Certificates will be issued and the Rights will become exercisable
upon the earlier of: (i) 10 days (or such later date as may be determined by a
majority of the Board of Directors) following a public announcement that a
person or group of affiliated or associated persons (an "Acquiring Person")
has acquired, or obtained the right to acquire, beneficial ownership of 15%
or more of the outstanding Common Shares; and (ii) 10 business days (or such
later date as may be determined by a majority of the Board of Directors)
following the commencement of, or announcement of an intention to make, a
tender offer or exchange offer the consummation of which would result in the
beneficial ownership by a person or group of 15% or more of the outstanding
Common Shares. The earliest of such dates is referred to as the "Distribution
Date."

         ISSUANCE OF RIGHTS CERTIFICATES; EXPIRATION OF RIGHTS.  As soon as
practicable following the Distribution Date, separate Rights Certificates
will be mailed to holders of record of the Common Shares as of the close of
business on the Distribution Date and such separate Rights Certificates alone
will evidence the Rights from and after the Distribution Date. All Common
Shares issued prior to


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the Distribution Date will be issued with Rights. Common Shares issued after
the Distribution Date may be issued with Rights if such shares are issued (i)
upon the conversion of outstanding convertible debentures or any other
convertible securities issued after adoption of the Rights Agreement or (ii)
pursuant to the exercise of stock options or under employee benefit plans or
arrangements unless such issuance would result in (or create a risk that)
such options, plans or arrangements would not qualify for otherwise available
special tax treatment. Except as otherwise determined by the Board of
Directors, no other Common Shares issued after the Distribution Date will be
issued with Rights. The Rights will expire on the earliest of (i) January 28,
2007 (the "Final Expiration Date"), (ii) redemption or exchange of the Rights
as described below, or (iii) consummation of an acquisition of the Company
satisfying certain conditions by a person who acquired shares pursuant to a
Permitted Offer as described below.

         INITIAL EXERCISE OF THE RIGHTS.  Following the Distribution Date,
and until one of the further events described below, holders of the Rights
will be entitled to receive, upon exercise and the payment of $150.00 per
Right, one one-thousandth share of the Series A Preferred. In the event that
the Company does not have sufficient Series A Preferred available for all
Rights to be exercised, or the Board of Directors decides that such action is
necessary and not contrary to the interests of Rights holders, the Company
may instead substitute cash, assets or other securities for the Series A
Preferred for which the Rights would have been exercisable under this
provision or as described below.

         RIGHT TO BUY COMPANY COMMON SHARES.  Unless the Rights are earlier
redeemed, in the event that an Acquiring Person becomes the beneficial owner
of 15% or more of the Company's Common Shares then outstanding, then each
holder of a Right which has not theretofore been exercised (other than Rights
beneficially owned by the Acquiring Person, which will thereafter be void)
will thereafter have the right to receive, upon exercise, Common Shares
having a value equal to two times the Purchase Price. Rights are not
exercisable following the occurrence of an event as described above until such
time as the Rights are no longer redeemable by the Company as set forth below.

         RIGHT TO BUY ACQUIRING COMPANY STOCK.  Unless the Rights are earlier
redeemed, in the event that, after the Shares Acquisition Date (as defined
below), (i) the Company is acquired in a merger or other business combination
transaction, or (ii) the Company consummates a merger or other business
combination transaction in which the Company is the continuing or surviving
corporation, or (iii) 50% or more of the Company's assets or earning power
are sold, each holder of a Right which has not theretofore been exercised
(other than Rights beneficially owned by the Acquiring Person, which will
thereafter be void) will thereafter have the right to receive, upon exercise,
shares of common stock of (i) the corporation acquiring the Company or (ii)
the Company or (iii) the purchaser of 50% or more of the Company's assets or
earning power, respectively, such shares in each case having a value equal to
two times the Purchase Price.

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     EXCHANGE PROVISION.  At any time after the acquisition by an Acquiring
Person of 15% or more of the Company's outstanding Common Shares and prior to
the acquisition by such Acquiring Person of 50% or more of the Company's
outstanding Common Shares, the Board of Directors of the Company may exchange
the Rights (other than Rights owned by the Acquiring Person), in whole or in
part, at an exchange ratio of one Common Share per Right.

     REDEMPTION.  At any time on or prior to the close of business on the
earlier of (i) the 10th day following the acquisition by an Acquiring Person
of 15% or more of the Company's outstanding Common Shares (the "Shares
Acquisition Date") or such later date as may be determined by a majority of
the Board of Directors and publicly announced by the Company, or (ii) the
Final Expiration Date of the Rights, the Company may redeem the
Rights in whole, but not in part, at a price of $.01 per Right.

     ADJUSTMENTS TO PREVENT DILUTION.  The Purchase Price payable, the
number of Rights, and the number of Series A Preferred or Common Shares or
other securities or property issuable upon exercise of the Rights are subject
to adjustment from time to time in connection with the dilutive issuances by
the Company as set forth in the Rights Agreement.  With certain exceptions,
no adjustment in the Purchase Price will be required until cumulative
adjustments require an adjustment of at least 1% in such Purchase Price.

     CASH PAID INSTEAD OF ISSUING FRACTIONAL SHARES.  No fractional portion
less than integral multiples of one Common Share will be issued upon exercise
of a Right and in lieu thereof, an adjustment in cash will be made based on
the market price of the Common Shares on the last trading date prior to the
date of exercise.

     NO STOCKHOLDERS' RIGHTS PRIOR TO EXERCISE.  Until a Right is exercised,
the holder thereof, as such, will have no rights as a stockholder of the
Company (other than any rights resulting from such holder's ownership of
Common Shares), including, without limitation, the right to vote or to
receive dividends.

     AMENDMENT OF RIGHTS AGREEMENT.  The provisions of the Rights Agreement
may be supplemented or amended by the Board of Directors in any manner
without the approval of Rights holders prior to the close of business on the
date of the acquisition by an Acquiring Person of 15% or more of the
Company's outstanding Common Shares.  After the Distribution Date, the
provisions of the Rights Agreement may be amended by the Board of Directors
in order to cure any ambiguity, defect or inconsistency, to make changes
which do not adversely affect the interests of holders of Rights (excluding
the interests of any Acquiring Person), or to shorten or lengthen any time
period under the Rights Agreement; provided, however, that no amendment to
adjust the time period governing redemption shall be made at such time as the
Rights are not redeemable.

     RIGHTS AND PREFERENCES OF THE SERIES A PREFERRED.  Series A Preferred
purchasable upon exercise of the Rights will not be redeemable.  Each share
of Series A Preferred will


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be entitled to an aggregate dividend of 1,000 times the dividend declared per
Common Share.  In the event of liquidation, the holders of the Series A
Preferred will be entitled to a minimum preferential liquidation payment
equal to $150,000 per share.  Each share of Series A Preferred will have
1,000 votes, voting together with the Common Shares.  In the event of any
merger, consolidation or other transaction in which the Common Shares are
changed or exchanged, each share of Series A Preferred will be entitled to
receive 1,000 times the amount received per Common Share.  These rights are
protected by customary anti-dilution provisions.

     Because of the nature of the dividend, liquidation and voting rights of
the shares of Series A Preferred, the value of the one one-thousandth
interest in a share of Series A Preferred purchasable upon exercise of each
Right should approximate the value of one Common Share.

     CERTAIN ANTI-TAKEOVER EFFECTS.  The Rights approved by the Board are
designed to protect and maximize the value of the outstanding equity
interests in the Company in the event of an unsolicited attempt by an acquiror
to take over the Company in a manner or on terms not approved by the Board of
Directors.  Takeover attempts frequently include coercive tactics to deprive
the Company's Board of Directors and its stockholders of any real opportunity
to determine the destiny of the Company or to evaluate and protect the
long-term value of the Company.  The Rights are not intended to prevent a
takeover of the Company.  The Rights may be redeemed by the Company at $.01
per Right within ten days (or such later date as may be determined by a
majority of the Board of Directors) after the accumulation of 15% or more of
the Company's shares by a single acquiror or group.  Accordingly, the Rights
should not interfere with any merger or business combination approved by the
Board of Directors.  Issuance of the Rights does not in any way weaken the
financial strength of the Company or interfere with its business plans.  The
issuance of the Rights themselves has no dilutive effect, will not affect
reported earnings per share, should not be taxable to the Company or to its
stockholders, and will not change the way in which the Company's shares are
presently traded.  The Company's Board of Directors believes that the Rights
represent a sound and reasonable means of addressing the complex issues of
corporate policy created by the current takeover environment.  However, the
Rights may have the effect of rendering more difficult or discouraging an
acquisition of the Company deemed undesirable by the Board of Directors.  The
Rights may cause substantial dilution to a person or group that attempts to
acquire the Company on terms or in a manner not approved by the Company's
Board of Directors, except pursuant to an offer conditioned upon the
negation, purchase or redemption of the Rights.

     On August 30, 1999, in connection with the execution of an Agreement and
Plan of Merger dated August 30, 1999 (the "Merger Agreement"), among the
Company, Guidant Corporation and Clydesdale Acquisition Corp., a wholly-owned
subsidiary of Guidant Corporation, the Company and the Rights Agent entered
into a First Amendment to Amended and Restated Preferred Shares Rights
Agreement, which provides that neither Guidant nor Clydesdale Acquisition
Corp. shall be an Acquiring Person under the Rights Agreement by reason of
the execution of the Merger Agreement or related agreements and that the
Rights Agreement will terminate at the Effective Time (as defined in the
Merger Agreement).

ITEM 2.     EXHIBITS

            1.   Specimen certificate for the Company's Common Stock (1)

            2.   Restated Certificate of Incorporation of the Company (2)

            3.   Bylaws of the Company (as amended)(3)

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            4.   Preferred Shares Rights Agreement, dated as of February 14,
                 1997, as amended and restated as of August 30, 1999, between
                 CardioThoracic Systems, Inc. and Norwest Bank Minnesota,
                 N.A. including the Certificate of Designations, the form of
                 Rights Certificate and the Summary of Rights attached
                 thereto as Exhibits A, B and C, respectively (4)

            5.   Certificate of Amendment of the Restated Certificate of
                 Incorporation of the Company (3)

            6.   First Amendment to Amended and Restated Preferred Shares
                 Rights Agreement, dated as of August 30, 1999, between
                 CardioThoracic Systems, Inc. and Norwest Bank Minnesota,
                 N.A. (4)

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            (1)  Incorporated by reference to Exhibit 4.1 to the Company's
                 Registration Statement of Form S-1  (Commission File No.
                 333-1840) declared effective by the Commission on April 17,
                 1996 (the "S-1 Registration Statement").

            (2)  Incorporated by reference to Exhibit 3.2 to the S-1
                 Registration Statement.

            (3)  Incorporated by reference to Exhibit 3.3 to the Company's
                 Annual Report on Form 10-K for the period ended January 2,
                 1998.

            (4)  Exhibit filed herewith.


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                                  SIGNATURE

     Pursuant to the requirements of Section 12 of the Securities Exchange
Act of 1934, the Registrant has duly caused this Registration Statement to be
signed on its behalf by the undersigned, thereto duly authorized.

                                CARDIOTHORACIC SYSTEMS, INC.


Date:   September 23, 1999
                                By: /s/ STEVE M. VAN DICK
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                                    Steve M. Van Dick
                                    Vice President, Finance and Administration,
                                    and Chief Financial Officer


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