<PAGE>
 
                              RESTATED BYLAWS OF

                         CARDIAC CONTROL SYSTEMS, INC.
                              (the "Corporation")

                                   ARTICLE I

                                    Offices
                                    -------

          Section 1.1. Offices. The registered office of the Corporation shall 
          -----------  -------     
be at No. 100 West Tenth Street, Wilmington, Delaware. The Corporation may have 
such other offices within or without the State of Delaware as the board of 
directors may from time to time establish.

                                  ARTICLE II

                                 Capital Stock
                                 -------------
 
         Section 2.1. Certificate Representing Shares. Shares of the classes of
          ------------ -------------------------------      
capital stock of the Corporation shall be represented by certificates in such
form or forms as the board of directors may approve; provided that, such form or
forms shall comply with all applicable requirements of law or of the certificate
of incorporation. Such certificates shall be signed by the president or a vice
president, and by the secretary or an assistant secretary, of the Corporation
and may be sealed with the seal of the Corporation or imprinted or otherwise
marked with a facsimile of such seal. In the case of any certificate
countersigned by any transfer agent or registrar, provided such countersigner is
not the Corporation itself or an employee thereof, the signature of any or all
of the foregoing officers of the Corporation may be represented by a printed
facsimile thereof. If any officer whose signature, or a facsimile thereof, shall
have been set upon any certificate shall cease, prior to the issuance of such
certificate, to occupy the position in right of which his signature, or
facsimile thereof, was so set upon such certificate, the Corporation may
nevertheless adopt and issue such certificate with the same effect as if such
officer occupied such position as of such date of issuance; and, issuance and
delivery of such certificate by the Corporation shall constitute adoption
thereof by the Corporation. The certificates shall be consecutively numbered,
and as they are issued, a record of such issuance shall be entered in the books
of the Corporation.

<PAGE>
 
          Section 2.2.  Stock Certificate Book and Shareholders of Record.  The 
          -----------   -------------------------------------------------
secretary of the Corporation shall maintain, among other records, a stock 
certificate book, the stubs in which shall set forth the names and addresses of 
the holders of all issued shares of the Corporation, the number of shares held 
by each, the number of certificates representing such shares, the date of issue 
of such certificates, and whether or not such shares originate from original 
issue or from transfer. The names and addresses of shareholders as they appear 
on the stock certificate book shall be the official list of shareholders of 
record of the Corporation for all purposes. The Corporation shall be entitled to
treat the holder of record of any shares as the owner thereof for all purposes, 
and shall not be bound to recognize any equitable or other claim to, or interest
in, such shares or any rights deriving from such shares on the part of any other
person, including, but without limitation, a purchaser, assignee, or transferee,
unless and until such other person becomes the holder of record of such shares,
whether or not the Corporation shall have either actual or constructive notice
of the interest of such other person.

          Section 2.3.  Shareholder's Change of Name or Address.  Each 
          -----------   ---------------------------------------
shareholder shall promptly notify the secretary of the Corporation, at its
principal business office, by written notice sent by certified mail, return
receipt requested, of any change in name or address of the shareholder from that
as it appears upon the official list of shareholders of record of the
Corporation. The secretary of the Corporation shall then enter such changes into
all affected Corporation records, including, but not limited to, the official
list of shareholders of record.

          Section 2.4.  Transfer of Stock.  The shares represented by any 
          -----------   -----------------
certificate of the Corporation are transferable only on the books of the
Corporation by the holder of record thereof or by his duly authorized attorney
or legal representative upon surrender of the certificate for such shares,
properly endorsed or assigned. The board of directors may make such rules and
regulations concerning the issue, transfer, registration and replacement of
certificates as they deem desirable or necessary.

          Section 2.5.  Transfer Agent and Registrar.  The board of directors 
          -----------   ----------------------------
may appoint one or more transfer agents or registrars of the shares, or both,
and may require all share certificates to bear the signature of a transfer agent
or registrar, or both.

                                      -2-
<PAGE>
 
          Section 2.6. Lost, Stolen or Destroyed Certificates. The Corporation 
          -----------  --------------------------------------
may issue a new certificate for shares of stock in the place of any certificate 
theretofore issued and alleged to have been lost, stolen or destroyed; but, the 
board of directors may require the owner of such lost, stolen or destroyed 
certificate, or his legal representative, to furnish an affidavit as to such 
loss, theft, or destruction and to give a bond in such form and substance, and 
with such surety or sureties, with fixed or open penalty, as the board may 
direct, in order to indemnify the Corporation and its transfer agents and
registrars, if any, against any claim that may be made on account of the alleged
loss, theft or destruction of such certificate.

          Section 2.7. Fractional Shares. Only whole shares of the stock of the
          -----------  -----------------
Corporation shall be issued. In case of any transaction by reason of which a
fractional share might otherwise be issued, the directors, or the officers in
the exercise of powers delegated by the directors, shall take such measures
consistent with the law, the certificate of incorporation and these bylaws,
including (for example, and not by way of limitation) the payment in cash of an
amount equal to the fair value of any fractional share, as they may deem proper
to avoid the issuance of any fractional share.


                                  ARTICLE III

                               The Shareholders
                               ----------------

          Section 3.1 Annual Meeting. Commencing in the calendar year 1981, the 
          ----------- --------------
annual meeting of the shareholders, for the election of directors and for the
transaction of such other business as may properly come before the meeting,
shall be held at the principal office of the Corporation, at 11:00 a.m. local
time, on April 10 of each year unless such day is a legal holiday, in which
case such meeting shall be held at such hour on the first day thereafter which
is not a legal holiday; or, at such other place and time as may be designated by
the board of directors. Failure to hold any annual meeting or meetings shall not
work a forfeiture or dissolution of the Corporation.

          Section 3.2. Special Meetings. Except as otherwise provided by law or 
          -----------  ----------------     
by the certificate of incorporation, special meetings of the shareholders may be
called by the chairman of the board of directors, the president, any one of the 
directors, or the holders of not less than one-tenth of all the shares having 
voting power at such meeting, and shall be held at the principal office of the 
Corporation or at such other place, and at such time, as may be stated in the 
notice calling such meeting.

                                      -3-

<PAGE>
 
Business transacted at any special meeting of shareholders shall be limited to 
the purpose stated in the notice of such meeting given in accordance with the 
terms of section 3.3.

          Section 3.3.  Notice of Meetings - Waiver.  Written notice of each 
          -----------   --------------------------- 
meeting of shareholders, stating the place, day and hour of any meeting and, in
case of a special shareholders' meeting, the purpose or purposes for which the
meeting is called, shall be delivered not less than fifteen nor more than sixty
days before the date of such meeting, either personally or by mail, by or at the
direction of the president, the secretary, or the persons calling the meeting,
to each shareholder of record entitled to vote at such meeting. If mailed, such
notice shall be deemed to be delivered when deposited in the United States mail
addressed to the shareholder at his address as it appears on the stock transfer
books of the Corporation, with postage thereon prepaid. Such further or earlier
notice shall be given as may be required by law. The signing by a shareholder of
a written waiver of notice of any shareholders' meeting, whether before or after
the time stated in such waiver, shall be equivalent to the receiving by him of
all notice required to be given with respect to such meeting. Attendance by a
person at a shareholders' meeting shall constitute a waiver of notice of such
meeting except when a person attends a meeting for the express purpose of
objecting, at the beginning of the meeting, to the transaction of any business
because the meeting is not lawfully called or convened. No notice of any
adjournment of any meeting shall be required.

          Section 3.4.  Closing of Transfer Books and Fixing Re-Date.  In
          -----------   --------------------------------------------
order that the Corporation may determine the shareholders entitled to notice of
or to vote at any meeting of shareholders or adjournment thereof, or to express
consent to corporate action in writing without a meeting, or entitled to receive
payment of any dividend or other distribution or allotment of any rights, or
entitled to exercise any rights in respect of any change, conversion or exchange
of stock or for the purpose of any other lawful action, the board of directors
may fix, in advance, a record date, which shall not be more than sixty nor less
than fifteen days before the date of such meeting, nor more than sixty days
prior to any other action. If no record date is fixed, the record date shall be
as follows: the record date for determining shareholders entitled to notice of
or to vote at a meeting of shareholders shall be at the close of business on the
day next preceding the day on which notice is given, or, if notice is waived, at
the close of business on the day next preceding the day on which the meeting is
held; the record date for determining shareholders entitled to express consent
to corporate action in writing without a meeting, when no prior action by the
board of

                                      -4-
<PAGE>
 

directors is necessary, shall be the day on which the first written consent is 
expressed; and, the record date for determining shareholders for any other 
purpose shall be at the close of business on the day on which the board of 
directors adopts resolution relating thereto.

          Section 3.5.   Voting List.  The Officer or agent having charge of the
          -----------    -----------
stock transfer books for shares of the Corporation shall make, at least ten days
before each meeting of shareholders, a complete list of the shareholders
entitled to vote at such meeting or any adjournment thereof, arranged in
alphabetical order, with the address of and the number of shares held by each,
which list, for a period of ten days prior to such meeting, shall be kept on
file at a place within the city where the meeting is to be held, which place
shall be specified in the notice of the meeting, or, if not so specified, at the
place where the meeting is to be held. The list shall be subject to lawful
inspection by any shareholder at any time during the usual business hours. Such
list shall also be produced and kept open at the time and place of the meeting
and shall be subject to the inspection of any shareholder during the whole time
of the meeting.

          Section 3.6.   Quorum and Officers.  Except as otherwise provided by
          -----------    -------------------
law, by the certificate of incorporation or by these bylaws, the holders of a
majority of the shares entitled to vote and represented in person or by proxy
shall constitute a quorum at a meeting of shareholders, but the shareholders
present at any meeting, although representing less than a quorum, may from time
to time adjourn the meeting to some other day and hour, without notice other
than announcement at the meeting. The shareholders present at a duly organized
meeting may continue to transact business until adjournment, notwithstanding the
withdrawal of enough shareholders to leave less than a quorum. The vote of the
holders of a majority of the shares entitled to vote and thus represented at a
meeting at which a quorum is present shall be the act of the shareholders'
meeting, unless the vote of a greater number is required by law. The chairman of
the board shall preside at, and the secretary shall keep the records of, each
meeting of the shareholders, and in the absence of either such officer, his
duties shall be performed by any other officer authorized by these bylaws or any
person appointed by resolution duly adopted at the meeting.

          Section 3.7.   Voting at Meetings.  Each outstanding share shall be 
          -----------    ------------------
entitled to one vote on each matter submitted to a vote at a meeting of
shareholders except to the extent that the certificate of incorporation or the
laws of the State of Delaware provide otherwise.

                                      -5-
<PAGE>
 
          Section 3.8. Proxies. A shareholder may vote either in person or by
          -----------  -------       
proxy executed in writing by the shareholder; but, no such proxy shall be voted
or acted upon after three years from its date, unless the proxy provides for a
longer period. A duly executed proxy shall be irrevocable if it states that it
is irrevocable and if, and only as long as, it is coupled with an interest
sufficient in law to support an irrevocable power. A proxy may be made
irrevocable regardless of whether the interest with which it is coupled is an
interest in the stock itself or an interest in the Corporation generally.

          Section 3.9. Balloting. All elections of directors shall be by written
          -----------  ---------
ballot. Upon the demand of any shareholder, the vote upon any other question
before the meeting shall be by ballot. At each meeting, inspectors of election
may be appointed by the presiding officer of the meeting; and, at any meeting
for the election of directors, inspectors shall be so appointed on the demand of
any shareholder present or represented by proxy and entitled to vote in such
election of directors. No director or candidate for the office of director shall
be appointed as such inspector. The number of votes cast by shares in the
election of directors shall be recorded in the minutes.

          Section 3.10. Voting Rights, Prohibition of Cumulative Voting for 
          ------------  --------------------------------------------------- 
Directors. Each outstanding share of common stock shall be entitled to one (1) 
---------
vote upon each matter submitted to a vote at a meeting of shareholders. No 
shareholder shall have the right to cumulate his votes for the election of 
directors but each share shall be entitled to one vote in the election of each 
director. In the case of any contested election for any directorship, the 
candidate for such position receiving a plurality of the votes cast in such 
election shall be elected to such position.

          Section 3.11. Record of Shareholders. The Corporation shall keep at
          ------------  ----------------------
its principal business office, or the office of its transfer agents or
registrars, a record of its shareholders, giving the names and addresses of all
shareholders and the number and class of the shares held by each.

          Section 3.12. Action Without Meeting. Any action required by statute
          ------------  ----------------------
to be taken at a meeting of the shareholders of the Corporation, or any action
which may be taken at a meeting of the shareholders, may be taken without a
meeting, without prior notice and without a vote, if a consent in writing,
setting forth the action so taken, shall be signed by the holders of outstanding
stock having not less than the minimum number of votes that would be necessary
to authorize or take such action at a meeting at which all shares entitled to
vote thereon were present and voted.

                                      -6-
<PAGE>
 
                                  ARTICLE IV

                            The Board of Directors
                            ----------------------

          "Section 4.1. Number, Qualifications and Term.  The business and 
           -----------  -------------------------------
affairs of the Corporation shall be managed or be under the direction of the 
board of directors; and, subject to any restrictions imposed by law, by the 
certificate of incorporation, or by these bylaws, the board of directors may 
exercise all the powers of the Corporation. The board of directors shall consist
of such number of directors as determined by the board of directors, but in no 
event shall be less than three (3) members, unless such minimum number is 
decreased by amendment of these bylaws, provided that no such decrease shall 
effect a shortening of the term of any incumbent director. Directors need not be
residents of Delaware or shareholders of the Corporation absent provision to the
contrary in the certificate of incorporation or laws of the State of Delaware. 
Except as otherwise provided in section 4.3 of these bylaws, each position on 
the board of directors shall be filled by election at the annual meeting of 
shareholders. Any such election shall be conducted in accordance with section 
3.10 of these bylaws. Each person elected a director shall hold office until his
successor is duly elected and qualified or until his earlier resignation or 
removal in accordance with section 4.2 of these bylaws."

          "Section 4.2.  Removal.  Any director or the entire board of directors
           -----------   -------
may be removed from office, with or without cause, at any special meeting of 
shareholders by the affirmative vote of a majority of the shares then entitled 
to vote at an election of directors, if notice of the intention to act upon
such matter shall have been given in the notice calling such meeting. If the
notice calling such meeting shall have so provided, the vacancy caused by such
removal may be filled at such meeting by the affirmative vote of a majority in
number of the shares then entitled to vote at an election of directors."

           Section 4.3.  Vacancies.  Vacancies and newly created directorships 
           -----------   ---------
resulting from any increase in the authorized number of directors may be filled
by a majority of the directors then in office, although less than a quorum, or
by a sole remaining director. When one or more directors shall resign from the
board, effective at a future date, a majority of the directors then in office,
including those who have so resigned, shall have power to fill such vacancy or
vacancies, the vote thereon to take effect when such resignation or resignations
shall become effective, and each director so chosen shall hold office as
provided in this section in the filling of other vacancies. A director elected
to fill a vacancy shall be elected for the unexpired term of his predecessor in
office.

                                      -7-
<PAGE>
 
          Section 4.4. Regular Meetings. Regular meetings of the board of 
          -----------  ----------------
directors shall be held immediately following each annual meeting of 
shareholders, at the place of such meeting, and at such other times and places
as the board of directors shall determine. No notice of any kind of such regular
meetings needs to be given to either old or new members of the board of
directors.

          Section 4.5. Special Meetings. Special meetings of the board of 
          -----------  ----------------
directors shall be held at any time by call of the chairman of the board, the 
president, the secretary or any one of the directors. The secretary shall give 
notice of each special meeting to each director at his usual business or 
residence address by mail at least three days before the meeting or by telegraph
or telephone at least one day before such meeting. Except as otherwise provided 
by law, by the certificate of incorporation, or by these bylaws, such notice 
need not specify the business to be transacted at, or the purpose of, such 
meeting. No notice shall be necessary for any adjournment of any meeting. The 
signing of a written waiver of notice of any special meeting by the person or 
persons entitled to such notice, whether before or after the time stated 
therein, shall be equivalent to the receiving of such notice. Attendance of a 
director at a meeting shall also constitute a waiver of notice of such meeting, 
except where a director attends a meeting for the express and announced purpose 
of objecting, at the beginning of the meeting, to the transaction of any 
business on the ground that the meeting is not lawfully called or convened.

          Section 4.6. Quorum. A majority of the number of directors fixed by 
          -----------  ------
these bylaws shall constitute a quorum for the transaction of business and the 
act of not less than a majority of such quorum of the directors shall be
required in order to constitute the act of the board of directors, unless the
act of a greater number shall be required by law, by the certificate of
incorporation or by these bylaws.

          Section 4.7. Procedure at Meetings. The board of directors, at each 
          -----------  ---------------------
regular meeting held immediately following the annual meeting of shareholders, 
shall appoint one of their number as chairman of the board of directors. The 
chairman of the board shall preside at meetings of the board. In his absence at 
any meeting, any officer authorized by these bylaws or any member of the board 
selected by the members present shall preside. The secretary of the Corporation 
shall act as secretary at all meetings of the board. In his absence, the 
presiding officer of the meeting may designate any person to act as secretary. 
At meetings of the board of directors, the business shall be transacted in such 
order as the board may from time to time determine.

                                      -8-
<PAGE>
 
          Section 4.8.  Presumption of Assent. Any director of the Corporation 
          -----------   ---------------------
who is present at a meeting of the board of directors at which action on any 
corporate matter is taken shall be presumed to have assented to the action taken
unless his dissent shall be entered in the minutes of the meeting or unless he 
shall file his written dissent to such action with the person acting as the 
secretary of the meeting before the adjournment thereof or shall forward such 
dissent by registered mail to the secretary of the Corporation immediately after
the adjournment of the meeting. Such right to dissent shall not apply to a 
director who voted in favor of such action.

          Section 4.9.  Action Without a Meeting. Any action required by statute
          -----------   ------------------------
or permitted to be taken at a meeting of the directors of the Corporation, or of
any committee thereof, may be taken without a meeting if a consent in writing,
setting forth the action so taken, shall be signed by all directors or all
committee members as the case may be, and if the consent in writing shall be
filed with the minutes of the proceedings of the board or committee.

          Section 4.10. Compensation. Directors as such shall not receive any 
          ------------  ------------
stated salary for their service, but by resolution of the board of directors, a 
fixed sum and reimbursement for reasonable expenses of attendance, if any, may 
be allowed for attendance at each regular or special meeting of the board of 
directors or at any meeting of the executive committee of directors, if any, to 
which such director may be elected in accordance with the following section 
4.11; but, nothing herein shall preclude any director from serving the 
Corporation in any other capacity or receiving compensation therefor.

          Section 4.11. Executive Committee. The board of directors, by 
          ------------  -------------------
resolution adopted by a majority of the number of directors fixed by these 
bylaws, may designate an executive committee, which committee shall consist of 
two or more of the directors of the Corporation. Such executive committee may 
exercise such authority of the board of directors in the business and affairs of
the Corporation as the board of directors may by resolution duly delegate to it 
except as prohibited by law. The designation of such committee and the 
delegation thereto of authority shall not operate to relieve the board of 
directors, or any member thereof, of any responsibility imposed upon it or him 
by law. Any member of the executive committee may be removed by the board of 
directors by the affirmative vote of a majority of the number of directors fixed
by the bylaws whenever in the judgment of the board the best interests of the 
Corporation will be served thereby.

                                      -9-
<PAGE>
 
          The executive committee shall keep regular minutes of its proceedings 
and report the same to the board of directors when required. The minutes of the 
proceedings of the executive committee shall be placed in the minute book of the
Corporation.

          Section 4.12.  Advisory Committees.  The board of directors may for 
          ------------   -------------------
its convenience, and at its discretion, appoint one or more advisory committees 
of two or more directors each; but, no such advisory committees shall have any 
power or authority except to advise the board of directors, any such committee 
shall exist solely at the pleasure of the board of directors, no minutes of 
the proceedings of any such committee shall be kept, and no member of any such 
committee shall receive any compensation for such membership except by way of 
reimbursement for reasonable expenses actually incurred by him by reason of such
membership.


                                   ARTICLE V

                                   Officers
                                   --------

          Section 5.1.  Number.  The officers of the Corporation shall consist
          -----------   ------
of a president, one or more vice presidents, a secretary and a treasurer; and,
in addition, such other officers and assistant officers and agents as may be
deemed necessary or desirable. Officers shall be elected or appointed by the
board of directors. Any two or more offices may be held by the same person
except that the president and the secretary shall not be the same person. In its
discretion, the board of directors may leave unfilled any office except those of
president, treasurer and secretary.

          Section 5.2.  Election; Term; Qualification.  Officers shall be chosen
          -----------   -----------------------------
by the board of directors annually at the meeting of the board of directors
following the annual shareholders' meeting. Each officer shall hold office until
his successor has been chosen and qualified, or until his death, resignation, or
removal.

          Section 5.3.  Removal.  Any officer or agent elected or appointed by 
          -----------   -------
the board of directors may be removed by the board of directors whenever in its 
judgment the best interests of the Corporation will be served thereby; but, 
such removal shall be without prejudice to the contract rights, if any, of the 
person so removed. Election or appointment of an officer or agent shall not of 
itself create any contract rights.
                                  
                                     -10-

<PAGE>
 
          Section 5.4.  Vacancies.  Any vacancy in any office for any cause may 
          -----------   ---------
be filled by the board of directors at any meeting.

          Section 5.5.  Duties.  The officers of the Corporation shall have such
          -----------   ------
powers and duties, except as modified by the board of directors, as generally 
pertain to their offices, respectively, as well as such powers and duties as 
from time to time shall be conferred by the board of directors and by these 
bylaws.

          Section 5.6.  The President.  The president shall have general 
          -----------   -------------
direction of the affairs of the Corporation and general supervision over its 
several officers, subject however, to the control of the board of directors. He 
shall at each annual meeting, and from time to time, report to the shareholders 
and to the board of directors all matters within his knowledge which, in his 
opinion, the interest of the Corporation may require to be brought to the notice
of such persons. He may sign, with the secretary or an assistant secretary, any 
or all certificates of stock of the Corporation. He shall preside at all 
meetings of the shareholders, shall sign and execute in the name of the 
Corporation (i) all contracts or other instruments authorized by the board of 
directors, and (ii) all contracts or instruments in the usual and regular course
of business, pursuant to Section 6.2 hereof, except in cases when the signing 
and execution thereof shall be expressly delegated or permitted by the board or
by these bylaws to some other officer or agent of the Corporation; and, in
general, shall perform all duties incident to the office of president and such
other duties as from time to time may be assigned to him by the board of
directors or as are prescribed by these bylaws.

          Section 5.7.  The Vice Presidents.  At the request of the president, 
          -----------   -------------------
or in his absence or disability, the vice presidents, in the order of their 
election, shall perform the duties of the president, and, when so acting, shall 
have all the powers of, and be subject to all restrictions upon, the president. 
Any action taken by a vice president in the performance of the duties of the 
president shall be conclusive evidence of the absence or inability to act of the
president at the time such action was taken. The vice presidents shall perform 
such other duties as may, from time to time, be assigned to them by the board of
directors or the president. A vice president may sign, with the secretary or an 
assistant secretary, certificates of stock of the Corporation.

                                     -11-
<PAGE>
 
          Section 5.8.  Secretary.  The secretary shall keep the minutes of all 
          -----------   ---------
meetings of the shareholders, of the board of directors, and of the executive
committee, if any, of the board of directors, in one or more books provided for
such purpose and shall see that all notices are duly given in accordance with
the provisions of these bylaws or as required by law. He shall be custodian of
the corporate records and of the seal (if any) of the Corporation and see, if
the Corporation has a seal, that the seal of the Corporation is affixed to all
documents the execution of which on behalf of the Corporation under its seal is
duly authorized; shall have general charge of the stock certificate books,
transfer books and stock ledgers, and such other books and papers of the
Corporation as the board of directors may direct, all of which shall, at all
reasonable times, be open to the examination of any director, upon application
at the office of the Corporation during business hours; and in general shall
perform all duties and exercise all powers incident to the office of the
secretary and such other duties and powers as the board of directors or the
president from time to time may assign to or confer on him.

          Section 5.9.  Treasurer.  The treasurer shall keep complete and 
          -----------   ---------
accurate records of account, showing at all times the financial condition of the
Corporation. He shall be the legal custodian of all money, notes, securities and
other valuables which may from time to time come into the possession of the 
Corporation. He shall furnish at meetings of the board of directors, or whenever
requested, a statement of the financial condition of the Corporation, and shall 
perform such other duties as these bylaws may require or the board of directors 
may prescribe.

          Section 5.10.  Assistant Officers.  Any assistant secretary or 
          ------------   ------------------
assistant treasurer appointed by the board of directors shall have power to 
perform, and shall perform, all duties incumbent upon the secretary or 
treasurer of the Corporation, respectively, subject to the general direction of 
such respective officers, and shall perform such other duties as these bylaws 
may require or the board of directors may prescribe.

          Section 5.11.  Salaries.  The salaries or other compensation of the 
          ------------   --------
officers shall be fixed from time to time by the board of directors. No officer 
shall be prevented from receiving such salary or other compensation by reason of
the fact that he is also a director of the Corporation.

          Section 5.12.  Bonds of Officers.  The board of directors may secure
          ------------   -----------------
the fidelity of any officer of the Corporation by bond or otherwise, on such
terms and with such surety or sure-

                                     -12-
<PAGE>
 
ties, conditions, penalties or securities as shall be deemed proper by the board
of directors.

          Section 5.13. Delegation. The board of directors may delegate 
          ------------  ----------
temporarily the powers and duties of any officer of the Corporation, in case of 
his absence or for any other reason, to any other officer, and may authorize 
the delegation by any officer of the Corporation of any of his powers and duties
to any agent or employee, subject to the general supervision of such officer.

                                  ARTICLE VI

                                 Miscellaneous
                                 -------------

          Section 6.1. Dividends. Dividends on the outstanding shares of the 
          -----------  ---------
Corporation, subject to the provisions of the certificate of incorporation, if 
any, may be declared by the board of directors at any regular or special 
meeting, pursuant to law. Dividends may be paid by the Corporation in cash, in 
property, or in the Corporation's own shares, but only out of the surplus of the
Corporation, except as otherwise allowed by law.

          Subject to limitations upon the authority of the board of directors 
imposed by law or by the certificate of incorporation, the declaration of and 
provision for payment of dividends shall be at the discretion of the board of 
directors.

          Section 6.2. Contracts. The president shall have the power and 
          -----------  ---------  
authority to execute, on behalf of the Corporation, contracts or instruments in 
the usual and regular course of business, and in addition the board of directors
may authorize any officer or officers, agent or agents, of the Corporation to 
enter into any contract or execute and deliver any instrument in the name of and
on behalf of the Corporation, and such authority may be general or confined to 
specific instances. Unless so authorized by the board of directors or by these 
bylaws, no officer, agent or employee shall have any power or authority to bind 
the Corporation by any contract or engagement, or to pledge its credit or to 
render it pecuniarily liable for any purpose or in any amount.

          Section 6.3. Checks, Drafts, etc. All checks, drafts, or other orders 
          -----------  -------------------
for the payment of money, notes, or other evidences of indebtedness issued in 
the name of the Corporation shall be signed by such officers or employees of the
Corporation as shall from time to time be authorized pursuant to these bylaws or
by resolution of the board of directors.

                                     -13-
<PAGE>
 
          Section 6.4. Depositories. All funds of the Corporation shall be 
          -----------  ------------
deposited from time to time to the credit of the Corporation in such banks or 
other depositories as the board of directors may from time to time designate, 
and upon such terms and conditions as shall be fixed by the board of directors. 
The board of directors may from time to time authorize the opening and
maintaining within any such depository as it may designate, of general and
special accounts, and may make such special rules and regulations with respect
thereto as it may deem expedient.

          Section 6.5. Endorsement of Stock Certificates. Subject to the 
          -----------  --------------------------------- 
specific directions of the board of directors, any share or shares of stock 
issued by any corporation and owned by the Corporation, including reacquired 
shares of the Corporation's own stock, may, for sale or transfer, be endorsed in
the name of the Corporation by the president or any vice president; and such 
endorsement may be attested or witnessed by the secretary or any assistant 
secretary either with or without the affixing thereto of the corporate seal.

          Section 6.6. Corporate Seal. The corporate seal, if any, shall be 
          -----------  -------------- 
in such form as the board of directors shall approve, and such seal, or a 
facsimile thereof, may be impressed on, affixed to, or in any manner reproduced 
upon, instruments of any nature required to be executed by officers of the 
Corporation.

          Section 6.7. Fiscal Year. The fiscal year of the Corporation shall 
          -----------  -----------
begin and end on such dates as the board of directors at any time shall 
determine.

          Section 6.8. Books and Records. The Corporation shall keep correct and
          -----------  -----------------
complete books and records of account and shall keep minutes of the 
proceedings of its shareholders and board of directors, and shall keep at its 
registered office or principal place of business, or at the office of its 
transfer agent or registrar, a record of its shareholders, giving the names and 
addresses of all shareholders and the number and class of the shares held by 
each.

          Section 6.9. Resignations. Any director or officer may resign at any 
          -----------  ------------
time. Such resignations shall be made in writing and shall take effect at the 
time specified therein, or if no time is specified at the time of its receipt by
the president or secretary. The acceptance of a resignation shall not be 
necessary to make it effective, unless expressly so provided in the resignation.

                                     -14-
<PAGE>
 
          Section 6.10. Indemnification of Officers, Directors, Employees and 
          ------------  -----------------------------------------------------
Agents. The Corporation shall indemnify any person who was or is a party or is 
------
threatened to be made a party to any threatened, pending or completed action, 
suit or proceeding, whether civil, criminal, administrative or investigative 
(other than an action by or in the right of the Corporation) by reason of the 
fact that he is or was a director, officer, employee or agent of the 
Corporation, or is or was serving at the request of the Corporation as a
director, officer, employee or agent of another corporation, partnership, joint
venture, trust or other enterprise, against expenses (including attorneys'
fees), judgments, fines and amounts paid in settlement actually and reasonably
incurred by him in connection with such action, suit or proceeding if he acted
in good faith and in a manner he reasonably believed to be in or not opposed to
the best interests of the Corporation, and, with respect to any criminal action
or proceeding, had no reasonable cause to believe his conduct was unlawful.

          The Corporation shall indemnify any person who was or is a party or is
threatened to be made a party to any threatened, pending or completed action or
suit by or in the right of the Corporation to procure a judgment in its favor by
reason of the fact that he is or was a director, officer, employee or agent of
the Corporation, or is or was serving at the request of the Corporation as a
director, officer, employee or agent of another corporation, partnership, joint
venture, trust or other enterprise against expenses (including attorneys' fees)
actually and reasonably incurred by him in connection with the defense or
settlement of such action or suit if he acted in good faith and in a manner he
reasonably believed to be in or not opposed to the best interests of the
Corporation and except that no indemnification shall be made in respect of any
claim, issue or matter as to which such person shall have been adjudged to be
liable for negligence or misconduct in the performance of his duty to the
Corporation unless and only to the extent that the court in which such action or
suit was brought shall determine upon application that, despite the adjudication
of liability but in view of all the circumstances of the case, such person is
fairly and reasonably entitled to indemnity for such expenses which the court
shall deem proper.

          Any indemnification under this section shall be made by the 
Corporation only as authorized in the specific case upon a determination that 
indemnification is proper because the director, officer, employee or agent has 
met the applicable standard of conduct set forth above. Such determination shall
be made as follows; by the board of directors by a majority vote of a quorum 
consisting of directors who are not parties to such action, suit or proceeding; 
or if such quorum is not obtainable,

                                     -15-
<PAGE>
 
or even if obtainable a quorum of disinterested directors so directs, by 
independent legal counsel in a written opinion; or by the shareholders.

          Any right of indemnification granted by this section 6.10 shall be in 
addition to and not in lieu of any other such right which an officer, director, 
employee or agent of the Corporation may at any time be entitled under the law 
of the State of Delaware.

          Section 6.11. Meetings by Telephone. Subject to the provisions 
          ------------  ---------------------
required or permitted by these bylaws or the laws of the State of Delaware for 
notice of meetings, members of the board of directors, or members of any 
committee designated by the board of directors, may participate in and hold any 
meeting required or permitted under these bylaws by telephone or similar 
communications equipment by means of which all persons participating in the 
meeting can hear each other. Participation in a meeting pursuant to this section
shall constitute presence in person at such a meeting, except where a person 
participates in the meeting for the express purpose of objecting, at the 
beginning of the meeting, to the transaction of any business on the ground that 
the meeting is not lawfully called or convened.

                                  ARTICLE VII

                                  Amendments
                                  ----------

          Section 7.1. Amendments. These bylaws may be altered, amended, or 
          -----------  ----------
repealed, or new bylaws may be adopted, by a majority of the board of directors 
at any duly held meeting of directors or by the holders of a majority of the 
shares represented at any duly held meeting of shareholders; provided that 
notice of such proposed action shall have been contained in the notice of any 
such meeting.

                           Certificate by Secretary
                           ------------------------

          The undersigned, being the secretary of Cardiac Control Systems, Inc.,
hereby certifies that the foregoing restated bylaws were duly adopted by the 
action of the board of directors of said corporation effective on January 26, 
1983.

          In Witness Whereof, I have signed this certification on this the 26 
day of January, 1983.

                                                  /s/ Simon J. Fuger
                                                  ------------------------------
                                                  Simon J. Fuger, Secretary

                                     -16-
<PAGE>
 
                 [LETTERHEAD OF CARDIAC CONTROL SYSTEMS, INC.]


                                 AMENDMENT TO 
                              RESTATED BYLAWS OF 
                        CARDIAC CONTROL SYSTEMS, INC. 
                              (the "Corporation")


     The Corporation's Bylaws are amended to include the following provision 
under Article V (Officers) thereof, effective October 8, 1994:

     Section 5.14 Chairman of the Board. The Chairman of the Board shall be an 
     ---------------------------------- 
     officer of the Corporation, shall preside at the Corporation's meetings,
     and shall have such other duties and responsibilities as an officer of the
     Corporation as the Board of Directors shall delegate.

     The foregoing amendment was adopted by the Board of Directors at a duly
held meeting on October 8, 1994.


                                                  /s/ Robert R. Brownlee
                                                  -----------------------------
                                                  Robert R. Brownlee
                                                  Secretary

                                     -17-