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                                                                     EXHIBIT 3.1
 
                                    RESTATED
 
                          CERTIFICATE OF INCORPORATION
 
                                       OF
 
                          CARDIAC PATHWAYS CORPORATION
 
     Cardiac Pathways Corporation, a corporation organized and existing under
laws of the State of Delaware, hereby certifies as follows:
 
     1. The name of the Corporation is Cardiac Pathways Corporation. Cardiac
Pathways Corporation was originally incorporated under the same name, and the
original Certificate of Incorporation of the Corporation was filed with the
Secretary of State of the state of Delaware on March 18, 1996.
 
     2. Pursuant to Sections 228, 242 and 245 of the General Corporation Laws of
the State of Delaware, this Restated Certificate of Incorporation restates and
integrates and further amends the provisions of the Certificate of Incorporation
of this corporation.
 
     3. The text of the Certificate of Incorporation as heretofore amended or
supplemented is hereby amended and restated to read in its entirety as follows:
 
          FIRST: The name of this corporation is Cardiac Pathways Corporation.
 
          SECOND: The address of the corporation's registered office in the
     State of Delaware is 1209 Orange Street, Wilmington, County of New Castle,
     Delaware 19801. The name of its registered agent at such address is The
     Corporation Trust Company.
 
          THIRD: The purpose of this corporation is to engage in any lawful act
     or activity for which corporations may be organized under the General
     Corporation Law of Delaware.
 
          FOURTH: This corporation is authorized to issue two classes of stock
     to be designated, respectively, "Common Stock" and "Preferred Stock." The
     total number of shares which the corporation is authorized to issue is
     35,000,000 shares. 30,000,000 shares shall be Common Stock, par value $.001
     per share, and 5,000,000 shares shall be Preferred Stock, par value $.001
     per share.
 
          The Preferred Stock may be issued from time to time in one or more
     series. The Board of Directors is authorized to fix the number of shares of
     any series of Preferred Stock and to determine the designation of any such
     series. The Board of Directors is also authorized to determine and alter
     the powers, rights, preferences and privileges and the qualifications,
     limitations and restrictions granted to or imposed upon any wholly unissued
     series of Preferred Stock and within the limitations or restrictions stated
     in any resolution or resolutions of the Board of Directors originally
     fixing the number of shares constituting any series, to increase or
     decrease (but not below the number of shares of such series then
     outstanding) the number of shares of any series subsequent to the issue of
     shares of that series, to determine the designation of any series, and to
     fix the number of shares of any series. In case the number of shares of any
     series shall be so decreased, the shares constituting such decrease shall
     resume the status which they had prior to the adoption of the resolution
     originally fixing the number of shares of such series.
 
          FIFTH: "Qualified Public Offering" as used in this Certificate of
     Incorporation shall mean the corporation's initial firm commitment
     underwritten public offering pursuant to an effective registration under
     the Securities Act of 1933, as amended, covering the offer and sale of
     Common Stock for the account of the Corporation to the public. For the
     management of the business and for the conduct of the affairs of the
     corporation, and in further definition, limitation and regulation of the
     powers of the
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     corporation, of its directors and of its stockholders or any class thereof,
     as the case may be, it is further provided that, effective upon the closing
     of a Qualified Public Offering:
 
             1. The management of the business and the conduct of the affairs of
        the corporation shall be vested in its Board of Directors. The number of
        directors which shall constitute the whole Board of Directors shall be
        fixed exclusively by one or more resolutions adopted from time to time
        by the Board of Directors.
 
             The Board of Directors shall be divided into three classes
        designated as Class I, Class II and Class III, respectively. Directors
        shall be assigned to each class in accordance with a resolution or
        resolutions adopted by the Board of Directors. At the first annual
        meeting of stockholders following the date hereof, the term of office of
        the Class I directors shall expire and Class I directors shall be
        elected for a full term of three years. At the second annual meeting of
        stockholders following the date hereof, the term of office of the Class
        II directors shall expire and Class II directors shall be elected for a
        full term of three years. At the third annual meeting of stockholders
        following the date hereof, the term of office of the Class III directors
        shall expire and Class III directors shall be elected for a full term of
        three years. At each succeeding annual meeting of stockholders,
        directors shall be elected for a full term of three years to succeed the
        directors of the class whose terms expire at such annual meeting.
 
             Notwithstanding the foregoing provisions of this Article, each
        director shall serve until his or her successor is duly elected and
        qualified or until his or her death, resignation or removal. No decrease
        in the number of directors constituting the Board of Directors shall
        shorten the term of any incumbent director.
 
             Any vacancies on the Board of Directors resulting from death,
        resignation, disqualification, removal, or other causes shall be filled
        by either (i) the affirmative vote of the holders of a majority of the
        voting power of the thenoutstanding shares of voting stock of the
        corporation entitled to vote generally in the election of directors (the
        "Voting Stock") voting together as a single class; or (ii) by the
        affirmative vote of a majority of the remaining directors then in
        office, even though less than a quorum of the Board of Directors. Newly
        created directorships resulting from any increase in the number of
        directors shall, unless the Board of Directors determines by resolution
        that any such newly created directorship shall be filled by the
        stockholders, be filled only by the affirmative vote of the directors
        then in office, even though less than a quorum of the Board of
        Directors. Any director elected in accordance with the preceding
        sentence shall hold office for the remainder of the full term of the
        class of directors in which the new directorship was created or the
        vacancy occurred and until such director's successor shall have been
        elected and qualified.
 
             2. In furtherance and not in limitation of the powers conferred by
        statute, the Board of Directors is expressly authorized to make, alter,
        amend, or repeal the Bylaws of the corporation.
 
             3. The directors of the corporation need not be elected by written
        ballot unless a stockholder demands election by written ballot at the
        meeting and before voting begins, or unless the Bylaws so provide.
 
             4. The affirmative vote of sixty-six and two-thirds percent
        (66-2/3%) of the voting power of the then outstanding shares of Voting
        Stock, voting together as a single class, shall be required for the
        adoption, amendment or repeal of the following sections of the
        corporation's Bylaws by the stockholders of this corporation: 2.2
        (Annual Meeting) and 2.3 (Special Meeting).
 
             5. No action shall be taken by the stockholders of the corporation
        except at an annual or special meeting of the stockholders called in
        accordance with the Bylaws.
 
             6. Advance notice of stockholder nomination for the election of
        directors and of business to be brought by stockholders before any
        meeting of the stockholders of the corporation shall be given in the
        manner provided in the Bylaws of the corporation.
 
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             7. Any director, or the entire Board of Directors, may be removed
        from office at any time (i) with cause by the affirmative vote of the
        holders of at least a majority of the voting power of all of the
        then-outstanding shares of the Voting Stock, voting together as a single
        class; or (ii) without cause by the affirmative vote of the holders of
        at least sixty-six and two-thirds percent (66 2/3%) of the voting power
        of all of the then-outstanding shares of the Voting Stock.
 
          SIXTH: Notwithstanding any other provisions of this Certificate of
     Incorporation or any provision of law which might otherwise permit a lesser
     vote or no vote, but in addition to any affirmative vote of the holders of
     any particular class or series of the Voting Stock required by law, this
     Certificate of Incorporation or any Preferred Stock Designation, the
     affirmative vote of the holders of at least sixty-six and two-thirds
     percent (66 2/3%) of the voting power of all of the then-outstanding shares
     of the Voting Stock, voting together as a single class, shall be required
     to alter, amend or repeal Article FIFTH or this Article SIXTH.
 
          SEVENTH: The corporation reserves the right to amend, alter, change or
     repeal any provision contained in this Certificate of Incorporation, in the
     manner now or hereafter prescribed by statute, except as provided in
     Article SIXTH of this Certificate, and all rights conferred upon the
     stockholders herein are granted subject to this right.
 
        EIGHTH:
 
          1. To the fullest extent permitted by the Delaware General Corporation
     Law as the same exists or as may hereafter be amended, a director of the
     corporation shall not be personally liable to the Corporation or its
     stockholders for monetary damages for breach fiduciary duty as a director.
 
          2. The corporation may indemnify to the fullest extent permitted by
     law any person made or threatened to be made a party to an action or
     proceeding, whether criminal, civil, administrative or investigative, by
     reason of the fact that he, his testator or intestate is or was a director,
     officer or employee of the corporation or any predecessor of the
     corporation or serves or served at any other enterprise as a director,
     officer or employee at the request of the corporation or any predecessor to
     the corporation.
 
          3. Neither any amendment nor repeal of this Article I, nor the
     adoption of any provision of the corporation's Certificate of Incorporation
     inconsistent with this Article EIGHTH, shall eliminate or reduce the effect
     of this Article EIGHTH, in respect of any matter occurring, or any action
     or proceeding accruing or arising or that, but for this Article EIGHTH,
     would accrue or arise, prior to such amendment, repeal, or adoption of an
     inconsistent provision.
 
          NINTH: Meetings of stockholders may be held within or without the
     State of Delaware, as the Bylaws may provide. The books of the corporation
     may be kept (subject to any provision contained in the statutes) outside of
     the State of Delaware at such place or places as may be designated from
     time to time by the Board of Directors or in the Bylaws of the corporation.
 
          TENTH. At all elections of directors of the corporation, each holder
     of stock or of any class or series of stock shall be entitled to as many
     votes as shall equal the number of votes which such stockholder would be
     entitled to cast for the election of directors with respect to his or her
     shares of stock multiplied by the number of directors to be elected, and
     may cast all of such votes for any director, or for any two or more of them
     as such stockholder may see fit.
 
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     IN WITNESS WHEREOF, this Restated Certificate of Incorporation has been
signed this 21st day of June, 1996.
 
                                          CARDIAC PATHWAYS CORPORATION
 
                                          By: /s/     WILLIAM N. STARLING
 
                                            ------------------------------------
                                                    William N. Starling
                                               President and Chief Executive
                                                           Officer
 
ATTEST:
 
/s/        J. CASEY MCGLYNN
- --------------------------------------
       Casey McGlynn, Secretary
 
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