<PAGE>

                                                                     EXHIBIT 4.1


                                 [QUINTON LOGO]

                               QUINTON CARDIOLOGY
                                 SYSTEMS, INC.

         NUMBER                                            SHARES
          QUIN                                          ____________
      COMMON STOCK                           SEE REVERSE FOR CERTAIN DEFINITIONS
                                                      CUSIP 748773 10 8

             INCORPORATED UNDER THE LAWS OF THE STATE OF CALIFORNIA



THIS CERTIFIES THAT

                    ----------------------------------------

IS THE OWNER OF

                    ----------------------------------------

           FULLY PAID AND NONASSESSABLE SHARES OF THE COMMON STOCK OF

                        QUINTON CARDIOLOGY SYSTEMS, INC.

transferable on the books of the Corporation by the holder hereof in person or
by duly authorized attorney upon surrender of this Certificate properly
endorsed. This Certificate is not valid until countersigned and registered by
the Transfer Agent and Registrar.

        WITNESS the facsimile seal of the Corporation and the facsimile
signatures of its duly authorized officers.

Dated:
       -------------------

                                     [SEAL]

/s/ Michael Matysik                               /s/ John R. Hinson
---------------------------                       --------------------------
          SECRETARY                                      PRESIDENT


COUNTERSIGNED AND REGISTERED:
        MELLON INVESTOR SERVICES LLC
             TRANSFER AGENT AND REGISTRAR

BY:
    ------------------------------------
                    AUTHORIZED SIGNATURE

<PAGE>
                        QUINTON CARDIOLOGY SYSTEMS, INC.

        A statement of the powers, designations, preferences and relative,
participating, optional, or other special rights, and the qualifications,
limitations or restrictions of such preferences and/or rights granted to or
imposed upon the respective classes or series of shares and upon the holders
thereof as established, from time to time, by the Articles of Incorporation of
the Corporation and by any certificate of determination, and the number of
shares constituting each class and series and the designations thereof, may be
obtained by the holder hereof upon request and without charge from the
Corporation at its principal office.

        The following abbreviations, when used in the inscription on the face
of this certificate, shall be construed as though they were written out in full
according to applicable laws or regulations:

<Table>
        <S>                                            <C>
        TEN COM   --  as tenants in common              UNIF GIFT MIN ACT -- ...................Custodian...............
        TEN ENT   --  as tenants by the entireties                                 (Cust)                    (Minor)
        JT TEN    --  as joint tenants with right of                         under Uniform Gifts to Minors
                      survivorship and not as tenants                        Act........................................
                      in common                                                                 (State)
        COM PROP  --  as community property             UNIF TRF MIN ACT  -- .............Custodian (until age.........)
                                                                                 (Cust)
                                                                             ....................under Uniform Transfers
                                                                                    (Minor)
                                                                             to Minors Act..............................
                                                                                                   (State)
</Table>


    Additional abbreviations may also be used though not in the above list.


        FOR VALUE RECEIVED,___________________________hereby sell, assign and
transfer unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
   IDENTIFYING NUMBER OF ASSIGNEE
--------------------------------------

--------------------------------------


_______________________________________________________________________________
 (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

_______________________________________________________________________________

_______________________________________________________________________________

________________________________________________________________________ Shares
of the common stock represented by the within Certificate, and do hereby
irrevocably constitute and appoint

______________________________________________________________________ Attorney
to transfer the said stock on the books of the within named Corporation
with full power of substitution in the premises.

Dated________________________


                                X_______________________________________________

                                X_______________________________________________
                       NOTICE:   THE SIGNATURE(S) TO THIS ASSIGNMENT MUST
                                 CORRESPOND WITH THE NAME(S) AS WRITTEN UPON THE
                                 FACE OF THE CERTIFICATE IN EVERY PARTICULAR,
                                 WITHOUT ALTERATION OR ENLARGEMENT OR ANY
                                 CHANGE WHATEVER.

Signature(s) Guaranteed




By___________________________________
THE SIGNATURE(S) SHOULD BE GUARANTEED
BY AN ELIGIBLE GUARANTOR INSTITUTION
(BANKS, STOCKBROKERS, SAVINGS AND
LOAN ASSOCIATIONS AND CREDIT UNIONS
WITH MEMBERSHIP IN AN APPROVED
SIGNATURE GUARANTEE MEDALLION PROGRAM),
PURSUANT TO S.E.C. RULE 17Ad-15.