<PAGE>

                                                                    EXHIBIT 31.2

          CERTIFICATION OF CHIEF FINANCIAL OFFICER PURSUANT TO SECTION
                    302(a) OF THE SARBANES-OXLEY ACT OF 2002

I, Michael K. Matysik, certify that:

            1. I have reviewed this quarterly report on Form 10-Q of Quinton
      Cardiology Systems, Inc.;

            2. Based on my knowledge, this quarterly report does not contain any
      untrue statement of a material fact or omit to state a material fact
      necessary to make the statements made, in light of the circumstances under
      which such statements were made, not misleading with respect to the period
      covered by this quarterly report;

            3. Based on my knowledge, the financial statements, and other
      financial information included in this quarterly report, fairly present in
      all material respects the financial condition, results of operations and
      cash flows of the registrant as of, and for, the periods presented in this
      quarterly report;

            4. The registrant's other certifying officer and I are responsible
      for establishing and maintaining disclosure controls and procedures (as
      defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrant,
      and we have:

                  a) Designed such disclosure controls and procedures to ensure
            that material information relating to the registrant, including its
            consolidated subsidiaries, is made known to us by others within
            those entities, particularly during the period in which this
            quarterly report is being prepared;

                  b) Evaluated the effectiveness of the registrant's disclosure
            controls and procedures and presented in this report our conclusions
            about the effectiveness of the disclosure controls and procedures,
            as of the end of the period covered by this report based on such
            evaluation; and

                  c) Disclosed in this report any change in the registrant's
            internal control over financial reporting that occurred during the
            registrant's most recent fiscal quarter (the registrant's fourth
            fiscal quarter in the case of an annual report) that has materially
            affected, or is reasonably likely to materially affect, the
            registrant's internal control over financial reporting.

            5. The registrant's other certifying officer and I have disclosed,
      based on our most recent evaluation of internal control over financial
      reporting, to the registrant's auditors and the audit committee of
      registrant's board of directors (or persons performing the equivalent
      function):

                  a) All significant deficiencies and material weaknesses in the
            design or operation of internal control over financial reporting
            which are reasonably likely to adversely affect the registrant's
            ability to record, process, summarize and report financial
            information; and

                  b) Any fraud, whether or not material, that involves
            management or other employees who have a significant role in the
            registrant's internal control over financial reporting.

            Date:  November 9, 2004

                                                 /s/ Michael K. Matysik
                                                 -------------------------------
                                                 Michael K. Matysik
                                                 Senior Vice President and Chief
                                                   Financial Officer