Abstract: An extra-corporeal, self-contained, on-line, beat-to-beat pacemaker function analyzer (PFA) for automatic evaluation and indication of the quality of performance of cardiac pacing systems implanted in place for: routine examination of ambulatory patients; long-term surveillance of hospitalized patients; and examination of ECG traces (including pacing artefacts) of remote pacemaker patients, transferred by telephone or radio to a central follow-up station. The PFA provides a comprehensive examination of asynchronous, demand and demand-hysteresis pacemakers of all makes, including the state of the pacemaker's battery, the intactness of the electronic circuitry and of the electrodes, and the proper location of the electrodes in the heart.