Victor Parsonnet, M.D., Alan D. Bernstein, M.D., and John C. Norman, M.D. ... Foremost among these is the true role of dual-chamber pacing in the treatment of slow and fast ..... Parsonnet V, Furman S, Smyth NPD, Bilitch. M. Report of the ...
Cardiac Pacing Review
Dual-Chamber Pacing for Cardiac Arrhythmias: Controversies in Cloning the Conduction System Victor Parsonnet, M.D., Alan D. Bernstein, M.D., and John C. Norman, M.D. From the outset, the art and science of cardiac pacing has been beset with a variety of problems. With the passage of time and concentrated effort in the interrelated sciences, many have been solved. We no longer are concerned with premature battery failure or leaking pulse-generator capsules, but now focus on an entirely new set of issues that beg for resolution. Foremost among these is the true role of dual-chamber pacing in the treatment of slow and fast cardiac arrhythmias of a multitude of etiologies. Secondary to that issue is the cascade of problems brought about by a burgeoning of technical capabilities, such as micro-miniaturized computing devices, complex pacemaker programmability with telemetry functions, the impact of these technologies on therapeutic indications and techniques, the proliferation of pacemaker utilization, and the summative
socioeconomic implications.
THE EMERGING medical and socioeconomic controversies in pacemaker therapy revolve around a delineation of the appropriate role of dual-chamber pacing (DCP) in the treatment of various cardiac arrhythmias. An associated concern is the impact of DCP devices on the complexity of care, on post-implantation surveillance, and on costs.
DUAL-CHAMBER PACING The theoretically ideal pacemaker is one that is so "physiologic" (i.e. able to restore normal cardiac timing) that it becomes both a substitute conduction system and a ratecontrolling device that responds in a systematic way to compensate for altered sino-
atrial impulse formation and atrioventricular (AV) conduction. This goal now can be achieved in part by a pacemaker that stimulates the atrium and ventricle in synchrony, or senses atrial depolarizations and stimulates the ventricle after a physiologically appropriate, but invariant, AV interval (a DDD pacemaker; pacing modes are conventionally described by means of the ICHD* Code summarized in Tables I and II.)' Within certain limits the device is physiologic in that anything that will accelerate the spontaneous atrial rate (such as exercise, fever, acidosis, or sympathetic tone) will be accompanied by a beat-for-beat increase in ventricular rate. *Inter-Society Commission for Heart Disease Resources
From the Newark Beth Israel Medical Center, Affiliate of College of Medicine and Dentistry of New Jersey, Newark, New Jersey.
Address for reprints: Victor Parsonnet, M.D., Newark Beth Israel Medical Center, 201 Lyons Avenue, Newark, New Jersey 07112
Texas Heart Institute Journal
208
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