Cardiac pacing in the 1980s: treatment and techniques in transition
V Parsonnet
and
AD Bernstein
The pacemaker of the 1980s is designed to maintain atrioventricular synchrony through dual-chamber pacing. This pacemaker is multiprogrammable and capable of telemetric transmission of biologic, electronic and electrophysiologic data. Several developments have made this therapeutic modality possible: 1) the cumulative survival rate of many lithium-battery pacemakers exceeds 95% at 5 years; 2) lead and connector problems are rare; 3) atrial and ventricular electrode malfunctions occur in less than 2% of implants; and 4) new introducer techniques have simplified implantation (mortality and major morbidity rates are 0.5 and 0.4%, respectively). With multiprogrammability, pacemaker function can be optimized for the patient's needs, and about 20% of reoperations can be avoided. Ninety-six dual-chamber (DDD) pacemakers, 55 of which have been followed up for more than 3 months, have provided trouble-free performance and have yielded salutary clinical results, particularly when implanted to replace previous ventricular inhibited units. Problems with these pacemakers have included unusual pacing electrocardiograms, pacemaker eccentricities, programmer maintenance, pacing and follow-up complexities and costs. In the 1980s, effort will be required to find a balance between rapidly evolving technology and the clinical need for complex pacing systems. From 1978 to 1981, the rate of pacemaker implantation grew from 309 to 513 implants per million population per year, and there are now approximately 500,000 patients with implanted pacemakers living in the United States. Indications for pacing are ill-defined, because in many cases the assessment of clinical response to pacing is largely subjective, lacking satisfactory quantitative indexes. This decade will be a time of reappraisal of the extent of clinical applicability of new techniques, particularly the multiprogrammable dual-chamber system which, after 3 years of clinical trial, shows promise of being the predominant pacemaker of the immediate future.
