A Paradigm Shift in Cardiac Pacing Therapy?

Abstract

Artificial pacemakers have been continuously improved since 1949, when Jack Hopps, from the National Research Council of Canada in Ottawa, first assembled an external generator for Wilfred Bigelow and John Callaghan in the basement of the Banting Institute at the University of Toronto.1 Although Hopps’ device was not the first artificial pacemaker,2–4 the presentation by Callaghan at the 1950 American College of Surgeons meeting in Boston, Mass, stimulated a surge of experimentation that quickly led to demonstration of the utility of cardiac pacing in humans and subsequent manufacture of implantable devices.3 Since that time, remarkable advances in lead design, battery duration, programming capability, and electronic circuitry have given rise to one of the most successful and accepted life-saving, palliative therapies in modern medicine.3,5 Furthermore, medical indications for pacing therapy have expanded beyond the management of symptomatic bradycardia to include treatments for hypertrophic cardiomyopathy, neurocardiogenic syncope, ventricular tachyarrhythmia, congestive heart failure, and atrial fibrillation.6,7 Nevertheless, in spite of the fact that pacemakers represent a state-of-the-art technology, there are significant problems associated with long-term cardiac pacing. Articles pp 992 and 1000 The permanent implantation of an electronic pacemaker device is associated with complications that “…vary in clinical significance from benign to life-threatening.”7 These include the need for replacement of generators (primarily attributable to limited battery life) and leads (because of fracture, displacement, inappropriate stimulation, loss of insulating material, or tissue perforation). These problems are often exacerbated in pediatric patients owing to their size and the demands imposed by growth. Other complications include infection, thrombosis, valve dysfunction, maladaptive cardiac remodeling, and a lack of autonomic neurohumoral responsiveness. Thus, pacing therapy, although effective, continues to have important limitations. Although further refinements in the longevity and size of devices, lead biomaterials, and microprocessors seem inevitable, on the basis of …