Pacing in heart failure: patient and pacing mode selection

Pharmacological therapy in the management of heart failure has been proven and is well established. In the last decade ACE inhibitors,1,2 beta-blockers,3,4 spironolactone5 and digoxin6 have contributed to a reduction in mortality of nearly 50%, a reduced frequency of hospital admissions and improvement in quality of life.7–9 However, congestive heart failure still endures a high overall annual mortality of about 10%, with a 50% incidence of sudden death. Furthermore, many patients remain symptomatic and have a poor functional status (classified as NHYA III and IV) despite optimal medical therapy. It is in such patients in whom cardiac haemodynamics may be improved through appropriate pacing modalities with reasonable expectation of a better functional status. Conventional dual-chamber and bi-ventricular pacing have shown promise in the management of heart failure. In this article we will present the evidence in support of both modalities, but, moreover, emphasize the importance of appropriate patient and pacing mode selection when such therapies are being considered. We will also outline directions for further development in an undoubtedly effective but fledgling approach to heart failure management. As our main emphasis is on patient and pacing mode selection, we have not detailed the use of implantable defibrillators nor the technical aspects of implantation. The journal articles referenced in this article were largely located and cross referenced through the Medline database. Keywords on searching for data included heart failure, biventricular, multi-site, and dual chamber pacing, resynchronization therapy and AV-delay. All landmark clinical trials as well as early non-randomized, non-controlled pilot investigations have been included in this review. In the late 1980s Hochleitner et al. experimented using dual-chamber pacing in patients with drug-resistant end-stage heart failure.10 Permanent dual-chamber systems were implanted in 16 critically ill patients with idiopathic dilated cardiomyopathy and angiography confirming absence of coronary …