EXPANDING INDICATIONS FOR PERMANENT PACEMAKERS

Purpose: To review the current clinical experience with new and expand ing indications for permanent cardiac pacing. Data Sources: A MEDLINE search was done of the English-language literature published from 1980 through 1994 about indications for permanent pacing. Five major areas were identified and searched: cardiomyopathies, atrial fibrillation, the long QT syndrome, cardiac transplantation, and vasovagal syncope. A manual search was then done for other contributions, including abstr acts. Study Selection: Because published reports in these areas are sc arce, all of the peer-reviewed articles and most of the relevant abstr acts found were reviewed. Data Extraction: Data were manually extracte d from the various sources, and the reports were classified and summar ized according to specific indications. Results: Pacing is becoming an important option in the treatment of patients with symptomatic drug-r esistant hypertrophic obstructive cardiomyopathy. Symptomatic and hemo dynamic benefits have been shown in patients with pacing over various periods of follow-up. In patients with the long QT syndrome in whom me dical therapy had failed, pacing at relatively fast rates markedly red uced symptoms and almost completely abolished fainting spells. Prelimi nary results suggest that pacing may be beneficial in dilated cardiomy opathy and in preventing episodes of paroxysmal atrial fibrillation. F urther studies are needed to clarify the mechanisms of and to improve selection criteria for pacing in these conditions. Our ability to sele ct cardiac transplant recipients for permanent pacing and our ability to optimize the timing of pacing in these patients have recently impro ved considerably. The role of pacing therapy in patients with neurally mediated (vasovagal) syncope remains incompletely understood. Better classification of these patients, made according to the sequence of he modynamic events leading to syncope, is likely to clarify the potentia l benefit of pacing in these patients and improve the selection of pat ients for pacing. Conclusion: Few peer-reviewed clinical trial have be en done, and further studies are needed to confirm the promising effec ts of pacing in patients with these newly recognized and expanding ind ications for pacing.