Evolving indications for permanent pacemakers.

ABSTRACT

New indications for permanent cardiac pacing have been developed in recent years, with numerous studies demonstrating improved clinical outcomes in a variety of disorders. Because hypertrophic obstructive cardiomyopathy, dilated cardiomyopathy, heart failure, neurocardiogenic syncope, and atrial fibrillation are common conditions, every clinician should be aware of evolving alternative therapies for them. Observational studies in patients with refractory, symptomatic hypertrophic obstructive cardiomyopathy and significant left ventricular outflow gradient at rest suggest that cardiac pacing may result in symptomatic and hemodynamic improvement. Clinical trials have not shown conclusive evidence regarding the long-term benefit from pacing in these patients, and it is unclear whether pacing will be a preferred treatment option. Preliminary data suggest that pacing is a viable adjunctive therapeutic approach for improving symptoms in patients with dilated cardiomyopathy and heart failure. Mortality benefit has yet to be established, but it is to be hoped that ongoing randomized clinical trials will provide definitive information on that issue. Patients with refractory neurocardiogenic syncope or those who are intolerant of medical treatment may benefit from pacing therapies, especially those that use rate-drop sensor algorithms. Biatrial pacing has emerged as a technique that resynchronizes atrial electrical activity and has been shown to prevent atrial fibrillation. Multisite atrial pacing for the prevention of atrial fibrillation is considered investigational but seems promising. Newer indications for pacing are expected to result in improved clinical outcomes for hypertrophic obstructive cardiomyopathy, dilated cardiomyopathy and heart failure, neurocardiogenic syncope, and the prevention of atrial fibrillation.