G Gregoratos1. 1. Cardiology Consultation Services, UCSF Stanford Medical Center, San Francisco, CA 94143-0327, USA.
Abstract
OBJECTIVE: To review (1) the physiologic changes of aging that may lead to the need for a permanent pacemaker; (2) the current standard indications for pacemaker implantation as reported in expert guidelines; (3) newer investigational uses of pacemakers; (4) advances in pacemaker technology; and (5) cost-effectiveness of permanent pacing. DATA SOURCES: Computer-assisted search of the English language literature (MEDLINE database), manual search of articles bibliographies, and review of data provided by a major pacemaker manufacturer. DESIGN: Pertinent articles were reviewed and data extracted. Studies and data involving older persons were emphasized, and these data were extracted and presented. RESULTS: Abnormalities in impulse generation and conduction are common in older people and form the substrate for the need of pacemaker implantation. Pacemaker use is high in older people, with an estimated 70 to 80% of all permanent pacemakers implanted in individuals aged 65 years and older. The hemodynamic changes of aging include a reduction of ventricular compliance and increased contribution of atrial contraction to ventricular filling. Pacemakers that maintain synchrony between atria and ventricles may, therefore, be particularly advantageous in older adults. Recent studies have validated this theoretical reasoning. Chronotropic incompetence is common in older people, and rate responsive ventricular pacing has been shown to improve quality of life compared with fixed rate devices in older patients. Sequential, dual chamber pacemakers reduce the symptoms of pacemaker syndrome and recurrences of atrial fibrillation in certain groups of patients. Potential utility of permanent pacing is being investigated in patients with severe left ventricular dysfunction, markedly prolonged atrioventricular conduction time, hypertrophic and dilated cardiomyopathy, and after cardiac transplantation. Biventricular pacing as therapy for severe heart failure is in the very early phases of investigation. Newer implantable pacemakers provide a host of technological options but are somewhat more expensive and require more frequent follow-up. Controversies still exist regarding the need for pacemakers in certain clinical conditions but are decreasing as new high quality studies are completed. CONCLUSIONS: Permanent pacing is highly cost-effective, safe, and simple to perform. Pacemakers are implanted in patients with sinus node dysfunction, acquired (both native and postsurgical) atrioventricular block, some forms of neurally mediated syndromes, fascicular blocks, and, occasionally, for the prevention of supraventricular or ventricular tachyarrhythmias. Although pacemakers are implanted in individuals of all ages, they are most often utilized in older adults; it is estimated that 70 to 80% of all pacemakers are implanted in patients 65 years of age or older. This is attributable to an increase in abnormalities of impulse generation and conduction with advancing age. Dual chamber pacemakers that maintain synchrony between atria and ventricles are preferable in older patients because of the increased contribution of atrial contraction to ventricular filling in this age group. This theoretical advantage has been confirmed by prospective studies in limited patient subgroups.
OBJECTIVE: To review (1) the physiologic changes of aging that may lead to the need for a permanent pacemaker; (2) the current standard indications for pacemaker implantation as reported in expert guidelines; (3) newer investigational uses of pacemakers; (4) advances in pacemaker technology; and (5) cost-effectiveness of permanent pacing. DATA SOURCES: Computer-assisted search of the English language literature (MEDLINE database), manual search of articles bibliographies, and review of data provided by a major pacemaker manufacturer. DESIGN: Pertinent articles were reviewed and data extracted. Studies and data involving older persons were emphasized, and these data were extracted and presented. RESULTS: Abnormalities in impulse generation and conduction are common in older people and form the substrate for the need of pacemaker implantation. Pacemaker use is high in older people, with an estimated 70 to 80% of all permanent pacemakers implanted in individuals aged 65 years and older. The hemodynamic changes of aging include a reduction of ventricular compliance and increased contribution of atrial contraction to ventricular filling. Pacemakers that maintain synchrony between atria and ventricles may, therefore, be particularly advantageous in older adults. Recent studies have validated this theoretical reasoning. Chronotropic incompetence is common in older people, and rate responsive ventricular pacing has been shown to improve quality of life compared with fixed rate devices in older patients. Sequential, dual chamber pacemakers reduce the symptoms of pacemaker syndrome and recurrences of atrial fibrillation in certain groups of patients. Potential utility of permanent pacing is being investigated in patients with severe left ventricular dysfunction, markedly prolonged atrioventricular conduction time, hypertrophic and dilated cardiomyopathy, and after cardiac transplantation. Biventricular pacing as therapy for severe heart failure is in the very early phases of investigation. Newer implantable pacemakers provide a host of technological options but are somewhat more expensive and require more frequent follow-up. Controversies still exist regarding the need for pacemakers in certain clinical conditions but are decreasing as new high quality studies are completed. CONCLUSIONS: Permanent pacing is highly cost-effective, safe, and simple to perform. Pacemakers are implanted in patients with sinus node dysfunction, acquired (both native and postsurgical) atrioventricular block, some forms of neurally mediated syndromes, fascicular blocks, and, occasionally, for the prevention of supraventricular or ventricular tachyarrhythmias. Although pacemakers are implanted in individuals of all ages, they are most often utilized in older adults; it is estimated that 70 to 80% of all pacemakers are implanted in patients 65 years of age or older. This is attributable to an increase in abnormalities of impulse generation and conduction with advancing age. Dual chamber pacemakers that maintain synchrony between atria and ventricles are preferable in older patients because of the increased contribution of atrial contraction to ventricular filling in this age group. This theoretical advantage has been confirmed by prospective studies in limited patient subgroups.