Pacemakers have been available for 50 years, and implantable cardiac
defibrillators for 25. Clear indications for each have been established on the basis of data from randomized clinical trials (RCTs).
METHODS: This review article is the product of a collaborative effort by a cardiologist and a cardiac surgeon. The authors arrived at a consensus through a selective review of the literature, with special attention to randomized controlled trials and registry data.
RESULTS: Atrioventricular (
AV) block only rarely necessitates permanent pacemaker stimulation after
inferior myocardial infarction, of which it is a rare (12% to 20%) and often transient accompaniment.
AV block is more common, however, in anterior wall
infarction (frequency ca. 5%), and often necessitates permanent pacemaker
therapy in such cases. Pacemaker complications are rare; they include oversensing (the detection of impulse noise) (0.7%), undersensing (the failure to detect impulses) (3.8%),
electrode fractures (3.8%), isolation defects (3.4%), perforation (<1%), dislocation (<1%), and
infection (<1% to 12%). Many RCTs have confirmed that
defibrillators are effective in the prevention of
sudden cardiac death (SCD): they lower the risk of SCD by 20% to 30% in primary prevention and by 20% to 40% in
secondary prevention.
Cardiac resynchronization therapy improves the clinical manifestations and outcome of patients with
congestive heart failure, with a relative risk reduction (RR) of 20% to 40%, even among patients in NYHA classes I and II (RR ca. 40%).
Implantable defibrillators only rarely cause problems or complications in either the short or the long term. Emotional disturbances, including anxiety, are a rare side effect, occurring in less than 1% of cases.
CONCLUSION: