Hauser et al nicely confirmed, in young subjects with complete atrioventricular block, that dual-chamber sequential pacing increased rest cardiac output, using a noninvasive, inert gas rebreathing method. However, their conclusion went beyond their protocol to suggest that this would benefit “hemodynamics and tolerability” in these patients. They did not measure exercise capacity, and tolerability was measured only in “pacemaker-related symptoms” tested acutely.

Young patients with complete atrioventricular block do remarkably well without pacemakers, and this study does not warrant the implication that a pacemaker is actually needed in these patients. A 12-year-old patient of mine had a pediatrician who thought he should have a pacemaker, so we did a treadmill test using the Bruce protocol. He completed the entire 18 minutes without symptoms, something I have almost never seen, even in athletes. Pacemakers in young patients are not a happy experience unless these patients are truly symptomatic. They might have syncope without pacemakers, but the same risk is present if the pacemaker fails. To my knowledge, no one has ever demonstrated that pacemakers improve life expectancy.