Prognosis in cardiac pacing. A comparison between patients with atrioventricular block and sick sinus syndrome.

The prognosis of 64 patients with atrioventricular (AV) block among 128 consecutive patients, 65 males and 63 females, treated with permanent pacemakers, was compared with that of 56 patients with sick sinus syndrome (SSS) during a mean observation period of 32.5 months. A poor survival rate was found in patients with known coronary heart disease (CHD) compared to those with isolated conduction defect (ICD). Among patients with CHD, a higher mortality was found in patients with AV block than in those with SSS (58 vs. 24%). Likewise, among patients with ICD the mortality in AV block was higher than in SSS (31 vs. 15%). Regression analysis showed a mortality excess in AV block vs. SSS (p=0.02), males vs. females (p=0.04). The mortality excess in patients with CHD vs. ICD was significant (p=0.01). It is concluded that the increased mortality rate in patients with AV block is related to widespread myocardial damage, this being especially pronounced in patients with CHD.