Chronotropic incompetence and mortality in middle-aged men with known or suspected coronary heart disease.

Aims: The objective is to study whether a heart rate (HR) increase from 40 to 100% of maximal work capacity in the exercise test (HR40-100) independently predicts mortality in men with known or suspected coronary heart disease (CHD).

Methods And Results: The subjects were 294 men, 42-61 years of age, from eastern Finland with known or suspected CHD but without use of HR-lowering medication at baseline. HR was measured at rest and during a maximal, symptom-limited exercise test. During an average follow-up of 11.0 years, there were 61 all-cause deaths. In Cox-multivariable model, mortality increased by 41% (95% confidence interval, 12-79%) with a 1-SD (15 b.p.m.) decrement in HR40-100. HR increase from rest to 40% of maximal work capacity was not associated with an increased risk of death. Synergism was observed between HR40-100 and workload achieved at HR of 100 b.p.m. so that men having low values for both these HR variables had a particularly adverse prognosis compared with men with high values for these variables.

Conclusion: An attenuated HR increase particularly during the latter half of a maximal exercise test is an independent predictor of death in men with known or suspected CHD.