Assessment of heart rate recovery after exercise stress test: implications for cardiac resynchronization therapy

Abstract

This editorial refers to ‘Cardiac resynchronization therapy improves exercise heart rate recovery in patients with heart failure’ by S. Okutucu et al. , on page 526. The autonomic nervous system plays a major role in the pathogenesis of chronic heart failure, which usually presents with excess sympathetic activity and a concomitant decrease in parasympathetic tone. Markers of neuroendocrine dysregulation, such as heart rate variability, baroreflex sensitivity, and serum levels of natriuretic peptides, can be measured and correlated with clinical outcomes. Exercise increases the sympathetic tone and decreases parasympathetic activity. Measurement of post-exercise heart rate recovery (HRR) is a non-invasive method to assess parasympathetic function as heart rate deceleration (HRD) during the first minute after peak exercise is mediated primarily by activation of the parasympathetic nervous system.1 Impaired HRR was shown to be associated with an increased mortality in subjects referred for stress testing regardless of cardiovascular disease history.2 Epidemiological studies in stable heart failure patients have shown that the extent of autonomic dysfunction bears a strong correlation with heart failure severity.3 Blunted HRR has been shown to be associated with an increased mortality and, more specifically, an increased relative risk of sudden cardiac death.4 Heart rate recovery may provide independent prognostic information in patients with heart failure, even after accounting for previously identified clinical and exercise-derived prognostic variables.5 Patients eligible for cardiac resynchronization therapy (CRT) represent a heterogeneous …