Predictive value of heart rate recovery after exercise testing in addition to brain natriuretic peptide levels in ambulatory patients with nonischemic dilated cardiomyopathy

Background: Heart rate recovery (HRR) is related to autonomic function and is a prognostic marker in cardiovascular disease. We sought to investigate the clinical utility of HRR in addition to BNP levels in ambulatory outpatients with nonischemic dilated cardiomyopathy (NICM). Methods: Seventy-nine NICM outpatients were followed for a mean of 19 months. HRR was defined as the difference in heart rate between peak exercise and 1 minute later. On the basis of the lower tertile value, we allocated the patients to two groups: with HRR >12 bpm (n = 48; normal) and with HRR >12 bpm (n = 31, abnormal). Results: The probability of cardiac event-free survival was significantly lower in the abnormal HRR group than in the normal HRR group (P = 0.002). Stepwise multivariate analysis revealed that plasma BNP and HRR were independent predictors of cardiac events. Patients with both HRR ≤12 bpm and BNP ≥200 pg/mL had significantly higher rates of cardiac events than those in whom only one, or neither, of these variables was abnormal. Conclusions: HRR after exercise testing, in addition to plasma BNP level, might be a useful indicator as a predictor for admission due to worsening heart failure and its combination is able to provide additive prognostic information in ambulatory outpatients with NICM.