摘要
The aim of this study was to assess the association between resting heart rate (HR), chronotropic index (CI), and clinical outcomes in optimally treated chronic heart failure (HF) patients on -blocker therapy. %26lt;br%26gt;We performed a sub-study in 1118 patients with HF and reduced ejection fraction (EF 35) included in the HF-ACTION trial. Patients in sinus rhythm who received a -blocker and who performed with maximal effort on the exercise test were included. Chronotropic index was calculated as an index of HR reserve achieved, by using the equation (220-age) for estimating maximum HR. A sensitivity analysis using an equation developed for HF patients on -blockers was also performed. Cox proportional hazards models were fit to assess the association between CI and clinical outcomes. Median (25th, 75th percentiles) follow-up was 32 (21, 44) months. In a multivariable model including resting HR and CI as continuous variables, neither was associated with the primary outcome of all-cause mortality or hospitalization. However, each 0.1 unit decrease in CI 0.6 was associated with 17 increased risk of all-cause mortality (hazard ratio 1.17, 95 confidence interval 1.011.36; P 0.036), and 13 increased risk of cardiovascular mortality or HF hospitalization (hazard ratio 1.13, 1.021.26; P 0.025). Overall, 666 of 1118 (60) patients had a CI 0.6. Chronotropic index did not retain statistical significance when dichotomized at a value of 0.62. %26lt;br%26gt;In HF patients receiving optimal medical therapy, a decrease in CI 0.6 was associated with adverse clinical outcomes. Obtaining an optimal HR response to exercise, even in patients receiving optimal -blocker therapy, may be a therapeutic target in the HF population.
- 出版日期2013-8