The importance of heart rate modulation in patients with cardiac failure

Česká verzia

Authors: J. Hradec
Published in the journal: Kardiol Rev Int Med 2011, 13(1): 24-29
Category: From Hypertension to Heart Failure

Summary

Tachycardia is one of the symptoms of heart failure and, in contrast to a healthy myocardium, lowers the heart’s efficiency and performance. There is sufficient convincing evidence of the fact that, similarly to other cardiovascular diseases, an increasing heart rate (HR) is a predictor of a bad prognosis in chronic heart failure. The slowing of the HR through beta blockers significantly improves the prognosis of patients with chronic heart failure, as proven in several large clinical studies. It is assumed that the chief mechanism leading to improved prognoses is the slowing of the HR. Beta blockers have, moreover, a number of other effects that could influence the prognosis of patients with heart failure, either positively or negatively. The blocker of the I_f channel ivabradine is a substance that selectively lowers the HR without having any other haemodynamic or electrophysiological effects. Ivabradine thus allows the study of the effects of lowered HR per se. The BEAUTIFUL study of patients with ischemic heart disease and systolic dysfunction of the left ventricle or heart failure showed a positive development in cardiovascular incidents only in patients with a resting HR of ≥ 70 min^-1. The subsequent SHIFT study, which included patients with heart failure and HR ≥ 70 min^-1, showed a significant reduction in the number of hospitalisations and deaths from heart failure. The placebo component of both studies then provided convincing evidence that HR is a strong, independent predictor of the cardiovascular prognosis. The SHIFT study then showed that the reduction in the incidence of the primary monitored endpoint was greater, the lower HR was achieved through ivabradine therapy. It seems therefore that HR is not only a predictor of risk, but also a real cardiovascular risk factor, pharmacological intervention of which can improve the prognosis. It seems that pharmacological modulation is useful with HR ≥ 70 min^-1, with an optimal target value of around 60 min^-1.

Keywords:
ivabradine – cardiovascular prognosis – heart rate – heart failure

Zdroje

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