Treatment strategies for heart failure: β blockers and antiarrhythmics

The role of β blockers and antiarrhythmic drugs in the management of patients with heart failure is reviewed. Although several investigators since the 1970s proposed β adrenergic blocking agents as a possible treatment for patients with heart failure,1 the simple observation that they can reduce myocardial contractility confined them to being absolutely contraindicated for the treatment of this condition. However, the medical approach to heart failure has changed dramatically over the past 10 years, progressing from a haemodynamic to a neurohormonal pathophysiological paradigm.2 Since activation of the sympathetic system is recognised as one of the cardinal pathophysiologic abnormalities in patients with chronic heart failure,3 the effects of β adrenergic receptor blockers have been specifically tested in randomised clinical trials. Consequently, over a relatively brief period of time, a treatment that was once contraindicated is now an established, evidence based recommended treatment for heart failure. ### Rationale for use The concentrations of circulating catecholamines are increased in patients with chronic heart failure.3 The adrenergic activation observed in these patients can be useful initially to maintain an acceptable cardiac performance by increasing contractility and heart rate, but ultimately the increase in the adrenergic drive can damage the failing human heart.4 In the human cardiac myocyte, there are three adrenergic receptors—β1, β2, and α1—whose activation can lead to cardiac myocyte growth (β1, β2, α1), positive inotropic response (β1, β2), positive chronotropic response (β1, β2), myocyte toxicity (β1, β2), and myocyte apoptosis (β1).5 Therefore, the continuously increased activation of the adrenergic system leads to several adverse biological signals to the cardiac myocytes through the adrenergic receptors. The rationale for the use of β adrenergic blocking agents in patients with heart failure is based mainly upon these observations. ### Effects on physiologic end points #### Left ventricular function and remodelling processes All available trials testing β blockers versus placebo showed that, apart from short term negative …