Beta-Adrenoceptor–Blocking Drugs (Class 2)

BETA-ADRENOCEPTOR–BLOCKING DRUGS (CLASS 2)

Cardiac Effects

Propranolol and similar drugs have antiarrhythmic properties by virtue of their β-receptor–blocking action and direct membrane effects. As described, some of these drugs have selectivity for cardiac β₁ receptors, some have intrinsic sympathomimetic activity, some have marked direct membrane effects, and some prolong the cardiac action potential. The relative contributions of the β-blocking and direct membrane effects to the antiarrhythmic effects of these drugs are not fully known. Although β blockers are fairly well toler-ated, their efficacy for suppression of ventricular ectopic depolariza-tions is lower than that of sodium channel blockers. However, there is good evidence that these agents can prevent recurrent infarction and sudden death in patients recovering from acute myocardial infarction .

Esmolol is a short-actingβblocker used primarily as an anti-arrhythmic drug for intraoperative and other acute arrhythmias.