Antiarrhythmic and anti-ischemic properties of calcium-channel antagonists

The calcium-channel blockers are an ever-enlarging, heterogeneous group of drugs with widely variable effects on myocardium, sinoatrial and atrioventricular nodal function and conduction, peripheral blood vessels, and coronary circulation. Since the development and characterization of calcium-channel antagonists in the 1960s, these agents have become increasingly important in the treatment of many cardiovascular diseases. Nine calcium-channel blockers-nifedipine, nicardipine, amlodipine, felodipine, isradipine, nimodipine, diltiazem, verapamil, and bepridil-are all approved for use in the United States. Each major category has its own unique physiologic features. These drugs are extremely useful in the management of cardiac arrhythmias (particularly supraventricular arrhythmias) and/or ischemia. As future generations of calcium-channel blockers are developed with greater vasoselectivity, less negative inotropic effects, and reduced tendency to activate the renin-angiotensin system, their indications for use will continue to grow.