Before starting any preventive drug treatment regimen, doctors first try to rule out reversible causes of ventricular arrhythmias: for example, caffeine, alcohol and tobacco consumption, and certain over-the-counter and prescribed medicines.
Also, because treatments pose substantial risks relative to the risk of the arrhythmias themselves, doctors tend not to treat ventricular arrhythmias unless they are tied to significant symptoms or are life-threatening. For this reason, FDA has not approved any treatments for premature ventricular beats.
However, there are several drugs approved for preventing ventricular tachycardia. The main types are beta blockers and sodium or potassium channel blockers. Most drugs to prevent ventricular tachycardias are taken orally up to four times daily and often must be taken for life.
Beta blockers, such as propranolol hydrochloride (Inderal and others), stem the automatic stimulation of heart contractions by the nervous system. Sodium and potassium channel blockers hamper transmission of electrical impulses in heart cells. Some sodium channel blockers are quinidine (Quinidex Extentabs, Quinaglute and others) and procainamide hydrochloride (Procan, Pronestyl and others). FDA approved in February 1996 a long-acting form of procainamide, Procanbid, which is taken only twice a day, compared with other procainamides, which must be taken four times daily.
Potassium channel blockers, such as amiodarone hydrochloride (Cordarone) and sotalol (Betapace), also are used to prevent ventricular tachycardias.
Doctors monitor the effectiveness of antiarrhythmia drug therapy with an ECG, or with electrophysiologic testing. Monitoring is essential not only to ensure effectiveness but safety, as well, because many of these drugs can make arrhythmias worse. Other side effects of antiarrhythmia drugs that can limit their use are low blood pressure, lung damage, nausea, and dizziness.
According to Wilber Aronow, M.D., a cardiologist with Mount Sinai School of Medicine in New York City, studies show that people treated with certain beta blockers following a heart attack have a significantly reduced risk of sudden cardiac death. But many large-scale studies of several different types of sodium channel blockers, as well as studies of certain potassium channel blockers, have shown that treatment with these drugs following heart attacks does not improve survival odds, or reduce them.
Ventricular arrhythmias are common within a month of a heart attack and are associated with an increased risk of sudden cardiac death.
