Therapy of ventricular tachycardia

Therapeutic modalities for ventricular tachycardia include antiarrhythmic drugs, direct current cardioversion, electrical pacing and surgical intervention. Lidocaine, procainamide and bretylium are all capable of controlling recurrent ventricular tachycardia; bretylium has the advantage of also being antifibrillatory and of raising the threshold for ventricular fibrillation. Lidocaine and bretylium are available only in i.v. form. Procainamide is available in i.v. as well as oral form. Other oral antiarrhythmic agents include quinidine, disopyramide, beta-blockers such as propranolol and verapamil. The latter may be useful in ventricular arrhythmias induced by ischemia; of these, only beta-blockers appear to significantly raise the threshold for ventricular fibrillation. Control of ventricular ectopy does not always preclude ventricular tachycardia and ventricular fibrillation. In treating ventricular tachycardia, bretylium tosylate is generally given 5 to 10 mg/kg i.v. over 10 to 20 minutes. Given too rapidly, it may cause nausea and vomiting. Orthostatic hypotension, a common side effect, generally abates with continued use and may be ameliorated with tricyclic antidepressants such as protriptyline. Significant supine hypotension may be encountered in patients with acute myocardial infarction and may be managed with pressor agents or fluids, or both. The antiarrhythmic efficacy of bretylium was analyzed in 40 patients. Five etiologic groups were defined by cardiac catheterization: 19 patients had atherosclerotic heart disease, 6 had primary myocardial disease, 4 had mitral valve prolapse, 4 had rheumatic heart disease and 7 had miscellaneous or no heart disease. All patients had recurrent ventricular tachycardia (VT); 23 had ventricular fibrillation (VF) as well. Other antiarrhythmic agents had failed in 38 patients.(ABSTRACT TRUNCATED AT 250 WORDS)