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)