- Clinical efficacy and electrophysiology during long-term therapy for recurrent ventricular tachycardia or ventricular fibrillation. Heger, J.J., Prystowsky, E.N., Jackman, W.M., Naccarelli, G.V., Warfel, K.A., Rinkenberger, R.L., Zipes, D.P. N. Engl. J. Med. (1981)