CLASSIFICATION OF CARDIOACTIVE DRUGS IN VIVO BY USING PROGRAMMED ELECTRICAL STIMULATION IN COMBINATION wITH MONOPHASIC ACTION POTENTIAL RECORDINGS AT DIFFERENT PACING RATES

Abstract

ABBREVIATIONS MDP = maximal diastolic potential, AP = action potential, Vmax = maximum rate of rise, ERP = effective refractory period, MAP = monophasic action potential, MAPD,, = time for 50% repolarization of MAP. ABSTRACTThe effect of antiarrhythmic drugs on myocardial refractoriness may be due to changes either in V, , , of phase 0 or the phase of repolarization of the AP or both. By using programmed electrical stimulation in combination with MAP recordings at different pacing rates in :he intact dog heart, it was possible to classify and to a certain extent to elucidate the mode of action of various cardioactive drugs in vivo.

The Mode of Antiarrhythmic Action of Melperone

“…Studies o n isolated heart muscle preparations (Refsum et a/. 1978;Arlock et al 1978), intact dog hearts Landmark et al 1981) a n d man (Edvardsson & Olsson 1981) have suggested that melperone may be a class 111 antiarrhythmic drug according t o the classification of Vaughan Williams (1975). Based o n their study on patients with acute myocardial infarction, however, Magelvang et a/.…”