Abstract
The relation between the alternation of the ST-T complex (ST-T alternans, STTA) and the incidence of ventricular arrhythmias (VA) was examined, and the effects of anti-arrhythmic agents on these were tested during acute coronary occlusion in dogs. From 2 to 10 points of epicardial and end-cardial surface of ischemic areas, bipolar electrocardiograms and unipolar electrocardiograms (EPeg) were recorded. At 2 to 4 min after the start of the occlusion, STTA apeared, and as the degree of STTA increased, VA occurred. VA usually followed the deep negative deflection of the ST-T complex in EPeg. VA in some cases was preceded by the delayed conduction of the ischemic areas, but in other cases, the first premature activation appeared in the border of the ischemic and normal areas. Phenytoin,10 mg/kg i.v., attenuated STTA and the incidence of VA. Quinidine, 10 mg/kg, slightly attenuated STTA and the incidence of VA. Procaineamide, 15 mg/kg, showed almost no effect on STTA. The incidence of VA correlated to the degree of STTA rather than to conduction delay. The present results suggest that there is a close relationship between STTA and the incidence of VA and that antiarrhythmic drugs did not always attenuate STTA.
Published Version
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