Procainamide prolonged ARI in all myocardial layers. The pooled ARI prolongation of the epicardium,midmyocardium and endocardium of the 6 animals was 66.8 ms+18.3 ms,70.3 ms+14.7 ms and 65.3ms+15.7 ms(P>0.05),respectively.

• 普鲁卡因胺对各层心肌的AR I均有延长作用；心外膜、中层心肌和心内膜的AR I分别延长了(66.；8±18