EFFECTS OF VERATRINE ON THE INSITU DOG HEART - EVIDENCE FOR INCREASED VENTRICULAR-FIBRILLATION THRESHOLD

  • 1 January 1979
    • journal article
    • research article
    • Vol. 208  (2) , 314-318
Abstract
The effect of veratrine on electrical stability of the mammalian ventricles was studied. In anesthetized open-chest dogs the effects of veratrine (0.001-0.3 mg/kg) on the threshold for ventricular fibrillation (VFT) were determined, during sinus rhythm (SR) and during atrial drive (AD) at 166 .+-. 7 beats/min. Veratrine (0.3 mg/kg) increased the VFT during SR from control levels of 33 .+-. 5 mA to 56 .+-. 4 mA (P < 0.05) and during AD from 34 .+-. 6 to 57 .+-. 9 mA (P < 0.05). VFT after veratrine infusion were higher than in control dogs, given the saline diluent, in which VFT during SR was 26 .+-. 3 mA (P < 0.001) and during AD was 24 .+-. 3 mA (P < 0.005). The increase in VFT during SR was independent of the decrease in heart rate, which fell from 147 .+-. 8 to 106 .+-. 6 beats/min (P < 0.001). It was associated with an increase in the QT interval during SR from control values of 254 .+-. 13 to 308 .+-. 19 ms (P < 0.02) and during AD from 238 .+-. 8 to 267 8 ms (P < 0.005). Small doses of veratrine apparently increase the electrical stability of the ventricles in the normal dog heart.