CARBON-MONOXIDE AND VENTRICULAR-FIBRILLATION THRESHOLD IN NORMAL DOGS

In a blind, randomized study, the effect of breathing 100 ppm of carbon monoxide versus compressed, purified air for 2 hr on ventricular fibrillation threshold was investigated in twenty anesthetized normal open-chested dogs. The mean arterial carboxyhemoglobin level was 1.12% in the air control period, 0.99% after air, 1.1 0% in the carbon monoxide control period, and 6.48% after carbon monoxide. Carbon monoxide increased the mean arterial carboxyhemoglobin (P <.001). Mean ventricular fibrillation thresholds were 19.9 ± 6.5 rnA in the carbon monoxide control period, 15.7 ± 5.6 rnA after carbon monoxide 20.8 ± 6.3 rnA in the air control period, and 24.5 ± 9.5 rnA after air. Carbon monoxide decreased the ventricular fibrillation threshold (P<.005). These data show that breathing 100 ppm of carbon monoxide for 2 hr reduces the ventricular fibrillation threshold in anesthetized normal open-chested dogs. © 1979 Taylor & Francis Group, LLC.