The effect of haloperidol on ventricular fibrillation threshold in pigs.

Ventricular fibrillation has been observed in association with the administration of haloperidol. This study was designed to determine the effect of intravenous haloperidol on ventricular fibrillation threshold (VFT). VFT's were determined prior to and 15 min. following an intravenous infusion of haloperidol (50 mg administered over 10 min.) in five pigs anaesthetized with alpha-chloralose. VFT's were determined using a single stimulus method. Mean arterial pressure (MAP), heart rate (HR), and electrocardiogram (ECG) were monitored continuously. Mean VFT (mA) at baseline and following haloperidol infusion was 50.2 +/- 4.6 and 65.1 +/- 12.8, respectively (P less than 0.05). Mean MAP (mmHg) at baseline and following haloperidol infusion was 127 +/- 32 and 107 +/- 23, respectively (P less than 0.05). Haloperidol infusion did not significantly influence mean HR, QRS duration or corrected QT interval. Intravenous haloperidol increases VFT and decreases MAP in pigs. In this model, haloperidol may offer protection against ventricular fibrillation. Further study is required to determine the clinical significance of the antifibrillatory effect of haloperidol.