Rattapong Sungnoon

Effects of Sildenafil Citrate on Defibrillation Efficacy

Introduction: Although fatal arrhythmia and sudden death have been reported in patients taking sildenafil citrate, its effect on defibrillation efficacy has not been investigated. The aim of this study was to test the hypothesis that sildenafil citrate increases the shock strength required to successfully defibrillate during ventricular fibrillation (VF).

Effects of garlic on the induction of ventricular fibrillation.

OBJECTIVE Previous studies have shown that oral and intravenous administrations of garlic provide a significant antiarrhythmic effect and improve defibrillation efficacy. We tested the hypothesis that garlic could decrease the inducibility of ventricular arrhythmia. METHODS Twenty-one pigs (25-30 kg) were divided into three groups. In each group, the ventricular fibrillation threshold (VFT) and the upper limit of vulnerability (ULV) were determined. After the control VFT and ULV values were obtained, solutions containing 20 mg/kg (group 1, n = 7) and 40 mg/kg (group 2, n = 7) of garlic (1.3% allicin) were administered intravenously. The VFT and ULV were determined again at the end of garlic infusion. In group 3 (n = 7), 100 mL of normal saline was administered instead of garlic. RESULTS The VFT values in groups 1 and 2 were not different from the control VFT. The ULV in group 1 was not different from the control ULV. However, the ULV in group 2 (328 +/- 58 V, 8 +/- 3 J) was significantly lower than the control ULV (415 +/- 24 V, 13 +/- 2 J), thus accounting for the reduction of approximately 21% by peak voltage and approximately 38% by energy. The effective refractory period and diastolic pacing threshold were not altered after garlic infusion. Saline did not alter VFT or ULV. CONCLUSION Garlic cannot alter the VFT, but it significantly decreases the ULV in a dose-dependent pattern, indicating that it can reduce the range of the stimulation strength between the VFT and ULV (vulnerability window) during the vulnerable period of a cardiac cycle.