Kanlop Natnicha, Shinlapawittayatorn Krekwit, Sungnoon Rattapong, Chattipakorn Siriporn, Lailerd Narissara, Chattipakorn Nipon
Cardiac Electrophysiology Unit, Department of Physiology, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, and Biomedical Engineering Center, Chiang Mai University, Chiang Mai, Thailand.
Med Sci Monit. 2008 Oct;14(10):BR205-9.
Sildenafil citrate at supratherapeutic levels has been reported to decrease defibrillation efficacy. However, its effects on ventricular fibrillation induction and the upper limit of vulnerability (ULV) have not been investigated. We tested the hypothesis that sildenafil citrate reduces the ventricular fibrillation threshold (VFT) and increases the ULV.
MATERIAL/METHODS: Twenty-one pigs (25-30 kg) were randomly assigned into 3 groups of 7 pigs each. A solution containing 100 mg (group 100) or 50 mg (group 50) sildenafil citrate or 100 cc saline (group control) was infused intravenously in each pig. A train of 10 S1s was delivered from an RV electrode, and an S2 stimulus was delivered at the peak of the T wave of the last S1 activation to determine the VFT and ULV, before and after drug administration.
The 100 mg sildenafil citrate significantly (P<0.03) decreased VFT, accounting for approximately 36% by peak voltage and approximately 52% by total energy, and significantly (P<0.009) increased ULV, accounting for approximately 28% by peak voltage, and approximately 56% by total energy.
Supratherapeutic concentrations of sildenafil citrate significantly decreased the VFT and increased the ULV, resulting in an expansion of the VF induction window during the vulnerable period.
据报道，超治疗剂量的枸橼酸西地那非会降低除颤效果。然而，其对室颤诱发及易损上限（ULV）的影响尚未得到研究。我们检验了枸橼酸西地那非会降低室颤阈值（VFT）并提高ULV这一假设。
材料/方法：21头猪（25 - 30千克）被随机分为3组，每组7头。每头猪静脉输注含100毫克（100毫克组）或50毫克（50毫克组）枸橼酸西地那非的溶液或100毫升生理盐水（对照组）。在给药前后，从右室电极发放一串10个S1刺激，并在最后一个S1激动的T波峰值处发放S2刺激，以测定VFT和ULV。
100毫克枸橼酸西地那非显著（P<0.03）降低VFT，按峰值电压计算约降低36%，按总能量计算约降低52%；并显著（P<0.009）提高ULV，按峰值电压计算约提高28%，按总能量计算约提高56%。
超治疗浓度的枸橼酸西地那非显著降低VFT并提高ULV，导致易损期室颤诱发窗口扩大。
