اثرات وابسته به سرعت آنتی آریتمی چرخشی گره دهلیزی بطنی سیمواستاتین در مدل گره دهلیزی بطنی ایزوله خرگوش

Background and purpose: Several previous studies have shown the direct and indirect effects of statins on supraventricular and ventricular arrhythmia. The purpose of the present study is to determine (1) whether Simvastatin modifies the rate-dependent properties of the ÂV node, (2) to what extent such changes are related to effect of Simvastatin on the basic properties of ÂV nodal conduction and refractoriness. Materials and methods: ÂV nodal refractoriness (ÂVËRP & ÂVFRP) and rate dependency protocols Fatigue and Facilitation were used to assesse the electrophysiological properties of ÂV node. We used an isolated perfussed rabbit with ÂV nodal preparation in one group (N=8). The stimulation protocols were carried out during control phase and in the presence of various concentrations of Simvastatin (0.5 , 0.8 , 1, 3 ,10 µm). Results: Simvastatin in concentration-dependent manner successfully prolonged effective and functional nodal refractory period (ÂVËRP & ÂVFRP). Âlso an increase in Wenckebach cycle length was observed. Simvastatin in high concentration (3,10 µm) increases the arrhythmia threshold. Various concentrations of simvastatin increased fatigue, but it reached to significant level only at 30 µM. Çonclusion: Simvastatin has potential anti-ÂVNRT effects by elevating arrhythmia threshold and prolongation of nodal refractoriness.