The effect of FTY720 on rhythm disturbance induced by ischemia/reperfusion in rat heart preparations. ECG recordings from Langendorff perfused heart in the presence and absence of FTY720. A_B: in the absence of FTY720, RR interval, P–R, QRS and QT intervals were significantly increased during ischemia and reperfusion, but in the presence of FTY720, RR interval, P–R, QRS and QT intervals were not significantly different than those during the control condition or during ischemia and reperfusion. Both tachycardia-related (ectopic beats, non-sustained and sustained episodes of ventricular tachycardia (VT) and ventricular fibrillation (VF)) and bradycardia-related (sinus bradycardia, sinus pause, sinus arrest, and A–V conduction block) arrhythmic events were frequently observed after 5–10 min in the presence of ischemic conditions. C: FTY720 greatly reduced the occurrence of premature ventricular beats, VT and sinus bradycardia as well as A-V conduction block caused by I/R injury.