Liver ischemia preconditions the heart against ischemia-reperfusion arrhythmias

OBJECTIVE(S): This study aimed to examine the hypothesis that an antiarrhythmic effect might be obtained by ischemic preconditioning of the liver, and also to characterize the potential underlying mechanisms. MATERIALS AND METHODS: Male Wistar rats were anesthetized by thiopental sodium (50 mg/kg, IP) followed by IV injection of heparin (250 IU). Remote ischemic preconditioning (RIPC) was induced by 3 cycles of 5 min liver ischemia followed by 5 min of reperfusion. The hearts were excised within 5 min after the final cycle of preconditioning and perfused using Langendorff’s system. The isolated perfused hearts were subjected to 30 min global ischemia followed by 90 min reperfusion. The myocardial arrhythmias induced by ischemia- reperfusion (I/R) were determined in accordance with the guidelines of Lambeth Conventions. The potential role of K(ATP) channels on RIPC was assessed by injection of glibenclamide (nonselective K(ATP) blocker) or 5-hydroxydecanoate (mitochondrial K(ATP) blocker) on rats 30 and 15 min before induction of RIPC in the liver, respectively. RESULTS: Hepatic remote preconditioning of the heart significantly (P<0.0001) prevented the incidence of myocardial arrhythmias induced by I/R in the perfused hearts (5.33±1.54 vs. 32.33±6.44,). However, the protective effects of remote preconditioning was significantly (P<0.01) abolished by the K(ATP) blocker, glibenclamide (25.5±4.9 vs. 5.33±1.54,). CONCLUSION: Hepatic RIPC may prevent the arrhythmias induced by I/R in the isolated perfused hearts via K(ATP) channels.