Querecetin prevents electrophysiolgical remodeling and reperfusion arrhythmias in dysmetabolic rats

Abstract Background Severe arrhythmias during reperfusion of myocardial infarctions are associated with increased mortality. High fat and fructose diet (HFFD) increases arrhythmic risk and predispose to diseases such as diabetes, hypertension, and dyslipidemia. Quercetin is a bioactive flavonol found in grapes and grapes derived products. This flavonoid has been proposed to prevent cardiovascular disease, but little is known about its electrophysiological properties. Objective To evaluate the electrophysiological effects of chronic quercetin administration in rats with increased arrhythmogenesis during the reperfusion due to a HFFD. Methods Male Wistar rats were fed for six weeks with control diet (C), HFFD (20% fat and 20% fructose w/w), HFFD supplemented with quercetin in a dose of 20 mg/kg/day (HFFDQ) or quercetin alone (Q). Isolated hearts were perfused with a Krebs-Henseleit solution and after 15 min stabilization, submitted to 10 min of regional ischemia followed by10 min of reperfusion. Epicardial action potential and arrhythmic events were analyzed. Results HFFD and HFFDQ developed metabolic syndrome, but action potential at 90% of repolarization lengthening only increased in HFFD (78±4 vs 55±3 ms, P<0.01 by ANOVAII). HFFD increased ventricular fibrillation incidence (HFFD 8 of 9; C 2 of 9 P=0.0152 by Fisher Exact test). Both groups treated with quercetin had low arrhythmic incidence (HFFDQ 2 of 10 and Q 1 of 9; P<0.0055 and P<0.0034, respectively when compared with HFFD). The severity of arrhythmias persisted high during reperfusion only in HFFD. Other less severe arrhythmias like salvos and extra beats occurred in similar proportion in the three other groups. Conclusion The above results confirm that a HFFD facilitates the occurrence of severe arrhythmias during reperfusion. Quercetin reduces arrhythmias and electrophysiological remodeling despite metabolic syndrome. Since quercetin is one of the most abundant dietary flavonoids, our results reinforce its nutraceutical potential. Acknowledgement/Funding I+D+i UNCuyo 2015