Effects of hydroalcoholic extract of Cynodon dactylon (L.) pers. on ischemia/reperfusion-induced arrhythmias

Background and purpose of the study: Probable antiarrhythmic effects of Cynodon dactylon(L.) pers. (family Poaceae) against ischemia/reperfusion (I/R)-induced arrhythmias wereinvestigated in isolated rat heart.Methods: The hearts were subjected to 30min regional ischemia followed by 30minreperfusion and perfused with hydroalcoholic extract of rhizome of C. dactylon (25, 50, 100and 200μg/ml).Results: During ischemia, the extract produced marked reduction in the number, durationand incidences of ventricular tachycardia (VT) at 25 and 50μg/ml (p 0.001 and p 0.01,respectively). Total number of ischemic ventricular ectopic beats (VEBs) were lowered by25-100μg/ml (p 0.001, p 0.001 and p 0.05, respectively). At the reperfusion phase, C.dactylon (25 and 50μg/ml) decreased incidence of VT from 100% (control) to 13 and 33%(p 0.001 and p 0.05) respectively. Duration and number of VT and total VF incidencewere also reduced at the same concentration (p 0.05 for all). Perfusion of the extract (25-100μg/ml) was markedly lowered reversible VF duration from 218±99sec to 0 sec, 0 secand 10±5sec (p 0.01, p 0.01 and p 0.05) respectively. Moreover, C. dactylon (25 and50μg/ml) decreased number of total VEBs from 349±73 to 35±17 (p 0.001) and 66±26(p 0.01). In this study, it was also shown that perfusion of the extract produced a markedand concentration-dependent positive inotropic effect.Conclusion: The findings of this study indicate that C. dactylon produce protective effectsagainst I/R-induced arrhythmias in isolated rat hearts probably by increase in themyocardial contractility and as a result by improvement of hemodynamic factors.