Effect of long-term application of Crataegus oxyacantha on ischemia and reperfusion induced arrhythmias in rats

The effect of long-term application of Crataegus oxyacantha on ischemia and reperfusion induced arrhythmias was investigated in Wistar rats on the heart In situ and on Langendorff preparations. Seventeen rats were fed for 8 weeks with 0.5 g/kg b.w. Crataegus extract per day, standardised to 2.2 % flavonoids. Twenty age-matched untreated rats served as controls. In the hearts in situ as well as In the Langendorff preparations the left anterior descending coronary artery (LAD) was ligated for 20 min and subsequently reperfused for 30 min. ECG was continuously recorded and the time spent between start of ischemia and onset of arrhythmias was measured. In addition, during ischemia and reperfusion the number of ventricular premature beats and bigemini and the duration of salves and ventricular flutter and fibrillation were determined. The ischemic area was evaluated in all experiments and coronary flow was measured in Langendorff preparations. In the present experiments, no cardio-protective effects of Crataegus oxyacantha could be detected, neither in the heart in situ nor in the Langendorff preparations. Although the ischemic areas were identical, arrhythmias occurred even earlier ih the Crataegus collectives than in the controls. Also the number and duration of ischemia and reperfusion induced arrhythmias tended to occur longer and more frequently in the Crataegus collectives, whilst coronary flow remained unchanged. The phenomenon that Crataegus rather aggravates than prevents arrhythmias may be reduced to a Crataegus induced increase in intracellular Ca2+-concentration proven true for the positive inotropic effects of Crataegus.