RESUMO
The antiarrhythmic effect of an oral 3-week-pretreatment with oligomer procyanidins derived from Vitis vinifera was investigated on the isolated perfused heart after global no-flow ischemia (procyanidin-treated group: n = 9, control group: n = 13). Hearts were perfused with a modified Krebs-Henseleit solution in which the K+ content was reduced to 3.0 mmol/l in order to lower the fibrillation threshold. Monophasic action potentials in addition to ECG were recorded. The durations of ischemia and reperfusion were 20 and 30 min, respectively. Arrhythmias including ventricular fibrillation (VF), ventricular tachycardia (VT), flutter (Fl) and bradycardia were evaluated. During the reperfusion, irreversible VF occurred in most of control hearts. The incidence of VF (percentage of the hearts in which VF occurred) was lowered by oligomer procyanidins from 84.6 to 55.6 %, and the duration of the episodes of VF (expressed as percentage relative to the total duration) was significantly shortened from 76.1 +/- 27.9 % to 36.6 +/- 40.6 % (p = 0.036). Simultaneously, the percentage of duration of normal sinus rhythm (NSR) increased from 19.5 +/- 30.3 % to 46.2 +/- 35.9 % (n.s.). VF occuring in the procyanidin-treated hearts could be reversed in two hearts within few minutes to a stage of "reversible arrhythmias" consisting of short episodes (1 to 60 s) of either Fl or VT or bradycardia or NSR alternating with each other. LDH (lactate dehydrogenase) release in the first drops appearing from the reperfused heart was significantly reduced in the procyanidin-treated rats (66.7 +/- 36.2 mU/min, n = 8) in comparison to controls (159.7 +/- 79.0 mU/min, n = 10; p = 0.010). These results demonstrate an antiarrhythmic and cytoprotective effect of oral pretreatment with oligomer procyanidins under the given experimental conditions.
