LACK OF CORRELATION BETWEEN THE ANTIARRHYTHMIC EFFECT OF L-PROPIONYLCARNITINE ON REOXYGENATION-INDUCED ARRHYTHMIAS AND ITS ELECTROPHYSIOLOGICAL PROPERTIES

1 The antiarrhythmic effect of L-propionylcarnitine (L-PC) was evaluated in the guinea-pig isolated heart; arrhythmias were induced with hypoxia followed by reoxygenation and by digitalis intoxication. 2 L-PC 1-mu-M, was found to be the minimal but effective antiarrhythmic concentration against reoxygenation-induced ventricular fibrillation. No antiarrhythmic effect was observed against digitalis-induced arrhythmias. D-Propionylcarnitine, L-carnitine and propionic acid did not exert antiarrhythmic effects. 3 During hypoxia and reoxygenation L-PC consistently prevented the rise of the diastolic left ventricular pressure, and significantly reduced the release of the cardiac enzymes creatine kinase (CK) and lactic dehydrogenase (LDH). 4 The electrophysiological effects of L-PC were then studied on either normal sheep cardiac Purkinje fibres or those manifesting oscillatory afterpotentials induced by barium or strophanthidin. 5 L-PC (1 and 10-mu-M) did not significantly modify action potential characteristics and contractility of normal Purkinje fibres, or the amplitude of OAP induced by strophanthidin or barium. 6 It is concluded that the antiarrhythmic action of L-PC on reoxygenation-induced arrhythmias is not correlated with its direct electrophysiological effects studied on normoxic preparations.