Lysolecithin and acute coronary ligation in the anaesthetised dog

The metabolism of lysolecithin by the normal and by the ischaemic heart was examined in eight anaesthetised dogs. Relative lysolecithin concentrations (%lysolecithin) were measured in arterial, local (ischaemic) venous and coronary sinus (nonischaemic) blood samples, withdrawn before and at 2, 6, 10, 15 and 20 min after ligation of the left anterior descending coronary artery. Before ligation, 9.0 +/- 0.8% of the arterial lecithin was in the form of the lyso-derivative. The heart extracted lysolecithin, as reflected by the positive arterio-venous difference of lysolecithin. Arterio-venous differences of %lysolecithin across both the ischaemic and nonischaemic myocardium tended to diminish after coronary ligation, whether or not the dogs developed ventricular fibrillation. These results do not support the view that the formation of lysolecithin during ischaemia precipitates arrhythmias, since lysolecithin levels do not reach those necessary to induce electrophysiological abnormalities in vitro. Nor will the uniform response of the ischaemic and nonischaemic tissue result in metabolic heterogeneity leading to electrophysiological heterogeneity, which is thought to be an important factor in the development of re-entry arrhythmias.