Epicardial ECG signals following global myocardial ischaemia

Experiments were performed on 10 dog hearts undergone 15 to 90-minute normothermic arrests and 60-minute reperfusion in a special heart-lung model. The purpose of the experiments was to characterize the global ischaemic effects recorded on epicardial electrograms. The duration of QRS complexes and of RR intervals, the integral of ST segment shifts (sigma ST), the number of points showed ST segment displacements (NoST) and the ST segment isopotential map obtained by computer control were evaluated. Only a minor ST segment deviation, a small increase in duration of QRS complexes and of RR intervals with bradycardia and a tendency to electrical stability were found after global ischaemic influences. These observations indicate that pathological electrical manifestations occurring after a global ischaemia are less serious than those occurring after a focal ischaemia.