Electrocardiographic abnormalities in cerebral disorders. Report of six cases and review of the literature

Factors influencing infarct size following experimental coronary artery occlusions

The purpose of this study was the determination of whether hemodynamic and pharmacologic factors influence the extent and severity of myocardial necrosis produced by coronary occlusion. In 48 dogs, 10 to 14 epicardial leads were recorded on the anterior surface of the left ventricle in the distribution and vicinity of the site of occlusion of a branch of the left anterior descending coronary artery. The average S-T segment elevation for each animal was determined at 5-min intervals after occlusion. This elevation was used as an index of the presence and severity of myocardial ischemic injury. The number of sites showing this elevation provided an additional measure of the size of the injured area. Occlusion alone raised the average S-T segment elevation from 0.22 ± 0.04 to 3.32 ± 0.37 mv (SEM). Isoproterenol, ouabain, glucagon, bretylium, and tachycardia given prior to a repeated occlusion increased the severity and extent of ischemic injury, while propranolol decreased it. Elevation of arterial pressure with methoxamine reduced the occlusion-induced S-T segment elevation, and lowering of the mean arterial pressure by hemorrhage had the opposite effect. In 19 additional experiments, propranolol, isoproterenol, and alterations in arterial pressure produced similar alterations in S-T segment elevation when these interventions were applied as long as 3 hr after ligation. In a third group of dogs, myocardial creatine phosphokinase (CPK) activity was determined 24 hr after occlusion at the same sites at which epicardial electrocardiograms were taken. Depression of myocardial CPK activity in injured portions of the left ventricle 24 hr after coronary artery ligation correlated well with S-T segment elevation in the same sites 15 min after ligation. Moreover, isoproterenol increased and propranolol decreased the area of depression of myocardial CPK activity. We conclude that the hemodynamic status and neurohumoral background at the time of occlusion and for up to 3 hr thereafter can alter the extent and severity of myocardial ischemic injury and myocardial necrosis.

Abnormal U waves in the electrocardiogram in subarachnoid haemorrhage

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Electrocardiographic abnormalities simulating myocardial infarction in intracerebral haemorhage and cerebral thrombosis

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Notched T waves in young persons with central nervous system lesions

Eighty-nine abnormal electrocardiograms taken on young persons with central nervous system (CNS) lesions were reviewed. Most had S-T segment and T-wave abnormalities of a nonspecific type. A high incidence of notched T waves was also noted. In this group of patients with CNS lesions the notching may be due to asymmetrical alterations in sympathetic tone to the ventricle.

Giant T wave inversion

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Functional distribution of right and left stellate innervation to the ventricles. Production of neurogenic electrocardiographic changes by unilateral alteration of sympathetic tone

Changes of the electrocardiogram and of ventricular refractory period were measured following either unilateral stellate ganglion stimulation or ablation in the open chest dog preparation.

Right stellate ganglionectomy or left stellate stimulation produces prolonged Q-T intervals and increased T-wave amplitude. Left stellate ganglionectomy or right stellate stimulation produces increased T-wave negativity without measurable change in the Q-T interval.

The differing patterns of electrocardiographic wave form resulting from changes in sympathetic tone mediated by right and left stellate innervation could be correlated with changes in ventricular refractory period. Following right stellate ganglionectomy, refractory period prolongations were most marked over the anterior ventricular surface; left stellate ganglionectomy produced the greatest prolongation on the posterior surface.

Although the right and left stellate innervations of the ventricles overlap, the left stellate influence is predominant over the posterior wall of the ventricles, while right stellate influence dominates the anterior ventricular walls.

The electrocardiographic form changes observed following unilateral alteration of sympathetic tone paralleled those electrocardiographic abnormalities seen in patients with lesions of the central nervous system, suggesting a possible functional explanation for these clinical findings.