The electrocardiogram and the central nervous system

Abnormalities of ECG wave form occur in some patients with central nervous system lesions. Distinctive electrocardiographic abnormalities associated with central nervous system lesions are prolonged QT intervals, large upright or deeply inverted T waves, bradycardia, and prominent U waves. In some instances deeply inverted T waves occur, similar to those due to acute myocardial infarction. Less striking abnormalities of the ST segments and T waves occur in some cases, and may be misinterpreted as due to ischemic heart disease, drugs, or electrolyte disorders.It is likely that the ECG changes are mediated by abnormalities of sympathetic tone to the heart. A functional change in action potential form as the cause of the ECG findings is supported by the findings of normal hearts at autopsy and by the experimental data showing almost immediate ECG changes during sympathetic stimulation and ablation. Anatomic cardiac lesions, however, have been reported in some patients dying with central nervous system disease and in experimental animals with central nervous system stimulation or induced lesions.