Effect of elevated plasma norepinephrine on electrocardiographic changes in subarachnoid hemorrhage.

We compared electrocardiographic abnormalities and plasma norepinephrine concentrations in 40 patients with subarachnoid hemorrhage within the first 24 hours, at 72 hours, and after 1 week. In 20 patients with high plasma norepinephrine concentrations within the first 24 hours, sinus tachycardia (p less than 0.02) and negative T waves (p less than 0.01) were more frequent than in the 20 patients with normal plasma norepinephrine concentrations. After 72 hours, only sinus tachycardia (p less than 0.03) was found with increased frequency in the 26 patients with high plasma norepinephrine concentrations. Although 24 patients had high plasma norepinephrine concentrations after 1 week, we found no differences in the frequency of electrocardiographic abnormalities compared to patients with normal plasma norepinephrine. However, QTc prolongation, U waves, ST depression, and arrhythmias were found with similar frequency in patients with both high and normal plasma norepinephrine concentrations. We conclude that, with the exception of sinus tachycardia and negative T waves, electrocardiographic changes in patients with subarachnoid hemorrhage do not depend on elevated plasma norepinephrine concentrations.