Electrocardiographic abnormalities after nontraumatic subarachnoid hemorrhage.

Electrocardiographic (ECG) abnormalities and rhythm disorders are frequently observed in the acute phase after spontaneous subarachnoid hemorrhage (SAH). These abnormalities are benign and transient in most cases; however, in some patients they can take the form of life-threatening arrhythmias such as ventricular flutter/fibrillation and torsade de pointe. Among the ECG abnormalities observed, prolongation of the Q-T interval, especially if associated with hypokalemia, deserves particular attention because it is frequently present in those patients who will develop life-threatening ventricular arrhythmias. In some cases, the ECG abnormalities mimic those observed in the setting of acute myocardial infarction. Elevated creatine phosphokinase-myocardial fraction isoenzyme, suggesting underlying cardiac damage, has also been reported. The pathophysiology of these abnormalities is related to an imbalance of autonomic cardiovascular control. Because some electrical and morphological heart abnormalities are experimentally induced by catecholamine injection, the role of circulating catecholamines has been investigated in depth. Pathologically, the hearts of patients who die after SAH can show a peculiar morphological lesion defined as "myocytolysis." Intramyocardial hemorrhages have also been described. These observations confirm the utility of continuous cardiac monitoring in patients with SAH.