Electrocardiographic changes and intracranial pathology.

A young woman who sustained severe head trauma presented to the operating room for emergent surgical intervention. Her electrocardiogram (ECG) exhibited signs of myocardial ischemia, which resolved several days postoperatively. ECG changes suggestive of cardiac pathology can be associated with intracranial pathology, most notably subarachnoid hemorrhage. Delay of operative therapy may have catastrophic results. Experimental data indicates massive sympathetic outflow results from stimulation of the lateral and posterior hypothalamic regions. Large amounts of norepinephrine are released into the systemic circulation, resulting in hypertension, tachycardia, dysrhythmias and ECG changes. Myocardial ischemia and injury can occur from the effects of this excessive sympathetic stimulation. In certain case reports, neurologic patients who experienced ECG changes had normal hearts on postmortem examination. This implies that myocardial recovery can occur despite the appearance of an abnormal ECG in the neurologic patient. Anesthetic management of these patients involves prevention of further increases in intracranial pressure and avoidance of hyperventilation in the presence of hypotension or vasospasm. Continuous ECG monitoring is essential. Ventricular dysrhythmias may prove resistant to conventional pharmaceutical management. Beta blockade may be indicated to prevent excessive cardiac stimulation by endogenous catecholamines, and, in addition, may prevent the formation of the microscopic cardiac lesions typical of this hyperstimulation.