The role of nuclear cardiac imaging in redefining neurogenic stunned myocardium in subarachnoid hemorrhage: a deeper look into the heart

Subarachnoid hemorrhage may be complicated by neurogenic stunned myocardium, a catecholamine-induced transient cardiomyopathy that displays a wide clinical spectrum of cardiac abnormalities, including electrocardiographic changes, arrhythmias, myocardial necrosis, and left ventricular systolic and diastolic dysfunction. However, less is known about the cardiac metabolic consequences of acute subarachnoid hemorrhage. Prunet and coworkers’ recent study provides scintigraphic evidence suggesting that glucose metabolism and sympathetic cardiac innervation are severely and globally depressed during the acute phase of the disease. Metabolic and innervation abnormalities are largely overlapped and are probably not causally related to myocardial ischemia, suggesting that impaired glucose metabolism is probably neurogenic in nature. The scintigraphic defects seem to reverse slowly, within months of the onset of cerebral bleeding. Interestingly, scintigraphic evidence of metabolic myocardial alterations may exist even in the absence of clinical features of cardiac disease, possibly representing a subclinical type of neurogenic stunned myocardium.