Monday January 2, 2006
Brain-Heart Connection - Neurogenic Cardiac Injury
Cardiac injury may occur following many types of brain injury, including trauma, ischemic stroke, and intracerebral hemorrhage. Less common etiologies include tumors, electroconvulsive therapy, and central nervous system infections such as meningitis. Although more difficult to prove, tremendous emotional stress typically following natural disasters 2 or during war may lead to augmented sympathetic tone, abnormal electrocardiogram (ECG) changes, and cardiac injury.
Subarachnoid hemorrhage (SAH)-induced cardiac injury provides a robust example of neurocardiogenic injury. Burch et al. first described neurogenic cardiac injury by demonstrating "cerebral T-wave" electrocardiographic abnormalities in humans with SAH. Elevated troponin levels 4 have also been described and provide evidence that myocardial necrosis may occur. The degree of neurologic injury is a strong predictor of myocardial necrosis after SAH. Cardiac injury, specifically left ventricular (LV) systolic dysfunction, has been described after SAH with an approximate incidence of 10% to 28%. 5 Despite recent advances in diagnostic techniques of cardiac disease, the pathophysiology remains unclear. A catecholamine-mediated mechanism of injury has been demonstrated in experimental and clinical studies.
Read interesting article on Predictors of Neurocardiogenic Injury After Subarachnoid Hemorrhage in stroke (Stroke. 2004;35:548), followed by editorial comment from Dr. Shunichi Homma Myocardial Damage in Patients With Subarachnoid Hemorrhage (Stroke. 2004;35:552.)
References: click to get article/abstract
1. Oppenheimer SM: The cardiac consequences of stroke. Neurol Clin North Am 1992, 10:167-176. via pubmed
2. Yamabe H, et al.: Deep negative t waves and abnormal cardiac sympathetic image (123 I-MIBG) after the great Hanshin Earthquake of 1995. Am J Med Sci 1996, 311:221-224. via pubmed
3. Fabinyi G: Myocardial creatine kinase isoenzyme in serum after subarachnoid haemorrhage. J Neurol Neurosurg Psychiatry 1977, 40:818-820.
4. Horowitz MB: aneurysmal subarachnoid hemorrhage. Acta Neurochir (Wien) 1998, 140:87-93. The use of cardiac troponin-I (cTnI) to determine the incidence of myocardial ischemia and injury in patients with aneurysmal and presumed Aneurysmal Subarachnoid Hemorrhage
5 Zaroff J, et al.: Frequency and regional distribution of LV systolic dysfunction after subarachnoid hemorrhage: an echocardiographic assessment. J Am Soc Echocardiogr 1998, 11:507.