Brain lateralization and sudden death: Its role in the neurogenic heart syndrome

Sudden cardiac death is the leading cause of mortality, accounting for approximately 50% of all cardiovascular deaths and 12% deaths. Although sudden deaths are commonly seen in patients with structural and ischemic heart diseases, some patients lack any evidence of coronary atherosclerosis or structural heart abnormalities. In these patients mental stress and abnormal neurological conditions can produce cardiovascular autonomic disturbances leading to life-threatening arrhythmias and sudden death. Emotional, physiological and physical stress is associated with increased rates of cerebrovascular events and sudden deaths. Human studies in healthy individuals showed lateralization of cardiovascular autonomic function exists in the forebrain, particularly the insular cortex.Considerable evidence exists regarding the role of forebrain lateralization in cardiovascular autonomic regulation in patients with ischemic and hemorrhagic stroke. Particularly insular cortex involvement is associated with more pronounced autonomic imbalance leading to life threatening arrhythmias and sudden death. Left-handers may have a lower risk of sudden death compared with right-handers. Future studies should focus on the association of handedness with cardiovascular autonomic networks and sudden death in different neurological diseases.Identification of patients at risk for neurogenic sudden death by clinical characteristics and noninvasive diagnostic tools may help implement prophylactic and therapeutic interventions that may reduce the mortality rate.