Effects of stroke localization on cardiac autonomic balance and sudden death

Background and Purpose-Stroke has been shown to alter autonomic function. T he purpose of this study was to show the differential effects of stroke loc alization on autonomic function parameters assessed by heart rate variabili ty (HRV), Methods-To determine the differential effect of ischemic stroke localizatio n on autonomic cardiac innervation, we evaluated 62 patients with ischemic stroke and 62 age- and sex-matched controls. The localization of the infarc t was determined by CT and MRI. Power spectrum analysis of HRV was performe d. Myocardial necrosis was ruled out by echocardiography and creatine kinas e myocardial isoenzymes measurements. Results-All stroke patients had significantly decreased low frequency, high frequency, and standard deviation of all relative risk intervals values (P <0.001). However, patients with right-middle cerebral artery (R-MCA) and in sula lesions had significantly lower power spectrum analysis values compare d with all other localizations (P<0.001). in addition, 5 patients with R-MC A insular lesions died suddenly compared with 2 patients with left-middle c erebral artery insular lesions during hospitalization. Both sympathetic- an d parasympathetic-controlled HRV were decreased in patients with ischemic s troke. The most pronounced decrease was found in the territory of R-MCA ins ular cortex, which suggests that cardiac autonomic tone may be regulated by insula and that these patients are more prone to cardiac complications suc h as arrhythmias and sudden death due to autonomic imbalance. Conclusion-We conclude that stroke in the region of insula (especially the right) leads to decreased HRV and to increased incidence of sudden death.