[Acute insular infarct increases risk of electrocardiogram changes and sudden cardiac death]

To investigate the influence of location and size of acute insular infarct on stroke-related electrocardiogram (ECG) changes and cardiovascular events.

Ninety-nine cases admitted to hospital from October 2007 to June 2009, who were diagnosed as acute middle cerebral artery territory infarct within 48 h after onset and without the history of cardiac diseases, were included in the study. The patients were further divided into three groups: major insular infarct, minor insular infarct and control group, according to the infarct size on MRI diffusion-weighted image. The clinical data, ECG changes and cardiovascular events were compared between left and right insular infarct. Logistic regression was applied to determine the independent risk factors of ECG changes and cardiovascular events.

Large artery atherosclerosis was the main cause of acute insular infarct (71.8 %), which was associated with higher NIHSS score compared to the control group (P < 0.01). Comparing the left and right insular infarct, the frequencies of sinus bradycardia and sudden cardiac death were significantly higher in left insular infarct (P < 0.01 and P < 0.05), while there was a trend that the frequency of atrial fibrillation was higher in right insular infarct (P = 0.079). With the larger size of insular infarct, the frequency of sinus bradycardia, new atrial fibrillation and sudden cardiac death (P<0.01, P<0.05 and P<0.05, respectively) became much higher. Logistic regression analysis showed that major insular infarct was related to the higher frequency of sinus bradycardia (OR = 4.660, 95% CI: 1.646 ~ 13.195; P = 0.004).

Acute insular infarct is associated with the stroke-related ECG changes and sudden cardiac death. Left insular infarct is related to sinus bradycardia, possibly due to the enhanced parasympathetic tone. It deserves clinical attention that the incidence of cardiac autonomic disturbance becomes higher with the enlarged insular infarct size.