Backgrounds: The right insular cortical stroke is believed to have arrhythmogenic potential such as secondary atrial fibrillation (AF). The P wave-triggered signal-averaged electrocardiogram (SA-ECG) can reveal the P wave dispersion which is associated with the risk of AF in the future. However, there has been no relevant clinical study and we investigated the P wave dispersion after stroke involving right insula.
Methods: We recruited acute stroke patients consecutively, who admitted from February 2012 to October 2013 and took routine work-up with SA-ECG. Patients who had AF on admission were excluded. SA-ECG was followed up two years after stroke onset. Significant P-wave dispersion was defined as ‘P-wave duration (PWD) >125ms for the predictor of future AF risk. We analyzed the difference of SA-ECG between the right insular cortex lesion and other stroke.
Results: A total of 252 subjects were enrolled and 49 among them had right insular involvement. Follow up SA-ECG were available in 69 patients. In acute stroke period, the patients with right insular lesion had longer P wave duration than the other stroke patients (154.0+29.6 vs. 133.5+26.5 ms, p<0.001). In the patients with right insular involvement, prolonged P wave duration in acute period was shortened in follow up SA-ECG after two years (n=17, 164.5+35.2 vs. 131.7+22.3 ms, p=0.003). However, patients with other stroke lesion did not show such interval change. During observation period, AF occurred more frequently in the subjects with right insular lesion than other stroke patients (33% vs 17%, p=0.01).
Conclusion: Our data suggest that the right insular lesion is associated with increased P wave dispersion transiently in acute stroke period and this might explain the development of secondary AF shortly after right insular cortex stroke.