 P-wave dispersion PWD is defined as the difference between the longest and the shortest P-wave duration recorded from multiple different surface electrocardiogram ECG leads, and it has been reported to be associated with inhomogeneous and discontinuous propagation of sinus impulses5, which are well known electrophysiologic characteristics of the atrium prone to fibrillation. Although it is plausible to hypothesize that PWD might be associated with the heterogeneously distributed microvascular dysfunction, and previous studies have demonstrated the abnormal PWD in patients with CSF, the correlation between TFC heterogeneity and PWD has never been evaluated. 