FXYD1 and myocardial infarction: The present study revealed, for the first time, the role of miRNA in ischemic ventricular arrhythmias in rats with estrogen deficiency and miR-151-5p as a new arrhythmogenic miRNA acting on FXYD1. We first found that miR-151-5p was significantly down-regulated in ventricular cardiac tissues of OVX +MI rats compared with MI rats, though OVX alone did not alter miR-151-5p expression.