Adiponectin Prolongs Repolarization in Rat Ventricular Myocardium

Adiponectin confers protective effects in the cardiovascular system. However, its effects on cardiac electrophysiological characteristics are unclear. The aim of the present study was evaluating myocardial electrophysiological parameters under chronic adiponectin treatment in rats. Epicardial mapping in 64 leads along with ECG recording were performed in the anaesthetized rats in 1 week after the placement of subcutaneous osmotic mini-pumps. The adiponectin group ( n = 9) received a pump containing adiponectin, and the control group ( n = 7) received an empty pump (sham surgery). In each epicardial lead, the activation time (AT), the end of repolarization time (RT), activation–repolarization intervals (ARI) and dispersion of repolarization (DOR) were determined. The rats treated with adiponectin showed prolonged ARIs in the left ventricle and the increased DOR as compared to the controls [20.82 (IQR 18.43–27.29) vs 14.36 (IQR 12.09–16.67), р = 0.02] and [35.1 (IQR 30.5–47.5) vs 26.75 (IQR 26.63–26.75), р = 0.03], in ms, respectively. At the same time, in the right ventricle similar parameters did not differ between groups. In line with the epicardial mapping parameters, QT and Tpeak-Tend intervals in the body surface ECG were prolonged in the adiponectin-treated animals as compared to the controls [0.07 (IQR 0.06–0.08) vs 0.06 (IQR 0.05–0.06), р = 0.02] and [0.04 (IQR 0.03–0.04) vs 0.02 (IQR 0.01–0.03), р = 0.009], in sec, respectively. Hyperadiponectinemia was associated with prolongation of ventricular repolarization.