Adiponectin Prolongs Repolarization in Rat Ventricular Myocardium

Adiponectin confers protective effects in the cardiovascularsystem. However, its effects on cardiac electrophysiological characteristicsare unclear. The aim of the present study was evaluating myocardial electrophysiologicalparameters under chronic adiponectin treatment in rats. Epicardialmapping in 64 leads along with ECG recording were performed in theanaesthetized rats in 1 week after the placement of subcutaneousosmotic 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 ratstreated with adiponectin showed prolonged ARIs in the left ventricleand 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. Atthe same time, in the right ventricle similar parameters did notdiffer between groups. In line with the epicardial mapping parameters,QT and Tpeak-Tend intervals in the body surface ECG were prolongedin 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 ventricularrepolarization.