Establishment of heart failure induced by rapid right ventricular pacing in the rat

Objective Rapid right ventricular pacing (RVP) is a classical method for studying the mechanism of congestive heart failure (CHF) . At present, most of the studies are in large animals models. The aim of this study was to establish rapid pacing induced heart failure in a rat model. Methods Eighteen healthy male SD rats (weight, 290-310 g) were randomly divided into Normal control group, Sham group and Pacing group respectively. The rats in normal control group were fed routinely, the sham and pacing group received pacemaker and electrode implantation and antibiotics for 7 days, then the sham group were fed routinely and the pacing group received the ventricular pacing (550 beats per minute) for 4 weeks. Results The animals in the pacing group showed decreased activity, anorexia, and shortness of breath. Compared with the normal control group and sham group, the weight, left ventricular ejection fractional (LVEF) and left ventricular fractional shortening (LVFS) [(474±20.34) g vs. (464±22.80) g vs. (410.07±19.46) g] , LVEF [ (83.30±2.30) % vs. (81.80±2.40) % vs. (64.30±2.20) %] and LVFS [(46.50±2.70) % vs. (44.70±2.40) % vs. (29.10±0.90) %] of the rats in pacing group decreased significantly, while the autonomic heart rate, heart mass and LVEDP increased significantly (the difference was statistically significant) . Pathological examination of myocardial tissue showed that there were myocardial edema, degeneration of some myocardial cells, congestion of the interstitium, infiltration of inflammatory cells and disorder of the arrangement of the fibers in the pacing group, and the fibrosis in pacing was more serious than that in control group. Conclusion The SD rat model of CHF induced by RVP was successfu in this study. Key words: Heart failure; Animal models; Rapid; Right ventricular pacing