Chronic heart failure model in rabbits based on the concept of the bifurcation/trifurcation coronary artery branching pattern

The aim of this study was to develop a reliable chronic heart failure model by coronary artery ligation in the rabbit on the basis of the new concept of the bifurcation/trifurcation classification system of the epicardial branching pattern of the left coronary artery (LCA). New Zealand White rabbits (n = 37) were divided into 3 experimental groups: a posterolateral division of the bifurcation pattern of the LCA was ligated at the 75% level from the apex along the course of the division (B75 group, n = 15); a lateral division of the trifurcation pattern at the 75% level (T75 group, n = 11); and a posterolateral division of the bifurcation pattern at the 50% level (B50 group, n = 11). The infarct size and the lung and liver water content were determined at 4 weeks following ligation. The Q or QS wave on electrocardiogram (ECG) and the left ventricular (LV) dimensions (LVIDs and LVIDd), fractional shortening (FS), and mitral E-point to septal separation on ultrasonography were assessed at 10 min and at preligation and at 1, 2, and 4 weeks following ligation. The B75 group showed higher mortality (46.7%) than the T75 and B50 groups. The mean infarct size in the B75 group was 22.55 +/- 5.34% which was significantly larger than in the B50 (13.84 +/- 5.46%) and T75 (12.90 +/- 2.67%) groups (p < 0.001). All 3 groups had significantly greater Q or QS wave amplitudes on ECG at 1, 2, and 4 weeks than at 10 min after ligation. At 1 and 2 weeks after ligation, LVIDd, LVIDs, and FS showed significant dfferences in the B75 group as compared with the other groups. The level of ligation of the LCA for the development of a reliable chronic heart failure model in the rabbit is recommended to be 50% from the apex along the course of the posterolateral division in the bifurcation pattern and 75% from the apex along the course of the lateral division in the trifurcation pattern.