OBJECTIVETo investigate the relationship between sympathetic remodeling and electrical remodeling at the infarcted border zone (IBZ) of rabbit with chronic myocardial infarction (MI).

METHODSThirty rabbits were randomly assigned into two groups: MI group (n = 20): ligation of the anterior descending coronary; sham operation (SO) group (n = 10): without contrary ligation. Eight weeks after surgery, transmural dispersion of repolarization (TDR) at baseline, during sympathetic nerve stimulation, TDR change (DeltaTDR) during sympathetic nerve stimulation and ventricular fibrillation threshold (VFT) were measured at the IBZ in MI group and corresponding zone in SO group. The distribution and densities of growth associated protein 43 (GAP43) and tyrosine hydroxylase (TH) positive nerves in ventricle were also detected with immunohistochemical techniques.

RESULTSEighteen rabbits in the MI group and 10 in the SO group survived to the end of the study. The densities of GAP43 and TH at the IBZ in the MI group were significantly higher than that at the corresponding zone in the SO group (both P < 0.05). The densities of GAP43 and TH in MI rabbits positively correlated with TDR at baseline, TDR or DeltaTDR during sympathetic nerve stimulation (all P < 0.01) and both showed a weak negative correlation with VFT (r =-0.44, P = 0.07; r = -0.41, P = 0.09, respectively).

CONCLUSIONSympathetic remodeling is correlated with electrical remodeling at the IBZ in rabbits with chronic MI.