Changes of transmural repolarization heterogeneity and ion currents in rabbits with left ventricular hypertrophy / 中国病理生理杂志

ABSTRACT

AIM: To investigate the changes of transmural repolarization heterogeneity and ion currents in rabbits with left ventricular hypertrophy. METHODS: Ventricular hypertrophy was induced by a partial constriction of the abdominal aorta in rabbits. Myocytes were isolated by a two steps enzymological method. The sub-endocardial (Endo) and sub-epicardium (Epi) tissues were separated from other region (midmyocardium, Mid) with a razor. Whole cell patch clamp technique was used to record the action potential and ion currents. RESULTS: The action potentials duration at 90% repolarization (APD 90 ) of Epi, Mid and Endo were all prolonged significantly in hypertrophy group compared to control group. This prolongation of APD 90 was more pronounced in Mid (26.0%?2.7%) than that in Epi (14.0%?1.6%) and Endo (10.0%?1.1%). The transmural repolarization heterogeneity was increased significantly in the hypertrophy group. The I Ks and I to density in Epi, Mid and Endo was decreased significantly in hypertrophy group compared to those in control group. This decrease in I Ks and I to density was more pronounced in Mid than in Epi and Endo. No significantly difference of I Ca,L and I Kr density between hypertrophy group and control group in three layers was observed. The I K1 density decreased significantly in hypertrophy group compared to control group, but the extent of the decrease had no differences among the three layers. CONCLUSIONS: The transmural repolarization heterogeneity increases significantly in rabbit hypertrophied ventricle. The decrease in transmural heterogeneity of I to and I Ks is the main causes. [