乙酰胆碱灌注与洗脱对离体家兔右房复极及跨壁离散度的影响

Influence of acetylcholine perfusion and washout on left atrial repolarization and transmural dispersion in isolated rabbit heart

目的:探讨乙酰胆碱(ACh)灌注与洗脱对离体家兔右房复极时限及跨壁复极离散度(TDR)的影响。方法:采用单相动作电位(MAP)记录技术,在Langendorff离体心脏灌流条件下,同步且同部位记录9例家兔右房心外膜心肌、中层心肌和心内膜心肌MAP,测量并计算ACh(10-5mol/L,0.3ml/kg)灌注及洗脱后,心房MAP复极达90%的时间(MAPD90)及TDR。结果:ACh灌注时,3层心房肌的MAPD90值较ACh灌注前明显缩短(P<0.05,给药后30±5s),TDR较给药前显著增加(P<0.05,给药后30±5s);在ACh洗脱后,三层右房心肌MAPD90及TDR值较灌注ACh前无显著差异(P>0.05,给药后100±5s)。结论:ACh灌注时与洗脱后在右房复极方面存在明显不同的电生理变化,它们所致心律失常的机制有必要从多角度进行进一步研究。

Objective:To investigate the influence of acetylcholine perfusion and washout on transmural dispersion of atrial repolarization in isolated rabbit heart.Methods:With the monophasic action potential(MAP)recording technique,MAPs of endocardial,midmyocardial,and epicardial cells were recorded at the atrial myocardium in isolated Langendorff perfused rabbit heart.Monophasic action potential duration at 90% repolarization(MAPD90)and transmural dispersion of repolarization(TDR)among three atrial myocardial layers were compared after perfusion and washout of ACh(10-5 mol/L,0.3 ml/kg).Results:During perfusion of ACh,MAPD90 was shorter(P<0.05),and TDR was longer(P<0.05)than before.Compared with the state before ACh perfusion,but MAPD90 and TDR did not alter significantly after washout of ACh(P>0.05).Conclusion:There were some different aspects in the mechanism of arrhythmia during perfusion and after washout of ACh on atrial repolarization and transmural dispersion.