Huang Congxin, Bao Mingwei, Jiang Hong, Liu Jie, Yang Bo, Wang Teng
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei, China.
Circ J. 2004 Dec;68(12):1205-9. doi: 10.1253/circj.68.1205.
The relationship between monophasic action potential duration (MAPD) and effective refractory period (ERP) is poorly understood after myocardial infarction (MI) in vivo.
Forty rabbits were randomized into either a sham operation (SO) group (n=10) or MI group (n=30), both of which underwent thoracotomy, but the left anterior descending coronary artery was occluded in the MI group only. The MAPD and ERP of the endocardial, midmyocardial and epicardial cells of the infarction zone were observed at baseline, 2 days after thoracotomy and then 5 min, 15 min, 30 min, 2 days, 14 days and 60 days after coronary occlusion (CO). At baseline, ERP correlated strongly with MAPD90. During the 5-30 min after CO, both MAPD90 and ERP of the 3 layers of the myocardium shortened markedly (eg, MAPD90 Mid) was approximately 50% of the baseline value at 5 min after CO). MAPD90 and ERP recovered gradually over the 2-60 days after MI. ERPMid exceeded MAPD90 Mid and the post repolarization refractoriness phenomenon appeared during the 5-30 min after CO.
The different changing trends of the MAPD and ERP of the mid-myocardial cells may underlie the arrhythmias that occur after MI.
在心肌梗死（MI）后的体内环境中，单相动作电位持续时间（MAPD）与有效不应期（ERP）之间的关系尚未完全明确。
40只兔子被随机分为假手术（SO）组（n = 10）和MI组（n = 30），两组均接受开胸手术，但仅MI组结扎左冠状动脉前降支。在基线、开胸术后2天以及冠状动脉闭塞（CO）后5分钟、15分钟、30分钟、2天、14天和60天观察梗死区心内膜、心肌中层和心外膜细胞的MAPD和ERP。在基线时，ERP与MAPD90密切相关。在CO后的5 - 30分钟内，心肌三层的MAPD90和ERP均显著缩短（例如，CO后5分钟时，心肌中层的MAPD90约为基线值的50%）。MI后2 - 60天，MAPD90和ERP逐渐恢复。在CO后的5 - 30分钟内，心肌中层的ERP超过MAPD90，出现复极后不应期现象。
心肌中层细胞的MAPD和ERP的不同变化趋势可能是MI后心律失常发生的基础。
