冠状动脉血管成形术对QT离散度的影响及其意义

Reduction in QT dispersion by successful coronary angioplasty in coronary heart disease

为阐明冠状动脉血管成形术（CA）对QT离散度（QTd）的影响，并探讨其意义。我们分析48例（心绞痛14例，心肌梗塞34例）CA术前后1天内所记录的心电图，测算QT、QTd、心率校正QT间期（QTc）和心率校正QT离散度（QTcd）。病例分为：心绞痛CA成功组、心肌梗塞CA成功组和CA失败组，分别对3组的4项指标作术前与术后比较。结论：前两组本前与本后QT和QTc差异均无显著性，但术后QTd和QTcd较术前显著减小（分别为38±13vs65±15ms，1．2±0．5vs2．4±0．8；38±16vs66±25ms，1．3±0．6vs2．1±0．9，P均＜0．001）。CA失败组术前后4项指标差异均无显著性。结论：成功的CA能显著减小心绞痛和心肌梗塞患者的QTd，提示可能改善患者的预后；术后QTd减小可能反映了顿抑或冬眠心肌的“苏醒”，并表明梗塞区尚有存活心肌。

The present study aimed at elucidating the effects of coronary angioplasty (CA) on QT dispersion (QTd) and finding out their significances. The electrocardiograms recorded be fore and after CA in 48 patients including 14 with angina pectoris (AP) and 34 with myocardial infarction (MI) were analyzed.QT intervals,QTd and heart-rate-corrected QT intervals (QTc) and QTd (QTcd) were gauged and calculated. The comparisions of these 4 indices be fore CA to those after CA were made respectively in 3 groups (AP CA success,MI CA success,and CA failure). In the former two groups,QT and QTc after CA were not significantly different from those be fore CA. But QTd and QTcd after CA were remarkably reduced (38±13 vs 65±15ms, 1. 2±0. 5 vs 2. 4±0. 8 in AP group; 38±16 vs 66±25ms, 1. 3± 0. 6 vs 2. 1±0. 9 in MI group respectively, all P values <0. 001 ). In CA failure group, however, no changes of the 4 indices were shown after CA. Successful CA could notably reduce QTd in patients with AP or with MI,suggesting that it might improve the prognosis of coronary heart disease. The reductions in QTd after CA might imply the revivals of stunned or hibernating myocardium as well as the existence of surviving myocardium in infarcted areas.