The aim of this study was to investigate QT dispersion during atrial pacing in patients with coronary artery disease (CAD) without clinical ischemia, such as angina pectoris and ST segment depression. Thirteen patients with normal coronary arteries and 42 patients with CAD (12 with single-vessel, 16 with two-vessel and 14 with three-vessel disease) having no angina pectoris or ST segment depression during atrial pacing with maximum rate of 120/minute were enrolled in the study. Twelve-lead surface ECGs were recorded at 100 mm/second paper speed before pacing, at maximum pacing rate, and during the recovery period for measurement of QT interval parameters.
Corrected QTd (QTcd) increased from 43.4 ±8.1 to 49.3 ±9.5 ms (p<0.05) in the control group, from 46.1 ±8.1 to 74.3 ±7.7 ms (p < 0.000 1) in the single-vessel disease group, from 48.5 ±10.4 to 93.8 ±22.1 ms in the two-vessel disease group (p< 0.0001), and from 49.7 ±13.6 to 128.5 ±31 ms (p<0.0001) in the three-vessel disease group at peak atrial pacing period. A positive correlation was found between the severity of CAD and QTcd (r=0.49, p<0.0001). It was found that pacing-induced QTc dispersion identifies coronary disease extent, even when there is no ST depression or T wave inversion during pacing.
研究发现,在最大房性起搏期间,对照组的校正QT离散度(QTcd)从43.4±8.1增加到49.3±9.5毫秒(p<0.05),单支病变组从46.1±8.1增加到74.3±7.7毫秒(p<0.0001),双支病变组从48.5±10.4增加到93.8±22.1毫秒(p<0.0001),三支病变组从49.7±13.6增加到128.5±31毫秒(p<0.0001)。发现CAD的严重程度与QTcd呈正相关(r=0.49,p<0.0001)。研究表明,起搏诱发的QTc离散度可以识别冠状动脉疾病的程度,即使在起搏期间没有ST段压低或T波倒置的情况下也能识别。