Sezgin Alpay Turan, Barutcu Irfan, Ozdemir Ramazan, Gullu Hakan, Topal Ergun, Esen Ali Metin, Tandogan Izzet, Acikgoz Nusret
Department of Cardiology, Baskent University, Practice and Research Hospital, Adana, Turkey.
Angiology. 2007 Jun-Jul;58(3):289-94. doi: 10.1177/0003319707302486.
QT interval dispersion reflects regional variations in ventricular repolarization and cardiac electrical instability. Previous studies have showed that QT interval dispersion changes during episodes of myocardial ischemia. Slow coronary flow (SCF) in epicardial coronary arteries is a rare and unique angiographic finding. Whether this pattern of flow is associated with electrocardiographic abnormalities is unknown. Therefore, this study was designed to investigate whether SCF results in electrocardiographic (ECG) changes compared to normal coronary flow. For this aim 24 patients with angiographically proven SCF who had no obstructive coronary lesion (group I) and 25 patients without coronary artery disease (group II) were included in the study. Both groups underwent a routine standard 12-lead surface electrocardiogram recorded at 50 mm/s during rest. QT dispersion (QTd), corrected QT (QTc), and corrected QT dispersion (QTcd) were calculated. Distributions of sex, age, body mass index (BMI), and cardiac risk factors were similar in the 2 groups. Mean heart rate was similar in the 2 groups (74 +/-8 vs 77 +/- 7 p > 0.05). Mean QRS interval durations were similar in the groups (92 +/-7 vs 90 +/-6 ms p > 0.005). In group I, QTd, QTcd, and QTc, were significantly higher than in group II (QTd: 73 +/-14 vs 40 +/-14; QTcd: 71 +/-15 vs 42 +/-9; QTc: 414 +/-14 vs 388 +/-13, respectively p <0.05). In conclusion, SCF was found to be associated with prolonged QT interval and increased QT dispersion. Ischemia in microvascular level and/or altered autonomic regulation of the heart may be responsible mechanisms.
QT间期离散度反映心室复极的区域差异和心脏电不稳定性。先前的研究表明，心肌缺血发作期间QT间期离散度会发生变化。心外膜冠状动脉慢血流（SCF）是一种罕见且独特的血管造影表现。这种血流模式是否与心电图异常相关尚不清楚。因此，本研究旨在调查与正常冠状动脉血流相比，SCF是否会导致心电图（ECG）改变。为实现这一目标，本研究纳入了24例经血管造影证实存在SCF且无阻塞性冠状动脉病变的患者（I组）和25例无冠状动脉疾病的患者（II组）。两组患者均在静息状态下以50mm/s的速度进行常规标准12导联体表心电图记录。计算QT离散度（QTd）、校正QT（QTc）和校正QT离散度（QTcd）。两组患者的性别、年龄、体重指数（BMI）和心脏危险因素分布相似。两组患者的平均心率相似（74±8 vs 77±7，p>0.05）。两组患者的平均QRS间期持续时间相似（92±7 vs 90±6ms，p>0.005）。I组的QTd、QTcd和QTc均显著高于II组（QTd：73±14 vs 40±14；QTcd：71±15 vs 42±9；QTc：414±14 vs 388±13，p均<0.05）。总之，发现SCF与QT间期延长和QT离散度增加有关。微血管水平的缺血和/或心脏自主调节改变可能是其相关机制。
