Mezilis N E, Parthenakis F I, Kanakaraki M K, Kanoupakis E M, Vardas P E
Cardiology Department, Heraklion University Hospital, Crete, Greece.
Pacing Clin Electrophysiol. 1998 Nov;21(11 Pt 2):2387-91. doi: 10.1111/j.1540-8159.1998.tb01187.x.
This study examined the changes in QT dynamics occurring during 5-minute intervals sampled immediately before and 1 hour after episodes of nonsustained ventricular tachycardia (VT) in patients with hypertrophic cardiomyopathy (HCM). Twenty-four hour Holter recordings were performed in 10 patients with HCM in the absence of antiarrhythmic medications and processed by the ELA Medical QT analysis software. All sinus complexes were averaged over 30-second segments and 2,880 templates were created. For each template, a mean corrected QTec (time interval between the onset of QRS and the end of the T wave) and QTac (time interval between the onset of the QRS and the peak of the T wave) were calculated, with their standard deviations (SDQTe and SDQTa) taken as indices of QT variability. The slopes of the regression line for the QTe and QTa against the corresponding RR also were calculated. Forty 5-minute segments were analyzed immediately before (sample A) and 1 hour after (sample B) 20 episodes of nonsustained VT. QTac was significantly longer in group A than in group B (321 +/- 20 vs 312 +/- 22, P < 0.0001) and SDQTa was significantly lower (2.8 +/- 1.2 vs 4.7 +/- 3.7, P < 0.03). There were no significant differences in QTec, SDQTe, QTe/RR and QTa/RR before and after the episodes. Our data indicate that in patients with HCM, the averaged QTac is significantly longer and the QTa variability significantly lower before episodes of nonsustained VT.
本研究检测了肥厚型心肌病（HCM）患者非持续性室性心动过速（VT）发作前即刻及发作后1小时采集的5分钟间期内QT间期动态变化情况。对10例未服用抗心律失常药物的HCM患者进行了24小时动态心电图记录，并采用ELA Medical QT分析软件进行处理。所有窦性复合波按30秒段进行平均，共创建了2880个模板。对于每个模板，计算平均校正QTec（QRS波起点至T波终点的时间间期）和QTac（QRS波起点至T波峰值的时间间期），并将其标准差（SDQTe和SDQTa）作为QT变异性指标。还计算了QTe和QTa相对于相应RR间期的回归线斜率。对20次非持续性VT发作前即刻（样本A）和发作后1小时（样本B）的40个5分钟时段进行了分析。A组的QTac显著长于B组（321±20 vs 312±22，P<0.0001），且SDQTa显著更低（2.8±1.2 vs 4.7±3.7，P<0.03）。发作前后QTec、SDQTe、QTe/RR和QTa/RR无显著差异。我们的数据表明，在HCM患者中，非持续性VT发作前平均QTac显著更长，QTa变异性显著更低。
