Viitasalo Matti, Oikarinen Lasse, Swan Heikki, Väänänen Heikki, Glatter Kathy, Laitinen Päivi J, Kontula Kimmo, Barron Hal V, Toivonen Lauri, Scheinman Melvin M
Department of Medicine, Cardiac Electrophysiology, University of California, San Francisco, USA.
Circulation. 2002 Nov 5;106(19):2473-8. doi: 10.1161/01.cir.0000036369.16112.7d.
Transmural dispersion of repolarization (TDR) may be related to the genesis of torsade de pointes (TdP) in patients with the long-QT (LQT) syndrome. Experimentally, LQT2 models show increased TDR compared with LQT1, and beta-adrenergic stimulation increases TDR in both models. Clinically, LQT1 patients experience symptoms at elevated heart rates, but LQT2 patients do so at lower rates. The interval from T-wave peak to T-wave end (TPE interval) is the clinical counterpart of TDR. We explored the relationship of TPE interval to heart rate and to the presence of symptoms in patients with LQT1 and LQT2.
We reviewed Holter recordings from 90 genotyped subjects, 31 with LQT1, 28 with LQT2, and 31 from unaffected family members, to record TPE intervals by use of an automated computerized program. The median TPE interval was greater in LQT2 (112+/-5 ms) than LQT1 (91+/-2 ms) or unaffected (86+/-3 ms) patients (P<0.001 for all group comparisons), and the maximal TPE values differed as well. LQT1 patients showed abrupt increases in TPE values at RR intervals from 600 to 900 ms, but LQT2 patients did so at RR intervals from 600 to 1400 ms (longest RR studied). Asymptomatic and symptomatic patients showed similar TDRs.
TDR is greater in LQT2 than in LQT1 patients. LQT1 patients showed a capacity to increase TDR at elevated heart rates, but LQT2 patients did so at a much wider rate range. The magnitude of TDR is not related to a history of TdP.
复极离散度（TDR）可能与长QT（LQT）综合征患者尖端扭转型室速（TdP）的发生有关。实验表明，与LQT1模型相比，LQT2模型的TDR增加，并且β-肾上腺素能刺激在两种模型中均会增加TDR。临床上，LQT1患者在心率升高时出现症状，而LQT2患者在心率较低时出现症状。T波峰至T波终点的间期（TPE间期）是TDR的临床对应指标。我们探讨了LQT1和LQT2患者中TPE间期与心率及症状的关系。
我们回顾了90例基因分型受试者的动态心电图记录，其中31例为LQT1患者，28例为LQT2患者，31例为未受影响的家庭成员，使用自动计算机程序记录TPE间期。LQT2患者的TPE间期中位数（112±5毫秒）大于LQT1患者（91±2毫秒）或未受影响患者（86±3毫秒）（所有组间比较P<0.001），最大TPE值也存在差异。LQT1患者在RR间期从600至900毫秒时TPE值突然增加，但LQT2患者在RR间期从600至1400毫秒（研究的最长RR间期）时出现这种情况。无症状和有症状患者的TDR相似。
LQT2患者的TDR大于LQT1患者。LQT1患者在心率升高时有增加TDR的能力，但LQT2患者在更宽的心率范围内均可如此。TDR的大小与TdP病史无关。
