Moss A J, Schwartz P J, Crampton R S, Tzivoni D, Locati E H, MacCluer J, Hall W J, Weitkamp L, Vincent G M, Garson A
Department of Medicine, University of Rochester School of Medicine and Dentistry, N.Y.
Circulation. 1991 Sep;84(3):1136-44. doi: 10.1161/01.cir.84.3.1136.
The Long QT Syndrome (LQTS) is an infrequently occurring familial disorder in which affected individuals have electrocardiographic QT interval prolongation and a propensity to ventricular tachyarrhythmic syncope and sudden death. We prospectively investigated the clinical characteristics and the long-term course of 3,343 individuals from 328 families in which one or more members were identified as affected with LQTS (QTc greater than 0.44 sec1/2).
The first member of a family to be identified with LQTS, the proband, was usually brought to medical attention because of a syncopal episode during childhood or teenage years. Probands (n = 328) were younger at first contact (age 21 +/- 15 years), more likely to be female (69%), and had a higher frequency of preenrollment syncope or cardiac arrest with resuscitation (80%), congenital deafness (7%), a resting heart rate less than 60 beats/min (31%), QTc greater than or equal to 0.50 sec1/2 (52%), and a history of ventricular tachyarrhythmia (47%) than other affected (n = 688) and unaffected (n = 1,004) family members. Arrhythmogenic syncope often occurred in association with acute physical, emotional, or auditory arousal. The syncopal episodes were frequently misinterpreted as a seizure disorder. By age 12 years, 50% of the probands had experienced at least one syncopal episode or death. The rates of postenrollment syncope (one or more episodes) and probable LQTS-related death (before age 50 years) for probands (n = 235; average follow-up 54 months per patient) were 5.0% per year and 0.9% per year, respectively; these event rates were considerably higher than those observed among affected and unaffected family members.
Among 232 probands and 1,264 family members with prospective follow-up, three factors made significant independent contributions to the risk of subsequent syncope or probable LQTS-related death before age 50 years, whichever occurred first (Cox hazard ratio; 95% confidence limits): 1) QTc (1.052; 1.017, 1.088), 2) history of cardiac event (3.1; 1.3, 7.2), and 3) heart rate (1.017; 1.004, 1.031). The findings from this prospective longitudinal study highlight the clinical features, risk factors, and course of LQTS.
长QT综合征（LQTS）是一种罕见的家族性疾病，患者心电图QT间期延长，易发生室性快速心律失常性晕厥和猝死。我们对来自328个家庭的3343名个体进行了前瞻性研究，这些家庭中一个或多个成员被确诊患有LQTS（校正QT间期大于0.44秒）。
家族中首个被确诊为LQTS的成员，即先证者，通常因儿童期或青少年期的晕厥发作而就医。先证者（n = 328）首次就诊时年龄较轻（21±15岁），女性比例较高（69%），入组前晕厥或心脏骤停复苏的发生率较高（80%），先天性耳聋发生率为7%，静息心率低于60次/分钟的比例为31%，校正QT间期大于或等于0.50秒的比例为52%，室性快速心律失常病史的比例为47%，均高于其他患病（n = 688）和未患病（n = 1004）的家庭成员。致心律失常性晕厥常与急性身体、情绪或听觉刺激有关。晕厥发作常被误诊为癫痫发作。到12岁时，50%的先证者至少经历过一次晕厥发作或死亡。先证者（n = 235；每位患者平均随访54个月）入组后晕厥（一次或多次发作）和可能的与LQTS相关死亡（50岁前）的发生率分别为每年5.0%和每年0.9%；这些事件发生率显著高于患病和未患病的家庭成员。
在接受前瞻性随访的232名先证者和1264名家庭成员中，有三个因素对50岁前随后发生晕厥或可能的与LQTS相关死亡（以先发生者为准）的风险有显著独立影响（Cox风险比；95%置信区间）：1）校正QT间期（1.052；1.017，1.088），2）心脏事件史（3.1；1.3，7.2），3）心率（1.017；1.004，1.031）。这项前瞻性纵向研究的结果突出了LQTS的临床特征、危险因素和病程。
