Meyer John S, Mehdirad Ali, Salem Bakr I, Kulikowska Agnieszka, Kulikowski Piotr
St. Luke's Hospital, Chesterfield, Missouri 63017, USA.
Am Fam Physician. 2003 Aug 1;68(3):483-8.
In approximately 5 percent of sudden cardiac deaths, no demonstrable anatomic abnormality is found. Some cases are caused by sudden arrhythmia death syndrome. A prolonged QT interval is a common thread among the various entities associated with sudden arrhythmia death syndrome. A number of drugs are known to cause QT prolongation (e.g., terfenadine), as are hypokalemia, hypomagnesemia, myocarditis, and endocrine and nutritional disorders. Recently, attention has focused on a group of inherited gene mutations in cardiac ion channels that cause long QT syndrome and carry an increased risk for sudden death. Some of the highest rates of inherited long QT syndrome occur in Southeast Asian and Pacific Rim countries. The median age of persons who die of long QT syndrome is 32 years; men are predominately affected. In addition to a prolonged QT interval, which occurs in some but not all persons with long QT syndrome, another characteristic electrocardiographic abnormality is the so-called Brugada sign (an upward deflection of the terminal portion of the QRS complex). Most cardiac events are precipitated by vigorous exercise or emotional stress, but they also can occur during sleep. Torsades de pointes and ventricular fibrillation are the usual fatal arrhythmias. Long QT syndrome should be suspected in patients with recurrent syncope during exertion and those with family histories of sudden, unexpected death. Unfortunately, not all persons with long QT syndrome have premonitory symptoms or identifiable electrocardiographic abnormalities, and they may first present with sudden death. Beta blockers, potassium supplements, and implantable defibrillators have been used for treatment of long QT syndrome. Identifying the specific gene mutation in a given patient with long QT syndrome can help guide prophylactic therapy.
在大约5%的心脏性猝死病例中，未发现明显的解剖学异常。一些病例是由心脏性猝死综合征引起的。QT间期延长是与心脏性猝死综合征相关的各种病症的一个共同特征。已知多种药物可导致QT间期延长（如特非那定），低钾血症、低镁血症、心肌炎以及内分泌和营养紊乱也可导致QT间期延长。最近，注意力集中在一组导致长QT综合征并增加猝死风险的心脏离子通道遗传性基因突变上。遗传性长QT综合征发病率最高的一些地区是东南亚和环太平洋国家。死于长QT综合征的人的中位年龄为32岁；男性受影响更为普遍。除了QT间期延长（在一些但并非所有长QT综合征患者中出现）外，另一个特征性的心电图异常是所谓的Brugada波（QRS波群终末部分向上偏移）。大多数心脏事件是由剧烈运动或情绪应激诱发的，但也可在睡眠期间发生。尖端扭转型室速和心室颤动是常见的致命性心律失常。对于在运动期间反复发生晕厥的患者以及有突然意外死亡家族史的患者，应怀疑患有长QT综合征。不幸的是，并非所有长QT综合征患者都有先兆症状或可识别的心电图异常，他们可能首次表现为猝死。β受体阻滞剂、补钾和植入式除颤器已用于治疗长QT综合征。确定特定长QT综合征患者的具体基因突变有助于指导预防性治疗。
