Wolff-Parkinson-White(WPW)syndrome is a congenital disorder of cardiac conduction system characterized by electrocardiographic preexcitation and episodes of paroxysmal supraventricular tachycardia.It is caused by a ca...Wolff-Parkinson-White(WPW)syndrome is a congenital disorder of cardiac conduction system characterized by electrocardiographic preexcitation and episodes of paroxysmal supraventricular tachycardia.It is caused by a cardiac developmental defect in the electrical insulation between the atria and the ventricles due to the presence of an accessory pathway.WPW syndrome is a common cause of supraventricular tachycardia with benign prognosis.However,this clinical entity also predisposes patients to an increased risk of sudden cardiac death,especially in the setting of preexcited atrial fibrillation.WPW syndrome is usually sporadic and of unknown etiology in most cases.During the past10years,a signifi cant heritable factor is increasingly recognized.Identifi cation of the genetic basis among patients with WPW syndrome has important implications for understanding the molecular mechanism of ventricular preexcitation and the development of therapeutic strategies for risk stratifi cation and management.The goal of this review is to examine the previous studies on hereditary variants,as well as to outline potential future avenues toward defi ning the heritability of WPW syndrome.展开更多
Background-The Brugada syndrome is an arrhythmogenic disease caused in part by mutations in the cardiac sodium channel gene, SCN5A. The electrocardiographic pattern characteristic of the syndrome is dynamic and is oft...Background-The Brugada syndrome is an arrhythmogenic disease caused in part by mutations in the cardiac sodium channel gene, SCN5A. The electrocardiographic pattern characteristic of the syndrome is dynamic and is often absent in affected individuals. Sodium channel blockers are effective i n unmasking carriers of the disease. However, the value of the test remains cont roversial. Methods and Results -We studied 147 individuals representing 4 large families with SCN5A mutations. Of these, 104 were determined to be at possible risk for Brugada syndrome and underwent both electrocardiographic and genetic ev aluation. Twenty-four individuals displayed an ECG diagnostic of Brugada syndro me at baseline. Of the remaining, 71 received intravenous ajmaline. Of the 35 ge netic carriers who received ajmaline, 28 had a positive test and 7 a negative aj maline test. The sensitivity, specificity, and positive and negative predictive values of the drug challenge were 80%(28:35), 94.4%(34:36), 93.3%(28:30), and 82.9%(34:41), respectively. Penetrance of the disease phenotype increased from 32.7%to 78.6%with the use of sodium channel blockers. In the absence of ST-s egment elevation under baseline conditions, a prolonged P-R interval, but not i ncomplete right bundle-branch block or early repolarization patterns, indicates a high probability of an SCN5A mutation carrier. Conclusions -In families with Brugada syndrome, the data suggest that ajmaline testing is valuable in the dia gnosis of SCN5A carriers. In the absence of ST-segment elevation at baseline, f amily members with first-degree atrioventricular block should be suspected of c arrying the mutation. An ajmaline test is often the key to making the proper dia gnosis in these patients.展开更多
文摘先天性长QT综合征(LQTS)是发病率在1/2 500左右的恶性遗传性心脏疾病。LQTS的典型心脏表现包括可导致心脏骤停和心脏猝死的晕厥发作,以及包括QT间期延长和T波异常在内的心电图异常。90年代中期,LQTS的治病基因被首次发现,至今已有13型被确认。致病基因主要是离子通道和转运相关蛋白。对于具有典型特征的患者,医生并无诊断困难。对于模棱两可的病例,需要参照特殊诊断标准,比如心电图,病史和家族史等等。此外,基因扫描正日益成为诊断过程的一部分。除非有明确的禁忌证,治疗上还是要首选β受体阻滞剂。若在接受足量β受体阻滞剂期间,还有1次以上的晕厥,需立即采取左侧交感神经切除术,并根据病人特征(年龄、性别、临床病史、24 h Holter在内的心电图特征、基因表型等)考虑安装埋藏式心脏转复除颤器。病人接受适当治疗后,一般预后较好。但是LQTS8(Timothy综合征)病人,携带KCNQ1突变的Jervel Lange-Nielsen综合征患者,以及伴有2∶1房室传导阻滞,病窦综合征或Brugada综合征的LQT3病患的预后极其不容乐观。
文摘Wolff-Parkinson-White(WPW)syndrome is a congenital disorder of cardiac conduction system characterized by electrocardiographic preexcitation and episodes of paroxysmal supraventricular tachycardia.It is caused by a cardiac developmental defect in the electrical insulation between the atria and the ventricles due to the presence of an accessory pathway.WPW syndrome is a common cause of supraventricular tachycardia with benign prognosis.However,this clinical entity also predisposes patients to an increased risk of sudden cardiac death,especially in the setting of preexcited atrial fibrillation.WPW syndrome is usually sporadic and of unknown etiology in most cases.During the past10years,a signifi cant heritable factor is increasingly recognized.Identifi cation of the genetic basis among patients with WPW syndrome has important implications for understanding the molecular mechanism of ventricular preexcitation and the development of therapeutic strategies for risk stratifi cation and management.The goal of this review is to examine the previous studies on hereditary variants,as well as to outline potential future avenues toward defi ning the heritability of WPW syndrome.
文摘Background-The Brugada syndrome is an arrhythmogenic disease caused in part by mutations in the cardiac sodium channel gene, SCN5A. The electrocardiographic pattern characteristic of the syndrome is dynamic and is often absent in affected individuals. Sodium channel blockers are effective i n unmasking carriers of the disease. However, the value of the test remains cont roversial. Methods and Results -We studied 147 individuals representing 4 large families with SCN5A mutations. Of these, 104 were determined to be at possible risk for Brugada syndrome and underwent both electrocardiographic and genetic ev aluation. Twenty-four individuals displayed an ECG diagnostic of Brugada syndro me at baseline. Of the remaining, 71 received intravenous ajmaline. Of the 35 ge netic carriers who received ajmaline, 28 had a positive test and 7 a negative aj maline test. The sensitivity, specificity, and positive and negative predictive values of the drug challenge were 80%(28:35), 94.4%(34:36), 93.3%(28:30), and 82.9%(34:41), respectively. Penetrance of the disease phenotype increased from 32.7%to 78.6%with the use of sodium channel blockers. In the absence of ST-s egment elevation under baseline conditions, a prolonged P-R interval, but not i ncomplete right bundle-branch block or early repolarization patterns, indicates a high probability of an SCN5A mutation carrier. Conclusions -In families with Brugada syndrome, the data suggest that ajmaline testing is valuable in the dia gnosis of SCN5A carriers. In the absence of ST-segment elevation at baseline, f amily members with first-degree atrioventricular block should be suspected of c arrying the mutation. An ajmaline test is often the key to making the proper dia gnosis in these patients.
