长QT综合征的危险分层

长QT综合征(Long QT Syndrome,LQTS)是指具有心电图上QT间期延长,T波异常,易产生室性心律失常、晕厥和猝死的一组综合征。按病因可分为获得性和遗传性两种类型[1]。本文综述对遗传性LQTS患者进行危险分层方面的研究进展。1 LQTS的临床表现 LQTS患者极易发生一种称做尖端扭转型室速(TdP)的室性心律失常(见图1)[2],后者可促进晕厥事件的发生。这种疾病常于青春期发病,典型地表现为剧烈运动与情绪波动后晕厥发作。在大多数情况下,这种心律失常可以自动终止,但TdP也可     

遗传性长QT综合征的研究进展

<正>遗传性长QT综合征是一种ECG表现为QT间期延长的遗传病,约有70%的患者是由基因缺陷导致[1],其基因突变与临床表型的一致性较好,因而临床中对长QT综合征的分型主要根据基因型进行。自1995年,发现第一个长QT综合征致病基因至今,目前国际上已发现13个LQTS致病基因上的950多个突变[2]。根据不同基因将LQTS划分为13个亚     

遗传性QT延长综合征研究新进展

遗传性QT延长综合征(LQTS)是一种家族遗传性电紊乱性心脏病,1957年由Jervell Lange-Nielsen首先发现并报道.临床主要表现为晕厥和猝死,心电图表现为QT间期延长、尖端扭转型室性心动过速(室速).     

先天性长QT综合征的药物治疗

先天性长QT综合征（long QT syndrome,LQTS）是遗传性心脏离子通道疾病,临床特征表现为心电图上QT间期显著延长和尖端扭转型室速（torsadede pointes,TdP）反复发作,是心脏结构正常的患者发生心源性猝死的最常见原因之一。     

获得性长QT间期综合征的防治建议

前言 长QT间期综合征(long QT syndrome,LQTS)亦称QT间期延长综合征,是一种心室复极时程延长、不均一性增大的疾病.心电图上表现为QT间期延长、T波和(或)U波异常、早搏后的代偿间歇及心率减慢时易于发生尖端扭转型室性心动过速(torsade de pointes,TdP).临床表现以晕厥、搐搦或猝死为特征的临床综合征.LQTS可以是先天性,也可以是获得性.先天性LQTS是一种由基因缺陷引起复极异常的遗传性心脏病.获得性LQTS是指由药物、心脏疾病[心力衰竭(心衰)、心肌缺血、心动过缓等]或者代谢异常等因素引起的以可逆性QT间期延长伴TdP发作的临床综合征,其中药物性LQTS最常见.本建议重点放在药物引起的获得性QT间期延长伴TdP的防治.     

副神经节瘤引起的长QT综合征一例

长QT综合征（LQTS）根据有无继发因素分为遗传性和获得性。遗传性LQTS由心肌离子通道基因异常引起。获得性LQTS主要由药物、电解质紊乱和中枢神经系统疾病等所致。本文报道1例由副神经节瘤引起的获得性LQTS,患者经手术切除副神经节瘤后QT间期缩短,未再出现心律失常和晕厥症状。本病例为获得性LQTS提供了一个新的诊治思...     

长QT综合征的ICD治疗

获得性长QT综合征(LQTS)通常与心肌局部缺血、心动过缓、电解质异常和应用某些药物有关。遗传性LQTS是一种常染色体遗传性心脏病，其发生率大约是1／5000-7000。临床上有两种形式：Romano—Ward Syndrome (RWS)和Jervell and Lange—Nielsen Syndrome(JINS)。特征性表现为心电图上QTc延长及Tdp导致的晕厥和猝死。对于有上述症状的LQTS患     

获得性长QT间期综合征的防治建议

<正>长QT间期综合征(long QTsyndrome,LQTS)亦称QT间期延长综合征,是一种心室复极时程延长、不均一性增大的疾病。心电图上表现为QT间期延长、T波和(或)U波异常、早搏后的代偿间歇及心率减慢时易于发生尖端扭转型室性心动过速(torsade de pointes,TdP)。临床表现以晕厥、搐搦或猝死为特征的临床综合征。LQTS可以是先天性,也可以是获得性。先天性LQTS是一种由基因缺陷引起复极异常的遗传性心脏病。获得性LQTS是指由药物、心脏疾病[心力衰竭(简称心衰)、心肌缺血、心动过缓等]或者代谢异常等因素引起的以可逆     

长QT综合征的诊疗常规

长QT综合征 (LQTS)是指具有心电图上QT间期延长、T波异常 ,易产生室性心律失常 ,尤其是尖端扭转性室性心动过速、晕厥和猝死的一组综合征。LQTS按病因可分为获得性和遗传性两种类型。获得性LQTS通常与心肌局部缺血、心动过缓、电解质异常和应用某些药物有关。遗传性LQTS的致病基因至少有 6个 ,已发现 10 0多个突变位点。临床上依基因型的不同可有特异性ECG表现。LQTS的标准治疗是抗肾上腺素能治疗 (β 阻断剂、左侧心交感神经切除术 ) ,对少数病例 ,需要辅以起搏器或埋藏式心脏复律除颤器治疗。其他如补钾、美西律等仅是探索性治疗措施。对高危情况下的无症状患者也应进行适当治疗     

遗传性长 QT 综合征

本文主要讨论了常见的遗传性长 QT 综合征（long-QT syndrome,LQTS）的不同表现、临床诊断及处理。过去的二十年,在遗传性心律失常诊治方面发生了巨大的变化。本文简述了 LQTS 的危险分层、可疑患者的筛选及对年轻运动员 LQTS 患者的建议。如有过晕厥、抽搐,尤其是在一级亲属中有无法解释的猝死,应进行有关 LQTS 的检查及诊断。对遗传性 LQTS 的治疗措施应包括生活方式的改变、合理的药物治疗及非药物治疗。     

Genetics of congenital and drug-induced long QT syndromes: current evidence and future research perspectives

The long QT syndrome (LQTS) is a condition characterized by abnormal prolongation of the QT interval with an associated risk of ventricular arrhythmias and sudden cardiac death. Congenital forms of LQTS arise due to rare and highly penetrant mutations that segregate in a Mendelian fashion. Over the years, multiple mutations in genes encoding ion channels and ion channel binding proteins have been reported to underlie congenital LQTS. Drugs are by far the most common cause of acquired forms of LQTS. Emerging evidence suggests that drug-induced LQTS also has a significant heritable component. However, the genetic substrate underlying drug-induced LQTS is presently largely unknown. In recent years, advances in next-generation sequencing technology and molecular biology techniques have significantly enhanced our ability to identify genetic variants underlying both monogenic diseases and more complex traits. In this review, we discuss the genetic basis of congenital and drug-induced LQTS and focus on future avenues of research in the field. Ultimately, a detailed characterization of the genetic substrate underlying congenital and drug-induced LQTS will enhance risk stratification and potentially result in the development of tailored genotype-based therapies.     

长QT综合征发生尖端扭转型室性心动过速时初始节律的研究

目的 比较先天性与获得性长QT综合征（LQTS）发生尖端扭转型室性心动过速（TdP）时的初始节律.方法分析6例先天性LQTS、8例获得性LQTS的Q-TC间期、校正的Tp-e间期（Tp-eC）及TdP发生阵数、初始节律.结果6例先天性LQTS中,Q-TC间期（565.2± 45.1）ms,Tp-eC（145.1±29.1）ms,共计Tdp14阵,平均2.3阵/例,TdP发作前可见窦性节律加快、频发室性期前收缩或室性心动过速.8例获得性LQTS中,Q-TC间期（591.3±67.3）ms,Tp-eC（154.2±56.9）ms,共计TdP237阵,平均29.6阵/例,TdP发生在缓慢节律的基础上频发室性期前收缩,呈短-长-短形式触发.结论获得性LQTS比先天性LQTS更具有危险性,TdP发生前的初始节律分析有助于鉴别先天性LQTS和获得性LQTS及指导临床治疗.     

A Combined Approach Using Patch-Clamp Study and Computer Simulation Study for Understanding Long QT Syndrome and TdP in Women

Female sex is an independent risk factor for development of torsade de pointes (TdP)-type arrhythmias in both congenital and acquired long QT syndrome (LQTS). In females, QT_c interval and TdP risk vary during the menstrual cycle and around delivery. Biological experiments including single-cell current recordings with the patch-clamp technique and biochemical experiments show that progesterone modulates cardiac K⁺ current and Ca²⁺ current via the non-genomic pathway of the progesterone receptor, and thus the cardiac repolarization duration, in a concentration-dependent manner. Incorporation of these biological findings into a computer model of single-cell and coupled-cell cardiomyocytes simulates fluctuations in QT_c interval during the menstrual cycle with reasonable accuracy. Based on this model, progesterone is predicted to have protective effects against sympathetic nervous system-induced arrhythmias in congenital LQTS and drug-induced TdP in acquired LQTS. A combined biological and computational approach may provide a powerful means to risk stratify TdP risk in women.Key Words: Long QT syndrome, sex hormone, nitric oxide, arrhythmia, patch-clamp, non-genomic pathway     

The long QT syndrome: therapeutic implications of a genetic diagnosis

The congenital long QT syndrome (LQTS) is a hereditary disorder characterized by a prolonged QT interval and a polymorphic ventricular tachycardia, known as torsade de pointes (TdP), leading to severe cardiac events such as syncope and/or sudden cardiac death. Molecular genetic studies have revealed a total of eight forms of congenital LQTS caused by mutations in genes of the potassium, sodium and calcium channels or membrane adapter located on chromosomes 3, 4, 7, 11, 12, 17 and 21. Genotype-phenotype correlation in clinical and experimental studies has been investigated in detail in the LQT1, LQT2 and LQT3 syndromes which constitute more than 90% of genotyped patients with LQTS, enabling us to stratify risk and to effectively treat genotyped patients.     

Anthracyclines for acute lymphoblastic leukemia in a child with congenital long QT syndrome

Anthracyclines are key drugs for the treatment of children with acute lymphoblastic leukemia (ALL). However, anthracyclines are known to induce QT prolongation, and life-threatening complications, such as torsades de pointe may also occur. To date, there have been no reports on the use of anthracyclines in patients with congenital long QT syndrome (LQTS). We report a child with ALL complicated by congenital LQTS who was treated with anthracyclines. The administration of anthracyclines caused QT-interval prolongation, but this was uneventful with the concomitant administration of magnesium sulfate.     

Is There a Role for Implantable Cardioverter Defibrillators in Long QT Syndrome?

ICDs in Long QT Syndrome. The congenital familial long QT syndrome (LQTS) is characterized by QT interval prolongation on ECG and potentially life‐threatening polymorphic ventricular arrhythmias. Antiadrenergic therapy, i.e., beta‐adrenoceptor blockade, left cardiac sympathetic denervation, and occasionally pacemaker therapy, sufficiently protects most LQTS patients. Implantable cardioverter defibrillator treatment, with some specific problems and setting requirements in LQTS patients, should at least be considered or implanted in patients with recurrent arrhythmias despite adequate antiadrenergic therapy. Some genetic subtypes, such as LQTS3, may not respond as well (or even adversely) to antiadrenergic therapy and, thus, benefit more from implantable cardioverter defibrillator therapy.     

Prevention of torsade de pointes in the congenital long QT syndrome: use of a pause prevention pacing algorithm

Torsade de pointes in the congenital long QT syndrome (LQTS) is often pause dependent. Thus, the main goal of pacemaker treatment in the LQTS may be the prevention of pauses that facilitate the onset of torsade de pointes. A pause prevention pacing algorithm (rate smoothing) was used for arrhythmia prevention in a 14 year old girl with congenital LQTS. By temporarily increasing the pacing rate after spontaneous premature beats, rate smoothing down of 18% prevented postextrasystolic pauses, pause related T-U changes, and recurrence of pause induced torsade de pointes. Rate smoothing is a potentially useful tool that ought to be evaluated for the prevention of torsade de pointes in the LQTS.

Keywords: long QT syndrome; torsade de pointes; ventricular fibrillation; ventricular tachycardia; pacing     

Genetic susceptibility to acquired long QT syndrome: pharmacologic challenge in first-degree relatives.

OBJECTIVES: The purpose of this study was to test for a genetic component to risk for acquired long QT syndrome (LQTS). BACKGROUND: Many drugs prolong the QT interval, and some patients develop excessive QT prolongation and occasionally torsades de pointes-the acquired LQTS. Similarities between the acquired and congenital forms of the long QT syndrome suggest genetic factors modulate susceptibility. METHODS: Intravenous quinidine was administered to 14 relatives of patients who safely tolerated chronic therapy with a QT-prolonging drug (control relatives) and 12 relatives of patients who developed acquired LQTS, and ECG intervals between groups were compared. RESULTS: Baseline QT and heart-rate corrected QT (QTc) were similar (QT/QTc: 394 +/- 28/410 +/- 20 ms vs 395 +/- 24/418 +/- 20 ms; control vs acquired LQTS) and prolonged equally in the two groups. The interval from the peak to the end of the T wave, an index of transmural dispersion of repolarization, prolonged significantly with quinidine in acquired LQTS relatives (63 +/- 17 to 83 +/- 18 ms, P = .017) but not in control relatives (66 +/- 19 to 71 +/- 18 ms, P = 0.648). In addition, the baseline peak to end of the T wave as a fraction of the QT interval was similar in both groups but was longer in acquired LQTS relatives after quinidine (16.3 +/- 3.5% and 19.5 +/- 3.9% in control and acquired LQTS relatives, respectively, P = .042). CONCLUSIONS: First-degree relatives of patients with acquired long QT syndrome have greater drug-induced prolongation of terminal repolarization compared to control relatives, supporting a genetic predisposition to acquired long QT syndrome.     

Assessment of Microvolt T‐Wave Alternans in High‐Risk Patients with the Congenital Long‐QT Syndrome

Background: Microvolt T‐wave alternans (MTWA) has been used for arrhythmogenic risk stratification in cardiac disease conditions associated with increased risk of sudden cardiac death. Macroscopic T‐wave alternans has been observed in patients with congenital long‐QT syndrome (LQTS). The role of MTWA testing in patients with LQTS has not been established. Objective: To determine the diagnostic value of MTWA testing in high‐risk patients with LQTS. Methods and results: We assessed MTWA in 10 consecutive LQTS index patients who survived cardiac arrest or had documented torsade de pointes tachycardia and 6 first‐degree family members with congenital LQTS which had been genotyped in 13 of 16 subjects (7 index patients, 6 family members). No LQTS‐causing mutation was identified in 3 index patients with overt QT prolongation. MTWA was assessed during standardized bicycle exercise testing using the spectral method and yielded negative (n = 8) or indeterminate (n = 2) results in index patients, respectively. Similarly, all first‐degree family members tested MTWA negative except for one indeterminate result. Two genotype positive family members could not be tested (two children—4 and 9 years of age). Conclusion: In patients with congenital LQTS, free from structural heart disease and with a history of life‐threatening cardiac arrhythmias, assessment of MTWA does not yield diagnostic value. Hence, determination of MTWA in lower risk LQTS patients without spontaneous arrhythmic events is likely not to be useful for arrhythmia risk stratification.     

Congenital and acquired long QT syndromes

Exploration into the underlying genetic causes of congenital long QT syndrome (LQTS) has opened the door to our understanding of repolarization disorders. Expression of LQTS mutations has led to an improved understanding of the mechanisms of arrhythmogenesis, clinical diagnostic tools and channel specific therapy. Further insight into the mechanisms underlying the more common acquired LQTS is emerging from gene and channel studies that have used the congenital syndrome as a springboard for directing research to improve understanding. This review summarizes the clinical, genetic and electrophysiological understanding of congenital and acquired LQTS.