获得性QT间期延长伴尖端扭转性室性心动过速30例临床分析

目的 总结获得性尖端扭转性室性心动过速(TdP)的诊治经验.方法 回顾性分析30例获得性TdP的临床特点及治疗经过.结果 30例患者中 女性占73％,60岁以上占60％,有基础心脏疾病者占75％,电解质紊乱者占70％,应用延长QT间期药物(胺碘酮、减肥药、卡马西平)者占10％.除1例因TdP反复发作蜕变为室颤治疗无效死亡外,其他患者均获救治.结论 获得性TdP与女性、高龄、电解质紊乱、基础心脏病、应用延长QT间期药物等明显相关,硫酸镁、异丙肾上腺素、补钾及临时起搏器治疗安全有效.对高危患者应加强监测.     

获得性长QT间期伴尖端扭转型室性心动过速20例临床分析

目的：探讨获得性长QT间期伴尖端扭转型室性心动过速患者的诊治经验。方法回顾性分析该院2010年2月至2013年4月收治的20例获得性长QT间期伴尖端扭转型室性心动过速患者的原发疾病、发作诱因、心电图表现、治疗情况等。20例获得性长QT间期伴尖端扭转型室性心动过速患者均伴不同程度低钾血症,所有患者均给予补钾、补镁治疗,2例扩张型心肌病患者植入心脏再同步化复律除颤器（CRTD）,5例严重缓慢心律失常患者安装了心脏永久起搏器。结果治疗后 QTc[（452.00±20.00）ms]明显小于治疗前[（540.00±39.00）ms],血清钾水平[（4.70±0.18）mmol/L]高于治疗前[（2.99±0.28）mmol/L],差异均有统计学意义（P<0.05）。结论获得性长QT间期伴尖端扭转型室性心动过速多发生在电解质紊乱、应用延长QT间期药物、伴器质性心脏病及严重缓慢心律失常患者。病情凶险,补钾、补镁、安装心脏起搏器治疗有效。避免发生低钾血症可减少其发生机会。     

药源性QT间期延长与扭转型室速

QT间期的延长是心肌电不稳定的标志,其中部分病人可因此而诱发严重的室性心律失常甚至心脏性猝死。一般将QT 间期延长分为先天性和获得性两大类,以后者较为常见。药源性QT 间期延长及TDP 是近年来被重视的一类心律失常。     

加强可引起QT间期延长和尖端扭转型室速药物的处方审核

临床应加强对可引起QT间期延长和尖端扭转型室速(TdP)的常用药物的处方审核,以便及时提出警示信息,确保用药合理有效。本文简要介绍药物引起QT间期延长及TdP的机制及相关药物,综述药源性TdP的危险因素,以及药师的处方审核方法等。     

非心血管药物引发QT间期延长和尖端扭转型室速

近年来发现,许多非心血管药物也可引起Q-T间期延长和诱发尖端扭转型室速(TdP)。本文对可能引起此类不良反应的非心血管药物、作用机制及防治措施作一简要介绍。     

药源性QT间期延长及室性心律失常

综述了引起ＱＴ间期延长及室性心律失常的药物，发病机制和防治措施。     

抗精神病药与QT间期延长关系研究进展

本文分析QT间期延长、尖端扭转性室速和心脏猝死之间的关系，并重点叙述QT间期延长的易感素质、抗精神病药对QT间期的影响以及如何预防QT间期延长。     

QT正常的尖端扭转型室性心动过速二例

尖端扭转型室性心动过速(Tdp)发病突然，致病因素不同，其中多数并发心室颤动，病情危重，需要迅速判断室速的类型，查明原因，及时采取正确的治疗方法。由极短联律间期室早所致Tdp诱发的QT间期正常罕见发生，笔者报告2例。     

尖端扭转型室性心动过速28例临床分析

尖端扭转型室速（TdP）属于一种特殊的多型室速,以心电图QRS 波的尖端围绕基线扭转而命名。长QT 综合征（LQTs）是在心电图上表现为QT 间期延长,易发生各种室性心律失常,尤其是TdP ,而在临床上表现为晕厥和猝死的一组综合征。TdP 多发生在LQTs 患者,但在临床上无QT 间期延长者也时常发生。本文就我院28 例TdP 患者的临床资料进行分析,总结其发作及终止的相关因素。现报告如下。     

正常QT伴极短联律间期的尖端扭转型室性心动过速

本文报告1例年青女性伴反复晕厥及特征性正常QT、极短联律间期的尖端扭转型室性心动过速。患者无明显器质性心脏病的临床证据,所有实验室检查均在正常范围,临床电生理学检查也未能诱发。但心内膜心肌活检首次证实心肌炎为其致病原因。本文还结合文献讨论了异搏定和阿托品的作用,及鉴别诊断要点。     

Dose-related effects of methadone on QT prolongation in a series of patients with torsade de pointes

STUDY OBJECTIVE: To investigate the relationship between the daily dose of the synthetic opioid methadone and the corrected QT (QTc) interval in a series of methadone-treated patients who developed torsade de pointes. DESIGN: Retrospective case series analysis. SETTING: Outpatient pain management center and methadone maintenance treatment programs. PATIENTS: Seventeen patients who developed torsade de pointes while receiving very high daily doses of methadone. MEASUREMENTS AND MAIN RESULTS: The QTc intervals were calculated for each patient. The relationship between daily methadone dose and QTc interval was assessed and adjusted for clinical characteristics that may have independently prolonged cardiac repolarization. The mean QTc interval was 615 +/- 77 msec. Multiple linear regression indicated that only the daily methadone dose was predictive of the QTc interval (r = +0.51, p = 0.03). All other variables examined, such as age, sex, presence of hypokalemia or structural heart disease, and presence of QT-prolonging drugs, were not predictive of the QTc interval (minimum p = 0.28). CONCLUSION: In this series, the daily methadone dose correlated positively with the QTc interval. This finding supports the possibility that methadone contributed to the development of arrhythmia.     

Antipsychotic-related QTc prolongation,torsade de pointes and sudden death

Sudden unexpected deaths have been reported with antipsychotic use since the early 1960s. In some cases the antipsychotic may be unrelated to death, but in others it appears to be a causal factor. Antipsychotics can cause sudden death by several mechanisms, but particular interest has centred on torsade de pointes (TdP), a polymorphic ventricular arrhythmia that can progress to ventricular fibrillation and sudden death. The QTc interval is a heart rate-corrected value that represents the time between the onset of electrical depolarisation of the ventricles and the end of repolarisation. Prolongation of the QTc interval is a surrogate marker for the ability of a drug to cause TdP. In individual patients an absolute QTc interval of >500 msec or an increase of 60 msec from baseline is regarded as indicating an increased risk of TdP. However, TdP can occur with lower QTc values or changes. Concern about a relationship between QTc prolongation, TdP and sudden death applies to a wide range of drugs and has led to the withdrawal or restricted labelling of several. Among antipsychotics available in the UK, sertindole was voluntarily suspended, droperidol was withdrawn, and restricted labelling introduced for thioridazine and pimozide. The degree of QTc prolongation is dose dependent and varies between antipsychotics reflecting their different capacity to block cardiac ion channels. Significant prolongation is not a class effect. Among currently available agents, thioridazine and ziprasidone are associated with the greatest QTc prolongation. Virtually all drugs known to cause TdP block the rapidly activating component of the delayed rectifier potassium current (I(kr)). Arrhythmias are more likely to occur if drug-induced QTc prolongation coexists with other risk factors, such as individual susceptibility, presence of congenital long QT syndromes, heart failure, bradycardia, electrolyte imbalance, overdose of a QTc prolonging drug, female sex, restraint, old age, hepatic or renal impairment, and slow metaboliser status. Pharmacodynamic and pharmacokinetic interactions can also increase the risk of arrhythmias. Further research is needed to quantify the risk of sudden death with antipsychotics. The risk should be viewed in the context of the overall risks and benefits of antipsychotic treatment. It seems prudent, where possible, to select antipsychotics that are not associated with marked QTc prolongation. If use of a QTc-prolonging drug is warranted, then measures to reduce the risk should be adopted.     

Iohexol contrast medium induces QT prolongation in amiodarone patients

AIMS: Amiodarone is widely used in ventricular tachyarrhythmias and atrial fibrillation, known to prolong QT-intervals. Concurrent administration of drugs prolonging QT- time can induce life-threatening ventricular tachyarrhythmia. METHODS: QT-interval changes following use of Iohexol contrast-medium for coronarangiography were observed comparing 21 patients taking long-term amiodarone therapy with 21 controls not taking amiodarone or QT-prolonging drugs retrospectively. RESULTS: Concurrent use of Iohexol and amiodarone was associated with significant prolongation of QTc-interval (433, 95%CI: 419-448 ms vs. 480, 95%CI: 422-483 ms, P < 0.001) the day after coronarangiograpgy. 6/21 patients showed severe prolonged QTc-interval of >500 ms. CONCLUSION: Caution is advised until more is known about pro-arrhythmic effects of Iohexol.     

Antihistamines and the torsade de point in children with allergic rhinitis

Allergic rhinitis (AR) is a very common disease, occurring in approximately 10% of children and up to 20% of adolescents. It is often underdiagnosed and its importance as a cause of morbidity is also underestimated, especially in asthmatic children. It has been estimated that 75% of asthmatic children suffer from AR, and its prevalence has increased during the last years, due to changes in environmental factors. AR may be a cause of serious discomfort for the child as well as for the family. AR may cause several complication, including serous otitis media, abnormal facial development with orthodontic problems, eustachian tube dysfunction and sinusitis. The frequent association of paranasal sinusitis in children with asthma has been observed and sinusitis has been considered a contributing factor in bronchial asthma Second-generation antihistamines are the golden therapy for AR. However, reports of potentially life-threatening dysrhythmias, specifically torsades de pointes, were described. In conclusion, we comment the in vitro inhibition of several ion channels, in particular predisposing the heart to dysrhythmias by terfenadine and astemizole. In this paper we examine recent reports on safety of both cetirizine and loratadine.     

OTc prolongation and torsade de pointes ventricular tachycardia in a small dose voriconazole therapy

Torsade de pointes (TdP) is a life-threatening arrhythmia that can result from long QT syndrome. Drug-induced QT prolongation is a potentially dangerous adverse effect of some drug combinations. A 34-year-old woman with history of nephrotic syndrome and rheumatic mitral valve disease was admitted to our Hospital because of high fever. The patient continued to be febrile until antifungal treatment was switched to voriconazole. The electrocardiogram demonstrated sinus tachycardia and a prolonged QTc interval of 580 ms. Patient was resuscitated with electrical cardioversion and had an emergent temporary pacemaker placed. We recommend careful monitoring for QTc prolongation and arrhythmia in patients who are receiving voriconazole, particularly those who have significant electrolyte disturbances.