Torsades de pointes complicating atrioventricular block: Evidence for a genetic predisposition

Chevalier, Philippe; Bellocq, Chloé; Millat, Gilles; Piqueras, Eric; Potet, F; Schott, Jean‐Jacques; Baró, Isabelle; LeMarec, Hervé; Barhanin, Jacques; Rousson, Robert; Rodriguez-Lafrasse, Claire

doi:10.1016/j.hrthm.2006.10.004

Cited by 44 publications

(23 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The study only included patients with profound QT interval prolongation and only identified one patient with TdP, who also had hypokalemia. The T p -T e interval was not measured and no ECGs before the development of AV block were obtained (8). Our study provided novel data on baseline (before the development of AV block), during AV block and pre-TdP ECG parameters, as well as probable genetic correlates of TdP in complete AV block.…”

Section: Genetic Mutations and Polymorphisms May Influence Repolarizamentioning

confidence: 95%

“…There is mounting evidence that acquired LQTS is a manifestation of reduced repolarization reserve, which is unmasked by physiological or pharmacological stressors (8)(9)(10). Bradycardia-induced TdP may be further proof of this phenomenon.…”

Section: Genetic Mutations and Polymorphisms May Influence Repolarizamentioning

confidence: 99%

“…These patients underwent genetic screening for mutations in ion channels known to cause congenital LQTS. Five of 29 patients had mutations in KCNH2 (8). The study only included patients with profound QT interval prolongation and only identified one patient with TdP, who also had hypokalemia.…”

Section: Genetic Mutations and Polymorphisms May Influence Repolarizamentioning

confidence: 99%

“…In patients with bradycardia-induced TdP, a number of electrocardiogram (ECG) parameters during bradycardia correlate with increased risk of TdP, including the QT interval (4-6), T wave morphology and T peak to T end (T p -T e ) (6). Although ECG parameters can be reasonable predictors of TdP in bradyarrhythmias (4-6), there are limited data on cellular or genetic mechanisms of bradycardia-induced TdP (7,8).We hypothesized that patients with bradycardia-mediated QT arrhythmia may have latent congenital LQTS or a vulnerable genetic polymorphism. In the setting of AV block, reduced repolarization reserve may be 'unmasked' in patients, manifesting as QT interval prolongation and TdP.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

See 4 more Smart Citations

Torsades de pointes during complete atrioventricular block: Genetic factors and electrocardiogram correlates

Subbiah

Gollob

Gula

et al. 2010

Canadian Journal of Cardiology

View full text Add to dashboard Cite

V entricular arrhythmias have been reported in the setting of complete atrioventricular (AV) block since 1918 (1). In 1966, Dessertenne (2) described such an arrhythmia as torsades de pointes (TdP), a polymorphic ventricular tachycardia preceded by QT interval prolongation, now known to be caused by congenital or acquired long QT syndrome (LQTS) (3).Bradyarrhythmias caused by high-grade AV block are common. It is, however, infrequent that bradyarrhythmias are associated with QT interval prolongation and TdP phenomena (4-6). In patients with bradycardia-induced TdP, a number of electrocardiogram (ECG) parameters during bradycardia correlate with increased risk of TdP, including the QT interval (4-6), T wave morphology and T peak to T end (T p -T e ) (6). Although ECG parameters can be reasonable predictors of TdP in bradyarrhythmias (4-6), there are limited data on cellular or genetic mechanisms of bradycardia-induced TdP (7,8).We hypothesized that patients with bradycardia-mediated QT arrhythmia may have latent congenital LQTS or a vulnerable genetic polymorphism. In the setting of AV block, reduced repolarization reserve may be 'unmasked' in patients, manifesting as QT interval prolongation and TdP. Such an occult form of LQTS has previously been reported among patients with undiagnosed congenital LQTS who develop marked QT interval prolongation and TdP when exposed to QT-prolonging drugs (9,10). Moreover, the development of TdP in the setting of AV block may identify ion channel mutations that have a propensity to cause TdP and sudden cardiac death. INtRodUCtIoN: Atrioventricular (AV) block is infrequently associated with QT prolongation and torsades de pointes (TdP). It was hypothesized that patients with AV block-mediated QT-related arrhythmia may have latent congenital long QT syndrome or a vulnerable genetic polymorphism. Methods: Eleven patients with complete AV block and TdP were prospectively identified. Patients underwent assessment, resting electrocardiography and telemetry at baseline, during AV block and pre-TdP. Genetic testing of KCNH2, KCNQ1, KCNE1, KCNE2 and SCN5A was performed. Thirty-three patients with AV block without TdP were included for comparison. ResULts: Genetic variants were identified in 36% of patients with AV block and TdP. Patients with AV block who developed TdP had significantly longer mean (± SD) corrected QT intervals (440±93 ms versus 376±40 ms, P=0.048) and T peak to T end (T p -T e ) intervals (147±25 ms versus 94±25 ms, P=0.0001) than patients with AV block alone. In patients with a genetic variant, there was a significant increase in T p -T e intervals at baseline, in AV block and pre-TdP compared with those who were genotype negative. A personal or family history of syncope or sudden death was more likely observed in patients with a genetic variant. CoNCLUsIoNs: TdP in the setting of AV block may be a marker of an underlying genetic predisposition to reduced repolarization reserve. The T p -T e interval at baseline, in AV block and pre-TdP may predict a genetic mutation ...

show abstract

Section: Genetic Mutations and Polymorphisms May Influence Repolarizamentioning

confidence: 95%

Section: Genetic Mutations and Polymorphisms May Influence Repolarizamentioning

confidence: 99%

Section: Genetic Mutations and Polymorphisms May Influence Repolarizamentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations