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Type 3 long QT syndrome: Is the effectiveness of treatment with beta-blockers population-specific?
Alexis Hermida1, Jean-Baptiste Gourraud2, Isabelle Denjoy3
1CNMR Maladies Cardiaques Héréditaires Rares, APHP, Hôpital Bichat, Paris, France; Service de Rythmologie, Centre Hospitalier Universitaire d'Amiens, Amiens, France.
Insights
Beta-blocker treatment efficacy in type 3 long QT syndrome (LQT3) is uncertain. This study found no protective effect of beta-blockers against cardiac events in LQT3 patients, suggesting alternative management strategies may be needed.
Area of Science:
- Cardiology
- Genetics
- Pharmacology
Background:
- The effectiveness of beta-blocker therapy for type 3 long QT syndrome (LQT3) is not definitively established.
- LQT3 is a genetic disorder associated with an increased risk of life-threatening cardiac arrhythmias.
Purpose of the Study:
- To investigate the association between beta-blocker use and cardiac events (CEs) in a French cohort of patients with LQT3.
- To evaluate the risk factors for CEs in this patient population.
Main Methods:
- A cohort of 147 patients with pathogenic variants in the SCN5A gene (associated with LQT3) was retrospectively analyzed.
- Cardiac events, including ventricular arrhythmias, syncope, and sudden death, were documented and analyzed.
- Statistical analysis was performed to identify independent predictors of CEs and the impact of beta-blocker treatment.
Main Results:
- In 141 patients followed for a median of 11 years, the cumulative probability of a CE by age 40 was 20.5%.
- QTc prolongation and proband status were independently associated with an increased risk of CEs.
- Beta-blocker treatment did not demonstrate a reduced cumulative probability of experiencing a first cardiac event or severe cardiac event.
Conclusions:
- Proband status and QTc prolongation are confirmed risk factors for CEs in LQT3.
- This study did not find evidence supporting a protective effect of beta-blocker treatment in LQT3 patients.
- Further research may be warranted to explore alternative or adjunctive therapies for LQT3 management.
Background:
The efficacy of beta-blocker treatment in type 3 long QT syndrome (LQT3) remains debated.
Objectives:
The purpose of this study was to test the hypothesis that beta-blocker use is associated with cardiac events (CEs) in a French cohort of LQT3 patients.
Methods:
All patients with a likely pathogenic/pathogenic variant in the SCN5A gene (linked to LQT3) were included and followed-up. Documented ventricular tachycardia/ventricular fibrillation, torsades de pointes, aborted cardiac arrest, sudden death, and appropriate shocks were considered as severe cardiac events (SCEs). CEs also included syncope.
Results:
We included 147 patients from 54 families carrying 23 variants. Six of the patients developed symptoms before the age of 1 year and were analyzed separately. The 141 remaining patients (52.5% male; median age at diagnosis 24.0 years) were followed-up for a median of 11 years. The probabilities of a CE and an SCE from birth to the age of 40 were 20.5% and 9.9%, respectively. QTc prolongation (hazard ratio [HR] 1.12 [1.0-1.2]; P = .005]) and proband status (HR 4.07 [1.9-8.9]; P <.001) were independently associated with the occurrence of CEs. Proband status (HR 8.13 [1.7-38.8]; P = .009) was found to be independently associated with SCEs, whereas QTc prolongation (HR 1.11 [1.0-1.3]; P = .108) did not reach statistical significance. The cumulative probability of the age at first CE/SCE was not lower in patients treated with a beta-blocker.
Conclusion:
In agreement with the literature, proband status and lengthened QTc were associated with a higher risk of CEs. Our data do not show a protective effect of beta-blocker treatment.
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