December 13, 2024Heart RhythmOpen Access

Novel risk predictor of arrhythmias for patients with potassium channel–related congenital long QT syndrome

Q: What are the key findings of this study?

A greater change in corrected QT interval between rest and recovery during an exercise stress test was significantly associated with an increased risk of lifetime cardiac events in patients with long QT syndrome type 1 (HR 1.022 per 1-ms increase) and type 2.

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Congenital long QT syndrome (LQTS type 1 and type 2) (n=1330). Intervention: Change in corrected QT (QTc) interval between rest and recovery (recovery-rest ΔQTc) during exercise stress test vs. Patients with lower recovery-rest ΔQTc. Primary outcome: Lifetime cardiac events (arrhythmic syncope, documented sustained ventricular tachycardia, or sudden cardiac death) in LQT1 discovery cohort (HR 1.022, 95% CI 1.015-1.030, p=<0.001).

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Key result

Greater rest-recovery ΔQTc links to ~2% higher cardiac event risk per 1-ms in LQT1 and LQT2.

HR 1.022
95% CI 1.015-1.030
P<0.001
n=1,330

Why the study?

Variability in congenital long QT syndrome severity remains largely unexplored, underscoring the limitations of current risk stratification methods.

Does the change in QTc interval between rest and recovery during an exercise stress test predict cardiac events in patients with congenital long QT syndrome types 1 and 2?

Population

695 patients in a discovery cohort and 635 in a validation cohort with LQTS type 1 and LQTS type 2

Comparison

Electrocardiographic markers from exercise stress testing evaluated across symptomatic and asymptomatic patients

Design

Discovery and validation cohort study

Authors

CJChristian Krijger JuárezAmsterdam University Medical Centers VPV M ProostAmsterdam Neuroscience MTMichael W.T. TanckElectrophysiology

Discussion

Member takes

Implication

Recovery-rest ΔQTc may aid risk stratification in LQTS 1/2; hypothesis-generating and requires prospective validation.

Study Design

Type

Cohort (n=1,330)

Multicenter

Yes

Structured PICO

Does the change in QTc interval between rest and recovery during an exercise stress test predict cardiac events in patients with congenital long QT syndrome types 1 and 2?

Population

1,330 genotyped patients with congenital long QT syndrome type 1 or 2 (probands and family members) who underwent an exercise stress test, evaluated for lifetime and future cardiac events.

Exposure

Electrocardiographic markers from the exercise stress test (EST), specifically recovery-rest ΔQTc (change in QTc interval between rest and 3-4 minutes into recovery)

Outcome

Cardiac events (lifetime arrhythmic events and future events occurring after the EST)hard clinical

Main Result

Hazard Ratio: 1.022 (95% CI 1.015–1.03)

p-value: p=<0.001

Dynamic QT interval measures obtained during exercise stress testing, specifically recovery-rest ΔQTc, can help identify a higher-risk subset of patients with LQTS types 1 and 2.

Limitations

Focus on LQT1 and LQT2 subtypes leaves applicability to other subtypes unknown
Relatively low event rate
Exercise tests were conducted using either a treadmill or a bicycle, and some were stopped at target heart rate rather than exhaustion
Smaller ΔQTc in LQT2 may be difficult for nonexperts to detect accurately

Cite This Study

Juárez et al. (2024) conducted a cohort in Congenital long QT syndrome (LQTS type 1 and type 2) (n=1,330). Change in corrected QT (QTc) interval between rest and recovery (recovery-rest ΔQTc) during exercise stress test vs. Patients with lower recovery-rest ΔQTc was evaluated on Lifetime cardiac events (arrhythmic syncope, documented sustained ventricular tachycardia, or sudden cardiac death) in LQT1 discovery cohort (HR 1.022, 95% CI 1.015-1.030, p=<0.001). A greater change in corrected QT interval between rest and recovery during an exercise stress test was significantly associated with an increased risk of lifetime cardiac events in patients with long QT syndrome type 1 (HR 1.022 per 1-ms increase) and type 2.

synapsesocial.com/papers/6a0f47e001be78fe815fa039 https://doi.org/10.1016/j.hrthm.2024.12.015

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December 13, 2024Heart RhythmOpen Access

Novel risk predictor of arrhythmias for patients with potassium channel–related congenital long QT syndrome

View Full Paper

Ask AI

Bookmark

Key result

Greater rest-recovery ΔQTc links to ~2% higher cardiac event risk per 1-ms in LQT1 and LQT2.

HR 1.022
95% CI 1.015-1.030
P<0.001
n=1,330

Why the study?

Variability in congenital long QT syndrome severity remains largely unexplored, underscoring the limitations of current risk stratification methods.

Does the change in QTc interval between rest and recovery during an exercise stress test predict cardiac events in patients with congenital long QT syndrome types 1 and 2?

Population

695 patients in a discovery cohort and 635 in a validation cohort with LQTS type 1 and LQTS type 2

Comparison

Electrocardiographic markers from exercise stress testing evaluated across symptomatic and asymptomatic patients

Design

Discovery and validation cohort study

Authors

CJChristian Krijger JuárezAmsterdam University Medical Centers VPV M ProostAmsterdam Neuroscience MTMichael W.T. TanckElectrophysiology

Discussion

Member takes

Implication

Recovery-rest ΔQTc may aid risk stratification in LQTS 1/2; hypothesis-generating and requires prospective validation.

Study Design

Type

Cohort (n=1,330)

Multicenter

Yes

Structured PICO

Does the change in QTc interval between rest and recovery during an exercise stress test predict cardiac events in patients with congenital long QT syndrome types 1 and 2?

Population

1,330 genotyped patients with congenital long QT syndrome type 1 or 2 (probands and family members) who underwent an exercise stress test, evaluated for lifetime and future cardiac events.

Exposure

Electrocardiographic markers from the exercise stress test (EST), specifically recovery-rest ΔQTc (change in QTc interval between rest and 3-4 minutes into recovery)

Outcome

Cardiac events (lifetime arrhythmic events and future events occurring after the EST)hard clinical

Main Result

Hazard Ratio: 1.022 (95% CI 1.015–1.03)

p-value: p=<0.001

Dynamic QT interval measures obtained during exercise stress testing, specifically recovery-rest ΔQTc, can help identify a higher-risk subset of patients with LQTS types 1 and 2.

Limitations

Focus on LQT1 and LQT2 subtypes leaves applicability to other subtypes unknown
Relatively low event rate
Exercise tests were conducted using either a treadmill or a bicycle, and some were stopped at target heart rate rather than exhaustion
Smaller ΔQTc in LQT2 may be difficult for nonexperts to detect accurately

Cite This Study

synapsesocial.com/papers/6a0f47e001be78fe815fa039 https://doi.org/10.1016/j.hrthm.2024.12.015

Also Consider

Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:

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