April 1, 2001Journal of Cardiovascular Electrophysiology
Electrocardiographic Prediction of Abnormal Genotype in Congenital Long QT Syndrome: Experience in 101 Related Family Members
Key result
Clinical and detailed ECG analyses did not permit an accurate diagnosis of gene carrier status in a homogeneous LQTS family, with sustained microvolt TWA showing 100% specificity but 18% sensitivity.
Why the study?
Do clinical and ECG techniques accurately predict gene carrier status in family members with congenital LQTS?
Population
101 genotyped members of a single family with congenital long QT syndrome, including 26 carriers of a HERG…
Design
Cross-sectional
Authors
Discussion
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Implication
May enhance targeted LQTS family screening via ECG and clinical markers; leaves open validation across mutations and populations.
Key Points
- The aim is to evaluate the effectiveness of ECG techniques in identifying gene carriers of congenital long QT syndrome within a family.
- Analyzed ECG and clinical data of 101 genotyped family members with congenital long QT syndrome.
- Conducted additional exercise testing and 24-hour Holter monitoring in 48 members for QT and T wave alternans analysis.
- Developed a logistic regression model to predict gene carrier status using QT interval and demographic factors.
- Overall, there was a substantial overlap (78%) in QTc values among carriers and non-carriers of the mutation.
- Sustained microvolt TWA showed 100% specificity but only 18% sensitivity for identifying LQTS.
- QTc measurements were not effective at distinguishing gene carriers in children aged 13 years or younger.
Study Design
Type
Observational (n=101)
Structured PICO
Do clinical and ECG techniques accurately predict gene carrier status in family members with congenital LQTS?
P
Population
101 genotyped members of a single family with congenital long QT syndrome, including 26 HERG mutation carriers, evaluated with clinical and ECG techniques.
E
Exposure
Clinical history, ECG analysis, exercise testing with QT and T wave alternans (TWA) analysis, and 24-hour Holter monitoring with QT and heart rate variability analysis.
O
Outcome
Prediction of gene carrier status (abnormal genotype).surrogate
Clinical and ECG parameters, including QTc and TWA, cannot reliably predict LQTS genotype even within a single family, reinforcing the necessity of genetic testing.
Cite This Study
Kaufman et al. (2001) conducted an observational in Congenital long QT syndrome (LQTS) (n=101). Clinical and ECG techniques (QTc, TWA, Holter) vs. Genetic testing (reference standard) was evaluated on Prediction of gene carrier status. Clinical and detailed ECG analyses did not permit an accurate diagnosis of gene carrier status in a homogeneous LQTS family, with sustained microvolt TWA showing 100% specificity but 18% sensitivity.