Diagnostic Performance of Various QTc Interval Formulas in a Large Family with Long QT Syndrome Type 3: Bazett's Formula Not So Bad After All …
Why the study?
Does Bazett's formula perform as well as newer QTc correction formulas in identifying SCN5A mutation carriers in a family with Long QT Syndrome Type 3?
Population
101 adult members of a large family with Long QT Syndrome Type 3, including 57 carriers and 44 noncarriers.
Comparison
QT interval correction using Bazett's formula… vs Comparison among different QTc formulas and…
Design
Cross-sectional
Authors
Discussion
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Implication
Supports Bazett's plus low-rate Holter for LQTS3 carrier detection; leaves open validation in larger, diverse cohorts.
Structured PICO
Does Bazett's formula perform as well as newer QTc correction formulas in identifying SCN5A mutation carriers in a family with Long QT Syndrome Type 3?
P
Population
101 adult members of a large family with Long QT Syndrome Type 3 (SCN5A 1795insD mutation), including 57 carriers (mean age 44.6 +/- 14.6 years) and 44 noncarriers (mean age 40.3 +/- 12.8 years).
I
Intervention
QT interval correction using Bazett's formula and newer formulas (Fridericia, Hodges, Framingham, logarithmic) applied to 12-lead ECG, exercise ECG, and 24-hour Holter ECG.
C
Comparator
Comparison among different QTc formulas and uncorrected QT interval.
O
Outcome
Diagnostic performance (sensitivity and specificity) for identifying carriers of the mutant gene.surrogate
Bazett's formula is as effective as newer QTc correction formulas for identifying SCN5A mutation carriers in LQTS3, especially when combined with 24-hour Holter monitoring at low heart rates.
Cite This Study
Brouwer et al. (2003) studied this question.