From Empirical to More Precise Correction: Multidimensional Performance Evaluation of QTc Formulas in a Cohort of...

The Bazett formula remains widely used for QT interval corrected for heart rate (HR) despite its limitations, yet its performance in healthy Asian youth is poorly characterized, necessitating a systematic evaluation against alternatives.

This cross-sectional study included 3258 healthy Asian individuals aged 18 to 22 years. QT interval corrected for HR was calculated using 6 formulas (Bazett, Fridericia, Framingham, Hodges, Rautaharju, Dmitrienko). Interformula consistency (Bland-Altman analysis), HR dependence (Spearman correlation), and HR's effect modification (generalized estimating equations) were assessed. Clinical equivalence (mean absolute deviation, ≤5 ms) was evaluated within HR subgroups (<60, 60-100, >100 bpm).

Bazett showed the strongest HR dependence (ρ=0.268) and poorest consistency (eg, mean absolute deviation versus Fridericia, 14.10 ms). Dmitrienko exhibited optimal HR independence (ρ=0.064). Framingham and Rautaharju demonstrated the highest agreement (bias, 0.395 ms). HR was the dominant effect modifier for all formula pairs (all interaction P<0.05). Framingham's mean absolute deviation was optimal at low/normal HRs (achieving clinical equivalence) and was comparable with the best-performing formula even at high HRs. Results were robust in sensitivity analyses.

For healthy Asian youth, the Framingham formula provides the most consistent and HR-robust QT interval corrected for HR estimation, supporting its use as a unified standard, particularly at low and normal HRs. Bazett's significant overestimation at high HRs warrants caution. These findings advocate for an evidence-based shift from Bazett toward precision QT interval corrected for HR.