Correction equation for QT interval [letter]

QT Interval: Correction for Heart Rate

There are several empirically based proposals in the literature for adjusting QT intervals for heart rate. Two widely used correction formulas are Bazett’s and Fridericia’s. This study examines the general formulation of heart rate correction of QT intervals, and several of the existing adjustments are used with this approach. Simple correction formulas for both populations and individuals have...

Correction of the QT interval in children.

We evaluated the usefulness of 11 formulas for correcting the QT interval in children, including the square root, cubic root, logarithmic, linear, exponential, and inverse formulas using the Mean-squared residual (MSR) values and Akaike Information Criterion (AIC) in 8,086 first-graders, 9,989 seventh-graders, and 5,786 tenth-graders. The subjects were divided into six groups according to age a...

QT Interval and QT Variability

T Wave Amplitude Correction of QT Interval Variability for Improved Repolarization Lability Measurement

OBJECTIVES The inverse relationship between QT interval variability (QTV) and T wave amplitude potentially confounds QT variability assessment. We quantified the influence of the T wave amplitude on QTV in a comprehensive dataset and devised a correction formula. METHODS Three ECG datasets of healthy subjects were analyzed to model the relationship between T wave amplitude and QTV. To derive ...

Assessment of the stability of the individual-based correction of QT interval for heart rate.

BACKGROUND Modeling the relationship between QT intervals and previous R-R values remains a challenge of modern quantitative electrocardiography. The technique based on an individual regression model computed from a set of QT-R-R measurements is presented as a promising alternative. However, a large set of QT-R-R measurements is not always available in clinical trials and there is no study that...