Abstract / Summary
The Ibarrola QTc formula is a heart-rate-band correction of the QT interval designed to give a corrected QT that does not depend on heart rate across the whole clinical range, in the general population as well as in athletes, in men and in women. Instead of a single exponent for all heart rates, the QT is corrected separately in bradycardia (<60 bpm), normocardia (60–100 bpm) and tachycardia (>100 bpm), with continuous transitions between bands. A sex-specific adjustment allows its use in wide-QRS rhythms (≥120 ms), such as bundle branch block. Decision thresholds are given for the general population (450 ms men, 460 ms women), athletes (470/480 ms) and children under 12 years (460 ms), together with a grey zone for manual and vectorcardiographic review. The formula was derived from more than 15,000 resting 12-lead ECGs from a single centre (2011–2026) and preliminarily validated against Bazett, Fridericia, Framingham, Hodges and Rautaharju, and against cardiologist-annotated public databases (FDA ECGRDVQ, LUDB, PhysioNet QT Database). It corrects the known undercorrection of Bazett at bradycardia and overcorrection at tachycardia, which affect athletes, elderly patients, patients on QT-prolonging drugs and anyone with heart rates far from 60 bpm. Intended uses: pre-participation screening, general clinical ECG interpretation, monitoring of QT-prolonging drugs, exercise testing and Holter recordings. The formula is implemented in the Ibarrola QTc calculator, which runs on any platform (Windows, macOS and Linux computers, tablets and iOS/Android smartphones) through a web browser, online or offline. A prospective multicentre validation by four sports cardiologists is ongoing. This record contains the full formula, coefficients, thresholds, worked examples and preliminary validation (version 1.0). Files are restricted; access and commercial licences on request to the author (martinibarrola@gmail.com). Licence: CC BY-NC-ND 4.0. How to cite: Ibarrola M. The Ibarrola QTc formula: a heart-rate-band correction of the QT interval for athletes and the general population. Version 1.0. Zenodo; 2026. doi:10.5281/zenodo.23284883