Beat-to-Beat QT Variability: A Population Study of the QT Variability Index Composition.

ABSTRACT: Background/Objectives: One of the topics of electrocardiographic risk factor studies is investigations of beat-to-beat QT interval variability. The seminal study that reported QT variability as a prognostic risk factor introduced the so-called QT variability index (QTVi). QTVi quantification relies not only on the variance of QT intervals but also on correction factors, including RR interval variance, heart rate, and overall QT interval duration. This study investigated the influence of all the measured factors on QTVi values. Methods: Long-term electrocardiograms (ECGs) were obtained from 251 healthy subjects (mean age 33.6 ± 9.1 years, 108 females) during repeated postural tests that involved supine, sitting, and standing positions maintained for 10 or 15 min. During each p

SUBMITTER: Rehor J 

PROVIDER: S-EPMC12896582 | biostudies-literature | 2026 Feb

REPOSITORIES: biostudies-literature