The Short QTc Is a Marker for the Development of Atrial Flutter and Atrial Fibrillation.

Simon W Rabkin,Jacky K K Tang,David J Chambers

doi:10.1155/2020/2858149

Abstract

A short QT interval has been difficult to define, and there is debate whether it exists outside of an extremely small group of individuals with inherited channelopathies and whether it predicts cardiac arrhythmias. The objective was to identify cases with short QT and their consequences. Our hospital ECG database was screened for cases with a QTc based on the Bazett formula (QTcBZT) of less than 340 ms. The QTc was recalculated using the spline (QTcRBK) formula, which more accurately adjusts for the heart rate and identifies cases based on percentile distribution of the QT interval. The exclusion criteria were presence of bundle branch block, arrhythmias, or electronic pacemakers. An age- and sex-matched cohort was obtained from individuals with normal QT intervals with the same exclusion criteria. There were 28 cases with a short QTc (QTcRBK < 380 ms). The age was 69.6 ± 14.6 years (mean ± SD) (50% males). The QT interval was 305.7 ± 61.1 ms with QTcRBK 308.4 ± 31.4 ms. Subsequent ECGs showed atrial flutter in 21%, atrial fibrillation in 18%, and atrial tachycardia in 4% of cases. Thus, atrial arrhythmias occurred in 43% of cases. This incidence was significantly (p < 0.0001) greater than the incidence of atrial arrhythmias in age- and sex-matched controls. In conclusion, a short QT interval can be readily identified based on the first percentile of the new QTc formula. A short QTc is an important marker for the development of atrial arrhythmias, including atrial flutter and atrial fibrillation, with the former predominating. It should be part of patient assessment and warrants consideration to develop strategies for detection and prevention of atrial arrhythmias.

Highlights

A short QT interval has been difficult to define, and there is debate whether it exists outside of an extremely small group of individuals with inherited channelopathies and whether it predicts cardiac arrhythmias. ere is no doubt that genetic mutations in cardiac ion channels can be associated with short QT intervals [1,2,3,4,5,6]
Our hospital ECG database was screened for cases with a computerized calculation of QTc based on the Bazett formula (QTcBZT) of less than 340 ms. is value was selected because it was recommended in the 2015 European Society of Cardiology guidelines for the diagnosis of the short QT syndrome [28]
None of the cases of short QTc had ST changes that fulfilled the criteria for early repolarization changes [31]

Summary

Introduction

A short QT interval has been difficult to define, and there is debate whether it exists outside of an extremely small group of individuals with inherited channelopathies and whether it predicts cardiac arrhythmias. ere is no doubt that genetic mutations in cardiac ion channels can be associated with short QT intervals [1,2,3,4,5,6]. E objective of the present study was to examine the short QT interval by applying the recently developed QTc spline heart-rate correction formula, and to determine whether it is associated with early repolarization (ER) changes and/or cardiac arrhythmias.

Results

Conclusion