An Evaluation of ECG Leads Used to Assess QT Prolongation

Abstract

Aims: The aim of the present study is to elucidate the optimal lead to be selected for the evaluation of drug-induced QT prolongation. Methods and Results: We assessed the validity of each electrocardiography (ECG) lead for the evaluation of QT intervals in 688 patients receiving psychotropic drugs. Abnormal QTc prolongation was observed in 96 (14%) patients using the longest ECG lead. Prevalence of QTc prolongation was larger when using leads I, III, aVR, aVL, aVF, V1, and V6 (>18%), and smaller when using lead V2 (10%). In the remaining 4 ECG leads, the overall accuracy to predict QTc prolongation was higher when using lead V3 (94%) compared with lead II (89%) or lead V5 (90%). Sensitivity to predict QTc prolongation was higher when using lead V4 (81%) compared with lead II (66%) or lead V2 (63%). Conclusion: When a single lead was used for the evaluation of QT prolongation, the results were not always similar to those using the lead which demonstrated the longest QT interval, and if only one lead is to be chosen, lead V3 or V4 should be selected.

Best leads in the standard electrocardiogram for the emergency detection of acute coronary syndrome

“…Selection of the best leads from a 12-lead ECG has previously been attempted for detection of coronary artery disease 3 and for the assessment of QT prolongation. 4 Artificial neural networks (ANNs) represents a machine learning tool that has proved useful for complex pattern recognition problems and is widely used for medical applications. 5 The networks learn by associating different ECG patterns with the desired classification, not by being fed a set of predefined diagnostic criteria.…”

Choice of an alternative lead for QT interval measurement in serial ECGs when Lead II is not suitable for analysis

“…As in our study, they too found that the mean QT interval measurement closest to that in lead II (353 AE 29 ms) was observed in lead aVF (351 AE 30 ms) while lead aVL had a mean QT interval measurement farthest from lead II (332 AE 31 ms). 20 Why is the QT interval in leads aVF or aVR closest to that in Lead II? It was previously thought that the difference in QT interval in various leads was due to transmural dispersion of ventricular repolarization.…”

A new ECG biomarker for drug toxicity: A combined signal processing and computational modeling study

“…It is noted that our analysis was performed on a single lead. Studies have shown that the accuracy and sensitivity to drug-induced QT prolongation varied when using different ECG leads [15]. Thus the optimal lead for detecting changes in JT area may be determined by repeating the same analysis on other leads.…”