Differences in the upslope of the precordial body surface ECG T wave reflect right to left dispersion of repolarization in the intact human heart

Neil T Srinivasan,Michele Orini,Rui Providencia,Ron Simon,Martin Lowe,Oliver R Segal,Anthony W Chow,Richard J Schilling,Ross J Hunter,Peter Taggart,Pier D Lambiase

doi:10.1016/j.hrthm.2018.12.006

Neil T Srinivasan, Michele Orini + Show 9 more

Open Access

https://doi.org/10.1016/j.hrthm.2018.12.006

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Abstract

BackgroundThe relationship between the surface electrocardiogram (ECG) T wave to intracardiac repolarization is poorly understood.ObjectiveThe purpose of this study was to examine the association between intracardiac ventricular repolarization and the T wave on the body surface ECG (SECGTW).MethodsTen patients with a normal heart (age 35 ± 15 years; 6 men) were studied. Decapolar electrophysiological catheters were placed in the right ventricle (RV) and lateral left ventricle (LV) to record in an apicobasal orientation and in the lateral LV branch of the coronary sinus (CS) for transmural recording. Each catheter (CS, LV, RV) was sequentially paced using an S1–S2 restitution protocol. Intracardiac repolarization time and apicobasal, RV–LV, and transmural repolarization dispersion were correlated with the SECGTW, and a total of 23,946 T waves analyzed.ResultsRV endocardial repolarization occurred on the upslope of lead V1, V2, and V3 SECGTW, with sensitivity of 0.89, 0.91, and 0.84 and specificity of 0.67, 0.68, and 0.65, respectively. LV basal endocardial, epicardial, and mid-endocardial repolarization occurred on the upslope of leads V6 and I, with sensitivity of 0.79 and 0.8 and specificity of 0.66 and 0.67, respectively. Differences between the end of the upslope in V1, V2, and V3 vs V6 strongly correlated with right to left dispersion of repolarization (intraclass correlation coefficient 0.81, 0.83, and 0.85, respectively; P <.001). Poor association between the T wave and apicobasal and transmural dispersion of repolarization was seen.ConclusionThe precordial SECGTW reflects regional repolarization differences between right and left heart. These findings have important implications for accurately identifying biomarkers of arrhythmogenic risk in disease.

Highlights

The relationship between intracardiac repolarization of the intact human heart and the surface electrogram T wave (SECGTW) is poorly understood
This study aimed to examine the association between intracardiac ventricular repolarization in the intact human heart and the SECGTW, at varying cycle lengths and activation wavefronts, in order to better understand the genesis of the SECGTW and examine the extent to which it represents local intracardiac repolarization
We studied the relationship between TpTe, the time difference between the end of the SECGTW upslope across all leads, and the difference between the start and end of the SECGTW in all leads to dispersion of repolarization in the major anatomic axes

Summary

Introduction

The relationship between intracardiac repolarization of the intact human heart and the surface electrogram T wave (SECGTW) is poorly understood. It is hypothesized that in order for the SECGTW to be concordant, waves of depolarization and repolarization must travel in opposite directions.[11] Several studies have demonstrated opposing depolarizing and repolarizing apicobasal wavefronts.[12,13,14] Other studies have demonstrated a transmural repolarization gradient[15,16] and have suggested that TpTe represents transmural dispersion of repolarization.[16] the repolarization sequence of the intact human ventricle is related to the sequence of activation,[17,18] and this may impart changes on the SECGTW. The relationship between the surface electrocardiogram (ECG) T wave to intracardiac repolarization is poorly understood

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