Differences in the Upslope of the Precordial Body Surface ECG T-Wave Reflect Right To Left Dispersion of Repolarization in the Intact Human Heart.

BACKGROUND: The relationship between the surface ECG T-wave to intracardiac repolarization is poorly understood.

OBJECTIVES: This study aimed to examine the association between intracardiac ventricular repolarization and the T-wave on the body surface ECG (SECGTW ).

METHODS: 10 normal heart patients (age 35 +/- 15yrs, 6Male), were studied. Decapolar EP catheters were placed in the right ventricle (RV) and lateral left ventricle (LV) to record in an apico-basal orientation and lateral LV branch of the coronary sinus (CS) for transmural (TM) recording. Each catheter (CS, LV, RV) was sequentially paced using an S1-S2 restitution protocol. Intracardiac repolarization time (RT) and apico-basal, RV-LV and TM repolarization dispersion were correlated with the SECGTW , with a total of 23,946 T-waves analyzed.

RESULTS: RV endocardial repolarization occurred on the upslope of lead V1, V2 and V3 SECGTW with a sensitivity of 0.89, 0.91 and 0.84, and a specificity of 0.67, 0.68 and 0.65 respectively. LV basal endocardial, epicardial and mid endocardial repolarization occurred on the upslope of lead V6 and I, with a sensitivity of 0.79 and 0.8, and specificity of 0.66 and 0.67. Differences between the end of the upslope in V1, V2 and V3 vs V6 strongly correlated with right to left dispersion of repolarization (ICC 0.81, 0.83, 0.85 respectively, p<0.001). Poor association between the T-wave to apicobasal and transmural dispersion of repolarization was seen.

CONCLUSION: The precordial SECGTW reflects regional repolarization differences between right and the left heart. These findings have important implications for accurately identifying biomarkers of arrhythmogenic risk in disease.