Electrical and mechanical interventricular dyssynchrony coupling in bradycardia patients; a UHF-ECG validation trial.

Abstract

Background: Ultra-high-frequency ECG (UHF-ECG) is a non-invasive tool visualizing the ventricular activation sequence. It was never compared to other methods of dyssynchrony assessment in bradycardia patients.

Objective: We aimed to compare UHF-ECG interventricular electrical dyssynchrony with interventricular mechanical dyssynchrony measured by echocardiography in patients with right ventricular (RVP) or conduction system pacing (CSP).

Methods: Fifty-three patients with advanced atrio-ventricular conduction disease and preserved ventricular systolic function were prospectively assigned to RVP (n=32) or CSP (n=21). Interventricular mechanical dyssynchrony (IVMD) was measured as a time difference between LV and RV pre-ejection periods. Interventricular e-DYS was software calculated as the time difference between activation in V1 and V7 chest electrodes using UHF-ECG.

Results: The median age of patients was 75 years, and both groups had similar clinical characteristics. Baseline IVMD and interventricular e-DYS were similar in the entire population (-2 [-8, 5] ms; resp. -1 [-6, 5] ms; p=0.52). Both methods showed the same dyssynchrony trends after the pacemaker implantation, i.e. while both IVMD and interventricular e-DYS increased in the RVP group (IVMD 28 [23, 33] ms vs. interventricular e-DYS 26 [19, 33] ms, p=0.99), they remained low in the CSP group (IVMD -7 [-16, 2] ms vs. interventricular e-DYS -5 [-12, 2] ms, p=0.91). There was a moderate overall correlation between IVMD and interventricular e-DYS for all studied ventricular rhythms (R=0.74).

Conclusion: UHF-ECG noninvasively expresses interventricular dyssynchrony from V7-V1 chest leads with similar results to echocardiography. RVP increases interventricular dyssynchrony, while CSP preserves synchronous ventricular activation.