BACKGROUND: Ultra-high-frequency electrocardiography (UHF-ECG) is a noninvasive tool visualizing the ventricular activation sequence. It was never compared with other methods of dyssynchrony assessment in patients with bradycardia. OBJECTIVE: We aimed to compare UHF-ECG interventricular electrical dyssynchrony (e-DYS) with interventricular mechanical delay (IVMD) measured by echocardiography in patients receiving right ventricular pacing (RVP) or conduction system pacing (CSP). METHODS: Fifty-three patients with advanced atrioventricular conduction disease and preserved ventricular systolic function were prospectively assigned to RVP (n=32 [60 %]) or CSP (n=21 [40 %]). IVMD was measured as the time difference between left ventricular and right ventricular preejection periods. Interventricular e-DYS was calculated by software as the time difference between activation in V1 and V7 chest electrodes using UHF-ECG. RESULTS: The median age of patients was 75 (interquartile range 72-80) years, and both groups had similar clinical characteristics. Baseline IVMD and interventricular e-DYS were similar in the entire population (-2 [-8 to 5] ms vs-1 [-6 to 5] ms, respectively; P=.52). Both methods showed the same dyssynchrony trends after pacemaker implantation; that is, 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=.99), they remained low in the CSP group (IVMD -7 [-16 to 2] ms vs interventricular e-DYS -5 [-12 to 2] ms; P=.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.

Cardiology 3rd Faculty of Medicine Charles University and University Hospital Kralovske Vinohrady Prague Czechia

Cardiovascular Research Institute Maastricht Maastricht The Netherlands

Department of Anesthesia and Intensive Care Charles University and University Hospital Kralovske Vinohrady Prague Czechia

Institute of Scientific Instruments of Czech Academy of Sciences Brno Czechia

International Clinical Research Center 1st Department of Internal Medicine Cardioangiology St Anne's University Hospital Brno Czech Republic

International Clinical Research Center 1st Department of Internal Medicine Cardioangiology St Anne's University Hospital Brno Czech Republic; Faculty of Medicine Masaryk University Brno Czech Republic

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