Ventricular dyssynchrony assessed by ultra-high-frequency electrocardiography predicts the response to biventricular cardiac resynchronization therapy

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Supported by the European Regional Development Fund - Project ENOCH No.CZ.02.1.01/0.0/0.0/16_019/0000868, by the project National Institute for Research of Metabolic and Cardiovascular Diseases (Programme EXCELES, ID Project No. LX22NPO5104) - Funded by the European Union – Next Generation EU, by the Ministry of Health of the Czech republic, grant number NU21-02-00584, and by the CAS project RVO:68081731. BACKGROUND: Ultra-High-Frequency ECG (UHF-ECG) visualizes ventricular dyssynchrony during spontaneous and paced rhythms. It is unknown whether the UHF-ECG can be used to predict the response to Biventricular cardiac resynchronization therapy (CRT) in patients with heart failure and wide QRS complex. PURPOSE: To show a predictive value of UHF-ECG dyssynchrony parameters in patients with an indication of Biventricular CRT. METHODS: This prospective study included consecutive patients with heart failure NYHA II-III, LVEF ≤ 35%, and QRS duration > 120 ms of nonRBBB morphology. All patients received biventricular CRT. Clinical data, UHF-ECG ventricular dyssynchrony assessment were done before, and echocardiography also six months after the CRT. A positive response was defined by a change in LVESV ≥ 10%. Ventricular dyssynchrony parameter e-DYS was defined as a difference between the first and last UHF-ECG ventricular activation. RESULTS: The study population included 92 patients of mean age 66±9 years, 76% men, LVEF 24±9%, and 45% with ischemic cardiomyopathy. The average change of the LVEF after six months of CRT was 5% and was greater in non-ischemic than ischemic CMP (7% vs. 3%, p < 0.001). 29% of the patients were nonresponders to CRT by the LVESV change. The optimal value of e-DYS to predict response after CRT was 47 ms (sensitivity 78%, specificity 79%). In univariate analysis, the e-DYS > 47 ms, QRSd ≥ 150ms, female sex, presence of non-ischemic heart disease, and Strauss LBBB were significant predictors of response; however, after multivariate analysis, only e-DYS > 47 ms remained significant predictor of response after CRT (p = 0.008). CONCLUSION: In nonRBBB patients with heart failure and CRT indication, UHF-ECG electrical ventricular dyssynchrony during the spontaneous rhythm is the predictor of echocardiographic response to CRT.