Cardiac resynchronization therapy is an established therapy for heart failure patients with sinus rhythm, reduced left ventricular ejection fraction, ventricular desynchronization with QRS duration >150 ms and left bundle branch block , . Transesophageal focused left heart electrocardiography is a non-invasive method for evaluation of cardiac desynchronization with electrical interatrial delay, left atrial delay, interventricular delay and left ventricular delay in heart failure patients , .
The aim of the study was to evaluate electrical left cardiac atrioventricular delay and interventricular desynchronization in sinus rhythm cardiac resynchronization therapy responder and non-responder.
Twenty-one heart failure patients with sinus rhythm, New York Heart Association class 3.1 ± 0.3, 26.6 ± 6.1% left ventricular ejection fraction and 170.6 ± 41.4 ms QRS duration were measured by surface ECG and focused transesophageal bipolar left atrial and left ventricular ECG (TO4, TO8 Osypka AG, Rheinfelden, Germany) before implantation of cardiac resynchronization therapy defibrillator (see Figure 1). The mean age of one female and 20 males was 67.7 ± 8.7 years. Left cardiac atrioventricular delay was measured between onset of left atrial signal and onset of left ventricular signal in the transesophageal ECG. Interventricular delay was measured between onset of QRS in the surface ECG and onset of left ventricular signal in the transesophageal ECG. Cardiac resynchronization therapy atrioventricular delay between right atrial and left ventricular electrodes and biventricular pacing delay between right ventricular and left ventricular electrodes were optimized by transthoracic impedance cardiography ,  (see Figure 2).
Statistical analysis was performed by Origin® 2016 software (OriginLab Corporation, Northampon, MA, USA) using paired and unpaired t-tests, as appropriate, with a statistical significance of p < 0.05 and with Pearson correlation coefficients.
Twenty-one heart failure cardiac resynchronization therapy patient left cardiac atrioventricular delay and interventricular delay desynchronization were 200.4 ± 45.4 ms left cardiac atrioventricular delay, 75.3 ± 23.5 ms interventricular delay and 2.35 ± 0.59 QRS duration to interventricular delay ratio.
3.1 Cardiac resynchronization therapy responder
There were 18 cardiac resynchronization therapy responders with 195.7 ± 46.7 ms left cardiac atrioventricular delay, 74.8 ± 24.5 ms interventricular delay and 2.44 ± 0.58 QRS duration to interventricular delay ratio with negative correlation between interventricular delay and QRS duration to interventricular delay ratio (r = −0.54, p = 0.022) (see Figure 3).
3.2 Cardiac resynchronization therapy non-responder
There were three cardiac resynchronization therapy non-responders with 228.7 ± 25.8 ms left cardiac atrioventricular delay, 78.0 ± 19.3 ms interventricular delay and 1.81 ± 0.35 QRS duration to interventricular delay ratio (see Figure 4). The left cardiac atrioventricular delay was shorter in cardiac resynchronization therapy responder than in cardiac resynchronization therapy non-responder with negative correlation (r = −0.998, p = 0.037).
3.3 Cardiac resynchronization therapy follow-up
During 9.4 ± 11.0 month cardiac resynchronization therapy follow-up, the cardiac resynchronization therapy responder New York Heart Association class improved from 3.1 ± 0.3 to 2.1 ± 0.2 (p = 0.038) (see Figure 5). During 5.7 ± 3.7 month cardiac resynchronization therapy follow-up, the cardiac resynchronization therapy non-responder New York Heart Association class not improved from 2.8 ± 0.3 to 2.7 ± 0.6.
Gold and co-workers evaluated the correlation between invasive electrical interventricular delay -measured between QRS onset and peak of left ventricular electrocardiogram- and left ventricular remodelling in 426 patients from the SMART-AV trail  with atrioventricular delay optimized cardiac resynchronization therapy . More than 95 ms interventricular delay predicted 6 month cardiac resynchronization therapy response with increasing of left ventricular ejection fraction and decreasing of quality of live, left ventricular end-systolic volume, left ventricular end-diastolic volume. Less than 95 ms interventricular delay predicted 6 month cardiac resynchronization therapy non-response without left ventricular remodelling .
Transesophageal electrocardiography can be utilized to analyse interventricular delay and left cardiac atrioventricular delay before implantation of cardiac resynchronization therapy devices. QRS duration to interventricular delay ratio was smaller in cardiac resynchronization therapy non-responder than in cardiac resynchronization therapy responder. Left cardiac atrioventricular delay was shorter in cardiac resynchronization therapy responder than in cardiac resynchronization therapy non-responder. Transesophageal interventricular and atrioventricular delay may be additional useful parameters to improve patient selection for cardiac resynchronization therapy.
Research funding: The author state no funding involved. Conflict of interest: Authors state no conflict of interest. Material and methods: Informed consent: Informed consent has been obtained from all individuals included in this study. Ethical approval: The research related to human use complies with all the relevant national regulations, institutional policies and was performed in accordance with the tenets of the Helsinki Declaration, and has been approved by the authors’ institutional review board or equivalent committee.
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About the article
Published Online: 2016-09-30
Published in Print: 2016-09-01
Citation Information: Current Directions in Biomedical Engineering, Volume 2, Issue 1, Pages 247–250, ISSN (Online) 2364-5504, DOI: https://doi.org/10.1515/cdbme-2016-0055.
©2016 Matthias Heinke et al., licensee De Gruyter.. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. BY-NC-ND 4.0