Second heart sound splitting as an indicator of interventricular mechanical dyssynchrony using a novel splitting detection algorithm. Issue 1 (5th January 2021)

• Record Type: Journal Article
• Authors: Luo, Hongxing; Westphal, Philip; Shahmohammadi, Mehrdad; Heckman, Luuk I. B.; Kuiper, Marion; Cornelussen, Richard N.; Delhaas, Tammo; Prinzen, Frits W.
• Is Part Of: Physiological reports. Volume 9:Issue 1(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-01-05
• Subjects: cardiac dyssynchrony -- heart sound -- pacing therapy -- S‐transform; Physiology -- Periodicals; 571
• DOI: 10.14814/phy2.14687
• Languages: English
• ISSNs: 2051-817X

Abstract

Abstract: Second heart sound (S2) splitting results from nonsimultaneous closures between aortic (A2) and pulmonic valves (P2) and may be used to detect timing differences (dyssynchrony) in relaxation between right (RV) and left ventricle (LV). However, overlap of A2 and P2 and the change in heart sound morphologies have complicated detection of the S2 splitting interval. This study introduces a novel S‐transform amplitude ridge tracking (START) algorithm for estimating S2 splitting interval and investigates the relationship between S2 splitting and interventricular relaxation dyssynchrony (IRD). First, the START algorithm was validated in a simulated model of heart sound. It showed small errors (<5 ms) in estimating splitting intervals from 10 to 70 ms, with A2/P2 amplitude ratios from 0.2 to 5, and signal‐to‐noise ratios from 10 to 30 dB. Subsequently, the START algorithm was evaluated in a porcine model employing a wide range of paced RV‐LV delays. IRD was quantified by the time difference between invasively measured LV and RV pressure downslopes. Between LV pre‐excitation to RV pre‐excitation, mean S2 splitting interval decreased from 47 ms to 23 ms ( p < .001), accompanied by a decrease in mean IRD from 8 ms to −18 ms ( p < .001). S2 splitting interval was significantly correlated with IRD in each experiment ( p < .001). In conclusion, the START algorithm can accurately assess S2 splitting and may serve as a useful tool to assess interventricular dyssynchrony. Abstract : We introduce an S‐transform amplitude ridge tracking (START) algorithm for estimation of 2nd heart sound (S2) splitting and investigated the relationship between S2 splitting and time difference in contraction between right and left ventricle in a porcine model. START was accurate in estimating S2 splitting interval in chirp‐model‐generated heart sounds. S2 splitting correlated well in pacing‐induced time differences in contraction of the ventricles in an animal model.