Electromechanical Dyssynchrony Is Associated With Right Ventricular Remodeling and Dysfunction Independently of Pulmonary Regurgitation Late After Tetralogy of Fallot Repair

Yuval Bitterman; Wei Hui; Chun-Po Steve Fan; Andreea Kiss; Luc Mertens; Rachel M Wald; Mark K Friedberg

doi:10.1016/j.echo.2023.06.010

Electromechanical Dyssynchrony Is Associated With Right Ventricular Remodeling and Dysfunction Independently of Pulmonary Regurgitation Late After Tetralogy of Fallot Repair

J Am Soc Echocardiogr. 2023 Dec;36(12):1315-1323. doi: 10.1016/j.echo.2023.06.010. Epub 2023 Jun 24.

Authors

Yuval Bitterman¹, Wei Hui¹, Chun-Po Steve Fan², Andreea Kiss³, Luc Mertens¹, Rachel M Wald³, Mark K Friedberg⁴

Affiliations

¹ Labatt Family Heart Centre, Department of Paediatrics, Hospital for Sick Children, Toronto, Ontario, Canada.
² Ted Rogers Computational Program, Ted Rogers Center for Heart Research, The Hospital for Sick Children, University Health Network, Toronto, Ontario, Canada.
³ Toronto General Hospital/University Health Network, Toronto, Ontario, Canada.
⁴ Labatt Family Heart Centre, Department of Paediatrics, Hospital for Sick Children, Toronto, Ontario, Canada. Electronic address: mark.friedberg@sickkids.ca.

PMID: 37356675
DOI: 10.1016/j.echo.2023.06.010

Abstract

Background: The aim of this study was to investigate the relationship among right ventricular (RV) dilatation, dysfunction, and electromechanical dyssynchrony (EMD) in patients with repaired tetralogy of Fallot (rTOF).

Methods: Data from a prospective rTOF registry of subjects with moderate or greater pulmonary regurgitation (PR) and contemporary imaging were analyzed. Electrocardiograms and echocardiograms were analyzed for EMD (prolonged QRS duration [QRSd], echocardiographic septal flash, and mechanical delay) and mechanical dispersion. The relationship among these, RV measurements on cardiac magnetic resonance, exercise capacity, and incident arrhythmia or death was analyzed with adjustment for PR.

Results: In total, 271 patients with rTOF (42% women; median age, 32 years; interquartile range [IQR], 23-34 years) were included. Patients had moderate to severe PR (median PR fraction, 38%; IQR, 30%-47%), moderate to severe RV enlargement (median RV end-diastolic volume index, 161 mL/m²; IQR, 138-186 mL/m²) and mild RV systolic dysfunction (median RV ejection fraction [RVEF], 44%; IQR, 38%-48%). Eleven patients (4%) experienced ventricular arrhythmia or death. Presence of EMD was associated with larger RV size (RV end-diastolic volume index and RV end-systolic volume index, P = .006 and P < .001, respectively) and lower RVEF (P < .001). A sharp inflection in the relation among QRSd, RV size, and RVEF was observed when QRSd exceeded 150 msec (3.1% decrease in RVEF for every 20-msec increase in QRSd between 160 and 200 msec). Similar inflection points were observed for the mechanical delay between the RV basal-lateral and midseptal segments. The mechanical delay was higher in patients with vs without incident atrial arrhythmia (371 vs 276 msec, P = .014).

Conclusions: In adults with rTOF, EMD is independently associated with larger RV size, lower RVEF, and incident atrial arrhythmias.

Keywords: Dyssynchrony; Electromechanical dyssynchrony; Tetralogy of Fallot.

MeSH terms

Adult
Atrial Fibrillation* / complications
Female
Humans
Male
Prospective Studies
Pulmonary Valve Insufficiency* / diagnosis
Tetralogy of Fallot* / complications
Tetralogy of Fallot* / surgery
Ventricular Dysfunction, Right* / diagnostic imaging
Ventricular Dysfunction, Right* / etiology
Ventricular Function, Right
Ventricular Remodeling