Objective Bileaflet mitral valve prolapse (MVP) with either focal or diffuse myocardial fibrosis has been linked to ventricular arrhythmia and/or sudden cardiac arrest. Left ventricular (LV) mechanical dispersion by speckle-tracking echocardiography (STE) is a measure of heterogeneity of ventricular contraction previously associated with myocardial fibrosis. The aim of this study is to determine whether mechanical dispersion can identify MVP at higher arrhythmic risk.
Methods We identified 32 consecutive arrhythmic MVPs (A-MVP) with a history of complex ventricular ectopy on Holter/event monitor (n=23) or defibrillator placement (n=9) along with 27 MVPs without arrhythmic complications (NA-MVP) and 39 controls. STE was performed to calculate global longitudinal strain (GLS) as the average peak longitudinal strain from an 18-segment LV model and mechanical dispersion as the SD of the time to peak strain of each segment.
Results MVPs had significantly higher mechanical dispersion compared with controls (52 vs 42 ms, p=0.005) despite similar LV ejection fraction (62% vs 63%, p=0.42) and GLS (−19.7 vs −21, p=0.045). A-MVP and NA-MVP had similar demographics, LV ejection fraction and GLS (all p>0.05). A-MVP had more bileaflet prolapse (69% vs 44%, p=0.031) with a similar degree of mitral regurgitation (mostly trace or mild in both groups) (p>0.05). A-MVP exhibited greater mechanical dispersion when compared with NA-MVP (59 vs 43 ms, p=0.0002). Mechanical dispersion was the only significant predictor of arrhythmic risk on multivariate analysis (OR 1.1, 95% CI 1.02 to 1.11, p=0.006).
Conclusions STE-derived mechanical dispersion may help identify MVP patients at higher arrhythmic risk.
- valvular heart disease
- cardiac arrest
- mitral regurgitation
- ventricular tachycardia
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Contributors SE: design of the study, analysis and interpretation of data, manuscript drafting. RG: analysis and interpretation of data, manuscript drafting. LL: identification of study patients, manuscript drafting. DB: acquisition of echocardiographic images, manuscript editing. QF: statistical analysis of data, manuscript editing. GN: statistical analysis of data, manuscript editing. TPA: conception of the study, critical manuscript revision for important intellectual content. NBS: conception of the study, critical manuscript revision for important intellectual content. FD: conception and design of the study, review of the data and their analysis, critical manuscript revision.
Funding This work was supported by research grant NIH K23HL116652, NIH R03HL145238 and by the UCSF Senate Resource Allocation Program (FND).
Competing interests None declared.
Ethics approval The study was approved by the University of California, San Francisco Institutional Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent for publication Obtained.