Patients with a mitral valve prolapse (MVP) with either focal or diffuse myocardial fibrosis have been found to be at risk of cardiac arrest or sudden death, however, current diagnostic methods continue to be limited. Speckle-tracking echocardiography (STE) derived mechanical dispersion is a parameter of heterogeneous ventricular contraction, and has been proposed as a predictor of arrhythmic complications in patients with MVP. In this prospective cohort study, investigators used STE to calculate global longitudinal strain (GLS) and mechanical dispersion for 32 individuals with arrhythmic MVP (A-MVP), 27 individuals with non-arrhythmic MVP (NA-MVP) and 39 healthy controls in order to examine the association between STE results and ventricular arrhythmia. Investigators found that there were no relevant differences in baseline clinical parameters for individuals with A-MVP versus those with NA-MVP, with the exception of antiarrhythmic medication use (p=0.009). There were also no differences between the A-MVP and NA-MVP groups in terms of standard echocardiographic parameters apart from a high number of bileaflet MVPs in the A-MVP group (p=0.031). In terms of STE results, GLS was similar between the two groups (p=0.37), but mechanical dispersion was higher in the A-MVP group (mean 59 ms) than in the NA-MVP group (mean 43 ms) (p<0.001). A multivariate model including mechanical dispersion, bileaflet involvement, and MR vena contracta width showed that the mechanical dispersion was the only predictor of arrhythmic risk (OR 1.1, 95% CI 1.02 to 1.11, p=0.006). In terms of reproducibility, the correlation coefficient for mechanical dispersion was 0.80 (95% CI 0.78 to 0.87). The results from this study indicate that STE-derived mechanical dispersion is associated with arrhythmic complications, and may be used in identifying patients with higher risk.
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