INTRODUCTION

LV mechanical dispersion along with LV GLS may provide additional valuable risk markers of VA and SCD in pre dialysis and dialysis patients [1,2]. Mechanical dispersion by strain echocardiography may be a marker of ventricular arrhythmias beyond EF. Mechanical dispersion was increased in those with any arrhythmic events (nsVT or sustained VT) vs. patients free of arrhythmic events [3,4]. Mechanical dispersion was pronounced in patients after TAVI. Mechanical dispersion was independently associated with mortality and could confer additional risk requiring closer post procedural follow-up [5]. LV mechanical dispersion assessed by speckle tracking echocardiography increases significantly with severity of AS and is significantly associated with all-cause mortality. However, LVEF may not recover after AVR and patients may remain symptomatic. Speckle tracking echocardiographic parameters of LV shortening and mechanical dispersion have been proposed to detect LV systolic dysfunction at an earlier stage than LVEF and are related to the presence of myocardial fibrosis on cardiac magnetic resonance [6]. There is increasing interest in assessment of left ventricula mechanical dispersion but normal data are limited [3].

METHODS

We prospectively studied 50 adult outpatients with normal diastolic function and normal LVEF. A complete two dimensional echocardiography examinations was performed, including speckle tracking with measurements of LV systolic global longitudinal strain and Mechanical Dispersion on a commercially available system Epiq7. Time intervals from start Q/R on electrocardiogram to peak negative strain during the study were assessed. Mechanical dispersion was defined as the standard deviation of this time interval from 16 left ventricular segments, reflecting myocardial contraction heterogeneity. p-value is significant at <0.05.

RESULTS

The values of GLS among the studies varied from/- 16.7/to/-24.2%/(Mean GLS = -19 ± 1.59%), p.0.0001, (T.N1) the values of MD varied from 1.4 to 33.6 (mean MD-14. 4 ± 8.5), p.0.0002 (Fig. 1.)

The values of EF varied from 55% to 63% (mean EF58 ± 2.5), p.0.0004 Age of patients varied from 16 to 52, (mean age-60.8), n=52%, 26 were male, n=48%, 24 were female (Tab. 1.).

CONCLUSION

This study determined values of mechanical dispersion in subjects with a normal EF and normal GLS. Further studies are needed to clarify the relation between mechanical dispersion and different cardiac disease