P959Assessment of right ventricular mechanics during physiological exercise in healthy individuals: a 2D speckle imaging study.


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Abstract

Background: 2D speckle imaging (2DSI) is a useful tool to evaluate right ventricular (RV) functionAim of the study: To determine RV mechanics at rest and during exercise in healthy subjects using 2DSI and parameters of RV function.Methods: 30 male healthy volunteers (24±2 yrs) underwent an intensive treadmill stress echocardiogram (GE Vivid E9). We stored apical 4C and 2C RV views at high frame rates and recorded PW DTI of the RV free wall at baseline, at 50%, 60% and 70% of theoretical maximum heart rate (TMHR) and during recovery. We measured TAPSE (mm), RV fractional area change (RV FAC, %), S maximal velocity (S max, cm/s) and RV strain ([Latin Small Letter Open E], %) values in the basal (bas), median (med) and apical (ap) segment of the lateral (lat) and inferior (inf) RV walls at each exercise level. We averaged lat values for the calculation of lat [Latin Small Letter Open E], inf values for inf [Latin Small Letter Open E], and all 6 values for global RV strain. We compared values at different levels of exercise.Results: [Latin Small Letter Open E] measurements could be performed in all pts until 60% of the TMHR and in 27 pts at 70%. During exercise, RV FAC, TAPSE and S progressively increased while all strain values progressively decreased.Conclusion: Despite an increase in all classical parameters of RV function, RV longitudinal strain progressively decreases during exercise in normal pts. Inotropic response of the infundibulum to sympathetic activation was shown to be greater than that of the inflow tract. As circumferential fibers predominate in the infundibulum and longitudinal in the inflow tract, predominant circumferential over longitudinal free wall contraction could represent an adaptive response to the increased preload induced by exercise, thereby explaining the relative decrease in longitudinal strain. Further studies allowing measurement of and showing an increase in RV circumferential strain during exercise should validate this hypothesis.

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