Abstract 4244: Longitudinal Cardiac Rotation Affects Systolic Myocardial Velocities and Velocity-Defined Measures Of Ventricular Dyssynchrony

Abstract

Background : Left ventricle (LV) of cardiac resynchronization therapy (CRT) candidates often displays rotational motion in the horizontal plane, a phenomenon we named longitudinal rotation (LR). We assessed if magnitude and direction of LR affects myocardial velocity-based measures of LV dyssynchrony. Methods : In 100 CRT patients (age 64±13 yrs, 76 men) LR was assessed in the apical 4-chamber view by speckle-tracking while myocardial systolic velocities of basal septum and lateral LV wall were measured from 2-dimensional color tissue Doppler data. Patients were classified into quartiles based on their LR values. Intraventricular dyssynchrony was calculated as the absolute, while septo-lateral delay was calculated as the true difference between the time to peak systolic velocity of the septum and lateral wall. Results : LR in all quartiles except Quartile 4 had a clockwise (negative) direction when viewed in apical 4-chamber view. As quartiles increased, patients were more frequently ischemic, systolic septal velocity and septo-lateral delay decreased, while intraventricular dyssynchrony showed a U shaped relationship (Table ). While difference in peak amplitude of basal septal and lateral systolic velocities and LR correlated with end-systolic volume (ESV) decrease at follow-up in non-ischemic patients (r = 0.44 and r = 0.49, p < 0.01 for both), neither intraventrivcular dyssynchrony nor septal-lateral delay correlated with ESV decrease in either etiology. Conclusions : LR affects amplitudes and timing of myocardial velocities. While difference in peak amplitude of basal septal and lateral systolic velocities and LR predict LV reverse remodeling, time-based velocity measures do not. ICM:/DCM: ischemic/dilated cardiomyopathy; T(sep/lat): time to peak (septal/lateral) systolic velocity; S(sep/lat): peak systolic (septal/lateral) velocity; S-L delay: septo-lateral delay; Dys: intraventricular dyssynchrony; ΔESV: end-systolic volume decrease