Opposing Wall Mechanics Are Significantly Influenced by Longitudinal Cardiac Rotation in the Assessment of Ventricular Dyssynchrony

Abstract

This study sought to assess whether longitudinal rotation (LR) affects myocardial systolic velocity profiles and to compare velocity-based measures of dyssynchrony with LR for predicting cardiac resynchronization therapy (CRT) response. Longitudinal rotation, a rocking motion often seen when the dilated left ventricle (LV) is imaged in its horizontal long-axis plane, is a recently recognized phenomenon and a new predictor of response to CRT. One hundred patients with CRT implants and suitable baseline echocardiograms were identified. Longitudinal rotation was assessed in the apical 4-chamber view by speckle-tracking techniques and myocardial systolic velocities for basal septum, and lateral LV were analyzed from tissue Doppler images. The quartiles of LR distribution were analyzed for differences in their systolic velocities. Correlation between measurements and reduction in LV end-systolic volume (ESV) at follow-up was performed. Quartile 1 had a mean LR of -6.8 +/- 2.3 degrees ; quartile 4 showed a mean LR of 2.3 +/- 1.6 degrees . A depressed peak velocity of lateral wall, when compared with the septum, was found for quartile 1 (p = 0.01), whereas the converse was noted in quartile 4 (p = 0.0001). The difference in amplitude of peak velocity between septal and lateral walls was found to correlate with the pattern of LR and with percentage reduction in LV ESV at follow-up in nonischemic patients. Septal-lateral delay was not correlated with the presence of LR, nor was it predictive of reduction in LV ESV. Patients with prominent clockwise LR have depressed long-axis systolic velocities of the lateral wall, whereas the patients with counterclockwise LR have depressed septal wall velocities. The difference in peak amplitude of basal septal and lateral systolic velocities is predictive of LR, and in the nonischemic subgroup correlates with quantitative LV reverse remodeling at follow-up. Velocity time-based measures, including septal-lateral delay were not predictive of CRT response.