Reduction in Mitral Regurgitation in Patients Undergoing Cardiac Resynchronization Treatment: Assessment of Predictors by Two-Dimensional Radial Strain Echocardiography

Background: We utilized the novel approach of 2D radial strain (2-DRS) to evaluate whether left ventricular (LV) mechanical dyssynchrony in mid-LV segments corresponding to papillary muscles insertion sites can predict early mitral regurgitation (MR) reduction post-cardiac resynchronization therapy (CRT). Methods: We evaluated 32 patients undergoing CRT (mean age 64 +/- 17 years, 54% males) with MR grade >= 3 determined by the MR jet area/left atrial area ratio (JA/LAA). Results: Fifteen (47%) patients responded to CRT (JA/LAA) < 25%). Sixty-seven percent of responders had mild or no residual MR and 33% had mild-to-moderate MR, while 70% of nonresponders had grade 3 or 4 MR (P = 0.0001) post CRT. The percent reduction in LV end-systolic volume was significantly higher in responders (P = 0.03), as was improvement in LVEF (P = 0.007). Significant delay of time-to-peak 2-DRS in the midposterior and inferior segments prior to CRT was found in responders compared with nonresponders (580 +/- 58 vs. 486 +/- 94, P = 0.002 and 596 +/- 79 vs. 478 +/- 127 ms, P = 0.005, respectively). Responders also had higher peak positive systolic 2-DRS in the posterior and inferior segments compared to nonresponders (22 +/- 13 vs. 12 +/- 7%, P = 0.01 and 17 +/- 9 vs. 9 +/- 7%, P = 0.02, respectively). Logistic regression analysis showed that the differences in pre-CRT inferoanterior time-to-peak 2-DRS of > 110 ms and MRJA/LAA < 40% as well as 2-DRS > 18% in the posterior wall were significant predictors of post-CRT improvement in MR. Conclusion: The presence of a significant time-to-peak delay on 2-DRS between inferior and anterior LV segments, preserved strain of posterior wall, and MRJA/LAA < 40% were found to be associated with significant MR reduction in patients post-CRT. (ECHOCARDIOGRAPHY, Volume 26, April 2009).