Improvement in MR and in the dyssynchrony between the mid segments predict super responders in patients undergoing CRT

Background: Twenty to thirty percent of patients with left heart failure in randomized trials do not respond clinically to cardiac resynchronization therapy (CRT). The objectives of our work were to estimate the effec-tiveness of CRT in our routine practice, and to find predictors of favorable response to CRT. Methods: Retrospective analysis of consecutive patients who underwent CRT from 2003-2007. Results: Fifty six consecutive patients (73.2% men, age 66.3 ± 10.2 years) with left heart failure (LHF) (ischemic cardiomyopathy 60.7%) received CRT and were followed for a mean of 27 months. After the implantation: Mean NYHA improved by one class (p < 0.001), LHF admissions were reduced by 79% (p < 0.0001) and mean ejection fruction improved by 31% (19.5% vs 25.6%, p < 0.002). Significant improvement in severity of mitral regurgitation (MR) was an important predictor of high responsiveness (p = 0.004). Improvement of MR was associated with complete left bundle branch block (CLBBB) (p = 0.04) and lower total mortality (p = 0.005). Improvement in synchronization between the mid lateral and mid septal segments, as was calculated with longitudinal strain using echocardiography (105 ± 38 vs 20 ± 23 msec, p = 0.008) was predictor of super responsiveness and reduction in MR among patients with moderate to severe MR prior to implantation. Worsening the delay between the mid posterior and mid anterior septal segments (21 ± 27 vs 120 ± 0 msec, p = 0.006) was associated with absence of response and lack of improvement in MR. Conclusions: Patients who improve mid segments dyssynchrony in four chamber view, have more chance to improve MR and to become super responders.