Abstract 2819: Identification and Characterization of Super-Responders to Cardiac Resynchronization Therapy: An Echocardiographic Study
In some patients, cardiac resynchronization therapy (CRT) has been recently shown to induce a spectacular effect on left ventricular (LV) function and inverted remodeling with nearby normalization of LV contraction.
Objectives: To analyze and characterize super-responders (CRTSR) by echocardiography before CRT. 186 patients have been investigated before and 6 months after implantation of a CRT device with conventional indication according to ESC guidelines. Echocardiographies including measurements of LV dimensions, and contraction by 2-dimensional strain, and pressure assessment, mitral valve analysis were performed at baseline and at 6 months in an independent core-center lab. CRTSR were defined as a reduction of end-systolic volume of at least 15% and an ejection fraction (EF)>50% and were compared to normal responder patients (CRTNo, patients with a reduction of end-systolic volume of at least 15% but an EF <50%). 17/186 patients (9.1%) were identified as CRTSR, only 2 with ischemic cardiomyopathy (p<0.01). No difference was observed regarding NYHA status, EKG duration or EF between CRTSR and CRTNo at baseline. CRTSR presented with significant lower end-diastolic and end-systolic diameters (64±9mm vs 73±9mm (p<0.01) and 53±7.4mm vs 63±8.4mm (p<0.01), respectively), and end-diastolic and end-systolic volumes 161±44ml vs 210±76ml (p<0.02) and 123±43ml vs 163±69ml (p<0.01)) as well as a higher LV dP/dtmax (714±251mmHg.s−1 vs 527±188 mmHg.s−1 (p<0.05)). Regarding strain analysis, CRTSR had significantly higher longitudinal values than CRTNo (−12.8±3% vs −9±2.6%, p<0.001) whereas no difference was observed for other components (p ns). Global longitudinal strain obtained by ROC curves was identified as the best parameter for predicting CRTSR with a cut-off value of −11% (Se=80%, Spe=87%, AUC=0.89, p<0.002) and was confirmed as an independent predictor by the logistic regression (RR: 21.3, p<0.0001). In a large multicenter study, CRT super-responders (EF>50%) were observed in 9% of the population and were associated with less-depressed LV function as determined by strain analysis. Global longitudinal strain appears to be the best predictor of CRTSR.