LAUSR

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in heart failure individuals. Despite many efforts 30–40% patients with CRT still do not respond to therapy. The purpose was to propose and evaluate a novel dyssynchrony scoring system – Regional Strain Pattern Index (RSPI) in prediction of response to CRT. Forty-nine HF patients (age: 66.5±10 years, LV ejection fraction: 24.9±6.4%, QRS: 173.1±19.1 ms, NYHA class II/III: 34.7%/63.3%, ischemic aetiology: 57.1%) underwent CRT implantation. Transthoracic echocardiography was performed before and 15±7 months after CRT implantation. Baseline dyssynchrony was studied by standard indices, strain pattern analysis and novel, author's index- RSPI. RSPI constitutes a method of quantification of LBBB-related strain curve pattern analysis. RSPI was calculated using longitudinal strain by 2D speckle tracking as the sum of dyssynchronous components across 12 segments from all three apical views. In one view, four components were assessed: 1) the contraction of the early-activated wall, 2) the prestretching of the late activated wall, 3) the contraction of the early-activated wall in the first 70% of the systolic ejection phase and 4) the peak contraction of the late-activated wall after aortic valve closure. One point was attributed to each component, thus the maximum was 12 points. RSPI was prospectively evaluated in predicting response to CRT. The response to CRT was defined as ≥15% reduction in the left ventricular end-systolic volume after 15 month follow-up. Thirty-six (73.5%) patients were responders. There were no significant differences in the baseline demographics, clinical, echocardiographic parameters between responders and non-responders. The mean RSPI in the overall population was 5.39±2.9 and higher RSPI values were observed in responders (5.86±2.9) than in non-responders (4.08±2.4, p=0.044). The ROC curve indicated that RSPI significantly predicted CRT response (area under curve, AUC=0.691, p=0.014) with the cut-off value at 7 points. Therefore, study population was divided into two groups according to RSPI score: ≥7 points (19 patients, 38.8% of population) and <7 points (30 patients, 61.2%). In univariate logistic regression analysis, among all of the dyssynchrony indices only RSPI≥7 points predicted the positive response to CRT (OR: 12; 95% CI=1.33–108.17; p=0.0036) with specificity of 92.3%, sensitivity of 50%, positive of 64.7% and negative of 40% predictive value for CRT response. ROC curve for RSPI RSPI constitutes a novel, valuable predictor for CRT response. Grant for scientific research in the field of CRT efficacy funded by Medical University of Silesia.