الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Heart failure (HF) is a complex clinical syndrome resulting from structural and functional impairment of ventricular filling or ejection of blood. Although the clinical syndrome of HF may arise as a consequence of abnormalities or disorders involving all aspects of cardiac structure and function, most patients have impairment of myocardial performance.
Left ventricular (LV) dyssynchrony typically results from delay in the activation of lateral LV free wall and is manifest frequently by left bundle branch block (LBBB) on surface ECG.
Cardiac resynchronization is a pacing modality utilizing an LV pacing lead with the goal of re-synchronizing myocardial contraction in patients with heart failure, depressed systolic function, and significant LV activation delay. CRT was originally indicated in patients with significant LV dysfunction, defined as a left ventricular ejection fraction (LVEF) ≤ 35%, with New York Heart Association (NYHA) class III-IV heart failure symptoms, and with a QRS duration ≥120ms on optimal medical therapy, which varies in definition.
Not all patients respond favorably to CRT. Several characteristics predict improvement in morbidity and mortality, and the extent of reverse remodeling is one of the most important mechanisms of action of CRT.
A new CRT score was recently generated in Alexandria University to predict responders to CRT. All significant independent preimplantation predictors of CRT response in multinomial logistic regression analysis were included in the CRT-score according to their relative effect in the regression model to generate an initial CRT-score. The CRT-score consists of maximum 9 points. The CRT score includes QRS duration ≥150 ms, LBBB morphology of the QRS complex, non-ischemic cardiomyopathy (NICM), sinus rhythm at time of CRT implantation, preserved RV function with TAPSE ≥15 mm, female gender, the absence of history of renal disease and finally the absence of significant chronic obstructive pulmonary disease (COPD). Each parameter was assigned to a single point except QRS duration ≥150 ms was assigned to 2 points. The CRT score is the sum of all points. The CRT response rate has been markedly different according to the CRT score, and CRT response rate was 97.5% patients with CRT score >6 vs 40.7% if CRT score <6, p< 0.001.
Fifty patients were included in our study from February 2016 to September 2017. CRT was implanted in the 50 patients, among the study population, 43 patients had a score ≥ 6; 41 (95.3%) responded to CRT implantation (defined as improvement of NYHA functional class by > 1 NYHA class and reduction of LVESV > 15% at 6 months after CRT implantation) vs 7 patients had score < 6; 5 (71.4%) didn’t respond. The study was validating the study done in Alexandria university originating the CRT score as a preimplantation predictor of response to CRT.
CONCLUSIONS AND RECOMME