The role of standard 2D and M-mode echocardiography in assessment of good response to cardiac resynchronization therapy in patients with severe dilatated cardiomyopathy and heart failure-one year follow-up

Background: Cardiac resynchronization therapy (CRT) is considered to be a significant step forward in the treatment of patients with heart failure; it reduces morbidity and mortality due to proper selection of candidates for CRT. The aim of study was to assess the performance of echocardiographic parameters, including parameters of mechanical dyssynchrony, to predict CRT response. Methods: The 12-month trial was performed on 70 patients (53 men, 17 women) with standard inclusion criteria: New York Heart Association class III or IV heart failure, left ventricular ejection fraction (LVEF) ≤35 %, QRS ≥120 ms and optimal medical therapy. All echocardiographic parameters, using conventional and tissue Doppler-based methods, were evaluated. Indicator of positive CRT response was more than 20 % in improvement of LVEF. Results: LVEF increased >20 % in 60 % (42/70) pts. Out of twelve baseline echocardiographic parameters, six (left ventricular stroke volume, SV; left ventricular stroke index, SI; left ventricular fraction shortening, FS; right ventricular dimension, RVdim; peak velocity of mitral regurgitation, PVMR, proximal isovelocity surface area, PISA) had modest to good ability to predict LVEF response with sensitivity ranging from 62,2 % to 82,4 %, and specificity ranging from 56,5 % to 81,2 %. For those parameters, the area under the receiver operating characteristic curve for positive response to CRT was ≤0.76. Multivariate logistic regression analysis resulted in selection of left ventricular SI and FS as possible predictive independent echocardiographic parameters for a good CRT response The cutoff value for left ventricular stroke index was 38.7 ml/m2 (p=0.045, RR=0.896, 95 %CI for RR=0.805-0.998) and for left ventricular fraction shortening 13 % (p=0.032, RR=0.707, 95 % CI for RR= 0.515-0.970). Conclusions: The advantage of LVSI and LVFS, as independent predictors of good response to CRT, lies in simplicity of their assessing by conventional M-mode and 2D echocardiography. This could be an argument for adding them to the inclusion criteria for CRT.