P822Prediction of a good response to cardiac resynchronization therapy in severe heart failure patients: the role of conventional echocardiography.


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Abstract

Purpose: Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in patients with heart failure due to selection of appropriate candidates for CRT. We tested the performance of echocardiographic parameters, including parameters of mechanical dyssynchrony, to predict CRT response.Methods and Results: This 12-month trial was performed on 57 patients (45 men, 12 women) with standard inclusion criteria: New York Heart Association class III or IV heart failure, left ventricular ejection fraction ≤35%, QRS ≥120ms and optimal medical therapy. Forty-three echocardiographic parameters (including parameters of mechanical dyssynchrony: interventricular mechanical delay (IVMD) ≥40ms, septal-to-lateral wall delay of Ts in ejection phase ≥65ms, left ventricular diastolic filling time in relation to cardiac cycle length), based on both conventional and tissue Doppler–based methods. Indicator of positive CRT response was more than or equal to 15% in reduction of left ventricular end-systolic volume (LVESV). Left ventricular end-systolic volume decreased ≥15% in 54.4 % (31/57)of patients. Out of 43 echocardiographic parameters (parameters of left ventricular systolic and diastolic function, mitral regurgitation, right ventricular function and mechanical dyssynchrony), four parameters (changing rate of left ventricular pressure (LVdp/dt), left ventricular septal-to-lateral wall delay, interventricular mechanical delay, myocardial performance index) had modest to good ability to predict response to CRT with sensitivity ranging from 62.5% to 87.1% and specificity ranging from 42.3% to 87.5%. For those parameters, the area under the receiver operating characteristic (ROC) curve for positive response to CRT was less than or equal to 0.738. Out of these parameters, the left ventricular dp/dt stands out as additional predictive echocardiographic parameter for a good CRT response, with its cutoff value of 456 mmHg/s (p=0.02, RR=0.993, 95% CI for RR=0.987-0.999), sensitivity of 62.5% and specificity of 87.5%.Conclusions: Given the modest to good sensitivity and specificity to the changing rate of left ventricular pressure, its significance to inclusion criteria for CRT is to be confirmed in larger trials. As easy to assess parameter by conventional echocardiography, it could improve patient selection with better effectiveness and less cost, contrary to more sophisticated echocardiography techniques

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