Incremental Value of Speckle Tracking Echocardiography to Predict Cardiac Resynchronization Therapy (CRT) Responders

Abstract

Background Speckle tracking echocardiography ( STE ) is reported as a useful method to predict cardiac resynchronization therapy ( CRT ) responders. This study aimed to identify the incremental value of a STE parameter to predict CRT responders. Methods and Results We enrolled 171 patients from the Speckle Tracking imaging for the Assessment of cardiac Resynchronization Therapy ( START ) study. CRT responders were defined as patients with ≥15% reduction of left ventricular ( LV ) end‐systolic volume at 6 months post‐ CRT . Based on multivariable logistic regression analysis, incremental values of STE were assessed by c‐statistics, net reclassification improvement ( NRI )/integrated discrimination improvement ( IDI ), and decision curve analysis. Six parameters (left bundle branch block or right ventricular pacing, use of beta‐blocker, blood urea nitrogen ≤3.0 mg/dL, LV end‐systolic diameter ≤50 mm, mitral regurgitation index ≤40%, and STE parameter standard deviation of time from QRS onset to first peak on the circumferential strain curves [ T SD ] ≥116 ms) were identified as the determinants. Compared to the multivariable logistic regression model without T SD (model 1), that with T SD (model 2) showed significant improvement to predict CRT responders: c‐statistic (0.86 vs 0.77; P <0.001), NRI =0.19, P <0.001, and IDI =0.17, P <0.001. The decision curve of model 2 was higher than that of model 1 at threshold probabilities ≥0.2. Based on model 2, a START score was constructed. Compared to the Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy ( MADIT ‐ CRT ) score, the decision curve of the START score was higher than that of the MADIT ‐ CRT score at threshold probabilities ≥0.2. Conclusions Based on various statistical methods, this study revealed that STE had an incremental value to predict CRT responders.