Role of ultrasonic tissue characterization in evaluating and predicting effect of Cardiac Resynchronization Therapy on left ventricular remodeling

Background - The aim of this study was to evaluate the short term effect of cardiac resynchronization therapy (CRT) on myocardial structure and function using integrated backscatter (IBS) analysis in patients with evidence of reverse remodeling (RR) at follow-up. Methods and Results – Forty-six consecutive patients submitted to CRT were enrolled. Data were collected at baseline and at 6 months follow-up. RR was identified by a reduction at follow-up in LV end systolic volume (LVESV) 15% versus baseline. Thirty-eight patients (28 male; mean age: 68.6 ± 10.8 years; NYHA class III: 27 patients; ischemic etiology:19 patients) entered follow-up and a RR was observed in twenty-three patients. Among these patients only baseline LV end diastolic diameters (LVEDD) was shown to predict LV RR, particularly in non ischemic patients (ROC analysis: AUC 0.81; p<0,005) and the value with the optimal predictive accuracy was 67 mm (sensitivity 62%; specificity 100%). The IBS analysis showed at follow-up a significant improvement of the cyclic variation index (CVIs%) and a decrease of pericardial indexed IBS value (mSperic) at the septum, indicating respectively an improvement of the intrinsic contractility and a reduction of the interstitial myocardial fibrosis. These findings were confirmed only in patients with a RR and with non ischemic cardiomyopathy. Conclusions – IBS analysis showed an improvement of the intrinsic contractility and a reduction of the interstitial myocardial fibrosis after CRT, that was evident only in patients with RR and non ischemic cardiomyopathy.