End-Diastolic Wall Thickness as a Predictor of Reverse Remodelling After Cardiac Resynchronization Therapy: A Two-Dimensional Echocardiographic Study

Background: 

The aim of this study was to evaluate whether in patients with ischemic heart failure (HF) with mechanical dyssynchrony the echocardiographic assessment of the extent of scarred ventricular tissue by end-diastolic wall thickness (EDWT) could predict reverse remodeling (RR) after cardiac resynchronization therapy (CRT). Recent studies using cardiac magnetic resonance imaging have shown that the burden of myocardial scar is an important factor influencing response to CRT, despite documented mechanical dyssynchrony. EDWT assessed by two-dimensional (2D) resting echocardiography is a simple and reliable marker to identify scar tissue in patients with ischemic left ventricular dysfunction. 

Methods:

Seventy-four patients with ischemic HF were evaluated 1 week before and 6 months after CRT. Inclusion criteria were New York Heart Association class III or IV, ejection fraction < 35%, QRS duration > 120 ms, and mechanical intraventricular dyssynchrony ≥ 65 ms. The left ventricle was divided into 16 segments; left ventricular (LV) segments with EDWT < 6 mm were considered scarred. Percentage global scar area (GSA) was calculated by dividing the number of scarred LV segments by 16. 

Results: 

RR, defined as a reduction of LV end-systolic volume ≥ 15%, was found in 38 patients (51.4%) with ischemic HF. A significant inverse linear relationship was found between GSA and RR (r = -0.57; P = .0001). Mean percentage GSA was significantly higher in nonresponders (31.6 ± 18% vs 6.4 ± 11%; P < .001). GSA ≤ 18% showed sensitivity and specificity of 94.7% and 77.8%, respectively (area under the curve, 0.86; 95% confidence interval, 0.71-0.95; P < .0001), to predict RR. 

Conclusion: 

The extent of ventricular segments with EDWT < 6 mm assessed by 2-D echocardiography is an important factor influencing response to CRT at follow-up. GSA may represent an essential simple adjunct to mechanical asynchrony to better select patients suitable for CRT.