Quantification of Ventricular Resynchronization Reserve by Radionuclide Phase Analysis in Heart Failure Patients: A Prospective Long-Term Study

2006, of whom 62.2% and 37.8%, respectively, were in New York Heart Association class 3 and 4. Mean QRS width was 17325 ms. ECG-gated radionuclide ventriculography to quantify interventricular and intraventricular dyssynchrony was performed at baseline with and without CRT and at the 3-month follow-up visit. Amino-terminal-pro-brain natriuretic peptide (NT-pro-BNP) levels were also determined at baseline and at 3 months. During a mean follow-up of 10.17.6 months, there were 37 (50%) clinical events that defined the nonresponder group, including cardiac death or readmission for worsening heart failure. In multivariate Cox model analysis, higher NT-pro-BNP blood levels were associated with a significant increase in the risk for event (hazard ratio1.085 for a 100 pg/L increase in NT-pro-BNP; 95% confidence interval, 1.014 to 1.161). Each 10° elevation in intraventricular dyssynchrony was associated with a decrease in the risk of events (hazard ratio0.456, 95% confidence interval, 0.304 to 0.683). Receiver operating characteristic curve analysis demonstrated that an interventricular dyssynchrony cutoff value of 25.5° for intraventricular synchrony yielded 91.4% sensitivity and 84.4% specificity for predicting a good response to CRT. Conclusions—The quantification of interventricular dyssynchrony with radionuclide phase analysis suggests that early postimplantation interventricular dyssynchrony may provide identification of CRT responders. (Circ Cardiovasc Imaging. 2011;4:114-121.)