Absence of left bundle branch block and blood urea nitrogen predict improvement in left ventricular ejection fraction in patients with cardiomyopathy and wearable cardioverter defibrillators

Abstract

Objective: To identify predictors of left ventricular ejection fraction (LVEF) improvement in patients with newly detected cardiomyopathy using wearable cardioverter defibrillators (WCDs). Background: WCDs are useful in preventing sudden cardiac death in patients with reduced LVEF <35% while awaiting implantable cardioverter defibrillator (ICD) placement. In many patients, LVEF improves and an ICD is not indicated. Methods: Patients who received WCDs from November 2013 to November 2015 were identified and followed over a period of 2 years. Clinical variables were examined. The primary outcome was improvement in LVEF ≥35%. Predictors of outcome were determined using a multivariate logistic regression model. Results: A total of 179 patients were followed. Median age was 65 (interquartile range [IQR]: 56, 73) years, 69.3% were men. Median baseline LVEF was 20% (IQR: 15, 30). LVEF improved ≥35% in 47.5% patients, with patients being younger (62 vs 68.5 years, P =.006), having lower blood urea nitrogen (BUN) (19 vs 24 mg/dL, P =.002), fewer left bundle branch block (LBBB 9.5% vs 25.8%, P =.004), shorter QRS duration (98 vs 112 ms, P