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.

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 < .001), and higher use of angiotensin converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) (92.9% vs 74.4%, P = .001) compared to those without LVEF improvement. Absence of LBBB (odds ratio [OR] 0.28, 95% confidence interval [CI] 0.11-0.70), lower BUN (OR 0.13, 95% CI 0.02-0.76), and ACEI/ARB use (OR 3.53, 95% CI 1.28-9.69) were identified as independent predictors. Ventricular tachycardia/ventricular fibrillation was observed in three patients, all of whom received successful WCD shocks. Conclusion Absence of LBBB, lower BUN, and ACEI/ARB use predicts LVEF improvement. WCDs help treat arrhythmic events.