A 67-year-old woman presented with exertional dyspnea. An electrocardiogram showed complete left bundle branch block. Cardiac magnetic resonance imaging revealed left ventricular (LV) dilatation with reduced ejection fraction, no evidence of myocardial ischemia and late gadolinium enhancement (LGE) in the inferior LV wall. She was diagnosed with decompensated heart failure (HF) secondary to non-ischemic dilated cardiomyopathy. Narrowing of the QRS complex, disappearance of LGE, and remarkable LV reverse remodeling along with improvement in HF symptoms were achieved by combination therapy with angiotensin II receptor blocker, beta-blocker, and mineralocorticoid receptor antagonist. This case highlights the role of triple-blockade therapy in the treatment of HF.<Learning objective: Complete left bundle branch block and late gadolinium enhancement usually represent irreversible damage of myocardial tissue, and are related to left ventricular (LV) remodeling. However, the clinical course of the present case indicated that optimal medical therapies including sufficient amount of renin-angiotensin-aldosterone inhibition and β-adrenergic blockade can improve ventricular conduction delay and myocardial tissue injury, and consequent remarkable LV reverse remodeling.>