Urgent cardiac resynchronization therapy is useful in patients with decompensated heart failure requiring inotropes and mechanical circulatory support.

Although cardiac resynchronization therapy (CRT) is beneficial in patients with heart failure (HF) and left ventricular dyssynchrony, its effectiveness has not been established in patients with decompensated HF on mechanical support. Here, we report two patients with decompensated HF depending on inotropes and intra-aortic balloon pumping (IABP), who were rescued by urgent CRT implantations. Both patients had non-ischemic cardiomyopathy with wide QRS of left bundle brunch block. IABP could be weaned just after introducing CRT. CRT can dramatically improve hemodynamics even in severely decompensated HF, and thus could be considered when left ventricular dyssynchrony is present. <Learning objective: The efficacy of cardiac resynchronization therapy (CRT) for acutely decompensated heart failure (HF) is controversial. However, the patients with wide QRS complex with left bundle brunch block and non-ischemic etiology can be the candidates of CRT implantation in order to wean inotrope and mechanical circulatory support.>.