“…Controlled trials have demonstrated that cardiac resynchronization therapy (CRT), achieved by biventricular (left ventricular [LV] and right ventricular [RV]) pacing improves survival, morbidity, symptoms, quality of life, exercise capacity, cardiac structure and function in heart failure (HF) patients with wide QRS complex [1][2][3][4][5][6][7][8]. However, some patients do not benefit from CRT, particularly those with HF of ischemic etiology [9,10].…”