Biton Y, et al. - In a total of 756 patients with left bundle branch block (LBBB) enrolled in the Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy (MADIT-CRT) allocated to the cardiac resynchronization therapy (CRT) with defibrillator (CRT-D) group, researchers assessed clinical and echocardiographic variables that could be used to develop a simple mortality risk stratification score in CRT. Using four clinical variables (age ≥ 65, creatinine ≥ 1.4 mg/dl, history of coronary artery bypass graft, and left ventricular ejection fraction < 26%), a simple clinical risk score for all-cause mortality was developed using best-subsets proportional-hazards regression analysis. Two-fold increased mortality was reported in relation to every 1 point increase in the score within the CRT-D arm. CRT-D vs implantable cardioverter defibrillator (ICD) only was found to be related to mortality reduction in patients with moderate risk.