Aim:To determine the baseline characteristics of heart failure patients in Singapore undergoing cardiac resynchronization therapy (CRT); the long term outcome and predictors of response to CRT. Methodology:Among patients undergoing CRT for severe heart failure according to indications stipulated in international Cardiology guidelines, baseline demographic data is collected. Age, gender, NYHA functional class, co-morbidities, QRS width on ECG, presence of left bundle branch block pattern on ECG, presence of atrial fibrillation, left ventricular ejection fraction (LVEF) on echocardiogram, ventricular dimensions, 6 min walk test distance are collected. In addition, during the CRT implant procedure, blood is drawn from the vascular access and analysed for NT-pro BNP levels and other biomarkers of heart failure. The echocardiographic and ECG parameters and blood biomarkers are reanalysed at 6 months and 12 months following CRT implant. Response to CRT is defined as a reduction in the iLVESV (left ventricular end-systolic volume index to body surface area) of \>/= 15% and/or an increase in the LVEF of \>/= 10%.