The Effect of "Cerclage Pacing" for the Heart Failure Patients Who Need Cardiac Resynchronization Therapy (CRT)

Inclusion Criteria: * who need cardiac resynchronization therapy (CRT) or CRT-non responder * Left bundle branch block \[LBBB\]) \> 120ms of QRS width * Ejection fraction (EF) \< 35% * NYHA class III-IV in spite of optimal medical Tx Exclusion Criteria: * Unsuitable coronary vein anatomy on cardiac CT * Subjects with prosthetic mechanical tricuspid valve * Active infection * Life expectancy less than 6 months