trans-coronary sinus intraseptal pacing (cerclage pacing)

This study is aimed at looking at the effect of "Cerclage pacing" for the heart failure patients who need cardiac resynchronization therapy (CRT). The study hypothesis is that parahisian pacing by 'cerclage pacing' may have a similar benefit as is seen with permanent Hisian pacing

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