Narrow QRS Ischemic Patients Treated With Cardiac Resynchronization Therapy (NARROW CRT)

Narrow QRS Ischemic Patients Treated With Cardiac Resynchronization Therapy

Current recommendations require a QRS duration of ≥120ms as a condition for prescribing cardiac resynchronization therapy (CRT). This study was designed to test the hypothesis that patients with heart failure of ischemic origin, current indications for defibrillator implantation and QRS <120ms may benefit from CRT in the presence of marked mechanical dyssynchrony.

Inclusion Criteria:

• NHYA class II-III heart failure
• ischemic cardiomyopathy
• ejection fraction of 35% or less
• QRS interval of 120ms or less
• evidence of mechanical dyssynchrony as measured on echocardiography

Exclusion Criteria:

• conventional indication for cardiac pacing
• persistent atrial fibrillation
• life expectancy lower than 1 year