High Intensity His Bundle Pacing in Heart Failure Patients With Narrow QRS Outcome Study

Cardiac Resynchronization Therapy (CRT) decreases heart failure hospitalizations and mortality and increases left ventricular Ejection Fraction (EF) in patients with dilated cardiomyopathy, left bundle branch block and QRS duration \>130msec. His bundle pacing has a similar effect in this category of patients. However, CRT is not beneficial in heart failure (HF) patients with narrow QRS. His-bundle pacing delivers physiological ventricular activation and has been shown to improve acute hemodynamic function in patients with heart failure, a prolonged PR interval, and either a narrow QRS or RBBB through AV delay optimization. We observed an acute hemodynamic effect during application of higher pacing output (3.5 Volts/1 msec) in HF patients with dilated or ischemic cardiomyopathy and narrow QRS independently of the paced QRS duration or AV delay shortening. This is a single-center, prospective randomized single-blinded study, recruiting a sub-population of patients with heart failure (dilated or ischemic cardiomyopathy, EF\<50%, narrow QRS (\<110 msec), in optimal medical treatment who have an indication for ICD.