Right Ventricular Septal Pacing in Patients With Right Bundle Branch Block and Heart Failure (The SPARK Trial)

This pilot clinical trial will be a randomized single blinded cross over trial. Each subject
will undergo three study stages. Subject will be randomized initially to either of the two
arms; experimental or placebo, and then will be followed up for 3 months for the first stage
to assess outcomes. In the second stage, both arms transition to a two months, intervention
free, wash out period. Finally, at the third stage both arms will cross over and subject will
be followed up for an additional 3 months for outcomes assessment.

Inclusion Criteria:

- Cardiomyopathy; ischemic or non-ischemic on optimal medical therapy per current heart
failure treatment guidelines for at least 3 months.

- LVEF < 35% by trans-thoracic echocardiogram assessment

- Prior implantation of pacemaker/defibrillator with at least an atrial and RV mid
septal lead. Atrial lead can be waived if RV lead has atrial sensing capabilities*

- Normal sinus rhythm at enrollment

- RBBB with QRS duration >120 msec on 12 lead surface EKG.

- PR interval <250 msec on 12 lead surface EKG

- Subjects with biventricular pacemaker/ICD will be eligible for enrollment if
their LV lead pacing function has been turned off by the subject's primary
cardiologist prior to study enrollment for at least 3 months (this could be due
to lead malfunction or the decision to deactivate the LV pacing therapy for any
reason per primary cardiologist discretion)

Exclusion Criteria:

- Age younger than 18 years old

- Pregnancy

- Acute Myocardial infarction within 6 months of entry into the study

- Inotrope dependent heart failure condition

- Left ventricular assist device or heart transplantation

- Any other known conditions other than heart failure that could limit survival to < 6
months.

- Atrial fibrillation or flutter burden >10% of the time within the last 6 months

- Atrioventricular node disease that requires ventricular pacemaker support >10% of the
time