BOAT: Beta Blocker Uptitration With OptiVol After Cardiac Resynchronization Therapy (CRT)

Beta-blocker Uptitration in Heart Failure Patients Receiving Cardiac Resynchronization Therapy With Optivol Fluid Status Monitoring System

Many heart failure patients are unable to reach target beta blocker doses. This study will address whether cardiac resynchronization therapy (CRT) will enable uptitration of beta-blockers to target doses and whether it will favorably affect remodeling by reducing left ventricular end systolic volume (LVESV), with measurable clinical benefit, beyond CRT alone (without changes in beta-blocker dose).

Beta blockers have been proven to have benefit in heart failure (HF) patients with regard to morbidity and mortality. However, initiation and uptitration remains a challenge in many patients. Worsening of heart failure, symptomatic hypotension and symptomatic bradycardia all limit up-titration to the target doses that have been shown to have mortality benefits (carvedilol [Coreg] 25 mg bid, metoprolol succinate [Toprol-XL] 200 mg qd) in the large clinical trials (COPERNICUS, MERIT-HF). It is debated whether the benefit of beta-blockade is solely due to heart rate reduction or more broadly from the cardiac, central and peripheral effects of blocking sympathetic activity. Clearly, there is a remodeling effect on the dilated ventricle. Furthermore, patients with heart rates of 64 bpm or less are rarely begun on beta-blocker therapy. It is not known whether these patients should be given a pacemaker in order to then safely initiate beta-blocker therapy. It is also clear that isolated right ventricular pacing can have deleterious effects on ventricular dyssynchrony and symptomatic heart failure despite medical therapy. Biventricular pacing (BIVPM), also known as cardiac resynchronization therapy (CRT), is the pacing mode of choice for patients with wide QRS complexes and symptomatic HF. It is hypothesized that CRT therapy allows for increased Beta -blocker dose (or initiation of beta-blocker in patients previously intolerant) with improved NYHA, ejection fraction, and remodeling effects. The synergy between two established heart failure therapies requires further evaluation in a prospective randomized trial.

Heart Failure, Beta blockers, Resynchronization, Congestive Heart Failure, NYHA III-IV, Candidate for BIVPM, Not on Target Dose (Coreg 25 Bid or Toprol XL 200 qd)

Both groups get CRT. Group 1 is uptitrated to target dose beta blocker after CRT. Group 2 maintains their b-blocker dose from study entry.

LVESVI change in patients with CRT/ increased dose of beta-blockers vs CRT and no change in beta-blocker dose.

Correlation of Optivol fluid measurement increases (decreased impedance) with symptomatic worsening of heart failure during beta blocker uptitration

Optivol measurements (decreased impedance, increase volume index) correlated with the need for adjusting diuretic therapy when uptitrating beta blocker dose

Inclusion Criteria: NYHA III-IV QRS > 120 msec On medical therapy, but beta blocker dose not @ target (carvedilol 25 bid, metoprolol succinate 200 qd) Exclusion Criteria: QRS < 120 msec On target beta blocker dose

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