Biventricular pacing improved the clinical composite score at 6 months compared to right ventricular pacing (53% vs 39% improved) in patients with AV block and systolic dysfunction.
RCT
Does biventricular pacing improve clinical composite score, quality of life, and NYHA functional class in patients with atrioventricular block, NYHA class I-III heart failure, and LVEF ≤50% compared to right ventricular pacing?
In patients with atrioventricular block and systolic dysfunction, biventricular pacing improves clinical composite scores, quality of life, and heart failure symptoms compared to right ventricular pacing.
Absolute Event Rate: 53% vs 39%
BACKGROUND: Sustained right ventricular (RV) apical pacing may lead to deterioration in ventricular function and an increased risk of heart failure, especially in patients with pre-existing systolic dysfunction. The BLOCK HF (Biventricular Versus Right Ventricular Pacing in Heart Failure Patients With Atrioventricular Block) trial demonstrated that biventricular-paced patients had a reduced incidence of a composite endpoint of death, heart failure-related urgent care, and adverse left ventricular remodeling. OBJECTIVES: In a pre-specified analysis, this study examined clinical outcomes, including clinical composite score, quality of life (QOL), and change in New York Heart Association (NYHA) functional classification. METHODS: The BLOCK HF trial randomized patients with atrioventricular block, NYHA symptom class I to III heart failure, and left ventricular ejection fraction ≤50% to biventricular or RV pacing. NYHA functional classification, QOL, and clinical composite score were assessed at 6, 12, 18, and 24 months. Bayesian statistical methods were used, with the pre-specified metric of benefit being a posterior probability ≥0.95. RESULTS: Patients with biventricular pacing showed greater improvement in NYHA functional class at 12 months, with 19% improved, 61% unchanged, and 17% worsened, compared with 12%/62%/23% in the RV arm. QOL was improved through 12 months. At 6 months, clinical composite score was improved/unchanged/worsened in 53%/24%/24% in the biventricular arm compared with 39%/33%/28% in the RV arm. This improvement in clinical composite score was sustained through 24 months. CONCLUSIONS: For patients with atrioventricular block and systolic dysfunction, biventricular pacing not only reduces the risk of mortality/morbidity, but also leads to better clinical outcomes, including improved QOL and heart failure status, compared with RV pacing. (Biventricular Versus Right Ventricular Pacing in Heart Failure Patients With Atrioventricular Block BLOCK HF; NCT00267098).
“These new data add to the growing body of evidence supporting the use of BiV pacing for treating patients who have AV block and left ventricular dysfunction who are indicated under current clinical guidelines for permanent RV pacing with a pacemaker. The BLOCK HF findings have previously demonstrated that BiV pacing delays disease progression, prevents heart failure-related events and preserves cardiac function in this patient population. The findings presented today confirm two additional, yet equally important clinical benefits associated with this innovative therapy - symptom and quality-of-life improvement.”
Curtis et al. (2016) conducted an RCT in Atrioventricular block and heart failure with reduced ejection fraction. Biventricular pacing vs. Right ventricular (RV) pacing was evaluated on Improvement in clinical composite score at 6 months. Biventricular pacing improved the clinical composite score at 6 months compared to right ventricular pacing (53% vs 39% improved) in patients with AV block and systolic dysfunction.