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J Am Coll Cardiol. 2016 May 10;67(18):2148-2157. doi: 10.1016/j.jacc.2016.02.051.

Improvement in Clinical Outcomes With Biventricular Versus Right Ventricular Pacing: The BLOCK HF Study.

Author information

1
Department of Medicine, University at Buffalo, Buffalo, New York. Electronic address: abcurtis@buffalo.edu.
2
The Heart Group, Lancaster General Health, Lancaster, Pennsylvania.
3
Ohio Heart and Vascular, The Christ Hospital Health Network, Cincinnati, Ohio.
4
Medtronic, PLC, Mounds View, Minnesota.
5
Cardiovascular Medicine Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.

Abstract

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).

KEYWORDS:

atrioventricular block; biventricular pacing; cardiac resynchronization therapy; heart failure; quality of life

PMID:
27151347
DOI:
10.1016/j.jacc.2016.02.051
[Indexed for MEDLINE]
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