Journal presentation: Curtis AB, et al. Biventricular Pacing for Atrioventricular Block and Systolic Dysfunction. N Engl J Med. 2013;368:1585-93

1. Biventricular Pacing for Atrioventricular
Block and Systolic Dysfunction
N Engl J Med. 2013;368:1585-93
Curtis AB, et al; Biventricular versus RV Pacing in HF Patients with
Atrioventricular Block (BLOCK-HF) Trial Investigators
Leonardo Paskah Suciadi, MD
Cardiology & Vascular Medicine, Universitas Padjadjaran-Bandung-
Indonesia

2. BACKGROUND
• Trials of CRT have included pts with advanced
systolic HF, sinus rhythm, and prolonged QRS
 excluded pts with AVB
• RV pacing  restoring an adequate HR in pts
with AVB
 RV apical pacing may lead to progressive LV
dysfunction
• Hypothesis:
biventricular pacing is superior to RV pacing in
AVB pts with mild-moderate HF in a composite
outcome consisting of death from any cause, an
urgent care visit for HF, or an increase of 15% or
more in the LVES volume index

3. METHODS (1); Subjects
Inclusion:
Pts with high-degree AVB indicated for pacemaker
+ systolic HF NHYA fc.I-III
Exclusion:
-ACS
- PCI within last 30 d
- previous cardiac implantable electrical device
- valvular disease indicated for surgery
- indication for a CRT device (according to the guidelines)
NB: Some subjects underwent PCI implantation for the primary prevention of SCD

4. METHODS (2); Study Procedure
• A prospective, multicenter, randomized double-blind
trial
High degree AVB indicated for pacemaker implantation
Baseline visit ;
Randomization (1:1) to receive either RV pacing or biventricular pacing
The pts were followed every 3 months until a predefined trial-stopping rule was satisfied
Clinical assessment every 6 months; NYHA class, HF stage, QoL, device interrogations
Echocardiography evaluation (at baseline visit, 6, 12, 18, and 24 month);
LVEF, LV end-systolic volume index

5. METHODS (3); Outcome Measures
• Primary outcome:
– Death from any cause
– Urgent care visit for HF symptoms
– Increased in the LVES-volume index of 15% or more
• Secondary outcome:
– Death or urgent care visit for HF
– Death or hospitalization for HF
– Death
– Hospitalization for HF

6. METHODS (3); Statistical Analysis
• Adaptive Bayesian study design 
randomization
• An intention-to-treat analysis served as the
primary analysis for all outcomes
• Hierarchical Bayesian proportional-hazards
model was used for analysis of the primary
and secondary outcomes
• Kaplan-Meier curves were generated for each
outcome in each of the study groups

7. RESULTS (1)
• 58 centers in US + 2 centers in Canada
• December 2003 – November 2011
• A total of 918 pts was enrolled; 691 of them
underwent randomization
• Implantation of a pacemaker or ICD was
attempted in 809 pts  successful in 758 pts
(93.7%)
– Unsuccessful: inability to cannulate the coronary-sinus
ostium (16 pts), dislodgement (11),
unacceptably high pacing threshold (11)
• Length of follow-up: mean of 37 months

8. RESULTS (2); Enrollment, randomization, follow-up
918 pts were assessed for eligibility
691 underwent randomization
349 biventricular pacing 342 RV pacing
42 withdrew or were lost to FU
75 died
13 crossed over to RV pacing
3 met primary end point
before crossover
349 were included in the
analysis
83 had data censored for
primary end point owing
to missing LVES-VI data
50 withdrew or were lost to FU
90 died
84 crossed over to bivent pacing
50 met primary end point
before crossover
342 were included in the
analysis
71 had data censored for
primary end point owing
to missing LVES-VI data
- Implantation of a
pacemaker or ICD was
attempted in 809 pts and
was successful in 758
(93.7%).
- 67 pts underwent
implantation but didn’t
undergo randomization

11. Freedom from a primary-outcome event
HR 0.74;
95% CI (0.60-0.90)

12. Freedom from the clinical components of the primary outcome, included death from
any cause or an urgent care visit for HF.
HR 0.73;
95% CI (0.57-0.92)

13. DISCUSSION (1)
Pts with AVB + LV dysfunction +
mild-moderate HF,
WITHOUT indication of CRT based
on current guidelines
HR in the pacemaker and ICD groups showed
a similar clinical effect, despite a marked
difference in the mean EF in these two groups
Biventricular pacing is superior than RV apical pacing;
Biventricular pacing is unlikely to be
tightly linked to the ejection fraction.
Lower incidence of HF symptoms deterioration,
progression of HF, and death

14. DISCUSSION (2)
• This study has shown another evidence that
biventricular pacing in pts with AVB preserves LV
systolic function
• Previous studies of RV pacing  adverse outcomes
related to HF;
– The Mode Selection Trial in Sinus-Node Dysfunction
(MOST): >40% increased risk of HF hospitalization.1
– The Dual Chamber and VVI Implantable Defibrillator
(DAVID): higher risk of a combined outcome of death of
any cause or HF hospitalization.2
• Potential alternative sites of pacing: RVOT and His
Bundle  evidence ??
1. Lamas GA, Lee KL, Sweeney MO, et. N Engl J Med 2002;346:1854-62.
2. Wilkoff BL, Cook JR, Epstein AE, et al.JAMA 2002;288:3115-23.

15. Study Limitations
 High number of crossover pts (97 pts)
 Intention to treat design
 High number of data censoring and exclusion
because of missing of echocardiograms (154
pts)

16. Leonardo Paskah Suciadi, MD