Is Rhythm Control with Pulmonary Vein Isolation Superior to Rate Control with AV Nodal Ablation in Patients with Heart Failure?
Quick View
Credits:Commentator: Dhanunjaya Lakkireddy MD, FACC, Director – Center for Excellence in Atrial Fibrillation, Bloch Heart Rhythm Center, University of Kansas Hospitals, Kansas City, KS.
Original Citation : Khan MN, Jaïs P, Cummings J, Di Biase L, Sanders P, Martin DO, Kautzner J, Hao
S, Themistoclakis S, Fanelli R, Potenza D, Massaro R, Wazni O, Schweikert R,
Saliba W, Wang P, Al-Ahmad A, Beheiry S, Santarelli P, Starling RC, Dello Russo
A, Pelargonio G, Brachmann J, Schibgilla V, Bonso A, Casella M, Raviele A,
Haïssaguerre M, Natale A; PABA-CHF Investigators. Pulmonary-vein
isolation for atrial fibrillation in patients with heart failure. N
Engl J Med. 2008 Oct 23;359(17):1778-85. Pubmed Link
Pulmonary-vein
isolation is increasingly being used to treat atrial fibrillation in
patients with heart failure. Is Pulmonary vein isolation better than AV nodal
ablation with bi-ventricular pacing in patients with heart failure?
This was a prospective,
multicenter clinical trial in which 81 patients with symptomatic,
drug-resistant atrial fibrillation, an ejection fraction of 40% or
less, and New York Heart Association class II or III heart failure were
randomized to undergo either catheter ablation for AF (n= 41) or
atrioventricular-node ablation with biventricular pacing (n=40). Catheter
ablation for AF primarily consisted of pulmonary vein isolation with or without
additional atrial substrate modification. The primary end points were change
in ejection fraction, 6-minute walk test and quality of life questionnaire in
HF. All patients completed the Minnesota Living with Heart Failure
questionnaire (scores range from 0 to 105, with a higher score
indicating a worse quality of life) and underwent echocardiography
and a 6-minute walk test (the composite primary end point). Over a
6-month period, patients were monitored for both symptomatic and
asymptomatic episodes of atrial fibrillation.
At 6 months, freedom
from AF in the catheter ablation group was 88% with or without antiarrhythmic
drugs and 71% without antiarrhythmic drugs. The composite primary
end point favored the group that underwent catheter ablation, with an improved
questionnaire score at 6 months (60, vs. 82 in the group that
underwent atrioventricular-node ablation with biventricular pacing;
P<0.001), a longer 6-minute-walk distance (340 m vs. 297 m,
P<0.001), and a higher ejection fraction (35% vs. 28%,
P<0.001). Non-fatal complications were slightly higher in the catheter
ablation group (10%) compared to the AV nodal ablation group. Progression of AF
was higher in patients with AV nodal ablation than those in catheter ablation
group (30% vs 0%). There was also slight reduction in the left atrial size in
the catheter ablation group than in the AV nodal ablation group.
In patients with known
heart failure, catheter ablation results in greater rhythm control off
antiarrhythmic drugs, halts of progression of AF, reduction of LA size,
improvement in ejection fraction and QoL score than AV nodal ablation and
biventricular pacing.
Rate vs rhythm control
is a much contested debate in the treatment of atrial fibrillation. Critical
trials like AFFIRM, SAVE and AF-CHF have not shown any significant difference
in primary outcomes of mortality, QoL and stroke. However, most of these trials
had used rhythm control strategy with the help of antiarrhythmic drugs, which
often times are associated with significant side effects and less than perfect
for rhythm control with poor success rates. So PABA-CHF tries to answer the
everlasting question if rhythm control using a non pharmacologic strategy like
catheter ablation that has superior success rates and lower side effects is
superior to rate control. In most of the prior pharmacologic rate vs rhythm
control trials, the rate control arm often times were in sinus rhythm and no
clear data on effective rate control was known. The current trial nicely
addresses that by potentially allowing for 100% rate control with biventricular
pacing. The strengths of this study are its prospective randomized controlled
nature, multicenter participation, use of techniques that are proven to have
superior results with minimal sideffects or complications in accomplishing
their respective end results. This study has answered the question that was
much debated very effectively. Few more details would have provided better
insights into this trial. It is not clear if the patients in the AV nodal
ablation group had an atrial lead or not; what percentage of patients had
failed AV nodal ablation; what percentage of patients had V-sensing above the
lower rate limits of the pacemaker or defibrillator. Were all patients in the
AV nodal ablation group taken off of the Amiodarone after the procedure? Could
some of the sinus rhythm in this group be attributed to the rhythm controlling
properties of the antiarrhythmic drugs? The sample of patients described in
this study seems to have a only mild to moderate left atrial enlargement. It
would have been helpful to see if there was a difference in outcomes between
ischemic and dilated cardiomyopathic groups in the catheter ablation group. The
current study is a critical piece that connects the puzzle in several ways. It
provides strong evidence that rhythm control using non-pharmacologic strategy
that effectively eliminates atrial fibrillation is definitely superior to the
true rate control strategy with AV nodal ablation.