Practice Update: Cardiology

ESC 2017: Catheter Ablation Improves Outcomes in Patients

With Heart Failure and Atrial Fibrillation – CASTLE-AF Trial

Catheter ablation may improve outcomes for patients with left ventricular dysfunction and atrial fibrillation. Patients

who received catheter ablation of atrial fibrillation had lower mortality and less hospitalization for worsening heart

failure than those receiving conventional drug treatment.

his outcome of Catheter Ablation vs

Standard conventional Treatment

in patients with LV dysfunction and

AF (CASTLE-AF) was reported at the 2017

European Society of Cardiology (ESC) Con-

gress, from August 26–30.

“The medical community continues to

debate the ideal treatment for atrial fibril-

lation in patients with left ventricular

dysfunction because clinical studies that

support one definitive treatment are lack-

ing. Common therapies for atrial fibrillation

include medication that regulates or slows

the heart rate,” said Nassir F. Marrouche,

MD, of the Comprehensive Arrhythmia

Research and Management (CARMA) Cen-

tre, University of Utah Health, Salt Lake City

Dr. Marrouche and Johannes Brachmann,

MD, of the Klinikum Coburg, Germany,

jointly conducted a clinical trial to exam-

ine the effect of catheter ablation on

all-cause mortality and hospitalization rates

in patients with atrial fibrillation and left

ventricular dysfunction, vs state-of-the art

conventional treatment recommended by

the American Heart Association and Euro-

pean Society of Cardiology.

CASTLE-AF is the first randomized clini-

cal trial comparing catheter ablation to

current first-line antiarrhythmic drug ther-

apy for patients with coexisting heart

failure (HF) and atrial fibrillation evaluat-

ing the primary outcome of mortality and

hospitalization for worsening heart failure.

After screening more than 3000 patients,

CASTLE-AF included 397 patients with

symptomatic paroxysmal or persistent atrial

fibrillation and heart failure with ejection

fraction <35%.

All patients were supplied with an implant-

able cardioverter defibrillator with home

monitoring capability to enable continuous

surveillance of atrial fibrillation. Patients were

recruited from more than 30 clinical centers

from North America, Europe, and Australia.

Patientswere randomized to radiofrequency

catheter ablation or conventional drug

COMMENT

By Clyde W Yancy

MD, MSc, MACC, FAHA, MACP, FHFSA

CASTLE-AF

“Catheter ablation versus standard con-

ventional treatment in patients with left

ventricular dysfunction and atrial fibril-

lation: the CASTLE-AF trial,” a study of

397 patients, evaluated the benefit of

catheter ablation of atrial fibrillation on

hard cardiovascular outcomes in the set-

ting of concomitant heart failure. Over

3000 patients from 30 countries were

screened for participation. All had an

ICD in place with home-monitoring func-

tionality. Patients were randomized to

ablation versus conventional therapy,

either rate or rhythm control. Follow-up

was 37.8 months. The primary endpoint

was all-cause mortality and heart failure

hospitalization. The study was positive,

with a 38% (HR, 0.62; 95% CI, 0.43–0.87;

P = .007) relative risk reduction in the

primary endpoint. The secondary end-

point of death alone demonstrated a 47%

reduction.

These are remarkable results that

are applauded but do raise important

questions:

•

Who were these patients? The large

number screened versus those

enrolled does raise the question of a

selection bias.

•

How was heart failure treated? The

mortality seen in the conventional

therapy arm would suggest more

advanced heart failure. Over the course

of this study, the management of heart

failure has changed.

•

How was medical therapy modified

over the trial, and were the adjustments

in medical therapy similar in both arms?

•

What were the power estimates for the

primary endpoint? Could this be a play

of chance?

Nevertheless, we should take away that

atrial fibrillation ablation in those with

heart failure is a consideration, but the

target patient population and the exact

magnitude of the treatment effect need

refinement. This could be a new direction

of care.

Dr Yancy is Chief of

Cardiology at

Northwestern University,

Feinberg School of

Medicine, Associate

Director of the Bluhm

Cardiovascular Institute at

Northwestern Memorial

Hospital, Magerstadt Endowed Professor of

Medicine Chair, Professor of Medical Social

Sciences, Vice-Dean of Diversity & Inclusion,

Northwestern University, Feinberg School of

Medicine, Chicago, Illinois.

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