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Catheter ablation improves outcomes in patients with heart failure and atrial fibrillation (CASTLE-AF)

Barcelona, Spain – 27 Aug 2017: Catheter ablation improves outcomes for patients with left ventricular dysfunction and atrial fibrillation, according to late-breaking results from the CASTLE-AF trial presented today in a Hot Line - LBCT Session at ESC Congress. (1) Patients who received catheter ablation of atrial fibrillation had lower mortality and less hospitalisation for worsening heart failure compared to those receiving conventional drug treatment.

Every year millions of people around the world are diagnosed with heart failure. One specific type of heart failure, left ventricular dysfunction, affects how the heart pumps oxygen-rich blood throughout the body. Atrial fibrillation (AF) is very common in this patient population, increasing the risk of mortality and morbidity already associated with heart failure. (2)

“The medical community continues to debate the ideal treatment for AF in patients with left ventricular dysfunction due to the lack of clinical studies that support one definitive treatment,” said principal investigator Prof Nassir F. Marrouche, professor in internal medicine, Comprehensive Arrhythmia Research and Management (CARMA) Centre, University of Utah Health, Salt Lake City, US. “Common therapies for AF include medication that regulates or slows the heart rate.”

Prof Marrouche and Prof Johannes Brachmann from the Klinikum Coburg, Germany, co-led a clinical trial to examine the effect of catheter ablation on all-cause mortality and hospitalisation rates in AF patients with left ventricular dysfunction, compared to state-of-the art conventional treatment recommended by the American Heart Association and the European Society of Cardiology.

After screening more than 3 000 patients, the CASTLE-AF (3) trial included 397 patients with symptomatic paroxysmal or persistent AF and heart failure with pump function (ejection fraction) less than 35%. All patients had an implantable cardioverter defibrillator (ICD) with Home Monitoring™ capability to enable continuous surveillance of AF. Patients were recruited from more than 30 clinical centres across the world, including North America, Europe, and Australia.

Patients were randomly allocated to undergo radiofrequency catheter ablation or conventional drug treatment (rhythm control or rate control) for AF. The primary endpoint was the composite of all-cause mortality and unplanned hospitalisation for worsening heart failure.

During a median follow-up of 37.8 months the rate of the primary endpoint was significantly lower in the ablation group (28.5%) versus the control group (44.6%) (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.43–0.87 p=0.007).

The secondary endpoints of all-cause mortality and heart failure hospitalisation were also significantly lower with catheter ablation compared to conventional treatment. Rates of all-cause mortality were 13.4% with catheter ablation versus 25% with conventional treatment (HR, 0.53; 95% CI, 0.32–0.86; p=0.011). Rates of heart failure hospitalisation were 20.7% with catheter ablation versus 35.9% with conventional treatment (0.56; 95% CI, 0.37-0.83; P=0.004).

Prof Marrouche said: “We found that compared to those receiving conventional treatment, patients receiving catheter ablation were 38% less likely to experience the primary endpoint, 47% less likely to die, and 44% less likely to be hospitalised with worsening heart failure. A significant number of patients undergoing the ablation treatment were still in normal rhythm at the end of the study.”

Prof Marrouche added that the study also had limitations, namely the fact that all patients had a previous ICD implanted, and this may have affected mortality in both groups.

“Nevertheless, this clinical trial sheds light on the importance of restoring and maintaining regular heart rhythm with ablation,” added Prof Marrouche.

“Until now we had no evidence that ablation, arrhythmia medications, or any other treatment was superior to another in saving lives and reducing hospitalisation,” said Prof Brachmann. “This study has the potential to change the way physicians manage many patients suffering from heart failure and atrial fibrillation.”

Prof Marrouche concluded: “The findings of CASTLE-AF will help not only save the lives of many patients suffering from heart failure and atrial fibrillation but will also have a major impact on the cost of treating those patients by keeping them out of hospital.”


Notes to editor

Sources of funding: The study was sponsored mostly by Biotronik GmbH.

Disclosures: Ownership Interest in Marrek, Inc., Cardiac Designs. Contracted Research with Biosense Webster, Medtronic, St Jude Medical, Boston Scientific. Consulting fees from Biotronik, Preventice.

References and notes:
(1) The study “Catheter ablation versus standard conventional treatment in patients with left ventricular dysfunction and atrial fibrillation: the CASTLE-AF trial” will be presented during:
• The press conference Hot Line - Late Breaking Clinical Trials 1 on Sunday 27 August from 8:00 to 9:00.
• The session Hot Line - Late Breaking Clinical Trials 1 on Sunday 27 August from 11:00 to 12:30 in Barcelona – Main Auditorium.
(2) Left ventricular dysfunction constitutes the final pathway for a host of cardiac disorders. AF is a quivering or irregular heartbeat (arrhythmia) that can lead to blood clots, stroke, heart failure and other heart-related complications.
(3) Catheter Ablation versus Standard conventional Treatment in patients with LEft ventricular dysfunction and Atrial Fibrillation (CASTLE-AF)

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This press release accompanies both a presentation and an ESC press conference at the ESC Congress 2017. Edited by the ESC from material supplied by the investigators themselves, this press release does not necessarily reflect the opinion of the European Society of Cardiology. The content of the press release has been approved by the presenter.