Catheter ablation improves outcomes for patients with left ventricular dysfunction and atrial fibrillation, according to late–breaking results from the CASTLE–AF trial presented in a Hot Line – LBCT Session at ESC Congress.

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.

“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 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.

“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.”