The merits of catheter ablation as a first-line treatment for atrial fibrillation (AF) were considered during the second day of AF Symposium 2021 (29–31 January, virtual), which brought together key data from recent clinical trials assessing ablative approaches to the treatment of the disease.
Speakers in the session included Paulus Kirchhof (University Heart and Vascular Centre UKE Hamburg, Hamburg, Germany and University of Birmingham, Birmingham, UK), who discussed the findings of the EAST AFNET 4 trial, first presented at the ESC Congress 2020 (Virtual, 29 August–1 September) and published in the New England Journal of Medicine.
“It has always been very tempting to speculate that early rhythm control would help patients with AF to improve outcomes, but we did not have the data to support systematic rhythm control therapy until recently” said Kirchhof discussing the study’s findings. EAST-AFNET 4 investigated whether systematic initiation of rhythm control therapy – with antiarrhythmic drugs or ablation—delivered soon after diagnosis improves outcomes.
“Early initiation of rhythm control therapy reduced cardiovascular outcomes in patients with early AF and cardiovascular conditions, without affecting nights spent in hospital,” Kirchhof explained. The early rhythm control strategy was associated with more, but overall very few adverse events related to rhythm control therapy, but the overall safety was comparable, he noted, commenting: “These results have the potential to inform the future use of rhythm control therapy.
“We think that systematic and early initiation of rhythm control therapy should be part of the management in all patients with recently diagnosed atrial fibrillation and concomitant cardiovascular conditions, in addition to oral anticoagulation, rate control and therapy of concomitant cardiovascular conditions.”
Following Kirchhof, Karl-Heinz Kuck (LANS Cardio, Hamburg, Germany) detailed findings from the ATTEST trial, which looked at the use of catheter ablation to modify progression of AF. Results from the Biosense Webster-sponsored trial were first shared ESC Congress in 2019 (31 August–4 September, Paris, France), and showed that patients treated with catheter ablation were almost 10 times less likely to develop persistent AF than patients on antiarrhythmic drugs at three years after study initiation.
“There is only a limited amount of data available on the impact of catheter ablation on atrial fibrillation, therefore this study objective was to determine whether ablation using an irrigated RF [radiofrequency] catheter, in conjunction with 3D electro-anatomical mapping, delays progression of AF, versus guideline directed drug therapy,” Kuck said.
After detailing the results of ATTEST, Kuck commented that there may be, “implications for future indications of catheter ablation in patients with paroxysmal atrial fibrillation”. He noted that to date, catheter ablation has been primarily indicated for second line symptomatic treatment of paroxysmal AF after failure of at least one antiarrhythmic drug, commenting that the ATTEST results, if confirmed by further studies, may introduce a new indication for catheter ablation in patients with paroxysmal AF.
Oussama Wazni (Cleveland Clinic, Cleveland, USA) offered a summary of three studies— STOP AF First, Cryo-FIRST, and the EARLY AF trial. STOP AF First sought to demonstrate the superiority of cryoballoon ablation using the Arctic Front Advance cardiac cryoballoon (Medtronic) versus antiarrhythmic drugs for maintaining freedom from AF, atrial tachycardia and atrial flutter in drug naive patients with symptomatic paroxysmal AF, Wazni explained. The study’s results, initially presented by Wazni at ESC Congress 2020 (29 August–1 September, virtual), demonstrated a 75% success rate with no recurrence of any atrial arrhythmia versus 45% in the anti-arrhythmic drug arm at 12 months
EARLY AF, presented at the American Heart Association Scientific Sessions (AHA 2020, 13–17 November, virtual) also studied the use of the Arctic Front Cryoballoon ablation compared with antiarrhythmic drug treatment, looking at the prevention of atrial arrhythmia recurrence in treatment-naive patients with persistent atrial fibrillation. Results from the multicentre investigator-initiated trial found that cryoablation was superior in maintaining freedom from AF, atrial tachycardia and atrial flutter, with 57.1% of patients in the catheter ablation group versus 32.2% in the antiarrhythmic drug group achieving treatment success at 12 months.
Similar to STOP AF First, Cryo-FIRST also found that cryoablation is superior to AAD therapy for the prevention of atrial arrhythmia recurrence in PAF patients who have not previously been treated with drug therapy.
Considering the implications of the three studies, Wazni said: “Once the diagnosis is made I think we should start working on an early ablation strategy. We have to follow up those patients well, whether with loop recorders or scheduled monitoring, and all of this is on the top of risk factor modification. It is also important to address with our patients the risk factors and how we can modify these for less atrial fibrillation and more importantly improvement in mortality.”
Later in the session Jason Andrade (University of British Columbia, Vancouver, Canada) and Peter Kowey (Thomas Jefferson University in Philadelphia, USA) took part in a debate aimed at addressing the ideal first treatment for AF, considering antiarrhythmic medications or a catheter ablation procedure.
Speaking in favour of ablation, Andrade commented that in the past year, several studies have confirmed that ablation is more effective than antiarrythmic drugs when used as a first treatment—including the aforementioned research. “Ablation is more effective than antiarrhythmic drugs at preventing arrhythmia recurrence, improving quality of life and preventing progression,” he commented, before adding: “Early ablation results in better procedure outcomes, less adverse clinical outcomes and less healthcare resource utilisation.”
Kowey offered a counter-view, noting that antiarrythmic drugs continue to be the approach of choice in a large number of cases, but acknowledging that there are a number of caveats for their use.
“I agree that using them early in the course of the disease may be helpful, but remember that antiarrhythmic drugs have been used for years and have been proven to be safe and effective in rigorous and well controlled randomised trials. Even though they have side effects, when properly used these are rarely life threatening. Most of the drugs we have can be administered out-of-hospital.”
Kowey acknowledged that understanding of the benefits of ablation are continuing to develop, but questioned some of the recent data in this area—particularly when considering an early ablation strategy.
“I refer patients for ablations fairly commonly, but I personally have a lot of problems with the ablation literature, especially some of the more recent trials that have been published as an excuse to go early after patients who have atrial fibrillation,” he said. “These studies of course are unblinded, high volume centres predominate. We do not have data from smaller volume centres, the numbers of patients enrolled are relatively small compared to what we have done with drug trials and unfortunately, even though there are differences, the differences in outcome are not robust when examined as early as a year.”
Considering this further, he commented: “I do not believe there should be a question of preferred therapy. I think that we should be looking at all of our alternatives in patients, including antiarrhythmic drugs as well as ablation early in therapy.”