When discussing catheter ablation for atrial fibrillation (AFib) since CABANA, it is commonly asked whether or not relieving symptoms is good enough. The answer is yes. There should be no dispute that catheter ablation can be effective for the treatment of AFib. Most patients with symptomatic paroxysmal AFib benefit significantly from catheter ablation. Claims that catheter ablation “does not work” are comparable to climate change denial. Our current efforts should be on how to safely relieve symptoms from AFib as much as possible in individual patients, and in as many patients as possible.
Targeting mortality reduction and stroke prevention with rhythm control strategies should be considered only after we have optimized our techniques to restore and maintain sinus rhythm. It’s important not to set ourselves up for failure, or to create unrealistic expectations. Take for example how many surgeries and procedures are performed in this country solely to improve quality of life. Cataract removal, joint replacements, circumcisions, repair of broken bones, hysterectomies, cholecystectomies, and percutaneous coronary interventions are among the top ten surgeries performed in the United States, and usually have little or no effect on mortality. Orthopedic surgeons are not trying to justify a $30,000 knee replacement in a patient with severe chronic knee pain by searching for evidence that knee surgery will make that patient live longer. Nor are they targeting patients for joint replacement who have abnormal imaging studies of their knee but have no symptoms. And they are not trying to determine if knee replacement surgery should be first-line therapy for patients with knee pain before ibuprofen. They are focused on the best possible techniques to safely provide durable relief of symptoms for patients with knee pain that is refractory to medical therapy.
Trying to demonstrate that maintaining sinus rhythm by any technique can make a patient live longer may in fact be very difficult. What is the evidence that atrial fibrillation worsens mortality? There are data that AFib is an independent predictor of mortality in patients with heart failure, but there is little evidence that AFib is an independent predictor of mortality in patients without structural heart disease. A subgroup analysis of lone atrial fibrillation from the Renfrew/Paisley study found no significant mortality access attributable to lone AFib.1
On the other hand, there is no dispute that ablation can significantly improve a patient’s quality of life when sinus rhythm can be achieved. It is only logical that a patient who has symptomatic atrial fibrillation will have fewer symptoms if an intervention reduces his or her AFib burden. It is also logical that such an intervention should be recommended if it can be done safely. Improving quality of life with ablation for atrial fibrillation has been formally demonstrated even in patients with persistent AFib. Data from the recently published CRYO4PERSISTENT AF trial showed a marked improvement in both physical and mental quality-of-life metrics at 12 months compared to baseline.2
The CABANA trial was essentially designed to ask two questions: whether catheter ablation improves outcomes beyond symptoms (specifically a composite endpoint of death, disabling stroke, serious bleeding, or cardiac arrest), and whether it should be performed as first-line therapy in patients with AFib. This study was presented in May at Heart Rhythm 2018, but at time of this writing has yet to be published. The results demonstrated no improvement in the primary endpoint with ablation. Other secondary analyses are being performed, but overall, CABANA was primarily considered a negative trial. However, it is important to state again that no one should interpret this trial as meaning that ablation for AFib is ineffective. Conduction of this trial was admirable, and required incredible resources and effort. More federal support is needed to fund multicenter trials for a condition as important as atrial fibrillation. However, are the questions asked by the CABANA trial the same questions that both electrophysiologists and most patients with AFib currently asking? One could argue that there are other critical questions related to AFib ablation in 2019, such as: 1) What is the best tool to durably and safely isolate the pulmonary veins?; 2) What should be done at the time of a first-time ablation for persistent AFib?; 3) How do we improve the safety of ablation for AFib?; and 4) Who are the best candidates for ablation? We must continue to focus on these four fundamental questions and help as many patients as possible with symptomatic AFib before we tackle other questions.
1. Stewart S, Hart CL, Hole DJ, McMurray JJ. A population-based study of the long-term risks associated with atrial fibrillation: 20-year follow-up of the Renfrew/Paisley study. Am J Med. 2002;113(5):359-364.
2. Boveda S, Metzner A, Nguyen DQ, et al. Single-Procedure Outcomes and Quality-of-Life Improvement 12 Months Post-Cryoballoon Ablation in Persistent Atrial Fibrillation: Results From the Multicenter CRYO4PERSISTENT AF Trial. JACC Clin Electrophysiol. 2018;4(11):1440-1447.