Vancouver, BC - Cryoballoon ablation produced better outcomes than antiarrhythmic drug (AAD) therapy among individuals receiving their initial treatment for atrial fibrillation (AF), according to the results of a new study led by Vancouver Coastal Health Research Institute scientist Dr. Jason Andrade.
The findings, published online in the New England Journal of Medicine in November 2020, were simultaneously presented at the American Heart Association’s Scientific Sessions 2020.
“Our research showed that cryoballoon ablation was better at preventing symptoms from recurring a little or at all, and reduced the amount of time some patients experienced atrial fibrillation,” says Andrade at the Centre for Cardiovascular Innovation. “This finding demonstrates that ablation may be a more effective first-line therapy for some patients.”
AF occurs when electrical signals in the right upper chamber of the heart malfunction, causing the heart to flutter or beat irregularly. AF affects over 500,000 Canadians, and puts individuals with the condition at greater risk of developing stroke or heart failure.
One treatment for AF is catheter ablation, which involves threading a long, thin tube through blood vessels to the heart muscle. Cardiac electrophysiologists then administer extreme cold to freeze away tissues with the aim of restoring the heart’s natural rhythm.
Cryoballoon ablation involves using a small balloon filled with a gas coolant to freeze away faulty heart tissue.
Andrade’s study is the largest randomized clinical trial to clearly identify superior health outcomes from the use of cryoablation in comparison to AAD medication—the current first-line treatment for AF, which involves taking medication two to three times per day.
Of the patients who received cryoballoon ablation, 57.1 per cent did not have a recurrence of some form of atrial tachyarrhythmia—an irregular heartbeat—by the one year mark compared with only 32.2 per cent of patients who received AAD. Eighty-nine per cent of cryoballoon ablation patients were free of symptomatic arrhythmia episodes, while this occurred for only 73.8 per cent of AAD patients.
The pan-Canadian study involved 18 health care centres and 303 participants who were treated for AF for the first time in their lives. Participants were on average around 58 years of age and approximately 73 per cent were male. Half of the cohort was randomly selected for cryoballoon ablation while the other half was treated with AAD.
Addressing the root cause right away
Reduced quality of life is a major factor for people with AF. Andrade’s findings show that life satisfaction was slightly higher among cryoballoon ablation patients.
“At an extreme level, some patients may become incapacitated when they go into atrial fibrillation,” says Andrade. “Others who experience more mild-to-moderate symptoms may be unable or reluctant to pursue daily activities, such as traveling or engaging in physical activity. During an episode they may have shortness of breath and feel generally unwell.”
“On top of the sometimes debilitating effects on patients, AF has a huge economic impact in terms of direct patient care and cost of essential health care resources, such as hospital visits, and indirect costs such as lost wages.”
A 2012 study estimated that the Canadian health care system spends around $815 million on in-hospital AF patient care. And while cryoablation is a more invasive procedure with its own risks, it can offer greater returns than AAD by addressing the root cause of AF, rather than treating its symptoms, says Andrade.
“All participants in the study fared better after receiving either procedure. However, patients who received cryoballoon ablation were more likely to be symptom-free and not require hospitalization for their atrial fibrillation.”
Andrade says that he and his research team plan to follow up with participants in three years to gather longitudinal data on the long-term impacts of both procedures.