Atrial fibrillation (AF) impacts over 37 million individuals globally and frequently co-exists with heart failure, notably impairing the heart's capacity to pump blood effectively. Particularly, heart failure with reduced ejection fraction (HFrEF) is identified when the left ventricular ejection fraction (LVEF) drops to 40% or below, affecting about 60% of heart failure patients. AF in heart failure patients is linked with higher risks of hospitalization, stroke, and mortality. Catheter ablation for AF, particularly using the prevalent radiofrequency (RF) method that employs heat to target heart tissue causing heart rhythm disturbance, is common but comes with significant risks and demands extensive training and procedural time.

Cryoballoon (CB) ablation, which uses cold temperatures to eliminate problematic heart tissue through a catheter, offers a simpler alternative. Yet, data comparing the efficacy of CB versus RF ablation in enhancing clinical outcomes, survival, and quality of life remains limited. Now, late-breaking research presented at ESC Congress 2024 shows that CB ablation matches the effectiveness of RF ablation in reducing AF and atrial tachycardia (AT) recurrence at one year in patients with HFrEF. Additionally, CB ablation offers the advantage of shorter procedure times and reduced fluid use during the procedure, potentially lowering the risk of worsening heart failure due to infusion overload during ablation.

The CRABL-HF trial conducted by the National Cerebral and Cardiovascular Center (Suita, Japan) involved 110 HFrEF and AF patients aged between 20-85 years across five Japanese sites, randomized to undergo either RF or CB ablation. The majority of participants were men, with a median age of 69. For those with cardiac implants, home monitoring tracked AF episodes, while others had twice-daily ambulatory ECGs for a year post-procedure after a 90-day blanking period. After one year, atrial tachyarrhythmias occurred similarly in both groups, with 21.8% in the RF group and 22.2% in the CB group experiencing episodes.

CB ablation not only required less time (median 101 versus 165 minutes) and fluid but also did not increase left atrium pulse pressure. Both procedures significantly improved left ventricular function and reduced left atrial volume index, enhancing cardiac function without notable safety differences between the groups. Each group experienced one procedural complication without causing exacerbation of heart failure or other severe outcomes. The one-year follow-up showed two deaths, one in each group, and hospitalizations due to heart failure were similarly rare and evenly distributed between groups. There was also no difference in the combined endpoint of death or heart failure hospitalization. Patient-reported quality of life, assessed by the Atrial Fibrillation Effect on Quality of Life questionnaire, improved significantly in both groups from baseline to one-year post-procedure.

“Our results show that CB ablation, a minimally invasive procedure that freezes out disruptive heart cells, is faster but as effective as the commonly used approach of burning the cells in order to put the heart back into a normal rhythm pattern,” said lead investigator Dr. Koji Miyamoto from the National Cerebral and Cardiovascular Center. “In addition, there was a very low risk of procedural complications in both groups, demonstrating that catheter ablation has become much safer over the years.” 

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