Hot Line 10: Answering questions about AF procedures
02 Sep 2024
The benefits of pulmonary vein isolation (PVI) vs. sham, whether to add low-voltage-area (LVA) ablation to PVI and the best ablation technique for treating atrial fibrillation (AF) in patients with heart failure and reduced ejection fraction (HFrEF) were discussed in Hot Line 10.
Despite considerable evidence in favour of performing PVI for symptomatic AF, there are concerns that PVI has a substantial placebo effect and there have been no trials comparing PVI with a sham procedure. Doctor Rajdip Dulai (University College London - London, UK) presented results from the first trial of its kind, the SHAM-PVI trial, which involved 126 patients with symptomatic paroxysmal or persistent AF, previously treated with at least one antiarrhythmic drug who had been referred for catheter ablation. Patients were randomised to undergo either PVI using cryoablation or a sham procedure involving phrenic nerve pacing to simulate an ablation procedure. The researchers found that at 6-month follow-up, average reduction in AF burden, assessed using an implantable heart monitor, was 60% in the ablation group and 35% in the sham intervention group. Measures of health-related quality of life improved in the ablation group vs. the sham intervention group at 6 months. “We expected that PVI would be more effective than a placebo procedure in patients with symptomatic AF, and indeed, the results proved our hypothesis was correct,” said Dr. Dulai. “Going forward we would expect that patients with symptomatic AF be referred for ablation treatment without hesitation.”
Next, Doctor Masaharu Masuda (Kansai Rosai Hospital - Amagasaki, Japan) described the SUPPRESS-AF trial comparing PVI alone with PVI and LVA ablation in 1,347 patients with persistent AF undergoing their first ablation. For the primary endpoint of recurrence of AF and atrial tachycardia (AT) without antiarrhythmic drugs at 1 year, there was no significant difference between the groups, with 61% of patients who had the additional LVA ablation and 50% of standard treatment patients recurrence free. Similarly, freedom from AF/AT recurrence with antiarrhythmic drugs was not different between the two groups (63% with LVA ablation vs. 55% with standard). However, in the subgroup of patients with left atrium enlargement (diameter ≥45 mm), additional LVA ablation reduced recurrence by 40%. There was no difference in the rates of serious complications such as stroke, which were low in both groups (1.7% vs. 1.8%). “Ablation targeting the diseased myocardium is widely performed, but our results show that routine addition to PVI is not recommended. This ablation should be performed only in cases of advanced atrial remodelling,” concluded Dr. Masuda.
The last presentation was by Doctor Kengo Kusano (National Cerebral and Cardiovascular Center Hospital - Osaka, Japan) who described the CRABL-HF trial comparing cryoballoon vs. radiofrequency ablation in 110 patients with AF and HFrEF. One year after the procedure, there was no significant difference in rates of atrial tachyarrhythmias (lasting 30 seconds or more), which occurred in 21.8% of patients receiving radiofrequency ablation and 22.2% of patients receiving cryoballoon ablation. Additionally, cryoballoon ablation could be performed with a significantly shorter procedure time (median 101 vs. 165 minutes) and less fluid volume without increasing left atrial pulse pressure. Left ventricular ejection fraction improved and left arterial volume index decreased significantly after the procedure in both groups. There were no significant differences in the overall safety profiles, with 1 procedure-related complication in each group, and a similar incidence of the composite of death from any cause and/or heart failure hospitalisations between the two groups. Taking these results together, the presenter concluded that the cryoballoon procedure should be the treatment of choice for AF in the majority of patients with HFrEF.
