Patient-tailored catheter ablation results in a significant reduction in atrial tachyarrhythmia (ATA) burden in shock-resistant persistent atrial fibrillation (AF) patients using implantable cardiac monitors (ICMs) implanted two months pre-procedure and conventional analysis may not capture the true impact of ablation among this cohort.
These were among the findings of the CLOSEMAZE study, which sought to determine the effect of catheter ablation on ATA burden in persistent AF patients undergoing first-time ablation with the use of an implantable ICM.
Outlining the details of the study in JACC: Clinical Electrophysiology, Louisa O’Neill (AZ Sint-Jan Hospital, Bruges, Belgium) and colleagues note that, in contrast to the high success rates seen with current optimised workflows in paroxysmal AF, the results of ablation for ongoing shock-resistant persistent AF are significantly more modest, with many requiring repeat ablation to maintain sinus rhythm. Few studies to date have evaluated the impact of catheter ablation on ATA burden in this population, they add.
The single-centre study involved patients with drug-resistant ongoing persistent AF and at least one previous failed cardioversion, implanted with an ICM (Reveal Linq, Medtronic) two months before the procedure.
A total of 60 patients were recruited, all of whom underwent pulmonary vein isolation (PVI) with or without additional substrate ablation depending on the presence of self-terminating AF on ICM and left atrium size. Median AF burden before and after ablation, off antiarrhythmic medication, was determined from ICM recordings after review by independent investigators.
Patients were followed after the ablation procedure, with clinical review, electrocardiography and device check at one, three, six and 12 months, as well as remote device monitoring performed weekly. The study had a primary endpoint of ICM-based ATA burden, which was defined as the percentage of time spent in ATA and the reduction in ATA burden in the first year after ablation.
Additional primary outcomes included the proportion of patients with reduction in ATA burden and the proportion of patients with residual ATA burden after ablation. The study’s secondary outcomes included safety and quality of life outcomes and findings at secondary procedures.
Patients enrolled in the study had a mean age of 66 years, and 70% were male. The mean left atrial diameter was 48mm, and median CHA2DS2VASc score was 2. The investigators report that 10 patients (17%) unexpectedly demonstrated self-terminating AF before ablation.
The median burden of ATA before ablation was 100%, decreasing to 0% after ablation during the post-blanking follow-up period. Almost half of the patients—27 (45%)—experienced recurrent ATA during 12-month follow-up, in whom the researchers recoded a median burden before ablation of 100% decreasing to 11.4% after ablation.
The investigators report that their study shows that catheter ablation results in a significant decrease in ATA burden from a median of 100% to 0% at one year, with 72% of patients experiencing a reduction in burden of greater than 95%. Furthermore, they write that in those with recurrent ATA, a significant decrease in ATA burden was also seen, from 100% to 11.4%.
“The findings of this study highlight the positive impact that catheter ablation has on ATA burden and quality of life in a population in whom conventionally defined success rates have been modest,” O’Neill et al write in discussion of the clinical implications of the findings. “It therefore follows that the presence of persistent AF should not be viewed as a deterrent to ablation and that ATA burden may be considered as an alternative and indeed superior method for defining treatment success.”
However, they note that implantation of ICMs may not be feasible in all patients, and longer term Holter monitoring may be considered in its place for monitoring of persistent AF after ablation.