Introduction and methods

A Randomized Ablation-based Atrial Fibrillation Rhythm Control Versus Rate Control Trial In Patients With Heart Failure And High Burden Atrial Fibrillation (RAFT-AF)

Presented at ACC.21 by Anthony Tang, MD (London, ON, Canada)

It was previously shown that rhythm control with anti-arrhythmic drugs is not superior to rate control in patients with AF. The RAFT-AF study investigated whether ablation-based rhythm control reduces all-cause mortality and HF events compared to rate control in patients with HF and AF.

RAFT-AF was a multicenter, multinational randomized control trial. Eligible patients had high burden AF and NYHA class II-III HF with either reduced or preserved ejection fraction and elevated NT-proBNP. A total of 411 patients were randomized 1:1 to either rate control or ablation-based rhythm control. Rate control consisted of medications targeting a resting heart rate ≤80 bpm and 6-minute walk heart rate ≤110 bpm. If the target heart rate was not achieved with medications, patients underwent atrio-ventricular node (AVN) modification and received a bi-ventricular pacemaker. Ablation-based rhythm control consisted of pulmonary vein isolation ± additional lesions. The composite primary outcome consisted of all-cause mortality and HF events. The trial was stopped early following a recommendation from the Data Monitoring Committee after interim analysis due to lower than expected enrollment rate and lower than expected event rate. Consequently, fewer patients were included in the trial than planned. The trial has therefore limited statistical power to reveal differences between the two treatments. Median follow-up was 37 months.

Main results

• 23.4% of patients in the ablation-based rhythm control group and 32.5% in the rate control group died or experienced a HF event. However, there was no statistically significant difference for the primary outcome of all-cause mortality and HF events between the two treatment groups (HR 0.71, 95%CI 0.49-1.03, P=0.066).

• When stratified according to LVEF, the composite primary endpoint occurred in 22.8% of patients with LVEF ≤45% in the ablation-based rhythm control group and 37.1% of patients in the rate control group. However, this difference was not statistically significant (HR 0.63, 95%CI 0.39-1.02, P=0.059). There was also no significant difference between treatment groups in patients with LVEF>45% (HR 0.88, 95%CI 0.48-1.61, P=0.67).

• Patients in the ablation-based rhythm control group experienced a numerically greater improvement of LV function and quality of life and a numerically greater reduction of NT-proBNP compared to patients in the rate control group. However, these differences were not statistically significant.

Conclusion

Among patients with HF and high burden AF, ablation-based rhythm control and rate control showed no statistically significant differences for the primary outcome of all-cause mortality and HF events.

Discussion

The discussant Rachel Lampert, MD (New Haven, CT, USA) said that while the primary endpoint was not met statistically, RAFT-AF has suggested that ablation-based rhythm control can improve outcomes over rate control in patients with AF and HFrEF. Lampert also emphasized that the improvement of quality of life in the ablation-based rhythm control group is of great importance in the light of patient-centered care.

-Our coverage of ACC.21 is based on the information provided during the congress –