Weight loss after ablation did not reduce atrial fibrillation recurrence in the HOBIT-AF trial

A program evaluated after ablation

Obesity is a risk factor for atrial fibrillation. But an association between weight reduction and fewer heart rhythm disturbances does not guarantee that a weight-loss program provides additional benefit after catheter ablation.

HOBIT-AF randomly assigned 167 participants to a complex weight-loss intervention, with 85 people, or a control group receiving usual care, with 82 people. The reported age was 59 years and body mass index was 35.6 kg/m². Atrial fibrillation was predominantly paroxysmal, meaning it occurred in episodes.

The intervention lasted 15 months, from the third to the eighteenth month after ablation. The abstract does not detail its various components. The primary outcome was the change in atrial fibrillation or atrial tachycardia burden, assessed using 14-day Holter recordings at the start and end of follow-up.

A metabolic benefit, with no observed reduction in recurrence

At the end of the intervention, the intervention group had lost an average of 6.8% of its initial weight, with improvements in metabolic parameters. However, the abstract does not specify which parameters improved or the magnitude of each change.

The proportion of participants free from atrial fibrillation or atrial tachycardia recurrence was comparable between groups: 70.4% with the intervention versus 69.6% with usual care. The researchers also observed no additional reduction in arrhythmia burden.

A finding specific to this setting

The authors suggest a possible explanation: after ablation, arrhythmia burden was already low, leaving little room for further improvement. This is an interpretive hypothesis, not a mechanism demonstrated by this trial.

These results do not show that losing weight is pointless for people with obesity and atrial fibrillation. They indicate that, in this setting, after ablation and over the period studied, the program did not demonstrate a reduction in recurrence. The absence of an observed difference is also insufficient to establish that the two strategies are equivalent.

What we can take away

In HOBIT-AF, weight loss was accompanied by a better metabolic profile, but not by a demonstrated benefit for arrhythmia recurrence after ablation. These two findings should not be confused.