Objective To evaluate whether in a population of patients with ‘lone atrial flutter’, the proportion of those engaged in long-term endurance sports is higher than that observed in the general population.

Design An age and sex-matched retrospective case–control study.

Setting A database with 638 consecutive patients who underwent ablation for atrial flutter at the University of Leuven. Sixty-one patients (55 men, 90%) fitted the inclusion criteria of ‘lone atrial flutter’, ie, aged 65 years or less, without documented atrial fibrillation and without identifiable underlying disease (including hypertension). Sex, age and inclusion criteria-matched controls, two for each flutter patient, were selected in a general practice in the same geographical region.

Methods Sports activity was evaluated by detailed questionnaires, which were available in 58 flutter patients (95%). A transthoracic echocardiogram was performed in all lone flutter patients.

Main outcome measures Types of sports, number of years of participation and average number of hours per week.

Results The proportion of regular sportsmen (≥3 h of sports practice per week) among patients with lone atrial flutter was significantly higher than that observed in the general population (50% vs 17%; p<0.0001). The proportion of sportsmen engaged in long-term endurance sports (participation in cycling, running or swimming for ≥3 h/week) was also significantly higher in lone flutter patients than in controls (31% vs 8%; p=0.0003). Those flutter patients performing endurance sports had a larger left atrium than non-sportsmen (p=0.04, by one-way analysis of variance).

Conclusion A history of endurance sports and subsequent left atrial remodelling may be a risk factor for the development of atrial flutter.