Heart Remodeling Common in Competitive Athletes

NEW YORK (Reuters Health) - Many highly trained athletes have an enlarged left atrium, one of the two upper chambers of the heart, Italian investigators report. However, the enlargement is usually not a health problem because rhythm irregularities arising in the atrium appear to be uncommon.

Dr. Antonio Pelliccia, of the National Institute of Sports Medicine, Rome, and colleagues measured the left atrial size of 1777 competitive athletes.

The average left atrial transverse dimension was 37 millimeters in men (ranging from 23 to 50 mm) and 22 mm in women (ranging from 20 to 46), the team reports in the Journal of the American College of Cardiology.

Overall, 347 athletes (20 percent) had an enlarged left atrial dimension -- that is, at least 40 mm. Thirty-eight subjects (2 percent) had marked dilation of at least 45 mm.

The type of sport "significantly influenced the variability in left atrial dimension; specifically, cycling, rowing/canoeing, ice hockey, and rugby had the largest influence on left atrial size."

Only 14 (0.8 percent) of the 1777 athletes had documented episodes of atrial rhythm disturbances. Considered together, these irregularities occurred with similar frequency in subjects with or without left atrial enlargement.

Nearly all the 347 athletes with an enlarged left atrium were followed for an average of 7 years. Most of them (61 percent) had continued their training and sports competition during that time, and 98 percent remained symptom-free with no evidence of cardiovascular abnormalities.

Pelliccia's group points out that knowing "the upper limits of atrial size in competitive athletes" should help doctors distinguish between benign remodeling and structural heart diseases.

This is important, they say, because heart enlargement "often represents the basis, in an effort to minimize the risk of disease progression or sudden death, for disqualifying athletes from competition."

SOURCE: Journal of the American College of Cardiology, August 16, 2005.