Abstract 16997: Left Atrial Size in Elite Athletes

Abstract

Background: The “athlete’s heart” is a cardiac adaptation to systematic exercise training and may include left atrial (LA) enlargement. We performed a meta-analysis of the published literature to investigate the relationship of high levels of exercise training to left atrial size. We also examined whether LA morphology is affected differently by dynamic and static exercise, mimicking volume and pressure overload, respectively.

Method: We conducted a systematic review of English-language studies in MEDLINE and EMBASE from inception through May 2012 that reported LA size in elite athletes. A mixed linear model meta-regression was used to determine the effect of exercise on LA size after adjustment for other factors.

Results: A total of 56 studies comprising 6203 elite athletes and 1157 controls were included. Forty eight of the 56 studies reported absolute LA dimensions in 406 strength-trained athletes (ST), 2009 endurance-trained athletes (ET), 434 combined endurance- and strength-trained athletes (CT), 3136 athletes in whom pure exercise classification was not possible (MT), and 1001 controls. Nine of the 56 studies (including 968 athletes and 177 controls) presented LA volume corrected for body surface area (BSA). The adjusted weighted mean LA diameter was 5.81 mm greater in athletes overall compared to sedentary controls (p < 0.0001) and LA volume index was 10.39 mL/m² greater in athletes compared to controls (p < 0.001). LA diameter was 5.01 mm greater in ST, (p < 0.01), 5.85 mm greater in ET (p < 0.0001) and 5.01 mm greater in CT (p < 0.001) compared to controls.

Conclusion: Elite endurance athletes have larger LA dimensions compared to controls when evaluated by either LA diameter or LA volume corrected for BSA. The largest average atrial diameters are reported in endurance athletes. Physicians evaluating athletes should be aware that the LA is increased in both strength and endurance trained elite athletes.