CORRESPONDENCE: LETTER TO THE EDITOR
Competitive Athletes and Left Atrial Remodeling
Edward G. Abinader, MD, FRCPI*
* Cardiology Clinic, Bet-el 26, Haifa, Israel (Email: abinader{at}netvision.net.il).
In a recent issue of the Journal, Pelliccia et al. (1) assessed the prevalence and clinical significance of left atrial (LA) enlargement in competitive athletes. Enlarged LA size was common and present in 20% of examined athletes, and we agree with the investigators that the possible determinants of these changes remain incompletely resolved. They found that LA enlargement occurred in association with left ventricular (LV) enlargement and were largely dependent on the type of sport practiced, with cycling, rowing, and canoeing showing maximal impact. In their opinion these changes are due to the increased preload as they revealed normal resting LV diastolic filling and systolic function.
Rowing and cycling represent typical strength and endurance sports involving combined dynamic and static exercise of large groups of muscles with marked increases in heart rates and systolic blood pressure up to 200 mm Hg during exercise (2). Thus, changes observed in this recent study may not only be due to the increased preload but may be a consequent to the combined volume and pressure overload. I find it hard to agree with the investigators claim that as their athletes showed normal LV diastolic filling "it is reasonable to conclude that their LA enlargement represents uniquely the physiologic consequence of chronic exercise training" as opposed to LA enlargement seen in certain pathologic conditions associated with impaired LV compliance or increased afterload (1). We have demonstrated that while athletes may show normal resting LV filling patterns, some, such as weightlifters, may reveal an abnormal response to isometric stress with reduction in E and marked increase in peak A velocity, resembling that seen in the hypertensive group (3). However, in runners the filling pattern remained normal during isometric stress as well (3,4).
Hence, isometric and isotonic training affect LV filling differently as revealed during isometric stress testing, although resting patterns may be normal. Therefore, one cannot claim that LA enlargement is due solely to changes in preload, as concluded in the present study, relying only on resting LV filling patterns. Moreover, the involvement of afterload changes during exercise may have determined which of their athletes showed the greatest impact on the LA size depending on the type of exercise they performed.
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References
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1. Pelliccia A, Maron BJ, Di Paolo FM, et al. Prevalence and clinical significance of left atrial remodeling in competitive athletes J Am Coll Cardiol 2005;46:690-696.[Abstract/Free Full Text]2. Pluim BM, Zwinderman AH, Van der Laarse A, Van der Wall EE. The athletes heart. A meta-analysis of cardiac structure and function Circulation 1999;100:336-344. 3. Abinader EG, Sharif D, Sagiv M, Goldhammer E. The effects of isometric stress on left ventricular filling in athletes with isometric or isotonic training compared to hypertensive and normal controls Eur Heart J 1996;17:457-461.[Abstract/Free Full Text] 4. Abinader EG, Sharif D, Sagiv M, Goldhammer E. Doppler echocardiographic assessment of isometric stress effects on left ventricular filling in physiologic hypertrophyIn: Dotson CO, Humphrey JH, editors. Exercise Physiology. New York, NY: AMS Press; 1990. pp. 89-99.
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