CORRESPONDENCE: LETTER TO THE EDITOR
Reply
Antonio Pelliccia, MD* and
Barry J. Maron, MD
* National Institute of Sports Medicine, Department of Medicine, via dei Campi Sportivi, 46, Rome 00197, Italy (Email: ant.pelliccia{at}libero.it).
We thank Dr. Basavarajaiah and colleagues for their comments regarding our study (1) recently published in JACC. We also appreciate their prior contributions to the left atrial (LA) remodeling in adolescent trained athletes (2,3) by establishing an appropriate threshold value, which is different from what we found in adult athletes.
The investigation by Dr. Basavarajaiah and colleagues have shown that atrial remodeling associated with athletic conditioning differs in young and adolescent athletes because of their incomplete body maturation and less strenuous conditioning programs. From this input, we know that transverse LA dimension rarely exceeds 45 mm in younger athletes (2) but may be >45 mm (and up to 50 mm) in adult trained athletes (1). These cut-off values can be used in clinical practice to differentiate the physiologic atrial enlargement associated with intensive athletic conditioning from the pathologic atrial remodeling associated with cardiomyopathies.
We also thank Dr. Spodick for his insights and wisdom regarding proper interpretation of the scalar electrocardiogram (ECG) in relation to LA enlargement. Dr. Spodick underscores the opportunity in our study to assess the presence of interatrial block (identified as P-wave duration  120 ms), which may be associated with LA enlargement and represents a marker of atrial dysfunction and risk for atrial arrhythmias (such as atrial fibrillation) (4,5). We do not dispute this suggestion, but we wish to emphasize that the primary focus of our study in highly trained athletes was the assessment of LA dimensional changes by echocardiography and the relation to clinical profile and course (including development of atrial fibrillation). Our data show that LA enlargement is not responsible, per se, for proclivity to atrial arrhythmias, including atrial fibrillation in trained individuals (6).
Dr. Spodick is also correct in suggesting that measurement of LA volume would be more sensitive than that of transverse LA dimension, which we have reported in the present study (and also in previous investigations) (1,7). However, our study design intentionally incorporated this quantitative measure of transverse LA size, which is most commonly used in the clinical practice, and conventionally employed in large epidemiological studies (6,8) so as to be consistent with customary echocardiographic laboratory interpretation and the published literature in this area.
Finally, Dr. Abinader’s comments regarding the mechanisms of LA enlargement in trained athletes are of interest. We agree with Dr. Abinader that rowing/canoeing and cycling involve both dynamic and static exercise of large muscle groups, which are responsible for an increase in both preload and afterload during prolonged training sessions, with the consequence of combined volume and pressure overload (9). Therefore, the atrial remodeling we have reported in the present study (1) and in previous investigations (7) are likely to be the consequence of this combined hemodynamic overload, as also suggested by the close relation we have demonstrated between LA and left ventricular dimensional changes (1).
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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. Makan J, Sharma S, Firoozi S, Whyte G, Jackson PG, McKenna WJ. Physiological upper limits of left ventricular cavity size in highly trained adolescent athletes Heart 2005;91:495-499.[Abstract/Free Full Text] 3. Sharma S, Maron BJ, Whyte G, Firoozi S, Elliott PM, McKenna WJ. Physiologic limits of left ventricular hypertrophy in elite junior athletesrelevance to differential diagnosis of athlete’s heart and hypertrophic cardiomyopathy. J Am Coll Cardiol 2002;40:1431-1436.[Abstract/Free Full Text] 4. Goyal SB, Spodick DH. Electromechanical dysfunction of the left atrium associated with interatrial block Am Heart J 2001;142:823-827.[CrossRef][Medline] 5. Frisella ME, Robinette MM, Spodick DH. Interatrial blockpandemic prevalence concealed by anachronistic electrocardiographic standards. Clin Cardiol 2005;28:381-383.[CrossRef][Web of Science][Medline] 6. Vaziri SM, Larson MG, Benjamin EJ, Levy D. Echocardiographic predictors of nonrheumatic atrial fibrillationthe Framingham Heart Study. Circulation 1994;89:724-730.[Abstract/Free Full Text] 7. Pelliccia A, Culasso F, Di Paolo FM, Maron BJ. Physiologic left ventricular cavity dilatation in elite athletes Ann Intern Med 1999;130:23-31.[Abstract/Free Full Text] 8. Benjamin EJ, D’Agostino RB, Belanger AJ, Wolf PA, Levy D. Left atrial size and the risk of stroke and deaththe Framingham Heart Study. Circulation 1995;92:835-841.[Abstract/Free Full Text] 9. 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]
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