G. Caselli

Clinical Significance of Abnormal Electrocardiographic Patterns in Trained Athletes

BACKGROUND-The prevalence, clinical significance, and determinants of abnormal ECG patterns in trained athletes remain largely unresolved. METHODS AND RESULTS-We compared ECG patterns with cardiac morphology (as assessed by echocardiography) in 1005 consecutive athletes (aged 24+/-6 years; 75% male) who were participating in 38 sporting disciplines. ECG patterns were distinctly abnormal in 145 athletes (14%), mildly abnormal in 257 (26%), and normal or with minor alterations in 603 (60%). Structural cardiovascular abnormalities were identified in only 53 athletes (5%). Larger cardiac dimensions were associated with abnormal ECG patterns: left ventricular end-diastolic cavity dimensions were 56. 0+/-5.6, 55.4+/-5.7, and 53.7+/-5.7 mm (P<0.001) and maximum wall thicknesses were 10.1+/-1.4, 9.8+/-1.3, and 9.3+/-1.4 mm (P<0.001) in distinctly abnormal, mildly abnormal, and normal ECGs, respectively. Abnormal ECGs were also most associated with male sex, younger age (<20 years), and endurance sports (cycling, rowing/canoeing, and cross-country skiing). A subset of athletes (5% of the 1005) showed particularly abnormal or bizarre ECG patterns, but no evidence of structural cardiovascular abnormalities or an increase in cardiac dimensions. CONCLUSIONS-Most athletes (60%) in this large cohort had ECGs that were completely normal or showed only minor alterations. A variety of abnormal ECG patterns occurred in 40%; this was usually indicative of physiological cardiac remodeling. A small but important subgroup of athletes without cardiac morphological changes showed striking ECG abnormalities that suggested cardiovascular disease; however, these changes were likely an innocent consequence of long-term, intense athletic training and, therefore, another component of athlete heart syndrome. Such false-positive ECGs represent a potential limitation to routine ECG testing as part of preparticipation screening.

Morphology of the “athlete's heart” assessed by echocardiography in 947 elite athletes representing 27 sports

In the present study, we used echocardiography to investigate the morphologic adaptations of the heart to athletic training in 947 elite athletes representing 27 sports who achieved national or international levels of competition. Cardiac morphology was compared for these sports, using multivariate statistical models. Left ventricular (LV) diastolic cavity dimension above normal (> 54 mm, ranging up to 66 mm) was identified in 362 (38%) of the 947 athletes. LV wall thickness above normal (> 12 mm, ranging up to 16 mm) was identified in only 16 (1.7%) of the athletes. Athletes training in the sports examined showed considerable differences with regard to cardiac dimensions. Endurance cyclists, rowers, and swimmers had the largest LV diastolic cavity dimensions and wall thickness. Athletes training in sports such as track sprinting, field weight events, and diving were at the lower end of the spectrum of cardiac adaptations to athletic training. Athletes training in sports associated with larger LV diastolic cavity dimensions also had higher values for wall thickness. Athletes training in isometric sports, such as weightlifting and wrestling, had high values for wall thickness relative to cavity dimension, but their absolute wall thickness remained within normal limits. Analysis of gender-related differences in cardiac dimensions showed that female athletes had smaller LV diastolic cavity dimension (average 2 mm) and smaller wall thickness (average 0.9 mm) than males of the same age and body size who were training in the same sport.(ABSTRACT TRUNCATED AT 250 WORDS)

Absence of left ventricular wall thickening in athletes engaged in intense power training

There is a widely held perception that power training increases left ventricular (LV) wall thickness. Consequently, in individual power-trained athletes, confusion may legitimately occur with regard to the differential diagnosis of athletes heart and nonobstructive hypertrophic cardiomyopathy. To investigate the effects of systematic strength training on cardiac dimensions (particularly absolute LV wall thickness), 100 relatively young and highly conditioned athletes participating in weight and power lifting, wrestling, bobsledding and weight-throwing events for 3 to 24 years (mean 7) were studied by echocardiography. No athlete showed a maximal absolute LV wall thickness that exceeded the generally accepted upper limits of normal (i.e., 12 mm; range 8 to 12). When compared with 26 normal, sedentary control subjects of similar age and body surface area, maximal septal thickness was mildly but significantly greater in athletes (9.6 +/- 0.8 vs 9.0 +/- 0.5 mm; p < 0.001), as was the calculated LV mass index (96 +/- 12 vs 81 +/- 8 g/m2; p < 0.001); LV end-diastolic cavity dimension was similar in athletes and controls (55 +/- 4 and 54 +/- 3, respectively; p > 0.05). Consequently, echocardiographic data in this selected group of purely strength-trained athletes show that whereas this form of conditioning is associated with increased LV mass and a disproportionate increase in wall thickness in relation to cavity dimension, only modest alterations in absolute wall thickness occur (which do not exceed upper normal limits). Therefore, in highly conditioned, strength-trained, competitive athletes, the presence of substantial LV wall thickening (> 13 mm) should suggest alternative explanations, such as the diagnosis of pathologic hypertrophy (i.e., hypertrophic cardiomyopathy).

RESPIRATORY SINUS ARRHYTHMIA AND CARDIOVASCULAR NEURAL REGULATION IN ATHLETES

ABSTRACTStudies using spectral analysis of cardiovascular variability as a noninvasive means for assessing autonomic nervous system activity have provided controversial results in athletes. One reason is that a slow breathing rate-a common feature in athletes-affects spectral estimation because it c

Lack of correlation between ventricular late potentials and left ventricular mass in top-level male athletes.

PURPOSE The aim of this study was to establish: 1) the prevalence of abnormal signal-averaged electrocardiogram (SAECG) in a large population of top-level athletes and 2) the relationship between SAECG parameters and left ventricular mass. One-hundred and fifty-three elite male athletes without apparent heart disease, symptoms, or arrhythmias were studied. METHODS Fifty-six athletes (37%) had increased left ventricular mass (> 134 g.m(-2)). All athletes underwent time-domain SAECG on 300-400 heart beats recorded at rest from three bipolar orthogonal tests with a filter setting of 40-250 Hz. Criteria for abnormality were 1) filtered QRS duration > 114 ms, 2) duration of low-amplitude signals > 38 ms, or 3) root mean square voltage of the last 40 ms of the filtered QRS < 20 microV. RESULTS The prevalence of abnormal SAECG was 7.2% (abnormality of one parameter), 6.5% (abnormality of two parameters), and 5.8%(abnormality of three parameters). The prevalence of abnormal SAECG was similar in athletes with or without increased left ventricular mass. CONCLUSIONS In conclusion, this study showed: 1) the low rate of positive results of SAECG parameters in top-level male athletes, similar to that found in healthy sedentary subjects; and 2) the lack of correlation between left ventricular mass and overall SAECG parameters.

Usefulness of transesophageal pacing during exercise for evaluating palpitations in top-level athletes

The aim of this study was to verify the use of transesophageal atrial pacing in reproducing tachyarrhythmias in 22 top-level athletes symptomatic for palpitations, with no evidence of arrhythmias or cardiac anomalies by the standard noninvasive diagnostic techniques. The transesophageal stimulation protocol was divided in 2 sections: at rest and during exercise on the bicycle ergometer in the upright position. Although transesophageal pacing at rest did not induce any arrhythmias in 18 of 22 athletes, during exercise it induced tachyarrhythmias. This occurred in all 16 athletes who had palpitations during physical activity. Electrophysiologic characteristics of induced atrial tachyarrhythmia suggested reentry within the atrioventricular node in 9 of 18 athletes: atrial fibrillation in 5, atrial flutter in 2, orthodromic reciprocating tachycardia due to concealed anomalous pathway in 1, and automatic atrial tachycardia in 1. This study stresses the clinical importance of palpitations during physical exercise and shows that transesophageal pacing performed during exercise is an important diagnostic tool in reproducing the previously described symptoms and in detecting the underlying tachyarrhythmias.