| Increased myocardial mass due to regular high-volume intense exercise
training (so-called athlete's heart) is not uncommon. Although directly
correlated with the extent of training loads, myocardial hypertrophy
is not present exclusively in well-trained or elite athletes. Athlete's
heart is considered a physiological phenomenon with no known harmful
consequences. However, extreme forms of myocardial hypertrophy due
to endurance training resemble a structural heart disease such as
hypertrophic cardiomyopathy, a condition associated with substantially
increased risk of cardiac event. Endurance sports such as rowing and
road cycling, rather than strength/power training, are most commonly
associated with left ventricular (LV) wall thickness compatible with
hypertrophic cardiomyopathy. The differentiation between physiological
and maladaptive cardiac hypertrophy in athletes is undoubtedly important,
since untreated cardiac abnormality often possesses a real threat
of premature death due to heart failure during intense physical exertion.
Luckily, the distinction from pathological hypertrophy is usually
straightforward using transthoracic echocardiography, as endurance
athletes, in addition to moderately and proportionally thickened LV
walls with normal acoustic density, tend to possess increased LV diameter.
In more uncertain cases, a detailed evaluation of myocardial function
using (tissue) Doppler and contrast echocardiography is effective.
When a doubt still remains, knowledge of an athlete's working capacity
may be useful in evaluating whether the insidious cardiac pathology
is absent. In such cases cardiopulmonary exercise testing typically
resolves the dilemma: indices of aerobic capacity are markedly higher
in healthy endurance athletes compared to patients. Other characteristics
such as a decrease of LV mass due to training cessation are also discussed
in the article.
KEY
WORDS: Left ventricle, physical exercises, physiological adaptation.
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