It has been known for a long time that healthy athletes can develop left ventricular
hypertrophy with typical electrocardiograhic and echocardiographic findings which
lead to the definition of the athletes' heart, as a separate physiological feature.
In some cases it is difficult to distinguish between pathological versus physiological
myocardial hypertrophy. Diastolic dysfunction is an early sign in the temporal sequence
of ischemic events in coronary heart disease. Similar changes occur in other types
of heart disease due to arterial hypertension or inflammation processes. Diastolic
function is changed even in idiopathic hypertrophic cardiomyopathies. In contrast
to these groups of patients, diastolic function remains unchanged or is improved in
healthy athletes depending on the type of training (isotonic or isometric exercise).
In cases with borderline changes, examinations during physical stress (exercise testing)
which provokes an oxygen demand/supply imbalance and consecutively impairs early diastolic
filling could clarify if an underlying heart disease is present. Although the physiology
of diastolic function is complex, the factors contributing to diastolic disturbances
can be differentiated into intrinsic and extrinsic left ventricular (LV) abnormalities.
Intrinsic mechanisms include a) impaired LV relaxation, b) increased overall chamber
stiffness, c) increased myocardial stiffness and d) increased LV asynchrony. All these
factors are part of pathological LV hypertrophy. Factors extrinsic to the LV causing
diastolic disorders include a) increased central blood volume, which will increase
left ventricular pressure without altering the LV pressure-volume relation, and b)
ventricular interaction mediated by pericardial restraint, which may cause a parallel
upward shift of the diastolic LV pressure-volume curve. Improved understanding of
LV relaxation and filling helps to differentiate pathological and physiological myocardial
hypertrophy. Ongoing heart disease of different types can be diagnosed early by stress
Doppler echocardiography in relation to other clinical findings and symptoms of the
patient.
Key words
Stress Doppler echo - left ventricular hypertrophy - diastolic dysfunction - coronary
artery disease - hypertensive heart disease
