Exercise for Cardiovascular Disease Prevention and Treatment From Molecular to Clinical, Part 1

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athletes versus controls, while all 2D and 3D systolic indexes were comparable in

both group [ 2 ]. Therefore, a “mild” reduction in RV function can be considered a

physiologic adaptation. It can be explained by the increased end diastolic volume

with a normal stroke volume that cause a reduced ejection fraction [ 2 ]. Anyway, a

severe reduction in global systolic function is not present in the athlete’s heart and

should be considered as a pathologic condition.

In the athlete’s heart it is very frequent the presence of a tricuspid valve regurgi-

tation on Color Doppler analysis in presence of normal valve leaflets and anulus. It

is often mild and it is a consequence of the enlarged size of right chambers. The

regurgitant jet is typically central and the PASP upper limit is 40 mmHg [ 23 ]. More

often the higher values of PASP are found in endurance athletes rather than strength

ones. Moreover, it has been found that the LV stroke volume is an independent pre-

dictor of PASP, that, in presence of normal pulmonary vascular resistance, can be

considered as a “physiological phenomena” of physical exercise.

The regional systolic function has been also evaluated using tissue deformation

imaging. In endurance athletes, both TDI and 2D–strain-derived parameters show

significant difference respect to healthy sedentary people [ 24 ]. The systolic defor-

mation of the inlet, the basal portion and, to a lesser extent, of the mid free wall of

the RV, is significantly lower than the same region in non-athletes. La Gerche et al.

demonstrated that this regional systolic wall anomalies at rest normalize itself at the

peak of exercise, demonstrating a preserved contractile reserve. This observation

suggests that the wall abnormality of regional systolic function at rest are not the

result of a ventricular damage, but a physiological adaptation in response to RV

dilatation [ 25 ].

About the RV diastolic function, there are non univocal data. Some authors have

reported increased filling pressure of the RV [ 22 , 26 , 27 ], while others found no

change compared with nonathletic controls [ 28 , 29 ]. Tissue Doppler velocity mea-

surements reveal an accentuated early-diastolic phase of the ventricular filling and

prolonged isometric relaxation time, similar to those described for LV. Indeed, the

time of regional release (RTm) and the velocity of early diastolic filling (Em) of the

free wall of RV correlates with stroke volume of LV, demonstrating an interdepen-

dent relation between the two chambers. RV RTm is prolonged providing an opti-

mal diastolic filling in order to reach a greater right systolic stroke volume. At the

same time, the augmented stroke volume of the LV determines an increased venous

return towards the right chambers with a higher flow that causes a prolongation of

the RTm. About the decline of diastolic function of RV in athletes, it has been dem-

onstrated that only the age and heart rate, and no other factors, such as amount of

endurance exercise, influence the diastolic parameters. So if an altered diastolic

function of RV is founded in a young athlete, it could indicate underling heart dis-

ease and require further investigation [ 30 ].

2 Acute and Chronic Response to Exercise in Athletes: The “Supernormal Heart”