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

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sion, in a recent observational study, D’Andrea et al. [ 40 ] examined 615 trained

athletes and found LA mild enlargement (LAVi 29–33  ml/m^2 ) in 150 athletes

(24.3%) and a moderate enlargement (LAVi ≥34 ml/m^2 ) only in 20 (3.2%) of ath-

letes (all were men). The upper limit was 36 ml/m^2 (Fig. 2.2, Table 2.3).

The type and duration of training are the most important independent predictive

factors of LAVi. In fact LAVi is significantly greater in endurance athletes. Because

of a mild or moderate dilation is frequent in athletes, a cut-off of 36 ml/m^2 may help

to identify the athletes with an abnormal LA dilation who require further investiga-

tion [ 2 , 40 ]. This cut off could also help to avoid to categorize erroneously a LA

dimension as abnormal for an athlete [ 2 ]. Thus, LA enlargement is a physiological

consequence of the enlargement of all cardiac chambers. Another study confronted

the LA dimension between athletes and a group of sedentary healthy control and

found that the LA enlargement (LAVi ≥34 ml/m^2 ) has a prevalence of 67% in ath-

letes [ 41 ]. Moreover, the major determinants of LAV in athletes are LV and-diastolic

volume index, age and LV mass, while in non athletes the major determinants are

the body mass index and the E/A ratio [ 30 , 41 ]. In patients with a suboptimal acous-

tic window, CMR is a rationale alternative to study LA dimension. It provides great

anatomic detail and also the presence of LA wall scar, for example after a radiofre-

quency ablation. Even if little data are available, also this technique has demon-

strated LAV enlargement in athlete’s heart. However, atrial volumes normalized for

total heart volume do not differ between athletes and controls, indicating that LA

enlargement is balanced on the total heart volume enlargement [ 42 ]. Of interest, the

female athletes have smaller LA dimension, confirming the results of the previous

studies performed with echocardiography [ 42 ].

22 23 24 25 26 27 28 29

Left Atrial Volume Index (ml/m^2 )

Within Normal Range

(n: 445; 72.5 %)

Mild Dilatation

(n: 150; 24.3.%)

Moderate

Dilatation

(n: 20: 3.2%)

30 31 32 33 34 35 36

0

4

15

47

62

68

92

67

50

39

28

12

Females

Males

9 11

(^63)
56
22
12
4 4 2 1 1
20
40
60
80
100
120
Fig. 2.2 Distribution of LA volume index in 615 athletes [ 40 ]
2 Acute and Chronic Response to Exercise in Athletes: The “Supernormal Heart”