Training-induced enlargement of the heart is balanced between the left and right atria and ventricles

Introduction

It is well known that long term endurance training induces morphological changes of the left ventricle. Few studies have investigated the effects of training on the volumes of the right and left atria and the right ventricle. Different pathologies can cause an enlargement of the chambers of the heart, e.g. dilated cardiomyopathy. We hypothesized that an enlargement of a healthy heart caused by long term endurance training should be well balanced between the left and right side.

Purpose

The aim of this study was to investigate if long tem endurance training can cause a balanced enlargement between the left and right atrium and the left and right ventricle.

Methods

Eighteen elite triathletes (6 female) and 27 healthy normal subjects (12 female) underwent cardiac magnetic resonance imaging (CMR). Left and right end-diastolic volume (LVEDV, RVEDV) and left and right atrial volumes (LA, RA) were calculated from short-axis images using planimetry. Mann-Whitney non-parametric test was used to compare atrial and ventricular volumes between groups. Linear regression was performed to assess the relationship between LVEDV and RVEDV and between LA and RA.

Results

Male triathletes had significantly larger LA and RA volumes (p < 0.0001, p < 0.01) and LV and RV EDV (p < 0.0001, p < 0.001) when compared to male normals. Female triathletes had significantly larger LV and RV EDV (p = 0.015, p < 0.01). There were no significant differences in atrial volumes between female triathletes and female normal subjects (LA p = 0.247 and RA p = 0.147). Linear regression showed a strong correlation between LVEDV and RVEDV (R² = 0.83, p < 0.0001) (Fig. 1A). The correlation between LA and RA was somewhat weaker, yet significant (R² = 0.56, p < 0.0001) (Fig 1B).

Figure 1

Conclusion

This study has shown that long term endurance training induces a balanced enlargement of the left and right atrial and ventricular dimensions in both males and females.