Systematic review and meta-analysis of training mode, imaging modality and body size influences on the morphology and function of the male athlete's heart

Context The athlete's heart (AH) remains a popular topic of study. Controversy related to training-specific cardiac adaptation in male athletes, and continuing developments in imaging technology and scaling prompted this systematic review and meta-analysis. Objective To provide new insight in relation to: 1) cardiac adaptation to divergent training patterns in male athletes, 2) a developing research database using cardiac magnetic resonance (CMR) in athletes; 3) functional data derived from tissue-Doppler analysis as well as right ventricular (RV) and left atrial (LA) measurements in athletes; and 4) an awareness of the impact of body size on cardiac dimensions. Study design Systematic review and meta-analysis of prospective trials. Data extraction performed by two researchers. Data sources Pub Med, Medline, Scopus and ISI Web of knowledge scholarly data base. Study selection Prospective studies were included if they were echocardiographic or CMR trials of elite young male athletes, with clear indication of type of sports and passed a quality criteria checklist. Results All left ventricular (LV) structural parameters were higher in athletes than in controls. Only LV end-diastolic diameter and volume were higher in endurance athletes than in resistance athletes: 54.8 mm (95% CI 54.1 to 55.6) vs 52.4 mm (95% CI 51.2 to 53.6); p<0.001 and 171 ml (95% CI 157 to 185) vs 131 ml (95% CI 120 to 142); p<0.001, respectively. RV end-diastolic volume, mass and LA diameter were higher in endurance athletes than controls. LV end-diastolic volume was larger when CMR was used rather than echocardiography: 178 ml (95% CI Q7 162 to 194) vs 135 ml (95% CI 128 to 142); p<0.001. Meta-analysis regression models demonstrated positive and significant associations between body surface area (BSA) and LV mass, RV mass and LA diameter. Conclusions Morphological features of the male AH were noted in both athlete groups. A training-specific pattern of concentric hypertrophy was not discerned in resistance athletes. Both imaging mode and BSA can have a significant impact on the interpretation of AH data.