Introduction: A novel hypothesis for increased ventricular pumping describes the heart as a displacement pump, in which atrioventricular plane displacement (AVPD) is an important mechanism. The hypothesis predicts that AVPD increases at high heart rates. The aim of the present study was to determine whether AVPD increases during exercise at high heart rates. A secondary aim was to study the left ventricular function and dimensions in endurance-trained young female athletes.
Methods: Eight female cross-country skiers (18.5 +/- 0.9 yr, 169.3 +/- 2.9 cm, 55.7 +/- 4.2 kg, and 64.8 +/- 3.7 mL x kg(-1) x min(-1) in maximal oxygen uptake) were compared with seven sedentary female controls (18.0 +/- 0.6 yr, 175.0 +/- 2.5 cm, 71.1 +/- 4.1 kg, and 42.8 +/- 3.0 mL x kg(-1) x min(-1) in maximal oxygen uptake). Cardiac anatomy and function were assessed by echocardiography.
Results: Whereas left ventricular ejection fraction (LVEF) increased in both groups, AVPD fell significantly during exercise. AVPD did not correlate with LVEF, and there were no differences in AVPD between groups either at rest or during exercise. Cardiac output index (mL x lean body mass(-0.67)) and stroke volume index (mL x lean body mass(-1)) were higher in the trained group. The trained group had a larger left ventricular mass, and left ventricular internal dimensions, scaled to lean body mass.
Conclusions: This first study to examine AVPD at rest and during exercise in endurance-trained athletes did not indicate that AVPD is an important mechanism of increased cardiac pumping during exercise. Endurance-trained female athletes have larger left ventricular dimensions and increased function as compared with sedentary subjects.