[Mitral flow during exercise in the healthy young adult. Use of an ultrasonic probe device].
Mitral flow velocity was studied during upright exercise on a bicycle ergometer using an original ultrasonic probe support device capable of maintaining a stable apical 4-chamber position. The Doppler sample volume was positioned at the tips of the mitral leaflets. Twelve men (mean age 25.3 +/- 5.8 years) without cardiac disease were studied. Exercise stress testing was performed with 30 watt increments of load of 3 minutes duration up to 120 watts. Mitral flow was recorded before exercise and at each increment of load until the exercise led to an average heart rate increase of 94%. The following changes were observed during exercise: a reduction in the duration of mitral flow (duration MF) and of the Duration MF/RR ratio; an increase in the mean mitral flow velocity of 154% at peak effort compared with basal values and the maximum A and E wave velocities which increased from T0 to T6 from 47 +/- 8.9 to 76 +/- 13 cm/s and from 62.4 +/- 13.1 to 107.8 +/- 14.9 cm/s respectively; the A/E ratio remained stable; mitral velocity time integrals (VTI) remained stable, indicating an increase in mitral surface area during exercise; the stability of the VTI at the A and E waves in absolute values but a mild increase of the A wave VTI/mitral VTI ratio, suggesting a slight increase in the role of atrial contraction during exercise. These results show that the increase in mitral flow velocity during upright exercise on a bicycle ergometer in healthy young adults is accompanied by a constant A/E ratio and mitral VTI which indicates that the mitral surface area increases on effort.
Brion
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Service de cardiologie, hôpital d'instruction des armées, Lyon.
Slama
M A
MA
D000328:Adult; D001783:Blood Flow Velocity; D015150:Echocardiography, Doppler / Q000295:instrumentation*; D005080:Exercise Test; D006801:Humans; D008297:Male; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000502:physiology*; D013318:Stroke Volume
Etude du flux mitral pendant l'effort chez l'adulte jeune sain. Utilisation d'un porte-sonde.