Age-related increase in systolic fraction of pulmonary vein flow velocity-time integral from transesophageal Doppler echocardiography in subjects without cardiac disease.

The pulmonary vein flow velocity-time profile would be equivalent to the pulmonary vein flow volume-time profile, provided that the cross-sectional area of the pulmonary vein remains unchanged during 1 cardiac cycle. The systolic fraction of the pulmonary vein flow velocity-time integral, a ratio of velocity-time integral of the S wave to the sum of velocity-time integrals of the S and D waves, represents the ratio of left atrial storage volume to left ventricular stroke volume. This systolic fraction may help early filling of the left ventricle through an appropriate storage of blood and generation of driving pressure in the left atrium. Because early filling of the left ventricle is progressively impaired with age, it was hypothesized that this systolic fraction is increased with age. Forty-four noncardiac surgical patients (age range 17 to 70 years) who underwent transesophageal Doppler echocardiography under general anesthesia were studied, and left upper pulmonary vein flow and mitral inflow velocities were recorded. The ratio of peak velocity of the E wave to that of the A wave of mitral inflow velocity-time profile (y) decreased with age (y = -0.0245 x age + 2.41; r = -0.672, p < 0.01). Systolic fraction (y) increased with age (y = 0.00373 x age + 0.514; r = 0.656, p < 0.01). The age-related increase in the systolic fraction of pulmonary vein flow velocity-time integral may account for the compensation for impaired early filling of the left ventricle in elderly patients.