Influence of postural change on transmitral flow velocity profile assessed by pulsed Doppler echocardiography in normal individuals and in patients with myocardial infarction.

The influence of postural change from lying to sitting on transmitral flow velocity profile was investigated by pulsed Doppler echocardiography in eight normal individuals and in eight patients with myocardial infarction. The postural change decreased early and atrial filling velocities in the normal individuals (61 +/- 10 to 49 +/- 7 cm/sec and 66 +/- 8 to 55 +/- 7 cm/sec, p less than 0.01, respectively), and also decreased early filling but increased atrial filling velocity in the eight patients (62 +/- 13 to 43 +/- 12 cm/sec and 56 +/- 11 to 65 +/- 14 cm/sec, p less than 0.01 and p less than 0.05, respectively). These changes were associated with a reduction in pulmonary artery wedge pressure in the normal subjects and in the patients (5 +/- 2 to 2 +/- 2 mm Hg and 12 +/- 4 to 8 +/- 3 mm Hg, p less than 0.01, respectively). These observations indicate that a preload reduction alters the left ventricular diastolic filling profile. The differences in Doppler alterations between the groups may be attributed to the fundamental differences in intrinsic left ventricular diastolic properties of normal subjects and patients with myocardial infarction.