| Abstrakt: |
Twenty-seven subjects without apparent cardiac abnormalities underwent transesophageal echocardiography to evaluate normal Doppler characteristics of pulmonary venous flow. In particular, the effects of normal respiration and straining during the Valsalva maneuver were analyzed. Pulmonary venous flow during systole consisted of one forward flow wave in 15 cases (56%) and of two forward flow waves in 12 cases (44%). In all instances one forward flow wave was seen during early diastole and in 23 subjects (85%) a retrograde wave related to atrial contraction was present. Maximal velocity during systole was 57 ± 13 cm/sec (mean ± SD), during early diastole was 58 ± 19 cm/sec, and during late diastole was 16 ± 9 cm/sec. Velocity time integral during systole was significantly higher than during early diastole (11.8 ± 4.9 vs 9.5 ± 3.9 cm, p< 0.05), while velocity time integral during late diastole was 1.1 ± 0.7 cm. During normal inspiration both early diastolic velocity and velocity time integral significantly decreased from 59 ± 15 to 54 ± 15 cm/sec (p< 0.01) and from 9.5 ± 3.9 to 8.5 ± 4.2 cm (p< 0.05), respectively. During normal expiration, systolic and early diastolic velocity time integral significantly increased, from 11.0 ± 4.1 to 11.8 ± 4.5 cm (p < 0.001) and from 9.5 ± 3.9 to 10.1 ± 4.3 cm (p< 0.05), respectively. Although statistically significant, the differences were small and do not seem of clinical importance. Straining during the Valsalva maneuver, however, obviously decreased pulmonary venous flow velocities. Systolic and early diastolic velocity decreased from 57 ± 15 to 32 ± 10 cm/sec and from 59 ± 18 to 34 ± 15 cm/sec, respectively, while velocity time integral during systole, early, and late diastole decreased from 12.0 ± 5.6 to 4.3 ± 2.6 cm, from 9.9 ± 4.4 to 5.2 ± 3.7 cm, and from 1.3 ± 0.8 to 0.8 ± 0.7 cm, respectively. In conclusion, pulmonary venous Doppler characteristics can adequately be analyzed with transesophageal echocardiography. Normal respiration only minimally influences pulmonary venous flow velocities in contrast to straining during the Valsalva maneuver; this should be considered when these variables are applied for clinical purposes. |
