It has previously been demonstrated that predictable changes occur in mitral flow velocities under different loading conditions. The purpose of this study was to relate changes in pulmonary venous and mitral flow velocities during different loading conditions as assessed by transesophageal echocardiography in the operating room. Nineteen patients had measurements of hemodynamics, that is, mitral and pulmonary vein flow velocities during the control situation, a decrease in preload by administration of nitroglycerin, an increase in preload by administration of fluids, and an increase in afterload by infusion of phenylephrine. There was a direct correlation between the changes in the mitral E velocity and the early peak diastolic velocity in the pulmonary vein curves (r = 0.61) as well as a direct correlation between the deceleration time of the mitral and pulmonary venous flow velocities in early diastole (r = 0.84). This indicates that diastolic flow velocity in the pulmonary vein is determined by the same factors that influence the mitral flow velocity curves. A decrease in preload caused a significant reduction in the initial E velocity and prolongation of deceleration time, and an increase in preload caused an increase in E velocity and shortening of deceleration time. An increase in afterload produced a variable effect on the initial E velocity and deceleration time and was dependent on the left ventricular filling pressure. The change in systolic forward flow velocity in the pulmonary vein was directly proportional to the change in cardiac output (r = 0.60). The pulmonary capillary wedge pressure correlated best with the flow velocity reversal in the pulmonary vein at atrial contraction (r = 0.81). Use of pulmonary vein velocities in conjunction with mitral flow velocities can help in understanding left ventricular filling.

Relation of pulmonary vein to mitral flow velocities by transesophageal Doppler echocardiography. Effect of different loading conditions.

To determine whether pulmonary venous flow and mitral inflow measured by transesophageal pulsed Doppler echocardiography can be used to estimate mean left atrial pressure (LAP), we prospectively studied 47 consecutive patients undergoing cardiovascular surgery. We correlated Doppler variables of pulmonary venous flow and mitral inflow with simultaneously obtained mean LAP and changes in pressure measured by left atrial or pulmonary artery catheters. Among the pulmonary venous flow variables, the systolic fraction (i.e., the systolic velocity-time integral expressed as a fraction of the sum of systolic and early diastolic velocity-time integrals) correlated most strongly with mean LAP (r = -0.88). Of the mitral inflow variables, the ratio of peak early diastolic to peak late diastolic mitral flow velocity correlated most strongly with mean LAP (r = 0.43), but this correlation was not as strong as that with the systolic fraction of pulmonary venous flow. Similarly, changes in the systolic fraction correlated more strongly with changes in mean LAP (r = -0.78) than did changes in the ratio of peak early diastolic to peak late diastolic mitral inflow velocity (r = 0.68). We conclude that in the surgical setting observed, pulmonary venous flow from transesophageal pulsed Doppler echocardiography can be used to estimate mean LAP. This technique may provide a rapid, simple, and relatively noninvasive means of gauging this variable in patients undergoing intraoperative transesophageal echocardiography.

Estimation of mean left atrial pressure from transesophageal pulsed doppler echocardiography of pulmonary venous flow

Background—Determinants of left atrial (LA) reservoir function and its influence on left ventricular (LV) function have not been quantified. Methods and Results—In an open-pericardium, paced (70 and 90 bpm) pig model of LV regional ischemia (left anterior descending coronary constriction), with high-fidelity LV, LA, and RV pressure recordings, we obtained the LA area with 2D automated border detection echocardiography, LA pressure-area loops, and Doppler transmitral flow. We calculated LV τ, LA relaxation (a−x pressure difference divided by time, normalized by a pressure), and stiffness (slope between x and v pressure points of v loop). Determinants of total LA reservoir (maximum−minimum area, cm2) were identified by multiple regression analysis. Different mean rates of LA area increase identified 2 consecutive (early rapid and late slow) reservoir phases. During ischemia, LV long-axis shortening (LAS, LV base systolic descent) and LA reservoir area change decreased (7.3±0.3 [SEM] versus 5.6±0.3 cm2, P<0....

Left Atrial Relaxation and Left Ventricular Systolic Function Determine Left Atrial Reservoir Function

Objective To determine standard left ventricular Doppler measurements in a large reference group of various ages to reflect the senescence process. Design We prospectively studied the influence of aging on left ventricular diastolic filling by performing Doppler echocardiography in 117 normal healthy volunteers. Material and Methods Transthoracic pulsed-wave Doppler echocardiographic studies of pulmonary venous flow and left ventricular inflow were done in the 53 male and 64 female study subjects. For analysis, the study subjects were arbitrarily classified into two groups: those younger than 50 years of age (group 1; N=61) and those 50 years old or older (group 2; N=56). Results A striking difference was found in pulmonary venous flow and left ventricular inflow between group 1 and group 2 subjects. Group 2 had increased pulmonary venous peak systolic flow velocity (71 ± 9 versus 48 ± 9 cm/s), decreased peak diastolic flow velocity (38 ± 9 versus 50 ± 10 cm/s), increased peak atrial reversal flow velocity (23 ± 4 versus 19 ± 4 cm/s), and increased percentage of forward flow in systole (65 ± 7 versus 55 ± 8%) in comparison with group 1. In group 2, peak early filling velocity (62 ± 14 versus 72 ± 14 cm/s) and ratio of early filling to atrial filling (1.1 ± 0.3 versus 1.9 ± 0.6) were lower and peak atrial filling velocity (59 ± 14 versus 40 ± 10 cm/s) was higher than in group 1. Deceleration time (210 ± 36 versus 179 ± 20 ms) and isovolumic relaxation time (90 ± 17 versus 76 ± 11 ms) were prolonged in group 2 in comparison with group 1. Conclusion This study confirms the major influence of the aging process on left ventricular diastolic function in a large series of normal subjects. This physiologic factor should be considered in Doppler assessment of left ventricular diastolic filling in future studies.

https://www.mayoclinicproceedings.org/article/S0025-6196(12)61059-3/pdf

Effects of age on left ventricular dimensions and filling dynamics in 117 normal persons.

We studied the physiology of pulmonary venous flow in 13 normal subjects and five patients with atrial rhythm disorders and atrioventricular conduction disturbances with pulsed Doppler and two-dimensional echocardiography. The left atrium, mitral valve, and pulmonary venous ostia were visualized through the apical four-chamber view. Mitral and pulmonary venous flows were obtained by placing the Doppler sample volume at the appropriate orifice. Pulmonary venous flow was biphasic: a rapid filling wave was observed during systole when the mitral valve was closed; a second wave was observed in diastole during the rapid ventricular filling phase of mitral flow, but was significantly delayed. In patients without atrial contraction (atrial fibrillation and sinoatrial standstill), the initial rapid filling was greatly diminished and only the second diastolic wave appeared to contribute to left atrial filling. In patients with high-grade atrioventricular block, each atrial contraction was followed by a surge in flow from the pulmonary veins. These results are consistent with data obtained from invasive measurements in both dogs and man, and confirm the validity of the use of pulsed Doppler echocardiography in the study of pulmonary venous flow. We suggest that pulmonary venous flow is influenced by dynamic changes in left atrial pressure created by contraction and relaxation of the atrium and ventricle. The initial peak in pulmonary venous flow occurs with atrial relaxation simultaneously with the reduction of left atrial pressure, and the second peak occurs with left ventricular relaxation and rapid transmitral filling of the ventricle.

Pulmonary venous flow pattern--its relationship to cardiac dynamics. A pulsed Doppler echocardiographic study.

The pattern of blood flow in the large extra parenchymal pulmonary veins is pulsatile in both dog and man. This pulsatility is dominated by the changes in left atrial pressure taking place throughout the cardiac cycle. No pulsatile component of low in the large pulmonary veins could be attributed to forward transmission of a flow pulse conducted from the lung capillaries. The findings suggest that there must be a region of considerable compliance in the pulmonary venous system which can absorb pulsations from the lung capillaries and eliminate their transmission to the left atrium.

Blood flow in pulmonary veins: I. Studies in dog and man.

The wave form of blood flow in the large extra parenchymal pulmonary veins has an inverse relationship to the pressure wave form in the left atrium during each cardiac cycle.

However, when vein flow from the lungs is separated from the left atrium by diverting it into a constant pressure reservoir, its wave form then resembles a lung capillary flow pulse, though delayed from it in time and reduced in amplitude.

The pulsatility of flow in pulmonary veins separated from the left atrium is further reduced when transcapillary pressure is elevated by lung inflation. However, in the intact state, the relation between the pattern of pulmonary vein flow and left atrial pressure remains unaffected by lung inflation.

It is postulated that the thin walled extraparenchymal pulmonary veins together behave as a collapsible reservoir which enables outflow from them to be determined by changes in left atrial pressure, in spite of variations of pulsatile flow into them from the lungs.

J. A. Friend

Papers

Blood flow in pulmonary veins: I. Studies in dog and man.

Blood flow in pulmonary veins: II. The influence of events transmitted from the right and left sides of the heart.