scholarly journals Left atrial conduit flow rate at baseline and during exercise: an index of impaired relaxation in HFpEF patients

2021 ◽  
Author(s):  
Paolo N. Marino ◽  
Jacopo Zanaboni ◽  
Anna Degiovanni ◽  
Chiara Sartori ◽  
Giuseppe Patti ◽  
...  
Keyword(s):  
Flow Rate ◽  
Left Atrial ◽  
Conduit Flow

P4379Pathophysiology of left atrial filling in mitral regurgitation. A new volumetric flow rate index describing disturbed left atrial filling behavior in mitral regurgitation by 3D TTE

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
D Frumkin ◽  
K Stangl ◽  
A Muegge ◽  
T Buck ◽  
B Plicht
Keyword(s):  
Mitral Regurgitation ◽  
Left Atrium ◽  
Flow Rate ◽  
Left Atrial ◽  
Volume Overload ◽  
Volumetric Flow Rate ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Mean Flow ◽  
Flow Rates

Abstract Background In chronic mitral regurgitation (MR) the left atrium (LA) is one of the first cardiac structures involved in remodeling by progressive volume overload. Real-time three-dimensional echocardiography is able to monitor volumetric changes of the left atrium during the heart cycle. Purpose We hypothesized that chronic volume overload due to MR leads to detectable changes in the LA filling behavior described by mean and maximum filling flow rates and their relation called volumetric flow rate index. Methods We prospectively analyzed data of 36 patients in different stages of chronic MR and 13 patients without MR. Transthoracic echocardiography was conducted using the Epiq 7G Ultrasound System. Standard 2D- and 3D apical 4-chamber views were recorded and stored for offline analysis. We generated volume-time-curves by 3D volume analysis to derive mean and maximum volumetric flow rates during LA reservoir, conduit and pump phase. Volumetric flow rate index was calculated as the quotient of mean flow rate/maximum flow rate. Results Average MR severity, calculated with the MR Scoring system introduced from Buck et al. and implicated in the ESC Guidelines, was 6.2 points (±2.5) according to Grade I-II. We included 13 patients without MR, 18 with mild MR, 12 patients with moderate MR, 6 patients with severe MR. Left ventricular ejection fraction was similar in the different groups (51,2±12,3%). Maximum and mean flow rate showed no significant correlation with MR severity. Correlation of MR severity with LA dilation (ml/m2 BSA) was r=0.41; p<0.001. Flow rate index showed strong significant correlation with MR severity in left atrial reservoir phase (r=−0.75; p<0.001). There was no statistically relevant difference of volumetric flow rate parameters in left atrial pump and conduit phase. Line chart Conclusions We observed a significant correlation of the volumetric flow rate index to MR severity in the left atrial reservoir phase with stronger correlation than MR severity to left atrial dilation. The results of this work encourage further investigations to establish the presented volumetric flow rate index as a progression marker of MR and to evaluate its prognostic value.

Left atrial phasic function interacts to support left ventricular filling during exercise in healthy athletes

2015 ◽  
Vol 119 (4) ◽  
pp. 328-333 ◽  
Author(s):  
Steve Wright ◽  
Zion Sasson ◽  
Taylor Gray ◽  
Anjala Chelvanathan ◽  
Sam Esfandiari ◽  
...  
Keyword(s):  
Left Atrial ◽  
Left Ventricular ◽  
Moderate Intensity ◽  
Diastolic Filling ◽  
Moderate Exercise ◽  
Moderate Intensity Exercise ◽  
Longitudinal Contraction ◽  
Maximal Volume ◽  
Conduit Flow ◽  
Filling Time

We studied the contribution of phasic left atrial (LA) function to left ventricular (LV) filling during exercise. We hypothesized that reduced LV filling time at moderate-intensity exercise limits LA passive emptying and increases LA active emptying. Twenty endurance-trained males (55 ± 6 yr) were studied at rest and during light- (∼100 beats/min) and moderate-intensity (∼130 beats/min) exercise. Two-dimensional and Doppler echocardiography were used to assess phasic volumes and diastolic function. LV end-diastolic volume increased from rest to light exercise (54 ± 6 to 58 ± 5 ml/m2, P < 0.01) and from light to moderate exercise (58 ± 5 to 62 ± 6 ml/m2, P < 0.01). LA maximal volume increased from rest to light exercise (26 ± 4 to 30 ± 5 ml/m2, P < 0.01) related to atrioventricular plane displacement ( r = 0.55, P < 0.005), without further change at moderate exercise. LA passive emptying increased at light exercise (9 ± 2 to 13 ± 3 ml/m2, P < 0.01) and then returned to baseline at moderate exercise, whereas LA active emptying increased appreciably only at moderate exercise (6 ± 2 to 14 ± 3 ml/m2, P < 0.01). Thus, the total atrial emptying volume did not increase beyond light exercise, and the increase in LV filling at moderate exercise could be attributed primarily to an increase in the conduit flow volume (19 ± 3 to 25 ± 5 ml/m2, P < 0.01). LA filling increases during exercise in relation to augmented LV longitudinal contraction. Conduit flow increases progressively with exercise in athletes, although this is driven by LV properties rather than intrinsic LA function. The pump function of the LA augments only at moderate exercise due to a reduced diastolic filling time and the Frank-Starling mechanism.

The Coupling Model of Wellbore Conduit Flow, Throttled Flow and Formation Seepage in Water Injection Wells

2012 ◽  
Vol 594-597 ◽  
pp. 2486-2489
Author(s):  
Bao Jun Liu ◽  
Hai Xia Shi ◽  
Yun Sheng Cai
Keyword(s):  
Flow Rate ◽  
Water Injection ◽  
Coupling Model ◽  
Water Flooding ◽  
Finite Radius ◽  
Injection Wells ◽  
Conduit Flow ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
Low Efficiency

Separate layer water flooding is adopted in most oilfields in China and the injection flow rate is controlled by the diameter of water nozzle of each layer. In order to ensure the effect of water injection, applicable water nozzles need to be adjusted to meet the requirements of injection flow rate. The adjustment is commonly realized according to experience, which leads to long adjustment time and low efficiency. To solve this problem, the coupling model of wellbore conduit flow, throttled flow and formation seepage was established based on theoretical analysis, which could provide theoretical basis for water nozzles adjustment. In the model, the Bernoulli Equation was adopted to analyze wellbore conduit flow; indoor experiments were done to research throttled flow; the research object of the seepage was finite radius well in homogeneous infinite formation.

Influence of heart rate and left atrial pressure on pulmonary venous flow pattern in dogs

1994 ◽  
Vol 266 (6) ◽  
pp. H2296-H2302 ◽  
Author(s):  
T. Steen ◽  
B. M. Voss ◽  
O. A. Smiseth
Keyword(s):  
Heart Rate ◽  
Flow Pattern ◽  
Flow Rate ◽  
Left Atrial ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Mean Flow ◽  
Venous Flow ◽  
Pulmonary Venous Flow ◽  
The Relationship

In six open-chest anesthetized dogs we investigated the effect of heart rate (HR) on the relationship between left atrial pressure (LAP) and pulmonary venous flow (QPV). QPV was measured by ultrasonic transit time during volume loading and right atrial pacing. Consistent with previous studies, we found a negative correlation between LAP and mean flow rate during atrial systole divided by mean flow rate in the R-R interval. However, this relationship was shifted upward by tachycardia. The QPV maximum amplitude divided by mean flow rate in the R-R interval increased with loading but decreased with tachycardia. mean flow rate during ventricular systole divided by mean flow rate during the R-R interval increased with both loading and tachycardia. Regression coefficients for HR and LAP as predictors of these indexes were all significantly different from zero (P = 0.0001). We conclude that HR significantly influences the relationship between the QPV pattern and LAP. This could be a limitation of the pulmonary venous flow pattern as an indicator of left ventricular diastolic function.

Left atrial conduit volume is generated by deviation from the constant-volume state of the left heart: a combined MRI-echocardiographic study

2004 ◽  
Vol 286 (6) ◽  
pp. H2416-H2424 ◽  
Author(s):  
Andrew W. Bowman ◽  
Sándor J. Kovács
Keyword(s):  
Flow Rate ◽  
Left Atrial ◽  
Left Ventricular ◽  
Constant Volume ◽  
Left Heart ◽  
Filling Rate ◽  
Average Flow Rate ◽  
Average Flow ◽  
Volume State ◽  
The Relationship

Although modeling the four-chambered heart as a constant-volume pump successfully predicts causal physiological relationships between cardiac indexes previously deemed unrelated, the real four-chambered heart slightly deviates from the constant-volume state by ventricular end systole. This deviation has consequences that affect chamber function, specifically, left atrial (LA) function. LA attributes have been characterized as booster pump, reservoir, and conduit functions, yet characterization of their temporal occurrence or their causal relationship to global heart function has been lacking. We investigated LA function in the context of the constant-volume attribute of the left heart in 10 normal subjects using cardiac magnetic resonance imaging (MRI) and contemporaneous Doppler echocardiography synchronized via ECG. Left ventricular (LV) and LA volumes as a function of time were determined via MRI. Transmitral flow, pulmonary vein (PV) flow, and lateral mitral annular velocity were recorded via echocardiography. The relationship between the MRI-determined diastolic LA conduit-volume (LACV) filling rate and systolic LA filling rate correlate well with the relationship between the echocardiographically determined average flow rate during the early portion of the PV D wave and the average flow rate during the PV S wave ( r = 0.76). We conclude that the end-systolic deviation from constant volume for the left heart requires the generation of the LACV during diastole. Because early rapid filling of the left ventricle is the driving force for LACV generation while the left atrium remains passive, it may be more appropriate to consider LACV to be a property of ventricular diastolic rather than atrial function.

Effect of outflow pressure on lung lymph flow in unanesthetized sheep

1985 ◽  
Vol 58 (1) ◽  
pp. 70-76 ◽  
Author(s):  
R. Drake ◽  
M. Giesler ◽  
G. Laine ◽  
J. Gabel ◽  
T. Hansen
Keyword(s):  
Escherichia Coli ◽  
Flow Rate ◽  
Left Atrial ◽  
Protein Concentration ◽  
Filtration Rate ◽  
Ringer Solution ◽  
Lymph Flow ◽  
Po Delta ◽  
Lung Lymph ◽  
Lung Lymph Flow

Studies in anesthetized animals have shown that the flow rate from lung lymphatics (QL) depends on the pressure at the outflow end of the vessels (Po). We tested this in unanesthetized sheep prepared with chronic lung lymph cannula. We measured QL with the lymph cannula held at various heights above the olecranon and calculated Po as the height + QL X cannula resistance. QL decreased with increases in Po (delta QL/delta Po = -8.2 +/- 6.4 microliter X min-1 X cmH2O-1, mean +/- SD). We increased QL by raising left atrial pressure or infusing Ringer solution or Escherichia coli endotoxin and found that QL was even more sensitive to Po (delta QL/delta Po = -32 +/- 22). Cannula resistance caused a 9–70% reduction in QL. Changes in QL caused by increasing Po were not associated with changes in lymph protein concentration for up to 330 min. This indicates that increases in Po shunt lymph away from cannulated vessels but do not substantially effect microvascular filtration rate. The shunted lymph may flow into other vessels or collect in the lung. We conclude that QL does not accurately represent microvascular filtration rate because it depends on the cannula resistance and position at which the investigator chooses to place the cannula.

Effect of blood flow rate and blood flow history on newborn pulmonary microcirculation

1991 ◽  
Vol 261 (2) ◽  
pp. H271-H279 ◽  
Author(s):  
C. D. Fike ◽  
M. R. Kaplowitz
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Left Atrial ◽  
Total Pressure ◽  
Pulmonary Blood Flow ◽  
Blood Flow Rate ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Flow Rates ◽  
Pulmonary Arterial

The purpose of this study was to determine whether increased pulmonary blood flow and/or the history of pulmonary blood flow alters microvascular pressures in lungs of newborns. Using the direct micropuncture technique, we measured pressures in 20- to 60-microns-diameter arterioles and venules in isolated lungs of newborn rabbits at consecutive blood flow rates of 50 (baseline), 100, and/or 200 ml.min-1.kg-1. Then in some lungs we returned blood flow rate to baseline and repeated microvascular pressure measurements. We kept left atrial pressure the same at all blood flow rates. When blood flow rate increased and left atrial pressure was maintained constant, pulmonary arterial, 20- to 60-microns-diameter arteriolar, and 20- to 60-microns-diameter venular pressures increased such that the percentage of total pressure drop that occurred across veins increased. When we returned blood flow to baseline, venular pressure returned to baseline, but arteriolar and pulmonary arterial pressures returned to values less than baseline so that the percentage of the total pressure drop that occurred across microvessels decreased. Thus both blood flow rate and blood flow history are important determinants of the longitudinal distribution of pulmonary vascular pressures across newborn lungs. These findings also suggest that in newborn lungs venules greater than 60 microns diameter are poorly distensible such that higher blood flow rates result in increased microvascular pressures. Hence, under conditions of increased pulmonary blood flow, such as occurs with left to right shunts, the tendency for edema formation will increase in newborn lungs even if left atrial pressure does not increase.

Lymph flow from edematous dog lungs

1987 ◽  
Vol 62 (6) ◽  
pp. 2416-2420 ◽  
Author(s):  
R. E. Drake ◽  
S. J. Allen ◽  
J. P. Williams ◽  
G. A. Laine ◽  
J. C. Gabel
Keyword(s):  
Flow Rate ◽  
Left Atrial ◽  
Lymph Flow ◽  
Effective Resistance ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Base Line ◽  
Lymph Vessels ◽  
Lymph System ◽  
Lung Lymph

We measured the flow rate (QLV) from cannulated lung lymph vessels in anesthetized dogs. Low-resistance lymph cannulas were used and the vessels were cannulated at the lung hilus. When we increased left atrial pressure to 42.9 +/- 5.7 (SD) cmH2O (base line = 6.6 +/- 4.6 cmH2O), the lungs became edematous and QLV increased from a base line of 20.4 +/- 21.5 microliters/min to 388 +/- 185 microliters/min. QLV plateaued at the higher level. We also measured the relationship between lymph flow rate and the height of the outflow end of the lymph cannula. From this relationship, determined at the end of the period of elevated left atrial pressure, we calculated the effective resistance and pressure driving lymph from the lungs. We also cannulated lymph vessels in the downstream direction and estimated the effective resistance and pressure opposing flow into the part of the lymphatic system between the lung hilus and the veins (extrapulmonary lymph vessels). We found that the effective resistance of the extrapulmonary part of the lymph system (0.042 +/- 0.030 (SD) cmH2O X min X microliter-1) was large compared with the resistance of the lymph vessels from the lungs (0.026 +/- 0.027). These data indicate that the resistance of the extrapulmonary part of the lung lymph system limits the maximum flow of lymph from edematous lungs.

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