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European Journal of Echocardiography 2005 6(2):107-116; doi:10.1016/j.euje.2004.07.009
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Copyright © 2005, The European Society of Cardiology

Pulmonary venous flow reversal and its relationship to atrial mechanical function in normal subjects – Umeå General Population Heart Study

F. Bukachia,*, A. Waldenströma, S. Mörnera, P. Lindqvista, M.Y. Heneinb and E. Kazzama,c

aDepartment of Public Health and Clinical Medicine, Medicine, University Hospital Umeå, S-901 85 Umeå, Sweden
bDepartment of Cardiology, Royal Brompton Hospital, London, UK
cDepartment of Internal Medicine, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates

Received 19 January 2004; received in revised form 27 July 2004; accepted after revision 27 July 2004.

* The study was performed at the Norrlands University Hospital, Umeå, Sweden.

* Corresponding author. Tel.: +46 907852652; fax: 46 90137633. frederick.bukachi{at}medicin.umu.se


   Abstract
Top
 Abstract
Introduction
 Methods
 Results
 Discussion
 Conclusion
 Acknowledgments
 References
 
Aims Although pulmonary venous flow reversal (Ar) is useful in the evaluation of left ventricular (LV) diastolic function, it is often difficult to study with transthoracic echocardiography (TTE). We determined the relationship between Ar and left atrial (LA) mechanical function and sought to define surrogate measurements for Ar.

Methods and results A total of 130 healthy subjects, mean age 54.3±18.3 years, 62 women, were studied and classified into three groups: [young (Y), 25–44 years; n=44], [middle-age (M), 45–64 years; n=43] and [elderly (E), ≥65 years; n=43]. Pulmonary venous flow and LV inflow studies were performed by TTE and LV basal free-wall motion was studied by Doppler tissue imaging (DTI). All images were acquired with a superimposed electrocardiogram. RR interval was similar in all groups while LA dimension and PR interval were increased in Group E vs. Y (P<0.001). LA contraction (Am) on DTI, transmitral A-wave (A) and Ar were simultaneous and started 84ms after onset of P wave and this interval increased with age (P=0.02). Similarly, the time intervals from the same landmark to peak Am, A, and Ar were prolonged with age (all, P<0.001). Despite this prolongation, peak Am coincided with peak Ar in every age group (r=0.97, P<0.001) and Ar acceleration and deceleration times were consistently equal.

Conclusion The timing of Am obtained by DTI can be used to accurately estimate corresponding measurements of Ar recorded by TTE in subjects without cardiac disease.

Keywords: Echocardiography; Atrial contraction; Electromechanical function; Ageing


   Introduction
Top
 Abstract
 Introduction
Methods
 Results
 Discussion
 Conclusion
 Acknowledgments
 References
 
Pulmonary venous flow reversal (Ar) assessment by Doppler echocardiography provides additive value to the evaluation of left ventricular (LV) diastolic function. Studies have shown that the difference between Ar and transmitral A-wave (A) durations is a useful measure of LV end-diastolic pressure,1,2 and it is also age independent.3,4 Likewise, increased Ar to A velocity ratio is a useful marker for detecting elevated pulmonary capillary wedge pressure.5,6 Clearly these indices highlight the diagnostic significance of the changes in the physiological relationship between forward flow (A-wave) and reversed flow (Ar-wave) during left atrial (LA) systole. This bi-directional flow, which is synchronous with LA contraction,7 is influenced by loading conditions,8,9 absent in atrial fibrillation,10 and disturbed in conditions that present with impaired LV relaxation11 including the elderly as part of the normal ageing process.12 In order to optimise the diagnostic utility of these indices, imaging techniques applied should have the ability to delineate both flow patterns accurately and if possible simultaneously.

Transthoracic echocardiography (TTE) a commonly used method is less reliable in quantifying Ar;13,14 its success rate in obtaining quality pulmonary venous (PV) flow recordings varies in some reports from 30–60%.13,15,16 Further, the method overestimates Ar duration17 and, to some extent, is equipment and operator dependent.18 Despite these limitations, PV flow values obtained by TTE are comparable to those obtained by transesophageal echocardiography (TEE).15 No study, however, has comprehensively explored the timing of Ar in relation to LA contraction with a view to identifying potential adjunct measurements for Ar.

This study, therefore, adopted non-invasive methods based on Doppler echocardiography and Doppler tissue imaging (DTI) to define regional and global atrial electromechanical events and their temporal relationships to Ar in a large sample of healthy subjects from young to the elderly. The study further sought to determine whether age had any effect on the timing of these events. Finally, we tested the hypothesis that the timings of Am could be used as a marker of Ar obtained by TTE, since Ar is dependent on LA contraction.


   Methods
Top
 Abstract
 Introduction
 Methods
Results
 Discussion
 Conclusion
 Acknowledgments
 References
 
Study subjects
One hundred and thirty participants (mean age 54.3±18.3 years, range 25–88 years, 62 women) were consecutively studied and arbitrarily classified into three groups: Y (young), M (middle-age) and E (elderly). Group Y (25–44 years) consisted of 44 subjects; Group M (45–64 years) and Group E (≥65 years) each consisted of 43 subjects. All study subjects were part of the Umeå General Population Heart Study, which consists of a cohort of 300 healthy volunteers aged 20–90 years; equal gender distribution in every age-decade, and all recruited from the Umeå General Population Register. All 130 participants had: (i) a normal clinical cardiovascular history and were not on any cardioactive medication, (ii) normal findings on physical examination including a 12-lead electrocardiogram (ECG), and (iii) clear analysable PV flow profiles on Doppler echocardiography with clear P waves on superimposed ECG were mandatory inclusion criteria for this study. Each participant gave informed consent and the local Ethics Committee approved the study.

Echocardiography
Immediately after physical examination and recording of a 12-lead ECG at rest, a complete M-mode, two-dimensional and Doppler examination was performed in each subject while lying in a left lateral decubitus position. Commercially available ultrasound system (Acuson Sequoia, Mountain View, Calf., USA) equipped with multi-frequency (2–3.5MHz) imaging transducer was used. All studies were performed according to the recommendations of the American Society of Echocardiography using conventional views and measurements.19 To minimise cardiac movement resulting from respiration, all echocardiographic data were obtained at end-expiration. M-mode and Doppler traces were all recorded with superimposed ECG lead II showing clear P waves and phonocardiogram (PCG) at sweep speeds of 50 and 100mm/s. The data were recorded on Magneto Optical Disks (Maxell Corp., New Jersey, USA) and later analysed off-line using the same ultrasound machine.

The transmitral flow (TMF) pattern was recorded using pulsed-wave Doppler technique with the sample volume positioned at the tip of the mitral valve leaflets on the apical four-chamber view. The peak early (E), late (A) diastolic velocities, the ratio of E to A and E-wave deceleration time (EDT) were also determined off-line. PV flow was obtained from the same view with the sample volume placed in the right superior pulmonary vein proximal to the LA guided by colour flow Doppler.

Myocardial DTI was performed with the sample volume placed at the endocardial border of the base of the LV lateral wall from the apical four-chamber view. The wall motion velocity pattern was recorded and expressed as: systolic wave (Sm), early diastolic wave (Em) and late diastolic wave (Am) (mid-panel, Fig. 1).


Figure 1
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  		Figure 1 Vertical lines show specific landmarks for time measurements in the cardiac cycle. Late diastolic timing relationships between Am, Ar and A-wave with respect to the onset of P wave on the ECG in a young and elderly subject, respectively. All begin immediately after atrial contraction (onset point). Am peaks at the same time as pulmonary reversal flow (Ar) (peak point), while A peaks later (late diastolic temporal discordance). PR', interval from peak R on the ECG to the onset of the preceding P wave; P-A/P-Ar/P-Am, from the onset of P wave to the onset of A-wave/Ar/Am; P-pA/P-pAr/P-pAm, from the onset of P wave to the peak of A-wave/Ar/Am; and PCG, PVF, TMF, DTI, Sm, Em, as described in the text.

 
Measurements and calculations
The following measurements were made from at least three different cardiac cycles.

Transmitral and pulmonary venous flow

(1) The time interval from the onset of P wave on the ECG to onset and then to the peak of:
- A-wave of the TMF (P-A and P-pA, respectively) (Fig. 1);
- Ar-wave on the PV flow (P-Ar and P-pAr, respectively).

(2) Duration, acceleration, deceleration times of A-wave and Ar. A-wave was measured from the onset to the cessation of the Doppler velocity profile.
(3) Peak A-wave and Ar velocities and their respective velocity–time integrals.
(4) PV systolic (S) and diastolic (D), velocities, time integrals and systolic fraction were derived.
(5) Isovolumic relaxation time (IVRT) as the time interval from A2 (aortic component of the second heart sound) on the PCG to the onset of transmitral E-wave.

Doppler tissue imaging

(1) The time interval from the onset of P wave on the ECG to the onset and the peak of Am (P-Am and P-pAm, respectively).
(2) Duration, acceleration, deceleration times, and peak velocity of Am.
(3) Late diastolic temporal discordance (LDTD) was calculated as the difference between (P-pA) and (P-pAm).
(4) Peak Em velocity was measured and the Em to Am ratio calculated.

Two-dimensional apical 2 and 4 chamber

(1) LV end-diastolic and end-systolic volumes were determined using modified Simpson's formula and the LV ejection fraction (LVEF) was derived from these volumes.

LV end-diastolic and end-systolic, and LA dimensions were all measured from standard transverse M-mode echocardiograms. RR intervals and heart rate (HR) were measured from every image examined and a mean value obtained.

The onset of the P wave on the ECG was first derived by manually measuring the PR interval on the standard 12-lead ECG, using a digital calliper. To maintain the same PR interval in all the measurements performed on every subject, individual measurements were made in reference to R wave of the ECG, which is a more reproducible landmark. Hence, the distance from the peak of R wave to the onset of the preceding P wave (PR' in Fig. 1, mid-panel) was determined and used throughout all measurements for each individual subject. This ensured a universal onset point of the P wave on every set of images studied thus eliminating possible errors associated with determination of the nadir point of the P waves.

Reproducibility of measurements
Intra-observer and inter-observer variabilities were tested in 22 subjects selected randomly from the three groups. Measurements, particularly timings and velocities upon which our conclusions are based, were repeated by one investigator and independently by a second at different times to determine intra- and inter-observer variability. Results were analysed using the method of agreement as described by Bland and Altman20 and presented as the coefficient of variation.

Statistical analysis
All values are expressed as mean±standard deviation. Comparison between groups was carried out by one-way analysis of variance (ANOVA) and correlation between variables by simple linear regression analysis. Student t tests for paired data were used whenever appropriate. Data analysis and calculations were performed using SPSS package (11.0, Chicago, Illinois) and the P-value was considered to be statistically significant when it was less than 0.05.


   Results
Top
 Abstract
 Introduction
 Methods
 Results
Discussion
 Conclusion
 Acknowledgments
 References
 
General and echocardiographic features
There were no significant differences in the 130 study participants with regard to diastolic blood pressure, HR and the RR interval. In addition, LV systolic function measured by ejection fraction was normal across all age groups. Gender balance was maintained with an almost equal ratio of men to women in the entire study group. Other important demographic, clinical, Doppler and echocardiographic data are presented in Table 1.


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  		Table 1 Demographic and echocardiographic variables (mean±SD)

 
Left atrial contraction: forward vs. reversal flow, and the effect of age
In Tables 2 and 3Go comparisons are made mainly between Group Y (age <45 years) and Group E (age >65 years) to reflect LA contraction, corresponding timings and the effect of age. During atrial contraction the duration of Am, forward flow (A-wave) and pulmonary reversal flow (Ar-wave) were all prolonged in the elderly compared to the young (114±14 vs. 92±13ms; P<0.001, 156±16 vs. 143±18ms; P=0.001, and 118±12 vs. 106±16; P<0.001, respectively). Similarly, deceleration time (DT) was significantly prolonged (elderly vs. young) with respect to Am (57±11 vs. 45±9ms; P<0.001) but had a modest change in the transmitral A-wave (83±16 vs. 73±16ms; P=0.003) and none in the pulmonary Ar (57±9 vs. 54±8ms; P=NS). Ar DT, however, showed a tendency to increase with age but did not achieve any level of significance. Overall, Ar DT was equal to the corresponding acceleration time (AT) (56±10 vs. 57±8; P=NS). The difference between Ar and A-wave durations had no correlation with age (r=–0.18; P=NS).


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  		Table 2 Transmitral A-wave (A), pulmonary venous flow reversal (Ar), and (Am-wave) Doppler-derived parameters (mean±SD)

 


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  		Table 3 Temporal interrelations between atrial contraction (Am), forward flow (A-wave) and pulmonary venous flow reversal (Ar) (mean±SD)

 
With advancing age there was a consistent increase in the corresponding peak velocities related to atrial contraction, (elderly vs. young): Am (15.6±2.5 vs. 11.0±2.9cm/s; P<0.001), A-wave (75.1±14.3 vs. 44.9±12.5cm/s; P<0.001) and Ar-wave (28.1±4.4 vs. 19.9±4.7cm/s; P<0.001). Ar to A velocity ratio was {approx}0.47 in the young and the middle-aged but significantly declined to {approx}0.39 in the elderly (P=0.005). Ar to Am velocity ratio, however, was not affected by age (r=–0.04; P=NS) and remained {approx}1.8 across all the age groups.

Effect of age on atrial electromechanical timings
The onset of atrial forward and reversal blood flow was synchronous with mechanical wall motion and all started approximately 84ms after the onset of the P wave (Table 3). This electromechanical time interval tended to prolong with age (P=0.02). Similarly, the time intervals from the same landmark to the peaks of Ar, A-wave and Am were consistently prolonged as age increased (P<0.001) (Fig. 2). In spite of this characteristic prolongation, peak atrial velocity coincided with peak reversal flow in every age group with an excellent correlation (r=0.97; P<0.001, Fig. 3). Peak A-wave, however, appeared approximately 20ms after peak Am in the young and the middle-aged, and this difference was significantly lower in the elderly (P=0.002) (Table 3).


Figure 2
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  		Figure 2 Age-related changes in the late diastolic time intervals – from onset P to the peaks of A, Am, and Ar, respectively (n=130). Mean values in different age groups young (Y), middle-age (M) and elderly (E) are shown.

 


Figure 3
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  		Figure 3 Scatter plot showing correlation between the time intervals to the peak of myocardial Am (P-pAm) and to the peak pulmonary flow reversal Ar (P-pAr), both measured from the onset of electrocardiographic P wave.

 
Effect of age on pulmonary velocities and atrial timings
Considering PV flow profile as a whole (Table 4), systolic flow velocity (S) increased (r=0.27; P=0.002) while diastolic flow velocity (D) decreased with age (r=–0.51; P<0.001) and effectively S to D ratio increased (r=0.69; P<0.001). Furthermore, peak Ar velocity correlated with age (r=0.69; P<0.001). Similarly there was a good correlation between age and regional Am duration and its corresponding velocity (r=0.66; P<0.001 and r=0.59; P<0.001, respectively). On the other hand, the timings to the peak of mechanical events measured from the onset of electrocardiographic P wave had only modest correlations with age P-Am (r=0.46; P<0.001), P-pA (r=0.33; P<0.001) and P-pAr (r=0.46; P<0.001) (Table 4).


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  		Table 4 Correlations of Doppler variables and timings with age (n=130)

 
Reproducibility of measurements
There were no significant variations in the duplicate measurements. All measurements from DTI images and Doppler-derived peak velocities had the best intra- and inter-observer variability of 2–3%. However, the intra- and inter-observer variability for the duration of Ar and A-wave were within the range of 4–6%.


   Discussion
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
Conclusion
 Acknowledgments
 References
 
This study comprehensively characterises and defines the timing of pulmonary venous flow reversal (Ar) in relation to other concurrent atrial mechanical events in a wide range of healthy subjects from young age to the elderly. The main findings of this study confirm that the onsets of Ar, transmitral A-wave (A) and atrial contraction (Am) were all simultaneous. The most robust and consistent observation, however, was that peak Ar coincided with peak Am across all age groups and the corresponding Ar to Am velocity ratio was age independent. Peak Ar has previously been shown from M-mode and pulsed-wave Doppler studies to coincide with the peaks of interatrial septum21 and longitudinal motion of the mitral annulus in late diastole22 corresponding to LA contraction. However, with the advent of DTI accurate definition of time relationships between blood flow velocities and corresponding mechanical events in the cardiac cycle can now be easily obtained.23–25 Thus, by using DTI to determine the time intervals in late diastole, this study defines a surrogate marker for the measurement of Ar obtained by transthoracic Doppler echocardiography (TTE).

Relationship between forward and retrograde blood flow during atrial systole
In healthy individuals LA contraction produces forward flow across the mitral valve (i.e. LV late diastolic A-wave velocity), as well as a small reverse flow in the pulmonary veins.26 This bi-directional flow is synchronous with regional atriogenic lateral LV velocity in late diastole as clearly shown by this study. LV cavity pressure and compliance during atrial contraction affect forward and reverse atrial flow.9 It is postulated that with decreased LV compliance, LA pressure will increase, during atrial contraction, and thus the reverse flow in the pulmonary veins will become relatively more prominent than the forward atrial flow across the mitral valve. Conversely, with increased ventricular compliance (which decreases LA pressure) as seen in the young, reverse flow in the pulmonary veins is decreased and forward flow is increased. The two mechanisms described generally reflect the physiologic atrioventricular changes that occur with advancing age, although it is expected that LV filling pressures remain normal or near normal in elderly persons with impaired diastolic filling.27 Thus, decreased LV compliance observed in healthy elderly people is likely to influence the timings and extent of both forward and reversal flow during atrial contraction.

Timing of A-wave and Ar durations
Previous studies have attempted to measure the time duration of events that occur in late diastole by using the QRS complex of the ECG as the reference point.14,21–23 In our study we sought to investigate these timings based on the hypothesis that late diastolic ventricular wall motion, transmitral forward flow (A-wave) and reversal flow into the pulmonary veins in normal subjects all depend on atrial contraction. We, therefore, used the onset of electrocardiographic P wave as the landmark to assess the time relationships between the onset of atrial depolarisation and these attendant mechanical events. Thus, we have demonstrated that both A-wave and Ar begin simultaneously after the onset of the P wave and are all synchronous with atrial contraction, and that this observation is consistent across all age groups. The tendency, however, for these time intervals to prolong with advancing age reflects the corresponding increase in the LA size and the PR interval.

Our results further show that peak atrial contraction strikingly coincides with peak reversal flow from the young to the elderly. This implies that in normal hearts, irrespective of age, reversal flow into the pulmonary veins is solely dependent on atrial contraction, an observation consistent with previous studies that showed absent Ar in patients with atrial fibrillation.10,21,28 The same pattern, however, is not observed in the forward flow (A-wave), which instead shows a diminishing time difference between the peak of Am and that of A-wave with increasing age. Again, highlighting that the elderly population becomes increasingly dependent on atrial systolic function and late diastolic LV filling.

Duration and velocities of A-wave and Ar
Our study confirmed previous work12,29,30 and partly contradicted others3,4,14 by showing that Ar duration, time integral and extent of velocity increased with advancing age. In addition, we showed a characteristic pattern of sequential increase in Ar AT and DT, which to a lesser extent mirrored similar changes observed in the corresponding transmitral A-wave as age increased. However, Ar AT was similar to the DT and this pattern was maintained from the young to the elderly. We also confirmed that the difference between Ar and transmitral A-wave durations is age independent. Furthermore, our observation that the ratio of Ar to Am velocity is also age independent merits further investigation as a potential sensitive marker for detecting decreased LV compliance.

Clinical application
Due to well known technical limitations,18 determination of Ar by TTE remains difficult in some adult patients. In contrast, it is easy to obtain measurements from the corresponding long-axis motion of the cardiac base, particularly with DTI, even in sub-optimal images.31 Therefore, in our study, by combining the two techniques, we have shown that the onset of Ar and Am are simultaneous and the time to their respective peaks, determined from the onset of the P wave on the ECG, is coincident. Moreover, this study has demonstrated that AT and DT of Ar are equal. Accordingly, by determining the time to the onset and to the peak of Am, Ar AT can be derived. Thus, the timing of Am can effectively be used to estimate the duration of Ar particularly in normal subjects in whom Ar-wave profiles are not clearly defined. This remains, however, to be assessed in patients with different pathologies and severity of ventricular and atrial disease.

Limitations
Diastolic ventricular filling is influenced by a number of factors, particularly: HR, pre-load and afterload. To minimise these factors we studied healthy persons at rest and our results showed no significant variations in HR. With a significant number of persons aged above 70 years in the study, a possibility of incipient coronary artery disease (CAD) cannot be excluded without performing exercise testing and cardiac catheterisation. These procedures, however, were outside the scope of this study. We therefore relied on the absence of: symptoms, history of symptoms and family history of CAD to exclude the likelihood of CAD among the elderly. Although this does not guarantee the state of the coronary arteries, it appears to be a uniform limitation in all previous studies that have examined large numbers of healthy subjects.12,14,17Am, Ar and A were technically not measured simultaneously, but rather from different cardiac cycles; however, HR was consistently similar in all recordings. Finally, this is a normal population study and therefore to achieve a wider generalisation of the results, our hypothesis will need to be tested in various disease conditions, especially specific situations where the duration of Ar has been used in clinical practice.


   Conclusion
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 Conclusion
Acknowledgments
 References
 
Peak atrial contraction coincides with the peak of atrial reversal flow into the pulmonary veins and this is consistent from the young to the elderly. Thus, the timing of regional atrial contraction by DTI can be used to accurately estimate corresponding measurements of pulmonary flow reversal obtained by transthoracic echocardiography in subjects with normal LA pressure.


   Acknowledgments
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 Conclusion
 Acknowledgments
References
 
We thank Anders Asplund, Department of Clinical Science, Umeå University, for technical support with the illustrations, and also Manne Andersson and Kerstin Rosenqvist for logistic support. This study was supported by the Swedish Heart and Lung Foundation. Dr. E. Kazzam received additional research grants from the Swedish Medical Association and the Ragnar Söderbergs Foundation.


   References
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 Conclusion
 Acknowledgments
 References
 

  1. Rossvol O., Hatle L.K. Pulmonary venous flow velocities recorded by transthoracic Doppler ultrasound: relation to left ventricular pressures. J Am Coll Cardiol (1993) 21:1687–1696.[Abstract]
  2. Sohn D.W., Choi Y.J., Oh B.H., Lee M.M., Lee Y.W. Estimation of left ventricular end-diastolic pressure with the difference in pulmonary venous and mitral A durations is limited when mitral E and A waves are overlapped. J Am Soc Echocardiogr (1999) 12:106–112.[CrossRef][Web of Science][Medline]
  3. Klein A.L., Abdalla I., Murray R.D., Lee J.C., Vandervoort P., Thomas J.D., et al. Age independence of the difference in duration of pulmonary venous atrial reversal flow and transmitral A-wave flow in normal subjects. J Am Soc Echocardiogr (1998) 11:458–465.[CrossRef][Web of Science][Medline]
  4. Malkowski M.J., Guo R., Gray P.G., Pearson A.C. Is the pulmonary venous–transmitral A-wave duration difference altered by age and hypertension? Am J Cardiol (1995) 76:722–724.[CrossRef][Web of Science][Medline]
  5. Ito T., Suwa M., Kobashi A., Hirota Y., Kawamura K. Ratio of pulmonary venous to mitral A velocity is a useful marker for predicting mean pulmonary capillary wedge pressure in patients with left ventricular systolic dysfunction. J Am Soc Echocardiogr (1998) 11:961–965.[CrossRef][Web of Science][Medline]
  6. Appleton C.P., Galloway J.M., Gonzalez M.S., Gaballa M., Basnight M.A. Estimation of left ventricular filling pressures using two-dimensional and Doppler echocardiography in adult patients with cardiac disease. Additional value of analyzing left atrial size, left atrial ejection fraction and the difference in duration of pulmonary venous and mitral flow velocity at atrial contraction. J Am Coll Cardiol (1993) 22:1972–1982.[Abstract]
  7. Keren G., Sherez J., Megidish R., Levitt B., Laniado S. Pulmonary venous flow pattern – its relationship to cardiac dynamics. A pulsed Doppler echocardiographic study. Circulation (1985) 71:1105–1112.[Abstract/Free Full Text]
  8. Keren G., Milner M., Lindsay J. Jr., Goldstein S. Load dependence of left atrial and ventricular filling dynamics by transthoracic and transesophageal Doppler echocardiography. Am J Card Imaging (1996) 10:108–116.[Medline]
  9. Nishimura R.A., Abel M.D., Hatle L.K., Tajik A.J. Relation of pulmonary vein to mitral flow velocities by transesophageal Doppler echocardiography. Effect of different loading conditions. Circulation (1990) 81:1488–1497.[Abstract/Free Full Text]
  10. Ren W.D., Visentin P., Nicolosi G.L., Canterin F.A., Dall'Aglio V., Lestuzzi C., et al. Effect of atrial fibrillation on pulmonary flow patterns: transesophageal pulsed Doppler echocardiographic study. Eur Heart J (1993) 14:1320–1327.[Abstract/Free Full Text]
  11. Masuyama T., Lee J.M., Yamamoto K., Tanouchi J., Hori M., Kamada T. Analysis of pulmonary venous flow velocity patterns in hypertensive hearts: its complementary value in the interpretation of mitral flow patterns. Am Heart J (1992) 124:983–994.[CrossRef][Web of Science][Medline]
  12. Klein A.L., Burstow D.J., Tajik A.J., Zachariah P.K., Bailey K.R., Seward J.B. Effects of age on left ventricular dimensions and filling dynamics in 117 normal persons. Mayo Clin Proc (1994) 69:212–224.[Web of Science][Medline]
  13. Masuyama T., Nagano R., Nariyama K., Lee J.M., Yamamoto K., Naito J., et al. Transthoracic Doppler echocardiographic measurements of pulmonary venous flow velocity patterns: comparison with transesophageal measurements. J Am Soc Echocardiogr (1995) 8:61–69.[CrossRef][Medline]
  14. Gentile F., Mantero A., Lippolis A., Ornaghi M., Azzolini M., Barbier P., et al. Pulmonary venous flow velocity patterns in 143 normal subjects aged 20 to 80 years old. An echo 2D colour Doppler cooperative study. Eur Heart J (1997) 18:148–164.[Abstract/Free Full Text]
  15. Castello R., Pearson A.C., Lenzen P., Labovitz A.J. Evaluation of pulmonary venous flow by transesophageal echocardiography in subjects with a normal heart: comparison with transthoracic echocardiography. J Am Coll Cardiol (1991) 18:65–71.[Abstract]
  16. Brunazzi M.C., Chirillo F., Pasqualini M., Gemelli M., Franceschini-Grisolia E., Longhini C., et al. Estimation of left ventricular diastolic pressures from precordial pulsed Doppler analysis of pulmonary venous and mitral flow. Am Heart J (1994) 128:293–300.[CrossRef][Web of Science][Medline]
  17. de Marchi S.F., Bodenmuller M., Lai D.L., Seiler C. Pulmonary venous flow velocity patterns in 404 individuals without cardiovascular disease. Heart (2001) 85:23–29.[Abstract/Free Full Text]
  18. Jensen J.L., Williams F.E., Beilby B.J., Johnson B.L., Miller L.K., Ginter T.L., et al. Feasibility of obtaining pulmonary venous flow velocity in cardiac patients using transthoracic pulsed wave Doppler technique. J Am Soc Echocardiogr (1997) 10:60–66.[CrossRef][Web of Science][Medline]
  19. Schiller N.B., Shah P.M., Crawford M., DeMaria A., Devereux R., Feigenbaum H., et al. Recommendations for quantitation of the left ventricle by two-dimensional echocardiography. J Am Soc Echocardiogr (1989) 2:358–367.[Medline]
  20. Bland J.M., Altman D.G. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet (1986) 1:307–310.[CrossRef][Web of Science][Medline]
  21. Chen Y.T., Kan M.N., Lee A.Y., Chen J.S., Chiang B.N. Pulmonary venous flow: its relationship to left atrial and mitral valve motion. J Am Soc Echocardiogr (1993) 6:387–394.[Medline]
  22. Keren G., Sonnenblick E.H., LeJemtel T.H. Mitral annulus motion. Relation to pulmonary venous and transmitral flows in normal subjects and in patients with dilated cardiomyopathy. Circulation (1988) 78:621–629.[Abstract/Free Full Text]
  23. Isaaz K., Munoz del Romeral L., Lee E., Schiller N.B. Quantitation of the motion of the cardiac base in normal subjects by Doppler echocardiography. J Am Soc Echocardiogr (1993) 6:166–176.[Medline]
  24. Garcia M.J., Rodriguez L., Ares M., Griffin B.P., Klein A.L., Stewart W.J., et al. Myocardial wall velocity assessment by pulsed Doppler tissue imaging: characteristic findings in normal subjects. Am Heart J (1996) 132:648–656.[CrossRef][Web of Science][Medline]
  25. Rodriguez L., Garcia M., Ares M., Griffin B.P., Nakatani S., Thomas J.D. Assessment of mitral annular dynamics during diastole by Doppler tissue imaging: comparison with mitral Doppler inflow in subjects without heart disease and in patients with left ventricular hypertrophy. Am Heart J (1996) 131:982–987.[CrossRef][Web of Science][Medline]
  26. Klein A.L., Tajik A.J. Doppler assessment of pulmonary venous flow in healthy subjects and in patients with heart disease. J Am Soc Echocardiogr (1991) 4:379–392. Review.[Medline]
  27. Kitzman D.W., Sheikh K.H., Beer P.A., Philips J.L., Higginbotham M.B. Age related alterations in Doppler left ventricular filling indexes in normal subjects are independent of left ventricular mass, heart rate, contractility and loading conditions. J Am Coll Cardiol (1991) 18:1243–1250.[Abstract]
  28. Keren G., Bier A., Sherez J., Miura D., Keefe D., LeJemtel T. Atrial contraction is an important determinant of pulmonary venous flow. J Am Coll Cardiol (1986) 7:693–695.[Abstract]
  29. Arakawa M., Akamatsu S., Terazawa E., Dohi S., Miwa H., Kagawa K., et al. Age-related increase in systolic fraction of pulmonary vein flow velocity–time integral from transesophageal Doppler echocardiography in subjects without cardiac disease. Am J Cardiol (1992) 70:1190–1194.[CrossRef][Web of Science][Medline]
  30. Masuyama T., Lee J.M., Tamai M., Tanouchi J., Kitabatake A., Kamada T. Pulmonary venous flow velocity pattern as assessed with transthoracic pulsed Doppler echocardiography in subjects without cardiac disease. Am J Cardiol (1991) 67:1396–1404.[CrossRef][Web of Science][Medline]
  31. Lindstrom L., Wranne B. Pulsed tissue Doppler evaluation of mitral annulus motion: a new window to assessment of diastolic function. Clin Physiol (1999) 19:1–10.[Medline]

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