© 2001 European Society of Cardiology
Doppler echocardiography reliably predicts pulmonary artery wedge pressure in patients with chronic heart failure even when atrial fibrillation is present
a Department of Cardiology, Montescano Medical Center, S. Maugeri Foundation Montescano Pavia, Italy
b Department of Cardiology, Ospedale A. Manzoni Lecco, Italy
* Corresponding author. Centro Medico Montescano, Via per Montescano 40, 27040 Montescano, Pavia, Italy. Tel.: +39-385-2471. E-mail address: e.traversi.montescano{at}fsm.it (E. Traversi).
 |
Abstract |
|---|
 Top Abstract 1. Introduction2. Methods3. Results4. Discussion5. ConclusionsReferences |
|---|
Background and aims: In patients with chronic congestive heart failure a high pulmonary artery wedge pressure (PAWP) is associated with poor prognosis, severe symptoms and low exercise tolerance. When atrial fibrillation is present the non-invasive prediction of PAWP by Doppler echocardiography is generally considered to be not reliable.
Methods: In 51 consecutive patients with chronic heart failure, due to either ischemic and non-ischemic dilated cardiomyopathy, and atrial fibrillation simultaneous Doppler echocardiographic and hemodynamic studies were used to estimate PAWP. The power of the obtained multivariate equation was compared with that of previously developed equations and was then prospectively tested in a group of 15 patients.
Results: The deceleration rate (DR) of early diastolic mitral flow, the left ventricular iso-volumic relaxation time (IVRT) and the systolic fraction of pulmonary venous flow (SF) were independent predictors of PAWP and the following multivariable equation was derived: PAWP = 24.04 + 1.23 x DR – 0.089 x IVRT – 0.175 x SF. The correlation between invasive PAWP and the PAWP non-invasively estimated by this equation in the testing group was 0.91 (standard error of estimate = 3.2 mmHg). The mean difference was 0.93 and the standard error of differences was 2.7 mmHg.
Conclusion: In patients with chronic heart failure due to dilated cardiomyopathy who are in atrial fibrillation a relatively accurate estimation of PAWP can be obtained by Doppler echocardiography of mitral and pulmonary venous flow.
Received February 19, 2000; Revised August 30, 2000; Accepted October 12, 2000
|
1. Introduction |
|---|
|
TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionsReferences |
|---|
Pulmonary artery wedge pressure (PAWP), a well-established index of cardiac function, is widely used to assess left ventricle filling pressures. In patients with chronic congestive heart failure a high PAWP is associated with poor prognosis, severe symptoms and low exercise tolerance. In order to avoid serial invasive procedures, we recently developed an equation which can reliably estimate PAWP by combining Doppler indices of mitral and pulmonary venous flow [1]. Regrettably, approximately 20% [2,3] of patients with chronic heart failure have atrial fibrillation. When atrial fibrillation is present, the loss of atrial contraction and of ventricular rate control affects both mitral and pulmonary venous flow and the relationship between Doppler variables and PAWP has not yet been clearly defined. An equation to determine PAWP in patients with atrial fibrillation was recently proposed [4] but it was derived from a non-homogeneous population and only a subgroup of patients had had simultaneous catheterization and echo-Doppler measurements. In another study an equation was derived from an elderly population of heart failure patients not eligible for heart transplantation and without considering pulmonary venous flow parameters [5]. We, therefore, performed this study to establish whether PAWP can be reliably assessed by Doppler-echocardiography in a large group of patients with congestive heart failure and atrial fibrillation simultaneously undergoing right heart catheterization and Doppler echocardiographic examination.
|
2. Methods |
|---|
|
TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionsReferences |
|---|
2.1. Study patients
The study population comprised 54 consecutive patients with chronic heart failure, due to either ischemic or non-ischemic dilated cardiomyopathy, and atrial fibrillation lasting from at least 3 months. All patients were admitted to our Heart Failure Unit and underwent right heart catheterization as part of a pre-transplant evaluation. All had had at least two episodes of heart failure requiring hospital admission. Dilated cardiomyopathy was defined by two-dimensional echocardiographic demonstration of a dilated left ventricle (left ventricle end diastolic volume >78 ml/m2) with severe systolic dysfunction (ejection fraction <35%). Before Doppler echocardiographic and hemodynamic evaluation a satisfactory heart rate control (mean heart rate <90 bpm) was reached by digitalis alone (40 patients) or in association with amiodarone (14 patients) or betablockade (31 patients). Patients with stable atrial flutter were not included in the study. Doppler echocardiographic recordings were judged inadequate in three patients who were therefore excluded from the study. Table 1 summarizes the principal characteristics of the remaining 51 patients who formed the study group. Hemodynamic and Doppler echocardiographic studies were performed simultaneously and analyzed, blind, by two independent observers.
|
2.2. Testing group
To test the reliability of the multivariable equation derived from the first 51 patients of the study group, the equation was prospectively applied in a second group of 15 patients, whose characteristics are summarized in Table 1 and who underwent simultaneous hemodynamic and Doppler echocardiographic studies at baseline and after either an infusion of nitroprusside (four patients), dobutamine (four patients) or after passive leg-lifting (the remaining eight patients, who had normal or near normal PAWP at baseline). In this group of patients PAWP was also estimated (at baseline) using: (i) only the averaged values of the first three beats; (ii) a simplified formula by Chirillo et al. [4]: PWAP=–94.26xpulmonary venous flow deceleration timex9.83xinterval QRS to onset of diastolic pulmonary venous flow wave+44.26; and (iii) the Doppler echocardiographic methods previously proposed by Temporelli et al. [5] (PAWP=–0.26xdeceleration time of transmitral flow wave+51).
2.3. Cardiac catheterization
Right heart catheterization was performed using a 7-F Swan–Ganz balloon-tipped catheter inserted into the right internal jugular vein and advanced through the right heart cavities into the pulmonary artery. The correct positioning of the catheter was confirmed by the appearance of a typical wedge pressure tracing or by the fluoroscopic observation of the catheter tip during balloon inflation, or both. Measurements were obtained with the patient in a supine position using a Hewlett-Packard transducer connected to a 7005 Marquette polygraph. Pressure tracings were recorded at a speed of 50 mm/s on a scale calibrated from 0 to 50 mmHg. Cardiac output was measured by the thermodilution method.
2.4. Doppler echocardiography
Either Sonos 2500 or 5000 Hewlett-Packard ultrasound systems with 2.5, 3.5 MHz and multifrequency S4 probes were used to perform the Doppler echocardiographic studies. These studies were performed simultaneously with hemodynamic measurements with the patients lying in a supine or slightly left lateral decubitus position; data were recorded on videotape and subsequently analyzed by the software operating in the ultrasound system. Blood flow velocity curves were recorded at a sweep velocity of 100 mm/s.
Left ventricular volumes and ejection fraction were assessed by two-dimensional apical two-and four-chamber views using the modified Simpson's rule. Using apical views, maximal left atrial area was taken on the frame preceding mitral valve opening and minimal area on that occurring just before mitral closure. Simpson's rule was then applied to assess maximal and minimal left atrial volumes. Mitral regurgitation was detected by color flow Doppler study and graded on the basis of the maximal regurgitant jet area obtained in two planes. The characteristics of patients with and without mitral regurgitation are also summarized in Table 1.
Mitral flow velocity was assessed by pulsed wave Doppler from the apical four-chamber view by placing a 3-mm sample volume between the tips of the mitral leaflets in diastole and recording at a sweep velocity of 100 mm/s. Over 10 consecutive cycles, excluding those shorter than 600 ms, we measured and averaged the peak velocity defined as the highest point of the spectrum; the deceleration time, measured as the interval between peak of diastolic velocity and the point at which the steepest deceleration slope was extrapolated to the baseline; the left ventricular isovolumic relaxation time, measured as the time interval between the aortic closure click and the start of mitral flow. Deceleration rate was then calculated by dividing peak velocity by deceleration time.
Pulmonary venous flow velocity was obtained by positioning a 3–5 mm sample volume in the right upper pulmonary vein approximately 1 cm from the atrial cavity. From 10 consecutive cycles we measured the peak velocity (using the leading edge convention) and time–velocity integral of systolic forward flow and of diastolic forward flow, the time interval from the Q wave of the ECG and the peak of late diastolic forward velocity and the time interval from the Q wave and the onset of diastolic forward velocity. Deceleration time of late diastolic forward velocity was calculated as the interval from the peak of late diastolic forward velocity and the point at which the steepest deceleration slope was extrapolated to the baseline. The duration of the late diastolic forward wave was calculated from the point at which the steepest acceleration was extrapolated on the baseline to the point extrapolated for the deepest deceleration slope. The systolic fraction of peak velocities was then calculated by dividing the systolic flow velocity by the sum of systolic plus diastolic forward flow velocities. When no, negative or turbulent systolic flow velocity was recorded, the systolic fraction was considered to be zero.
2.5. Statistical analysis
Statistical analysis was carried out using the SAS statistical package [6]. All descriptive data are given as mean ±1 S.D. To determine the relationship between Doppler echocardiographic data and PAWP, simple linear regression analysis was performed for each variable. A multilinear stepwise regression analysis was then performed to generate a multivariate equation for predicting PAWP. In the testing group PAWPs estimated by non-invasive methods were compared with invasive PAWPs using linear regression analysis and by calculating the mean difference between paired measurements and its standard deviation. Bland and Altman charts were used to show the agreement between the methods. A P-value <0.05 was considered as statistically significant. The presence of systematic bias and the standard error of estimate are described using Bland and Altman method [7] for each method.
2.6. Reproducibility of non-invasive estimations of pulmonary wedge pressure
Interobserver reproducibility of Doppler echocardiographic measurements was assessed in 40 consecutive patients. Videotape records were reviewed by a second independent observer and measurements were repeated using the criteria described above. The variability of each measurement and of estimated pulmonary artery wedge pressure was evaluated by calculating the mean relative difference between paired measurements and its standard deviation [7].
|
3. Results |
|---|
|
TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionsReferences |
|---|
3.1. Relationship of Doppler echocardiographic variables to pulmonary artery wedge pressure in the 51 study patients
As shown in Table 2, linear regression analysis revealed that several mitral and pulmonary venous flow indices were related to PAWP. Among the mitral flow velocity indices, deceleration rate showed the strongest correlation (r=0.75) (Fig. 1a), followed by left ventricular isovolumic relaxation time (Fig. 1b) and by deceleration time. A weaker correlation was found between pulmonary artery wedge pressure and mitral regurgitant jet area (Table 2). Significant mitral regurgitation was found in 28 patients (55%).
|
|
Among the pulmonary venous flow velocity indices, systolic fraction was the most strongly correlated variable on simple linear regression (r=–0.67) (Fig. 1c), followed by peak systolic forward velocity (r=–0.40), deceleration time of diastolic forward velocity (r=0.38) and duration of the interval QRS-onset of diastolic forward velocity (r=0.37) (Table 2). Atrial volumes and left ventricular ejection fraction were not correlated to pulmonary artery wedge pressure. In seven patients the systolic fraction of pulmonary venous flow was considered to be equal to 0.
When mitral and pulmonary flow velocity indices were included in the multilinear analysis relating Doppler echocardiographic parameters to PAWP, the resulting cumulative correlation coefficient was 0.69 (Table 3). The deceleration rate of transmitral flow velocity was the most relevant determinant whereas a smaller but significant contribution was made by the isovolumic relaxation time and the systolic fraction of pulmonary flow peak velocities. The mean relative difference between measured and estimated pulmonary artery wedge pressure was close to 0 indicating the absence of any systematic error (Fig. 2).
|
|
Similar correlations between Doppler variables and PAWP were found in patients with and without significant mitral regurgitation (Table 2).
3.2. Estimation of pulmonary wedge pressure in the testing group at baseline and after acute interventions
In a testing group the correlation between PAWP measured invasively and that estimated by substituting in the multivariable equation the Doppler variables averaged over 10 cardiac cycles was 0.91 (standard error of estimate=3.2 mmHg); the mean difference was 0.93 (standard error of estimate 2.7 mmHg). Fourteen out of 15 patients (93%) were correctly classified as having normal (<12 mmHg), moderately elevated (12–18 mmHg) or markedly elevated (>18 mmHg) pulmonary artery wedge pressure. Absolute values and changes of PAWP after acute interventions, simultaneously evaluated by hemodynamic and Doppler measurements in 14 patients, were accurately predicted by the equation (Fig. 3).
|
, dobutamine infusion; 
, nitroprusside infusion.Fig. 4 shows correlations and Bland–Altman's plots obtained using our equation but using data from averaging only three cardiac cycles; and the equations, simplified, proposed by Chirillo and Temporelli.
|
3.3. Reproducibility of non-invasive estimation of pulmonary artery wedge pressure by Doppler echocardiography
Close intra and interobserver agreement in the estimation of PAWP was observed. The mean relative differences between intraobserver and interobserver estimations were 0.15 (0.15) mmHg and 0.25 (1.64) mmHg, respectively.
|
4. Discussion |
|---|
|
TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionsReferences |
|---|
The ability to estimate left ventricular filling pressure non-invasively in patients with congestive heart failure would be of great value in assessing their degree of left ventricular dysfunction, monitoring the effect of unloading therapy and predicting prognosis. Previous studies [8–15] have shown that this estimation can be made by combining various Doppler echocardiographic variables. Patients with atrial fibrillation were, however, excluded from these studies, limiting the applicability of such estimations to patients in sinus rhythm. In our study we show that PAWP can be estimated by combining mitral and pulmonary venous flow Doppler variables in patients with chronic heart failure due to dilated cardiomyopathy even when atrial fibrillation is present.
It has been shown that in patients with heart failure and sinus rhythm elevated left atrial pressures can compensate for delayed left ventricular relaxation thus increasing early diastolic mitral flow velocity and its deceleration and decreasing isovolumic relaxation time. High left atrial pressure before atrial contraction together with a stiff left ventricle shortens and reduces mitral flow velocity wave at atrial contraction. This leads to the so-called pseudonormal and restrictive patterns that in heart failure patients are reliable indices of elevated left ventricular filling pressures.
Pulmonary venous flow in sinus rhythm patients shows a triphasic pattern which is predominantly related to left atrial function and reflects the oscillations of left atrial pressures [16]. Thus, the systolic forward flow velocity is determined by the combined backward effect of the decrease in left atrial pressure, due to both left atrial relaxation and mitral annulus descent, and the forward propagation of systolic right ventricular pressure [17]. Occasionally two different systolic components can be recorded, the first being caused by atrial relaxation. The diastolic forward flow velocity, which occurs when the mitral valve is open and the left atrium behaves as a passive conduit, slightly follows and is closely related to early diastolic mitral flow velocity. The reverse diastolic flow velocity wave is determined by atrial contraction and its duration depends mainly on left ventricular compliance. In patients with heart failure and sinus rhythm, when the left atrial pressure is high (and left atrial compliance is reduced) the systolic flow velocity is blunted [12]; the diastolic forward flow velocity is high and its deceleration is rapid; the reverse flow is prolonged and its duration exceeds that of forward mitral flow at atrial contraction.
When atrial fibrillation occurs the active atrial contraction is lost so that the whole blood volume filling left ventricle is detected in a monophasic E wave. Contemporary Doppler of pulmonary venous flow shows a loss of the late diastolic reverse flow. Loss of the active left atrial relaxation causes the disappearance of the first component of the systolic forward flow velocity. Besides these effects on left ventricular and atrial filling due to the loss of an active atrial contraction, irregular cardiac cycle lengths produce marked beat-to-beat variations in both mitral and pulmonary venous flow velocities.
Despite all these differences between Doppler echocardiographic findings in patients with sinus rhythm and atrial fibrillation a relatively accurate estimation of PAWP can be achieved in heart failure patients who are in atrial fibrillation. In particular our results show that in patients with atrial fibrillation, indices of early left ventricular diastolic filling (namely isovolumic relaxation time, deceleration time and deceleration rate) and the systolic fraction of pulmonary venous flow (Fig. 1) are almost as strongly correlated with PAWP as they are in patients who have similar characteristics but who are in sinus rhythm [1]. This is not surprising since one would expect that even in atrial fibrillation early diastolic left ventricular filling velocities are governed by the same interactions between left ventricular and atrial pressures operating in patients with sinus rhythm. Similarly, although loss of atrial relaxation abolishes the first component of the systolic pulmonary venous flow velocity wave [18], a significant (albeit less pronounced) systolic pulmonary venous flow velocity is recorded, and, as in sinus rhythm patients, is likely to be dependent on left atrial compliance and inversely correlated with mean and V-wave pulmonary artery wedge pressures.
An irregular heart rate produces beat-to-beat variations in contractility, pre-load, after-load, and mitral regurgitation [19] which lead to increased variability in Doppler measurements. To minimize this problem we investigated our patients when they were receiving optimal medical therapy including medications that were able to reduce sufficiently (and synchronize as much as possible) their ventricular heart rate. Moreover, we did not analyze short cardiac cycles that caused fusion of pulmonary venous flow waves. Dubrey and Falk [20] investigated the optimal number of beats for Doppler measurement of cardiac output in atrial fibrillation and concluded that it is approximately three times that necessary in sinus rhythm. Finally we must remember that, as observed by Oki et al. [19], changes in pulmonary venous flow velocities induced by variations of cardiac cycles are consistent with variations in pulmonary artery wedge V-pressure (the shorter the duration of the preceding cardiac cycles the higher the V-pressure and the lower the systolic pulmonary venous flow velocity). Thus, variability of Doppler measurements may somewhat reflect that of pulmonary artery wedge pressure and may, therefore, not limit the accuracy of the estimation provided that a sufficient number of cycles are averaged. Accordingly, we calculated the Doppler echocardiographic parameters over three and 10 consecutive cycles and found that the estimation of PAWP by averaging three cardiac cycles is indeed much more inaccurate than that obtained by averaging 10 cycles.
Our results are generally consistent with those of the few previous studies investigating this matter [4,5,21]. Temporelli et al. found a strong correlation between early diastolic deceleration time of mitral flow and pulmonary artery wedge pressure that emerged as the sole independent predictor in a population of patients with a low ejection fraction. In Temporelli's study, however, pulmonary venous flow Doppler variables were not taken into account. This was also the case in the study by Nagueh, who investigated a group of patients much older than ours, most of whom were mechanically ventilated in an intensive care unit. The best correlations he found were with peak acceleration of mitral velocity and with isovolumic relaxation time. However, in the subgroup of patients with low left ventricular ejection fraction a fairly good correlation between early diastolic deceleration time of mitral flow and left ventricular filling pressures was found by Chirillo et al. who analyzed both pulmonary venous and mitral flow velocities and showed that in patients with atrial fibrillation, associated with various cardiac diseases, pulmonary venous flow variables provide additional useful information. In particular, he found that the first component of the deceleration of diastolic pulmonary venous flow velocity was more strongly correlated with PAWP than the deceleration time of mitral flow. In our study this variable was significantly but more weakly correlated with pulmonary wedge pressure and was not retained as an independent factor in the multivariable equation. Differences in populations selected and technical difficulties in obtaining a clear deceleration slope in patients with enlarged atria and pulmonary veins (and thus low flow velocities) may account for these discrepancies. The prospective application of these methods and their direct comparison in the testing group confirms that they provide fairly good correlations with PAWP. However, the correlation was stronger (and scatter of values less) by applying the equation we have specifically developed in patients with chronic heart failure due to dilated cardiomyopathy (Fig. 4).
4.1. Study limitations
Several limitations of the present study should be acknowledged. First of all this study was performed in a selected population of patients with chronic heart failure, a dilated left ventricle and poor systolic function in whom adequate ventricular rate control had been obtained. Thus, the results of this study cannot be generalized to other patients with normal or less compromised left ventricular function and a higher heart rate. Secondly, to obtain meaningful results a strict and time-consuming methodology must be used, which may limit the everyday application of this method in a busy clinical practice. Finally, in the present study early diastolic mitral flow velocities were not normalized by relatively load-independent indices (such as the early diastolic velocity of mitral annulus displacement as assessed by tissue Doppler or propagation velocity of mitral flow) which, according to recent studies could improve the non-invasive estimation of left ventricular filling pressures.
|
5. Conclusions |
|---|
|
TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionsReferences |
|---|
Despite these limitations our results provide evidence that, in patients with dilated cardiomyopathy and heart failure, pulmonary artery wedge pressure can be reliably estimated by combining Doppler echocardiographic variables of mitral and venous flow even when atrial fibrillation is present. Doppler echocardiography, a simple, readily available, non-invasive tool, may reduce the need for right heart catheterization in a significant proportion of CHF patients, including those suffering from atrial fibrillation.
|
Acknowledgements |
|---|
The authors are grateful to Dr Rachel Stenner for her contribution to this study.
|
References |
|---|
|
TopAbstract1. Introduction2. Methods3. Results4. Discussion5. ConclusionsReferences |
|---|
- Pozzoli M., Capomolla S., Pinna G., et al. Doppler echocardiography reliably predicts pulmonary artery wedge pressure in patients with chronic heart failure with and without mitral regurgitation. J Am Coll Cardiol (1996) 27:883–893.[Abstract]
- Kopecky S.I., Gersh B.J., McGoon M.D., et al. The natural history of lone atrial fibrillation: a population-based study over three decades. New Engl J Med (1987) 317:669–674.[Abstract]
- Kannel W.B., Abbott R.D., Savage D.D., Mc Namara P.M. Epidemiologic features of chronic atrial fibrillation. New Engl J Med (1982) 306:1018–1022.[Abstract]
- Chirillo F., Brunazzi M.C., Barbiero M., et al. Estimating mean pulmonary artery wedge pressure in patients with chronic atrial fibrillation from transthoracic Doppler indexes of mitral and pulmonary venous flow velocity. J Am Coll Cardiol (1997) 30:19–26.[Abstract]
- Temporelli P.L., Scapellato F., Corra’ U., et al. Estimation of pulmonary wedge pressure by transmitral Doppler in patients with chronic heart failure and atrial fibrillation. Am J Cardiol (1999) 83:724–727.[CrossRef][Web of Science][Medline]
- SAS institute. SAS technical report P-229. SAS/STAT software changes and enhancement (release 6.07). Cary (NC): SAS Institute, 1992:633–679.
- Bland J.M., Altman D.J. Statistical methods for assessing agreement between two methods of clinical measurements. Lancet (1986) 1:307–310.[CrossRef][Web of Science][Medline]
- Vanoverschelde J.L.J., Raphael D.A., Robert A.R., Cosyns R. Left ventricular filling in dilated cardiomyopathy: relation to functional class and hemodynamics. J Am Coll Cardiol (1990) 15:1288–1295.[Abstract]
- Appleton C.P., Hatle L.K., Popp R.L., Jones J.V. Relation of transmitral flow velocity patterns to left ventricular diastolic function: new insights from a combined hemodynamic and Doppler echocardiographic study. J Am Coll Cardiol (1988) 12:426–440.[Abstract]
- Pozzoli M., Capomolla S., Opasich C., et al. Left ventricular filling pattern and pulmonary wedge pressure are closely related in patients with recent anterior myocardial infarction and left ventricular dysfunction. Eur Heart J (1992) 13:1067–1073.
[Abstract/Free Full Text] - Berger M., Bach M., Hecht S.R., Van Tosh A. Estimation of pulmonary artery wedge pressure by pulsed Doppler echocardiography and phonocardiography. Am J Cardiol (1992) 69:562–564.[CrossRef][Web of Science][Medline]
- Kuecherer H.F., Kusumoto F.M., Muhiudeen I.A., Cahalan M.K., Schiller N.B. Pulmonary venous flow patterns by transesophageal pulsed Doppler echocardiography: relation to parameters of left ventricular systolic and diastolic function. Am Heart J (1991) 122:1683–1693.[CrossRef][Web of Science][Medline]
- Brunazzi M.C., Chirillo F., Pasqualini M., 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]
- Rossvoll O., Hatle L.K. Pulmonary flow velocities recorded by transthoracic Doppler ultrasound: relation to left ventricular diastolic pressures. J Am Coll Cardiol (1993) 21:1687–1696.[Abstract]
- Appleton C.P., Galloway J.M., Gonzales M.S., Gaballa M., Basnight M.A. Estimation of left ventricular filling pressures using two-dimensional and Doppler echocardiography in adult patients with cardiac diseases. 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]
- Keren G., Sherez J., Megidish R., Levitt B., Laniado S. Pulmonary venous flow pattern — its relationship to cardiac dynamics. Circulation (1985) 71:1105–1112.
[Abstract/Free Full Text] - Smiseth O.A., Thompson C.R., Lohavanichbutr K., et al. The pulmonary venous systolic flow pulse — its origin and relationship to left atrial pressure. J Am Coll Cardiol (1999) 34:802–809.
[Abstract/Free Full Text] - Ren W.D., Visentin G.L., Nicolosi F.A., et al. Effect of atrial fibrillation on pulmonary venous flow patterns: transoesophageal pulsed Doppler echocardiographic study. Eur Heart J (1993) 14:1320–1327.
[Abstract/Free Full Text] - Oky T., Tabata T., Yamada H., et al. Evaluation of left atrial filling using systolic pulmonary venous flow velocity measurements in patients with atrial fibrillation. Clin Cardiol (1998) 21:169–174.[Web of Science][Medline]
- Dubrey S.W., Falk R.H. Optimal number of beats for the Doppler measurements of cardiac output in atrial fibrillation. J Am Soc Echocardiogr (1997) 10:67–71.[CrossRef][Web of Science][Medline]
- Nagueh S.F., Kopelen H.A., Quinones M.A. Assessment of left ventricular filling pressures by Doppler in the presence of atrial fibrillation. Circulation (1996) 94:2138–2145.
[Abstract/Free Full Text]
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  C. Li, J. Zhang, C. Zhou, L. Huang, H. Tang, and L. Rao Will simultaneous measurement of E/e' index facilitate the non-invasive assessment of left ventricular filling pressure in patients with non-valvular atrial fibrillation? Eur J Echocardiogr, January 6, 2010; (2010) jep218v2. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Maines, D. Catanzariti, C. Cirrincione, S. Valsecchi, J. Comisso, and G. Vergara Intrathoracic impedance and pulmonary wedge pressure for the detection of heart failure deterioration Europace, January 3, 2010; (2010) eup419v1. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Meta-analysis Research Group in Echocardiography ( Independence of restrictive filling pattern and LV ejection fraction with mortality in heart failure: An individual patient meta-analysis Eur J Heart Fail, August 1, 2008; 10(8): 786 - 792. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Grewal, R. McKelvie, E. Lonn, P. Tait, J. Carlsson, M. Gianni, C. Jarnert, and H. Persson BNP and NT-proBNP predict echocardiographic severity of diastolic dysfunction Eur J Heart Fail, March 1, 2008; 10(3): 252 - 259. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. A. Whalley, S. P. Wright, A. Pearl, G. D. Gamble, H. J. Walsh, M. Richards, and R. N. Doughty Prognostic role of echocardiography and brain natriuretic peptide in symptomatic breathless patients in the community Eur. Heart J., February 2, 2008; 29(4): 509 - 516. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Persson, E. Lonn, M. Edner, L. Baruch, C. C. Lang, J. J. Morton, J. Ostergren, R. S. McKelvie, and for the Investigators of the CHARM Echocardiograph Diastolic Dysfunction in Heart Failure With Preserved Systolic Function: Need for Objective Evidence: Results From the CHARM Echocardiographic Substudy-CHARMES J. Am. Coll. Cardiol., February 13, 2007; 49(6): 687 - 694. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G A Whalley, G D Gamble, and R N Doughty Restrictive diastolic filling predicts death after acute myocardial infarction: systematic review and meta-analysis of prospective studies Heart, November 1, 2006; 92(11): 1588 - 1594. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. E. Moller, P. A. Pellikka, G. S. Hillis, and J. K. Oh Prognostic Importance of Diastolic Function and Filling Pressure in Patients With Acute Myocardial Infarction Circulation, August 1, 2006; 114(5): 438 - 444. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||