Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 


 
 Table of Contents  
REVIEW ARTICLE
Year : 2013  |  Volume : 23  |  Issue : 4  |  Page : 91-95

The ventricular-arterial coupling: From basic pathophysiology to clinical application in the echocardiography laboratory


1 Cardiologia Preventivae Riabilitativa, S. Maria degli Angeli, Pordenone, Italy
2 Cardiologia Preventivae Riabilitativa, S. Maria degli Angeli, Pordenone; Scuola di Specializzazione in Malattie Cardiovascolari, Università di Trieste, Trieste, Italy
3 Cardiologia, San Daniele del Friuli, Università di Pisa, Pisa, University of Pisa, Pisa, Italy
4 Cardiologia, San Vito al Tagliamento, Università di Pisa, Pisa, University of Pisa, Pisa, Italy
5 Dipartimento Cardiotoracicoe Vascolare, Università di Pisa, Pisa, University of Pisa, Pisa, Italy
6 Cardiologia, Azienda Ospedaliera S. Maria degli Angeli, Pordenone, Italy

Date of Web Publication20-Feb-2014

Correspondence Address:
Francesco Antonini-Canterin
SSD Cardiologia Preventiva e Riabilitativa, Via Montereale, 24, Pordenone - 33170
Italy
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2211-4122.127408

Rights and Permissions
  Abstract 

The interplay between cardiac function and arterial system, which in turn affects ventricular performance, is defined commonly ventricular-arterial coupling and is an expression of global cardiovascular efficiency. This relation can be expressed in mathematical terms as the ratio between arterial elastance (EA) and end-systolic elastance (EES) of the left ventricle (LV). The noninvasive calculation requires complicated formulae, which can be, however, easily implemented in computerized algorithms, allowing the adoption of this index in the clinical evaluation of patients. This review summarizes the up-to-date literature on the topic, with particular focus on the main clinical studies, which range over different clinical scenarios, namely hypertension, heart failure, coronary artery disease, and valvular heart disease.

Keywords: Echocardiography, hypertension, left ventricular function, ventricular-arterial coupling


How to cite this article:
Antonini-Canterin F, Poli S, Vriz O, Pavan D, Bello VD, Nicolosi GL. The ventricular-arterial coupling: From basic pathophysiology to clinical application in the echocardiography laboratory. J Cardiovasc Echography 2013;23:91-5

How to cite this URL:
Antonini-Canterin F, Poli S, Vriz O, Pavan D, Bello VD, Nicolosi GL. The ventricular-arterial coupling: From basic pathophysiology to clinical application in the echocardiography laboratory. J Cardiovasc Echography [serial online] 2013 [cited 2019 May 20];23:91-5. Available from: http://www.jcecho.org/text.asp?2013/23/4/91/127408


  Theoretical Basis Top


The interaction between left ventricle (LV) and arterial system, termed usually ventricular-arterial coupling, is recognized nowadays as a key determinant of global cardiovascular performance. [1],[2] The cardiovascular system is structured to provide adequate pressure and flow to the tissues both at rest and during exercise. Studying LV efficiency requires not only investigating the properties of LV itself, but also of the modulating role of the arterial system on LV performance and cardiac energetics.

The analysis of this interaction requires LV and arterial system to be described in similar mathematical terms. [3] Actually the best way to assess arterial afterload would be aortic input impedance derived from the Fourier analysis of aortic pressure and flow. [4] However, aortic input impedance is described in the frequency domain, whereas measures of LV contractility are best described in the time domain; consequently direct comparisons between arterial and LV function is difficult. To overcome this limitation, the ventricular-arterial coupling is commonly calculated by the ratio of effective arterial elastance (EA), a measure of afterload, to LV end-systolic elastance (EES), a relatively load independent measure of LV chamber performance. Both these measures are expressed in mmHg/ml and therefore comparable mathematically. Normal invasively determined EEA and EES values in resting subjects are 2.2 ± 0.8 mmHg/ml and 2.3 ± 1.0 mmHg/ml, respectively. As a consequence, when EA/EES ratio is approximately equal to 1.0, LV and arterial system are optimally coupled to produce stroke work, a measure of the efficiency of LV work, corresponding to the product of systolic arterial pressure and stroke volume, and related to O 2 consumption. [5] When EA/EES ratio is <1.0, the stroke work remains close to optimal values, but when EA/EES ratio is >1.0, the stroke work significantly falls and the LV becomes progressively less efficient.

In practice, EES indicates how much the LV end-systolic volume increases and stroke volume decreases in response to an elevation of end-systolic pressure. In a patient with a failing heart, EES is reduced and EA is increased. In this situation, LV and arterial system are coupled in a suboptimal way resulting in a EA/EES ratio >1.0. [6] An increase in heart rate will further increase EA, worsening the coupling. [7] On the contrary, vasodilator therapy, lowering EA, brings the EA/EES ratio back down toward 1.0, improving the coupling. Similarly, inotropic therapy, increasing EES, improves the coupling. [8]


  How to Measure EA And EES in The Echo Lab? Top


The arterial system is functionally described by the relation between the stroke volume and the end-systolic arterial pressure. [9],[10] The higher the stroke volume, the greater the arterial end-systolic pressure. The slope of this relation represents the EA. Assuming that zero stroke volume is associated with zero pressure, then EA can be simply calculated as the ratio of end-systolic pressure to stroke volume [Figure 1]. Arterial pressure can be conveniently estimated using a cuff sphygmomanometer; end-systolic pressure can be estimated as 0.9 times the peak brachial systolic pressure. Thus, EA can be easily calculated as 0.9 times the brachial systolic pressure divided by stroke volume, determined at LV outflow tract level by Doppler techniques.

Analogous assessment of EES is unfortunately much more complicated. Traditionally, LV has been evaluated by the analysis of pressure-volume loops, plotting LV pressure versus volume through the cardiac cycle. Varying the load and connecting the end-systolic points of several beats, LV end-systolic pressure-volume relation can be derived. The slope of this relation approximately corresponds to EES. An increase in contractility tends to shift the relation to the left, increasing EES. The above described approach, however, requires usually invasive measurements and is time-consuming; so it is not commonly employed in the clinical practice.
Figure 1: Relation between stroke volume and end-systolic arterial pressure. The slope of the relation is the arterial elastance (EA), which can be easily calculated by the ratio between end-systolic pressure and stroke volume, since the relation intercepts the point zero

Click here to view


Because LV end-systolic pressure-volume relation does not intercept the point zero, EES cannot be accurately calculated simply as end-systolic pressure divided by the end-systolic volume [Figure 2]. Actually a rough estimate of ventricular-arterial coupling could be obtained using such a simplified approach:
Figure 2: Relation between end-systolic left ventricular pressure and end-systolic left ventricular volume. The slope of the relation in end-systolic elastance of the left ventricle (EES). Since this linear relation does not intercept the point zero, EES cannot be simply calculated by the ratio between end-systolic pressure and end-systolic volume

Click here to view


EA = ESP/SV, EES = ESP/ESV

where ESP is the end systolic pressure, SV is the stroke volume, and ESV is the end systolic volume. So:

EA/EES = (ESP/SV)/(ESP/ESV) and then simplifying, eliminating ESP:

EA/EES = ESV/SV

The problem with this simplified approach is that the ESV/SV ratio is related in mathematical terms to the ejection fraction (1/EF - 1) and therefore it does not add substantial information to the traditional ejection fraction measurement.

The significant advantage of a correctly measured EA/EES ratio over ejection fraction is that examining the different components of EA/EES allows to evaluate whether alterations are due to changes in arterial properties, LV properties or both, allowing a better clinical assessment of the patient and a tailored therapy.

To date, the echocardiographic/Doppler gold standard for the determination of EA/EES ratio is the so-called single-beat method developed by Chen and coworkers. [11] According to this method, EES can be calculated noninvasively by the formula:

EES = (DBP − (E nd(est) × SBP × 0.9))/E nd(est) × SV

where DBP and SBP are diastolic and systolic arm-cuff blood pressures, E nd(est) is the estimated normalized ventricular elastance at the onset of ejection, and SV is Doppler-derived stroke volume. E nd(est) is described by an apparently very complicated formula:

E nd(est) =

0.0275 − 0.165 × EF + 0.3656 × (DBP/SBP × 0.9) + 0.515 × E nd(avg) ,

where EF is the basal ejection fraction and E nd(avg) is derived by the following formula:

E nd(avg) =

0.35695 − 7.2266 × tNd + 74.249 × tNd 2 −307.39 × tNd 3 + 684.54 × tNd 4 - 856.92 × tNd 5 + 571.95 × tNd 6 − 159.1 × tNd 7

where tNd is the ratio of preejection period to total systolic period.

Similarly, the elastance of the arterial system can be numerically expressed as EA, using the following formula [12] ;

EA = (SBP × 0.9)/SV

In this way, being EES and EA expressed in the same units, the calculation of EA/EES ratio is correctly feasible.

Obviously, to allow clinical application, all these formulas have to be implemented in computerized algorithms; the operator is just requested to insert simple noninvasive parameters which can be collected easily: systolic and diastolic blood pressures, stroke volume, ejection fraction, preejection and total systolic periods [Figure 3].
Figure 3: The echo figures display the evaluation of ejection fraction (panel A), time-velocity integral (VTI), preejection and ejection time (panel B) using aortic pulsed-Doppler waveform on the left ventricular outflow tract (LVOT). These parameters, along with systolic and diastolic and systolic blood pressure and LVOT diameter, allow the correct determination of EA/EES ratio

Click here to view



  Clinical Applications Top


The clinical role of ventricular-arterial coupling is currently being investigated in several clinical scenarios. One of the main applications is the pathophysiology of hypertension as a determinant of heart failure. The rationale is supported by preclinical findings such as the work of Prabhu, [13] which described that, in an animal model of tachycardia induced heart failure, ventricular-arterial coupling impairment precedes pump dysfunction. Lam et al., [14] considered 527 hypertensive patients from the Valsartan in Diastolic Dysfunction (VALIDD) and the Exforge Intensive Control of Hypertension to Evaluate Efficacy in Diastolic Dysfunction (EXCEED) trials, without clinical signs of heart failure, with normal LV ejection fraction and with ventricular diastolic dysfunction. After antihypertensive therapy a reduction of EA/EES ratio was found to be in direct relation to the degree of blood pressure lowering, in parallel with modest reductions in LV mass, concentric remodeling, and brain natriuretic peptide (BNP) hematic levels. These results were blunted in women and in obese individuals: The smaller impact of antihypertensive therapy on ventricular-arterial coupling in this subset of patients may lead to greater mechanical inefficiency and compensatory LV remodeling, which may explain the predisposition to the development of heart failure with preserved ejection fraction. Osranek et al., [15] examined 18 hypertensive patients without other forms of cardiopathy, before and after obtaining good blood pressure control. The peculiarity of this work consists in the experimental determination of EES for each patient plotting ESP versus LV volume at rest and during isometric exercise. EA/EES ratio decreased in all patients, especially in those with a shorter history of hypertension. The reduction of EA/EES ratio determines a net increase in mechanical efficiency at the cost of a minor decrease in stroke volume and permits a smaller loss of mechanical efficiency in case of afterload increase. In the context of risk factor interaction with cardiac function, Miyoshi et al., [16] devised a more complex model, postulating an interplay between left atrium, LV, and arterial system; a detailed analysis of this model, however, lies outside the aims of this article.

The studies presented above did not consider the clinical outcome of the patients. In the last years, however, some papers addressed the prognostic role of the ventricular-arterial coupling in several clinical conditions. In the context of coronary artery disease EA/EES ratio emerged as an independent echocardiographic correlate of BNP levels in patients with previous myocardial infarction and as a predictor of long-term cardiovascular mortality equivalent to BNP itself. [17] The best cutoff to discriminate patients with good prognosis from those with a worse outcome, according to receiver operating characteristic (ROC) curves analysis, was identified as a EA/EES ratio of 1.47, which had approximately the same discrimination capacity of a BNP cutoff of 250 pg/ml. An analogous correlation between Ea/Ees ratio and BNP level has been previously highlighted by Mehra et al., [18] in the setting of heart transplantation: the transplanted organ is unable to interact with the vasculature, and therefore, operates with low efficiency which is paralleled by a tandem increase in BNP independently from alterations in blood pressure.

Young Her et al., [19] studied ventricular stiffness and ventricular-arterial interaction parameters in patients with nonischemic dilated cardiomyopathy (NIDM). They enrolled 25 patients with NIDM and advanced systolic dysfunction which were matched with uncomplicated hypertensive patients and marathon runners. EA/EES ratio and diastolic elastance emerged as reliable predictors of exercise capacity. In the wake of these results the authors suggested the clinical validation of a new index of "total ventricular stiffness" which incorporates an index of diastolic efficiency. However, this concept still lacks adequate clinical validation.

Another possible field of application of ventricular-arterial coupling is the clinical management of candidates for cardiac resynchronization therapy. Zanon et al., [20] found in a population of 78 patient with dilated cardiomyopathy with ischemic and non-ischemic etiology, that a high basal EA/EES ratio was a good predictor of responsiveness to cardiac resynchronization therapy both in term of quality of life and end systolic volume, especially in nonischemic patients, where the responsiveness to resynchronization is not influenced by the localization of necrotic tissue.

Still pertaining to heart failure, Reil et al., [21] found recently in a subpopulation of the Systolic Heart Failure Treatment With the If Inhibitor Ivabradine Trial (SHIFT), that further reduction of heart rate with ivabradine in heart failure patients already treated with optimized medical therapy, determined a reduction of EA/EES. This result was mainly ascribable to the reduction of EA as a result of decreased vascular pulsatile load with unaltered systemic vascular resistance and left ventricular contractility, the last notoriously unaffected by ivabradine.

EA/EES ratio seems to be a reliable tool in valvular heart disease as well. Guarracino et al., [22] evaluated the hemodynamic effects of the MitraClip procedure in terms of improvement of ventricular-arterial coupling. The main concern with the correction of severe mitral regurgitation, especially in severely compromised patients, is the possible further impairment of LV systolic function, which, on the other hand, is hardly comparable in term of ejection fraction before and after the procedure. Interestingly, the authors observed, though in a numerically limited cohort, that the MitraClip procedure does not deteriorate significantly EA/EES ratio, despite a reduction in ejection fraction. [Table 1] summarizes the main findings of the published studies using the single beat EA/EES ratio method.
Table 1: Clinical application of single beat EA/EES ratio method: Published studies


Click here to view


Finally, in the last years, the concept of ventricular-arterial interaction has been extensively studied in the field of aortic valve stenosis. Lancellotti et al., [23] enrolled 163 asymptomatic patients with severe aortic stenosis and normal systolic function and identified four parameters associated with development of symptoms during a mean follow-up of 20 months. Among peak aortic jet velocity, LV systolic longitudinal deformation and left atrial area index, valvular-arterial impedance emerged as a relevant determinant of disease progression. This parameter, calculated as the sum of systolic arterial pressure and mean transvalvular pressure gradient divided by the stroke volume index, though mathematically different from the EA/EES ratio, can be considered another expression of ventricular-arterial interaction. Similar results were obtained by Hachicha et al., [24] in a retrospective study of 544 asymptomatic patients with moderate-to-severe aortic stenosis: The level of valvular-arterial impedance was indirectly related to their survival at a median follow-up of 2.1 years.


  Conclusions Top


Ventricular-arterial coupling represents a comprehensive expression of cardiac function and efficiency which can be numerically described by the ratio between arterial and ventricular elastance. In the echocardiography laboratory these parameters can be estimated with good accuracy noninvasively using mathematical formulae, apparently complicated, but which can be easily implemented in a computerized algorithm. The potentials of the application of ventricular-arterial coupling in clinical practice are large, emerging from the promising results of the first studies, in different settings, in particular in the field of hypertension, heart failure, coronary artery disease, and valvular heart disease.

 
  References Top

1.Starling MR. Left ventricular-arterial coupling relations in the normal human heart. Am Heart J 1993;125:1659-66.  Back to cited text no. 1
    
2.Little WC, Pu M. Left ventricular-arterial coupling. J Am Soc Echocardiogr 2009;22:1246-8.  Back to cited text no. 2
    
3.Little WC, Cheng CP. Left ventricular-arterial coupling in conscious dogs. Am J Physiol 1991;261:H70-6.  Back to cited text no. 3
    
4.Murgo JP, Westerhof N, Giolma JP, Altobelli SA. Aortic input impedance in normal man: Relationship to pressure wave forms. Circulation 1980;62:105-16.  Back to cited text no. 4
    
5.De Tombe PP, Jones S, Burkhoff D, Hunter WC, Kass DA. Ventricular stroke work and efficiency both remain nearly optimal despite altered vascular loading. Am J Physiol 1993;264:H1817-24.  Back to cited text no. 5
    
6.Borlaug BA, Kass DA. Ventricular-vascular interaction in heart failure. Heart Fail Clin 2008;4:23-36.  Back to cited text no. 6
    
7.Ohte N, Cheng CP, Little WC. Tachycardia exacerbates abnormal left ventricular-arterial coupling in heart failure. Heart Vessels 2003;18:136-41.  Back to cited text no. 7
    
8.Binkley PF, Van Fossen DB, Nunziata E, Unverferth DV, Leier CV. Influence of positive inotropic therapy on pulsatile hydraulic load and ventricular-vascular coupling in congestive heart failure. J Am Coll Cardiol 1990;15:1127-35.  Back to cited text no. 8
    
9.Sunagawa K, Sugimachi M, Todaka K, Kobota T, Hayashida K, Itaya R, et al. Optimal coupling of the left ventricle with the arterial system. Basic Res Cardiol 1993;88 Suppl 2:75-90.  Back to cited text no. 9
    
10.Antonini-Canterin F, Carerj S, Di Bello V, Di Salvo G, La Carrubba S, Vriz O, et al. Research Group of the Italian Society of Cardiovascular Echography (SIEC). Arterial stiffness and ventricular stiffness: a couple of diseases or a coupling disease? A review from the cardiologist's point of view. Eur J Echocardiogr 2009;10:36-43.  Back to cited text no. 10
    
11.Chen CH, Fetics B, Nevo E, Rochitte CE, Chiou KR, Ding PA, et al. Noninvasive single-beat determination of left ventricular end-systolic elastance in humans. J Am Coll Cardiol 2001;38:2028-34.  Back to cited text no. 11
    
12.Kelly RP, Ting CT, Yang TM, Liu CP, Maughan WL, Chang MS, et al. Effective arterial elastance as index of arterial vascular load in humans. Circulation 1992;86:513-21.  Back to cited text no. 12
    
13.Prabhu SD. Altered left ventricular-arterial coupling precedes pump dysfunction in early heart failure. Heart Vessels 2007;22:170-7.  Back to cited text no. 13
    
14.Lam CS, Shah AM, Borlaug BA, Cheng S, Verma A, Izzo J, et al. Effect of antihypertensive therapy on ventricular-arterial mechanics, coupling, and efficiency. Eur Heart J 2013;34:676-83.  Back to cited text no. 14
    
15.Osranek M, Eisenach JH, Khandheria BK, Chandrasekaran K, Seward JB, Belohlavek M. Arterioventricular coupling and ventricular efficiency after antihypertensive therapy: A noninvasive prospective study. Hypertens 2008;51:275-81.  Back to cited text no. 15
    
16.Miyoshi H, Mizuguchi Y, Oishi Y, Iuchi A, Nagase N, Ara N, et al. Early detection of abnormal left atrial-left ventricular-arterial coupling in preclinical patients with cardiovascular risk factors: Evaluation by two-dimensional speckle-tracking echocardiography. Eur J Echocardiogr 2011;12:431-9.  Back to cited text no. 16
    
17.Antonini-Canterin F, Enache R, Popescu BA, Popescu AC, Ginghina C, Leiballi E, et al. Prognostic value of ventricular-arterial coupling and B-type natriuretic peptide in patients after myocardial infarction: A five-year follow-up study. J Am Soc Echocardiogr 2009;22:1239-45.  Back to cited text no. 17
    
18.Mehra MR, Milani RV, Richie MB, Uber PA, Park MH, Ventura HO, et al. Ventricular-vascular uncoupling increases expression of B-type natriuretic peptide in heart transplantation. Transplant Proc 2004;36:3149-51.  Back to cited text no. 18
    
19.Her AY, Kim JY, Choi EY, Kim SA, Jae RS, Shim CY, et al. Value of ventricular stiffness index and ventriculoarterial interaction in patients with nonischemic dilated cardiomyopathy. Circ J 2009;73:1683-90.  Back to cited text no. 19
    
20.Zanon F, Aggio S, Baracca E, Pastore G, Corbucci G, Boaretto G, et al. Ventricular-arterial coupling in patients with heart failure treated with cardiac resynchronization therapy: May we predict the long-term clinical response? Eur J Echocardiogr 2009;10:106-11.  Back to cited text no. 20
    
21.Reil JC, Tardif JC, Ford I, Lloyd SM, O'Meara E, Komajda M, et al. Selective heart rate reduction with ivabradine unloads the left ventricle in heart failure patients. J Am Coll Cardiol 2013;62:1977-85.  Back to cited text no. 21
    
22.Guarracino F, Ferro B, Baldassarri R, Bertini P, Forfori F, Giannini C, et al. Non invasive evaluation of cardiomechanics in patients undergoing MitrClip procedure. Cardiovasc Ultrasound 2013;11:13.  Back to cited text no. 22
    
23.Lancellotti P, Donal E, Magne J, Moonen M, O'Connor K, Daubert JC, et al. Risk stratification in asymptomatic moderate to severe aortic stenosis: The importance of the valvular, arterial and ventricular interplay. Heart 2010;96:1364-71.  Back to cited text no. 23
    
24.Hachicha Z, Dumesnil JG, Pibarot P. Usefulness of the valvuloarterial impedance to predict adverse outcome in asymptomatic aortic stenosis. J Am Coll Cardiol 2009;54:1003-11.  Back to cited text no. 24
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1]


This article has been cited by
1 Diastolic Intra–Left Ventricular Pressure Difference During Exercise: Strong Determinant and Predictor of Exercise Capacity in Patients With Heart Failure
Shingo Tsujinaga,Hiroyuki Iwano,Miwa Sarashina,Taichi Hayashi,Michito Murayama,Ayako Ichikawa,Masahiro Nakabachi,Hisao Nishino,Shinobu Yokoyama,Arata Fukushima,Takashi Yokota,Kazunori Okada,Sanae Kaga,Pavlos P. Vlachos,Toshihisa Anzai
Journal of Cardiac Failure. 2019;
[Pubmed] | [DOI]
2 Value of combined cardiopulmonary and echocardiography stress test to characterize the haemodynamic and metabolic responses of patients with heart failure and mid-range ejection fraction
Nicola Riccardo Pugliese,Iacopo Fabiani,Claudia Santini,Ilaria Rovai,Roberto Pedrinelli,Andrea Natali,Frank L Dini
European Heart Journal - Cardiovascular Imaging. 2019;
[Pubmed] | [DOI]
3 Pulse wave velocity to global longitudinal strain ratio in hypertension
Ignatios Ikonomidis,Spyridon Katsanos,Hellen Triantafyllidi,John Parissis,Stavros Tzortzis,George Pavlidis,Paraskevi Trivilou,Georgios Makavos,Maria Varoudi,Alexandra Frogoudaki,Agathi-Rosa Vrettou,Dimitrios Vlastos,John Lekakis,Efstathios Iliodromitis
European Journal of Clinical Investigation. 2019; 49(2): e13049
[Pubmed] | [DOI]
4 A novel principled method for the measurement of vascular robustness uncovers hidden risk for premature CVD death
Lutz E. Kraushaar,Alexander Dressel,Alexander Massmann
Journal of Applied Physiology. 2018; 125(6): 1931
[Pubmed] | [DOI]
5 Cardiovascular aging
Antonio Cannata’,Marco Merlo,Jessica Artico,Piero Gentile,Luca Camparini,Jacopo Cristallini,Aldostefano Porcari,Francesco Loffredo,Gianfranco Sinagra
Journal of Cardiovascular Medicine. 2018; : 1
[Pubmed] | [DOI]
6 High Spatial Resolution Multi-Organ Finite Element Modeling of Ventricular-Arterial Coupling
Sheikh Mohammad Shavik,Zhenxiang Jiang,Seungik Baek,Lik Chuan Lee
Frontiers in Physiology. 2018; 9
[Pubmed] | [DOI]
7 Echodynamics: Interpretation, Limitations, and Clinical Integration!
Ashraf Roshdy
Journal of Intensive Care Medicine. 2018; 33(8): 439
[Pubmed] | [DOI]
8 Left ventricular-arterial coupling is associated with prolonged mechanical ventilation in severe post-cardiac surgery patients: an observational study
Xu Wang,Yun Long,Huaiwu He,Guangliang Shan,Rui Zhang,Na Cui,Hao Wang,Xiang Zhou,Xi Rui,Wanglin Liu
BMC Anesthesiology. 2018; 18(1)
[Pubmed] | [DOI]
9 Prognostic value of left ventricular-arterial coupling in elderly patients with septic shock
Jing Yan,Xiaoyang Zhou,Bangchuan Hu,Shijin Gong,Yihua Yu,Guolong Cai,Li Li
Journal of Critical Care. 2017; 42: 289
[Pubmed] | [DOI]
10 Influence of non-dipping pattern of blood pressure in gestational hypertension on maternal cardiac function, hemodynamics and intrauterine growth restriction
A. Ilic,DJ. Ilic,S. Tadic,M. Stefanovic,A. Stojsic-Milosavljevic,K. Pavlovic,A. Redzek,L. Velicki
Pregnancy Hypertension. 2017; 10: 34
[Pubmed] | [DOI]
11 Enhanced ventricular-arterial coupling during a 2-year physical activity programme in patients with rheumatoid arthritis: a prospective substudy of the physical activity in rheumatoid arthritis 2010 trial
P. Sarajlic,C. Fridén,L. H. Lund,A. Manouras,A. Venkateshvaran,S. C. Larsson,B. Nordgren,C. H. Opava,I. E. Lundberg,M. Bäck
Journal of Internal Medicine. 2017;
[Pubmed] | [DOI]
12 Heart failure preserved ejection fraction (HFpEF): an integrated and strategic review
Carolyn L. Lekavich,Debra J. Barksdale,Virginia Neelon,Jia-Rong Wu
Heart Failure Reviews. 2015; 20(6): 643
[Pubmed] | [DOI]
13 Ventricular kinetic energy may provide a novel noninvasive way to assess ventricular performance in patients with repaired tetralogy of Fallot
Daniel Jeong,Petros V. Anagnostopoulos,Alejandro Roldan-Alzate,Shardha Srinivasan,Mark L. Schiebler,Oliver Wieben,Christopher J. François
The Journal of Thoracic and Cardiovascular Surgery. 2015; 149(5): 1339
[Pubmed] | [DOI]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Theoretical Basis
How to Measure E...
Clinical Applica...
Conclusions
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed4930    
    Printed151    
    Emailed5    
    PDF Downloaded647    
    Comments [Add]    
    Cited by others 13    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]