Abstract
Transthoracic echocardiography plays a crucial role in clinical diagnosis and is increasingly being used around the world. Comprehensive echocardiographic examinations require accurate measurements and the operators to have excellent technical skills. Despite the availability of several published echocardiographic guidelines, the absence of recommended operational manuals in daily practice has resulted in significant variation in the content of echocardiography reports across different medical institutions. This variability has created communication barriers between medical institutions and also hampered the development of a national echocardiography database in Taiwan. Balancing quality and efficiency is a critical concern in echocardiography, and most published guidelines for echocardiography primarily focus on disease categorization. In the current document, we focus on information about the scanning sequence, including scanning techniques, common pitfalls, simple disease interpretation, and the recommended intensity. Based on a growing body of research, we particularly emphasize right-sided imaging and measurement information. We also discuss equipment settings, which have often been overlooked but are essential to obtaining good imaging and accurate measurements. Our recommendations could enhance clinicians’ and sonographers’ understanding of the core aspects of echocardiography and were developed with consideration of the health-care payment system in Taiwan. Implementing our recommendations may subsequently enable the establishment of a national echocardiography database in Taiwan.
Keywords: Echocardiographic operational manual, Echocardiography common pitfalls
Abbreviations
2D, Two-dimensional
A, Mitral peak A-wave at late diastole
A2C, Apical two-chamber
A3C, Apical three-chamber
A4C, Apical four-chamber
A5C, Apical five-chamber
AR, Aortic regurgitation
Ar, Atrial systolic reversal of pulmonary vein or hepatic vein
AS, Aortic stenosis
AT, Acceleration time
AV, Aortic valve
AVA, Aortic valvular area
CW, Continuous wave
D, Peak velocity of pulmonary vein or hepatic vein at early diastole
E, Mitral peak E-wave at early diastole
e′, Tissue velocity at early diastole
EROA, Effective regurgitant orifice area
FAC, Fraction area change
HVSFF, Hepatic vein systolic filling fraction
IVC, Inferior vena cava
IVSd, Interventricular septum thickness atend-diastole
LA, Left atrium or left atrial
LAP, Left atrial pressure
LAVI, Left atrial volume index
LV, Left ventricle or left ventricular
LVEDV, Left ventricular end-diastolic volume
LVEF, Left ventricular ejection fraction
LVESV, Left ventricular end-systolic volume
LVIDd, LV internal diameter at end-diastole
LVIDs, LV internal diameter at end-systole
LVMI, LV mass index
LVOT, Left ventricular outflow tract
M mode, Motion mode
MAC, Mitral annular calcification
MR, Mitral regurgitation
MS, Mitral stenosis
MV, Mitral valve
MVA, Mitral valvular area
PA, Pulmonary artery
PAH, Pulmonary arterial hypertension
PG, Pressure gradient
PH, Pulmonary hypertension
PHT, Pressure half time
PISA, Proximal iso-velocity surface area
PLAX, Parasternal long axis
PM, Papillary muscle
PR, Pulmonary regurgitation
PRF, Pulse repetition frequency
PSAX, Parasternal short axis
PV, Pulmonary valve
PVe, Pulmonary veins
PVR, Pulmonary vascular resistance
PW, Pulse wave
PWd, Posterior wall thickness at end-diastole
RA, Right atrium or right atrial
RAA, Right atrial area
Reg V, Regurgitation volume
RV, Right ventricle
RVOT, Right ventricular outflow tract
S, Peak velocity of pulmonary vein or hepatic vein at systole
s′, Tissue velocity at systole
SC, Subcostal view
SPAP, Systolic pulmonary arterial pressure
SV, Stroke volume
TAPSE, Tricuspid annular plane systolic excursion
TDI, Tissue doppler imaging
TEE, Transesophageal echocardiography
TR, Tricuspid regurgitation
TV, Tricuspid valve
VC, Vena contracta
Vel, Velocity
Vmax, Peak velocity
VTI, Velocity time integral
Table of contents
Introduction
1. Parasternal long axis (PLAX) view
1.1 General view, color Doppler
1.1.1 Two-dimensional (2D) left ventricular (LV) linear measurements
1.1.2 Motion-mode (M mode) LV linear measurements
1.1.3 Proximal Right Ventricular Outflow Tract (RVOT)
1.2 Left atrium (LA) linear measurements
1.3 Left ventricular outflow tract (LVOT) and aortic valve (AV), Zoom
1.3.1 AV, color Doppler, vena contracta (VC)
1.4 Mitral valve (MV), zoom
1.4.1 MV, color Doppler, VC
2. Right ventricular inflow view
2.1 General view
2.1.1 Tricuspid annulus dimension
2.1.2 Tricuspid valve (TV), color Doppler and continuous wave (CW), tricuspid regurgitation (TR)
3. Parasternal short axis (PSAX) view, aortic valve level
3.1 General view
3.1.1 Tricuspid annulus dimension
3.1.2 TV, color Doppler and CW, TR
3.2.1 Proximal and distal RVOT, pulmonary artery
3.2.2 RVOT and pulmonary valve (PV), color Doppler, pulmonary regurgitation (PR)
3.2.3 RVOT, CW, pulmonary stenosis
3.2.4 RVOT, CW, PR
3.2.5 RVOT, PR VC/PV annulus ratio
3.2.6 RVOT, pulse wave (PW), acceleration time
3.2.7 RVOT, PW, pulmonary vascular resistance
3.3.1 RVOT, blood flowpulmonary (Qp): blood flowsystemic (Qs)
3.4.1 AV, zoom
3.4.2 Three-dimensional measurement of AV
4. PSAX, mitral valve level
4.1 General view
4.2.1 MV, zoom, mitral valvular area (MVA)
4.2.2 MV, zoom, mitral annulus calcification
4.3 Three-dimensional measurement of MVA
5. PSAX, papillary muscle (PM) and apical level
5.1 General view, PM level
5.2 LV wall motion, visual assessment
5.3 General view, apical level
6. Apical 4-chamber view (A4C)
6.1 General view, color Doppler
6.2.1 2D LV volumetric measurements (biplane method of discs)
6.2.2 LV global longitudinal strain, speckle tracking
6.2.3 LV three-dimensional volumetric measurements
6.2.4 LV wall motion, visual assessment
6.3.1 MV, PW, mitral inflow
6.3.2 MV, PW, mitral E-velocity deceleration time
6.3.3 MV, CW, pressure half time (PHT) and mean pressure gradient for MVA
6.3.4 MV, CW, velocity time integral (VTI) for MVA from the continuity equation method
6.3.5 Mitral regurgitation (MR), effective regurgitant orifice area (EROA) and regurgitant volume from the proximal isovelocity surface area (PISA) method
6.3.6 Three-dimensional measurement of MR, VC area
6.3.7 MV, tissue Doppler, tissue velocity at early diastole (e′)
6.4.1 Pulmonary veins, PW
6.4.2 Pulmonary veins, PW, atrial systolic reversal (Ar) - mitral A duration
6.5 Biplane LA volume index
6.6 Right ventricular (RV) function and TV morphology
6.6.1 RV/LV basal diameter ratio
6.7 RV-focused view
6.7.1 RV size
6.7.2 RV fractional area change
6.7.3 RV 2D longitudinal strain
6.7.4 Right atrial area
6.7.5 Tricuspid annulus dimension
6.7.6 Tricuspid annulus, M mode, tricuspid annular plane systolic excursion
6.7.7 TV, tissue Doppler, tissue velocity at systole (s′)
6.8.1 TV, color Doppler
6.8.2 TV, color Doppler, VC
6.8.3 TV, color Doppler, PISA radius
6.8.4 TV, CW, TR velocity
6.8.5 TR EROA and regurgitant volume from the PISA method
7. Apical 5-Chamber view (A5C)
7.1 General view, color Doppler
7.1.1 LVOT, PW, VTI
7.1.2 AV, CW, aortic stenosis
7.1.3 AV, CW, PHT
7.1.4 Isovolumic relaxation time
8. Apical 2-Chamber view (A2C)
8.1 General view, color Doppler
8.2.1 2D LV volumetric measurements (biplane method of discs)
8.2.2 LV global longitudinal strain, speckle tracking
8.2.3 LV wall motion, visual assessment
8.3 Biplane LA volume index
9. Apical 3-Chamber view (A3C)
9.1 General view
9.2 LV global longitudinal strain, speckle tracking
9.3 LV wall motion, visual assessment
10. Subcostal (SC) 4-Chamber view
10.1 General view
10.2 TV, color Doppler, TR
10.3 RV wall thickness
11. Inferior vena cava (IVC), SC long axis view
11.1 IVC, collapsibility (or respiratory variation)
11.2 Hepatic vein, color Doppler and PW
12. Suprasternal notch (SSN) view
12.1 General view, color Doppler and CW
13. Right parasternal view
13.1 General view, color Doppler and CW
14. Equipment settings
14.1 Term
14.2 Resolution
14.3 2D control
14.4 Spectral Doppler control
14.5 Color Doppler control
Conclusion
References
INTRODUCTION
Echocardiography plays a crucial role in clinical diagnosis. A growing body of research on echocardiography has led to an increasing number of diagnostic parameters. However, the time available for examinations in daily practice is limited, and no recommended operational manuals have been developed, resulting in substantial variation in the content of echocardiography reports across different medical institutions. This inconsistency has not only hindered communication between medical institutions but also been an obstacle to the development of a comprehensive national echocardiography database in Taiwan.
In 2023, the Imaging Committee of the Taiwan Society of Cardiology (TSOC) decided to develop the first set of recommendations for transthoracic echocardiography examinations to reduce inconsistencies in echocardiography reporting across medical institutions. Five online meetings were held before starting the draft. These recommendations were established with a focus on information about echocardiography scanning sequence, including scanning techniques, common errors, basic interpretation, and the recommended intensity. The strength of each recommendation (Table 1) is based on its importance according to previous guidelines, its diagnostic value, and consideration of the health insurance payment system in Taiwan. The evidence supporting our recommendations was primarily derived from non-randomized studies, retrospective cohort studies, registries, and expert consensus. These recommendations also include those regarding equipment settings, which have often been overlooked but are critical in ensuring the quality and accuracy of measurements. At the 2023 winter conference of the TSOC, a symposium led to modifications of the draft based on the expressed opinions. These recommendations aim to improve the overall standard of echocardiography in Taiwan and facilitate the establishment of a national echocardiography database.
Table 1. Class of recommendation.
| Class of recommendation | Definition |
| Class I (Benefit >>> Risk) | Evidence and/or general agreement that a given imaging technique is useful. |
| Class II | Conflicting evidence and/or different opinions about the usefulness of the given imaging technique. |
| Class IIa (Benefit >/>> Risk) | Weight of evidence/opinion is in favor of usefulness. |
| Class IIb (Benefit ≥ Risk) | Usefulness is less well established by evidence/opinion. |
| Class III (Benefit ≤ Risk) | Evidence and/or general agreement that a given imaging technique is not useful. |
SCANNING SEQUENCES
1. Parasternal Long Axis (PLAX) View
2. Right Ventricular Inflow View
3. Parasternal Short Axis (PSAX) View, Aortic Valve Level
4. PSAX, Mitral Valve Level
5. PSAX, Papillary Muscle (PM) and Apical Level
6. Apical 4-Chamber View (A4C)
7. Apical 5-Chamber View (A5C)
8. Apical 2-Chamber View (A2C)
9. Apical 3-Chamber View (A3C)
10. Subcostal (SC) 4-Chamber View
11. Inferior Vena Cava (IVC), SC Long Axis View
12. Suprasternal Notch (SSN) View
13. Right Parasternal View
14. Equipment Settings
Figure 1.
Demonstration of the adjustment of 2D controls on the panel of an echocardiography machine (left panel: GE, right panel: PHILIPS).
CONCLUSION
The Doctrine of the Mean teaches that the path of a superior person is similar to a journey that starts nearby and to climbing a mountain; it begins from the base.
The National Health Insurance system in Taiwan is widely known for its exceptional accessibility and ability to deliver high-quality care at a low cost. As the healthcare system has evolved over time, advanced diagnostic examinations such as echocardiography have become deeply embedded in the institutional framework. Within this framework, a delicate balance exists between productivity and quality of the examinations. Clinicians and sonographers, who are integral to the echocardiography process, struggle daily to cope with their substantial workloads.
Our recommendations provide a strategic guide for the echocardiography process. By emphasizing the need for meticulous attention to detail and adherence to standardized protocols, we hope to improve the efficiency of echocardiography examinations and ensure their accuracy and informativeness.
This operational manual represents the first set of recommendations for transthoracic echocardiography examinations in Taiwan. It signifies a pivotal transformation in echocardiographic practices, and is expected to foster the pursuit of excellence within the healthcare framework in Taiwan. Furthermore, it anticipates the establishment of an extensive national echocardiography database, which could become a significant milestone in the field of cardiovascular medicine in Taiwan.
DECLARATION OF CONFLICTS OF INTEREST
All authors declare no conflict of interest.
SUPPLEMENTARY MATERIALS
Download:
[Supp. 1-3] https://www.tsoc.org.tw/upload/files/A0008_Supp_1-3.pdf
[Supp. 4-14] https://www.tsoc.org.tw/upload/files/A0008_Supp_4-14.pdf
Acknowledgments
This manuscript was edited by ATS Medical Editing.
REFERENCES
- 1.Lang RM, Badano LP, Mor-Avi V, et al. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015;28:1–39 e14. doi: 10.1016/j.echo.2014.10.003. [DOI] [PubMed] [Google Scholar]
- 2.Lee L, Cotella JI, Miyoshi T, et al. Normal values of left ventricular mass by two-dimensional and three-dimensional echocardiography: results from the World Alliance Societies of Echocardiography Normal Values Study. J Am Soc Echocardiogr. 2023;36:533–542 e1. doi: 10.1016/j.echo.2022.12.016. [DOI] [PubMed] [Google Scholar]
- 3.Canepa M, Pozios I, Vianello PF, et al. Distinguishing ventricular septal bulge versus hypertrophic cardiomyopathy in the elderly. Heart. 2016;102:1087–1094. doi: 10.1136/heartjnl-2015-308764. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Chetrit M, Roujol S, Picard MH, et al. Optimal technique for measurement of linear left ventricular dimensions. J Am Soc Echocardiogr. 2019;32:476–483 e1. doi: 10.1016/j.echo.2018.12.001. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Guzzetti E, Tastet L, Annabi MS, et al. Effect of regional upper septal hypertrophy on echocardiographic assessment of left ventricular mass and remodeling in aortic stenosis. J Am Soc Echocardiogr. 2021;34:62–71. doi: 10.1016/j.echo.2020.08.022. [DOI] [PubMed] [Google Scholar]
- 6.Otto CM, Nishimura RA, Bonow RO, et al. 2020 ACC/AHA guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Joint Committee on clinical practice guidelines. Circulation. 2021;143:e72–e227. doi: 10.1161/CIR.0000000000000923. [DOI] [PubMed] [Google Scholar]
- 7.Baumgartner H, Hung J, Bermejo J, et al. Recommendations on the echocardiographic assessment of aortic valve stenosis: a focused update from the European Association of Cardiovascular Imaging and the American Society of Echocardiography. J Am Soc Echocardiogr. 2017;30:372–392. doi: 10.1016/j.echo.2017.02.009. [DOI] [PubMed] [Google Scholar]
- 8.Pandian NG, Kim JK, Arias-Godinez JA, et al. Recommendations for the use of echocardiography in the evaluation of rheumatic heart disease: a report from the American Society of Echocardiography. J Am Soc Echocardiogr. 2023;36:3–28. doi: 10.1016/j.echo.2022.10.009. [DOI] [PubMed] [Google Scholar]
- 9.Toh H, Mori S, Izawa Y, et al. Varied extent of mitral annular disjunction among cases with different phenotypes of mitral valve prolapse. JACC Case Rep. 2021;3:1251–1257. doi: 10.1016/j.jaccas.2021.06.038. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Tani T, Konda T, Kitai T, et al. Mitral annular disjunction-a new disease spectrum. Cardiol Clin. 2021;39:289–294. doi: 10.1016/j.ccl.2021.01.011. [DOI] [PubMed] [Google Scholar]
- 11.Mitchell C, Rahko PS, Blauwet LA, et al. Guidelines for performing a comprehensive transthoracic echocardiographic examination in adults: recommendations from the American Society of Echocardiography. J Am Soc Echocardiogr. 2019;32:1–64. doi: 10.1016/j.echo.2018.06.004. [DOI] [PubMed] [Google Scholar]
- 12.Addetia K, Yamat M, Mediratta A, et al. Comprehensive two-dimensional interrogation of the tricuspid valve using knowledge derived from three-dimensional echocardiography. J Am Soc Echocardiogr. 2016;29:74–82. doi: 10.1016/j.echo.2015.08.017. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Kou S, Caballero L, Dulgheru R, et al. Echocardiographic reference ranges for normal cardiac chamber size: results from the NORRE study. Eur Heart J Cardiovasc Imaging. 2014;15:680–690. doi: 10.1093/ehjci/jet284. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Rudski LG, Lai WW, Afilalo J, et al. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr. 2010;23:685–713; quiz 86-88. doi: 10.1016/j.echo.2010.05.010. [DOI] [PubMed] [Google Scholar]
- 15.D'Alto M, Di Maio M, Romeo E, et al. Echocardiographic probability of pulmonary hypertension: a validation study. Eur Respir J. 2022;60 doi: 10.1183/13993003.02548-2021. [DOI] [PubMed] [Google Scholar]
- 16.Terzikhan N, Bos D, Lahousse L, et al. Pulmonary artery to aorta ratio and risk of all-cause mortality in the general population: the Rotterdam Study. Eur Respir J. 2017;49:1602168. doi: 10.1183/13993003.02168-2016. [DOI] [PubMed] [Google Scholar]
- 17.Humbert M, Kovacs G, Hoeper MM, et al. 2022 ESC/ERS guidelines for the diagnosis and treatment of pulmonary hypertension. Eur Heart J. 2022;43:3618–3731. doi: 10.1093/eurheartj/ehac237. [DOI] [PubMed] [Google Scholar]
- 18.Lancellotti P, Tribouilloy C, Hagendorff A, et al. Recommendations for the echocardiographic assessment of native valvular regurgitation: an executive summary from the European Association of Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging. 2013;14:611–644. doi: 10.1093/ehjci/jet105. [DOI] [PubMed] [Google Scholar]
- 19.Zaidi A, Knight DS, Augustine DX, et al. Echocardiographic assessment of the right heart in adults: a practical guideline from the British Society of Echocardiography. Echo Res Pract. 2020;7:G19–G41. doi: 10.1530/ERP-19-0051. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Zaidi A, Oxborough D, Augustine DX, et al. Echocardiographic assessment of the tricuspid and pulmonary valves: a practical guideline from the British Society of Echocardiography. Echo Res Pract. 2020;7:G95–G122. doi: 10.1530/ERP-20-0033. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Abbas AE, Fortuin FD, Schiller NB, et al. Echocardiographic determination of mean pulmonary artery pressure. Am J Cardiol. 2003;92:1373–1376. doi: 10.1016/j.amjcard.2003.08.037. [DOI] [PubMed] [Google Scholar]
- 22.Augustine DX, Coates-Bradshaw LD, Willis J, et al. Echocardiographic assessment of pulmonary hypertension: a guideline protocol from the British Society of Echocardiography. Echo Res Pract. 2018;5:G11–G24. doi: 10.1530/ERP-17-0071. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Huang WC, Hsieh SC, Wu YW, et al. 2023 Taiwan Society of Cardiology (TSOC) and Taiwan College of Rheumatology (TCR) Joint Consensus on connective tissue disease-associated pulmonary arterial hypertension. Acta Cardiol Sin. 2023;39:213–241. doi: 10.6515/ACS.202303_39(2).20230117A. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Mallery JA, Gardin JM, King SW, et al. Effects of heart rate and pulmonary artery pressure on Doppler pulmonary artery acceleration time in experimental acute pulmonary hypertension. Chest. 1991;100:470–473. doi: 10.1378/chest.100.2.470. [DOI] [PubMed] [Google Scholar]
- 25.Milan A, Magnino C, Veglio F. Echocardiographic indexes for the non-invasive evaluation of pulmonary hemodynamics. J Am Soc Echocardiogr. 2010;23:225–239; quiz 332-334. doi: 10.1016/j.echo.2010.01.003. [DOI] [PubMed] [Google Scholar]
- 26.Aduen JF, Castello R, Lozano MM, et al. An alternative echocardiographic method to estimate mean pulmonary artery pressure: diagnostic and clinical implications. J Am Soc Echocardiogr. 2009;22:814–819. doi: 10.1016/j.echo.2009.04.007. [DOI] [PubMed] [Google Scholar]
- 27.Rajagopalan N, Simon MA, Suffoletto MS, et al. Noninvasive estimation of pulmonary vascular resistance in pulmonary hypertension. Echocardiography. 2009;26:489–494. doi: 10.1111/j.1540-8175.2008.00837.x. [DOI] [PubMed] [Google Scholar]
- 28.Baumgartner H, De Backer J. The ESC clinical practice guidelines for the management of adult congenital heart disease 2020. Eur Heart J. 2020;41:4153–4154. doi: 10.1093/eurheartj/ehaa701. [DOI] [PubMed] [Google Scholar]
- 29.Nagueh SF, Smiseth OA, Appleton CP, et al. Recommendations for the evaluation of left ventricular diastolic function by echocardiography: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2016;29:277–314. doi: 10.1016/j.echo.2016.01.011. [DOI] [PubMed] [Google Scholar]
- 30.Robinson S, Ring L, Augustine DX, et al. The assessment of mitral valve disease: a guideline from the British Society of Echocardiography. Echo Res Pract. 2021;8:G87–G136. doi: 10.1530/ERP-20-0034. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.Chang SN, Sung KT, Huang WH, et al. Sex, racial differences and healthy aging in normative reference ranges on diastolic function in Ethnic Asians: 2016 ASE guideline revisited. J Formos Med Assoc. 2021;120:2160–2175. doi: 10.1016/j.jfma.2020.12.024. [DOI] [PubMed] [Google Scholar]
- 32.Oxborough D ZA, Sharma S, Somauroo J. The echocardiographic assessment of the right ventricle with particular reference to arrhythmogenic right ventricular cardiomyopathy: a protocol of the British Society of Echocardiography. Journal of the British Society of Echocardiography. 2013 [Google Scholar]
- 33.Hahn RT, Lerakis S, Delgado V, et al. Multimodality imaging of right heart function: JACC scientific statement. J Am Coll Cardiol. 2023;81:1954–1973. doi: 10.1016/j.jacc.2023.03.392. [DOI] [PubMed] [Google Scholar]
- 34.Dreyfus J, Durand-Viel G, Raffoul R, et al. Comparison of 2-dimensional, 3-dimensional, and surgical measurements of the tricuspid annulus size. Circ Cardiovasc Imaging. 2015;8:e003241. doi: 10.1161/CIRCIMAGING.114.003241. [DOI] [PubMed] [Google Scholar]
- 35.Genovese D, Mor-Avi V, Palermo C, et al. Comparison between four-chamber and right ventricular–focused views for the quantitative evaluation of right ventricular size and function. J Am Soc Echocardiogr. 2019;32:484–494. doi: 10.1016/j.echo.2018.11.014. [DOI] [PubMed] [Google Scholar]
- 36.Vahanian A, Beyersdorf F, Praz F, et al. 2021 ESC/EACTS guidelines for the management of valvular heart disease. Eur J Cardiothorac Surg. 2021;60:727–800. doi: 10.1093/ejcts/ezab389. [DOI] [PubMed] [Google Scholar]
- 37.Hahn RT, Thomas JD, Khalique OK, et al. Imaging assessment of tricuspid regurgitation severity. JACC Cardiovasc Imaging. 2019;12:469–490. doi: 10.1016/j.jcmg.2018.07.033. [DOI] [PubMed] [Google Scholar]
- 38.Hahn RT, Badano LP, Bartko PE, et al. Tricuspid regurgitation: recent advances in understanding pathophysiology, severity grading and outcome. Eur Heart J Cardiovasc Imaging. 2022;23:913–929. doi: 10.1093/ehjci/jeac009. [DOI] [PubMed] [Google Scholar]
- 39.Song JM, Jang MK, Choi YS, et al. The vena contracta in functional tricuspid regurgitation: a real-time three-dimensional color Doppler echocardiography study. J Am Soc Echocardiogr. 2011;24:663–670. doi: 10.1016/j.echo.2011.01.005. [DOI] [PubMed] [Google Scholar]
- 40.Dahou A, Ong G, Hamid N, et al. Quantifying tricuspid regurgitation severity: a comparison of proximal isovelocity surface area and novel quantitative Doppler methods. JACC Cardiovasc Imaging. 2019;12:560–562. doi: 10.1016/j.jcmg.2018.11.015. [DOI] [PubMed] [Google Scholar]
- 41.Kebed KY, Addetia K, Henry M, et al. Refining severe tricuspid regurgitation definition by echocardiography with a new outcomes-based "massive" grade. J Am Soc Echocardiogr. 2020;33:1087–1094. doi: 10.1016/j.echo.2020.05.007. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 42.Zoghbi WA, Adams D, Bonow RO, et al. Recommendations for noninvasive evaluation of native valvular regurgitation: a report from the American Society of Echocardiography developed in collaboration with the Society for Cardiovascular Magnetic Resonance. J Am Soc Echocardiogr. 2017;30:303–371. doi: 10.1016/j.echo.2017.01.007. [DOI] [PubMed] [Google Scholar]
- 43.de Marchi SF, Windecker S, Aeschbacher BC, Seiler C. Influence of left ventricular relaxation on the pressure half time of aortic regurgitation. Heart. 1999;82:607–613. doi: 10.1136/hrt.82.5.607. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 44.Griffin BP, Flachskampf FA, Reimold SC, et al. Relationship of aortic regurgitant velocity slope and pressure half-time to severity of aortic regurgitation under changing haemodynamic conditions. Eur Heart J. 1994;15:681–685. doi: 10.1093/oxfordjournals.eurheartj.a060567. [DOI] [PubMed] [Google Scholar]
- 45.Griffin BP, Flachskampf FA, Siu S, et al. The effects of regurgitant orifice size, chamber compliance, and systemic vascular resistance on aortic regurgitant velocity slope and pressure half-time. Am Heart J. 1991;122:1049–1056. doi: 10.1016/0002-8703(91)90471-s. [DOI] [PubMed] [Google Scholar]
- 46.Ma Q, Shi X, Ji J, et al. The diagnostic accuracy of inferior vena cava respiratory variation in predicting volume responsiveness in patients under different breathing status following abdominal surgery. BMC Anesthesiol. 2022;22:63. doi: 10.1186/s12871-022-01598-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 47.Piskin O, Oz II. Accuracy of pleth variability index compared with inferior vena cava diameter to predict fluid responsiveness in mechanically ventilated patients. Medicine (Baltimore) 2017;96:e8889. doi: 10.1097/MD.0000000000008889. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 48.Long E, Oakley E, Duke T, Babl FE Paediatric Research in Emergency Departments International C. Does respiratory variation in inferior vena cava diameter predict fluid responsiveness: a systematic review and meta-analysis. Shock. 2017;47:550–559. doi: 10.1097/SHK.0000000000000801. [DOI] [PubMed] [Google Scholar]
- 49.de Oliveira OH, Freitas FG, Ladeira RT, et al. Comparison between respiratory changes in the inferior vena cava diameter and pulse pressure variation to predict fluid responsiveness in postoperative patients. J Crit Care. 2016;34:46–49. doi: 10.1016/j.jcrc.2016.03.017. [DOI] [PubMed] [Google Scholar]
- 50.Airapetian N, Maizel J, Alyamani O, et al. Does inferior vena cava respiratory variability predict fluid responsiveness in spontaneously breathing patients? Crit Care. 2015;19:400. doi: 10.1186/s13054-015-1100-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 51.Klein AL, Hatle LK, Burstow DJ, et al. Comprehensive Doppler assessment of right ventricular diastolic function in cardiac amyloidosis. J Am Coll Cardiol. 1990;15:99, 108. doi: 10.1016/0735-1097(90)90183-p. [DOI] [PubMed] [Google Scholar]
- 52.Welch TD, Ling LH, Espinosa RE, et al. Echocardiographic diagnosis of constrictive pericarditis: Mayo Clinic criteria. Circ Cardiovasc Imaging. 2014;7:526–534. doi: 10.1161/CIRCIMAGING.113.001613. [DOI] [PubMed] [Google Scholar]
- 53.Solomon SD, Wu JC, Gillam LD, Bulwet BE ScienceDirect. Essential echocardiography: a companion to Braunwald’s Heart disease. Philadelphia, Pennsylvania: Elsevier; 2019. [Google Scholar]