Regional Systolic Function

From Wikiecho
Jump to: navigation, search

Evaluation of regional systolic function is particularly useful in order to detect coronary artery diseases at rest or during stress (exercise or pharmacological) although other cardiac diseases might be associated with abnormal regional systolic function. The most common assessment of regional systolic function is usually based on a qualitative or semi-quantitative visual evaluation of the myocardial thickening. However, techniques based on Doppler (tissue Doppler imaging) or more recently based on the tracking of the speckles (speckle tracking imaging) allow a quantitative evaluation of regional systolic function.

Contents

Left ventricular segmentation

16 and 17 segment model

In order to assess regional systolic function, the left ventricle is artificially divided into different segments. The currently recommended segmentation is a 17-segment model as described in the figure. [1]
17-segment model
The left ventricle is divided into 6 walls: anterior, anteroseptal, inferoseptal, posterolateral and anterolateral. Each wall is divided into a basal, mid and apical segment and the apical cap represents the 17th segment. However, some echocardiographic softwares are still based on a 16-segment model without the apical cap.

Coronary flow distribution and left ventricular segmentation

Anatomic variability regarding coronary artery blood supply is important. However, based on the most common anatomy, current guidelines assigned each segment to one coronary artery as follows[2]:

  • Segments 1, 2, 7, 8, 13, 14, and 17 to the left anterior descending coronary artery;
  • Segments 3, 4, 9, 10, and 15 are assigned to the right coronary artery;
  • Segments 5, 6, 11, 12, and 16 generally are assigned to the left circumflex artery.
However, the following variations are common:
  • The segment 9 (mid inferoseptal): right coronary artery or left anterior descending artery;
  • The segments 5 (basal inferolateral) and 11 (mid inferolateral): right coronary artery or circumflex;
  • The segments 6 (basal anterolateral), 12 (mid anterolateral),and 16 (apical anterolateral) : left anterior descending artery or circumflex.

Right ventricular segmentation

The right ventricle is divided into 3 walls: anterior, lateral (also called right ventricular free wall) and posterior wall and share the septal wall with the left ventricle. Each wall is divided into a basal, mid and apical segment. [3] The right coronary artery is the primary coronary supply to the right ventricle via acute marginal branches.

Visual Wall motion analysis

Visualization of left ventricular walls

The classical echocardiographic views allow assessment of the 6 walls with the 17 left ventricular segments as follows:

  • The parasternal long axis view and 3-apical chamber views assessing the anteroseptal and posterolateral walls;
    Left ventricular segments: parasternal long axis view
  • The short axis views assessing the 6 walls at the basal, mid and apical levels;
    Left ventricular segments: parasternal short axis view at the basal level
    Left ventricular segments: parasternal short axis view at the mid-ventricular level
    Left ventricular segments: parasternal short axis view at the apical level
  • The apical 4-chamber view assessing the inferoseptal and anterolateral walls;
    Left ventricular segments: apical 4-chamber view
  • The apical 2-chamber view assessing the inferior and anterior walls.
    Left ventricular segments: apical 2-chamber view

Endocardial motion and myocardial thickening

Echocardiography can overestimate the amount of ischemic or infarcted myocardium, as wall motion of adjacent regions may be affected by tethering, disturbance of regional loading conditions and stunning. Therefore, wall thickening appears more precise than motion in order to evaluate the extent of regional systolic abnormalities. Regional wall motion abnormalities may occur in the absence of coronary artery disease.

Definitions

  • Hyperkinesis= increase in thickening. This phenomenon may be observed for example in the remote segments of a myocardial infarction.
  • Normokinesis= normal thickening of the myocardial segment
  • Hypokinesis= decrease in thickening
  • Akinesis= absence of thickening
  • Dyskinesis= paradoxical systolic motion
  • Aneurysm= diastolic deformation

Wall motion score index

Wall motion score index is a semi-quantitative analysis of regional systolic function. Each segment is analyzed individually and scored on the basis of its motion and systolic thickening. Ideally, the function of each segment should be confirmed in multiple views. This score is a 5-level score defines as follows:

  • score 1= normokinesis or hyperkinesis
  • score 2= hypokinesis
  • score 3= akinesis
  • score 4= dyskinesis
  • score 5= aneurysm
Wall motion score index is derived as a sum of all scores divided by the number of segments visualized.

Regional systolic function abnormalities in coronary artery diseases

Although regional wall motion abnormalities at rest may not be seen until the luminal diameter stenosis exceeds 85%, analysis of regional systolic function during stress (pharmacological or exercise) is useful to unmask significant coronary lesion. [4] (See Basic Principles of stress echocardiography)

Opacification of the left ventricle

Analysis of regional systolic function requires good endocardial border definition. In patients with suboptimal acoustic windows, contrast administration improves image quality through improvement of endocardial border definition and enhances detection of regional systolic function abnormalities. [5] (See Contrast Agents)

Quantitative techniques: Tissue Doppler and speckle tracking imaging

Although assessment of regional systolic function is commonly based on visual analysis of myocardial thickening, more recent techniques allow quantitative evaluation of regional systolic function. Those techniques are based on Doppler (Technique of Tissue Doppler Imaging) or on the tracking of the speckles (Technique of Speckle Tracking imaging). [6]

References

  1. Manuel D Cerqueira, Neil J Weissman, Vasken Dilsizian, Alice K Jacobs, Sanjiv Kaul, Warren K Laskey, Dudley J Pennell, John A Rumberger, Thomas Ryan, Mario S Verani, American Heart Association Writing Group on Myocardial Segmentation and Registration for Cardiac Imaging
    Standardized myocardial segmentation and nomenclature for tomographic imaging of the heart. A statement for healthcare professionals from the Cardiac Imaging Committee of the Council on Clinical Cardiology of the American Heart Association.
    Circulation: 2002, 105(4);539-42
    [PubMed:11815441] [WorldCat.org] (I p)

  2. Manuel D Cerqueira, Neil J Weissman, Vasken Dilsizian, Alice K Jacobs, Sanjiv Kaul, Warren K Laskey, Dudley J Pennell, John A Rumberger, Thomas Ryan, Mario S Verani, American Heart Association Writing Group on Myocardial Segmentation and Registration for Cardiac Imaging
    Standardized myocardial segmentation and nomenclature for tomographic imaging of the heart. A statement for healthcare professionals from the Cardiac Imaging Committee of the Council on Clinical Cardiology of the American Heart Association.
    Circulation: 2002, 105(4);539-42
    [PubMed:11815441] [WorldCat.org] (I p)

  3. Lawrence G Rudski, Wyman W Lai, Jonathan Afilalo, Lanqi Hua, Mark D Handschumacher, Krishnaswamy Chandrasekaran, Scott D Solomon, Eric K Louie, Nelson B Schiller
    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(7);685-713; quiz 786-8
    [PubMed:20620859] [WorldCat.org] [DOI] (I p)

  4. Rosa Sicari, Petros Nihoyannopoulos, Arturo Evangelista, Jaroslav Kasprzak, Patrizio Lancellotti, Don Poldermans, Jen-Uwe Voigt, Jose Luis Zamorano, European Association of Echocardiography
    Stress echocardiography expert consensus statement: European Association of Echocardiography (EAE) (a registered branch of the ESC).
    Eur J Echocardiogr: 2008, 9(4);415-37
    [PubMed:18579481] [WorldCat.org] [DOI] (I p)

  5. Roxy Senior, Harald Becher, Mark Monaghan, Luciano Agati, Jose Zamorano, Jean Louis Vanoverschelde, Petros Nihoyannopoulos
    Contrast echocardiography: evidence-based recommendations by European Association of Echocardiography.
    Eur J Echocardiogr: 2009, 10(2);194-212
    [PubMed:19270054] [WorldCat.org] [DOI] (I p)

  6. Victor Mor-Avi, Roberto M Lang, Luigi P Badano, Marek Belohlavek, Nuno Miguel Cardim, Genevieve Derumeaux, Maurizio Galderisi, Thomas Marwick, Sherif F Nagueh, Partho P Sengupta, Rosa Sicari, Otto A Smiseth, Beverly Smulevitz, Masaaki Takeuchi, James D Thomas, Mani Vannan, Jens-Uwe Voigt, Jose Luis Zamorano
    Current and evolving echocardiographic techniques for the quantitative evaluation of cardiac mechanics: ASE/EAE consensus statement on methodology and indications endorsed by the Japanese Society of Echocardiography.
    Eur J Echocardiogr: 2011, 12(3);167-205
    [PubMed:21385887] [WorldCat.org] [DOI] (I p)

Personal tools
Namespaces

Variants
Actions
Navigation
Toolbox