Test 5 - Ischemic Heart Disease and Contrast

What is one of the most common indications for echocardiography?

Assessing left ventricular function in a patient with ischemic heart disease

What is ischemia?

Reduced blood flow, and thus oxygen, within an area

How is ischemic heart disease visually assessed?

From right and left ventricular wall thickening and wall motion by echo

Can you see the coronary arteries well by echo?

No

What is very important on patients in the ER with chest pain for diagnosis of coronary artery disease?

The presence or absence of wall motion abnormalities

Indications of ischemic heart disease are used….

to evaluate for other complications associated with CAD and with acute myocardial infarction

Diagnostic tests:

• Electrocardiogram

• Exercise stress test

• Nuclear stress test

• Cardiac MRI

• Cardiac catheteriztion

• Echocardiogram

• Exercise stress echocardiogram

What is the gold standard out of the diagnostic tests?

Cardiac catheterization

Myocardial ischemia:

• Lack of oxygen to the heart muscle caused by blockages in the coronary arteries

• Greater than 70% narrowing

• Increased demand for oxygen by exertion, emotional stress — the coronary arteries cannot supply enough blood to the muscle

• Causes a change in wall motion in the affected area — hypokinesis

Does myocardial ischemia cause permanent damage?

No — wall motion will return to normal when demand for oxygen returns to normal

Angina:

• Chest discomfort due to ischemia (lack of oxygen) to the heart muscle

• Chest tightness or pressure, heaviness

• Can radiate into the left arm, jaw, and back

• Women and men’s symptoms can differ

What can women experience with angina? (4)

1. Nausea

2. Vomiting

3. Shortness of breath

4. General uneasiness

Sequence of events in myocardial ischemia: (4)

1. Describes what occurs within the heart when ischemia begins

2. Perfusion abnormalities are the first abnormalities that can be observed (observed by nuclear imaging)

3. Wall motion abnormalities are observed a little further into the cascade (observed by echocardiography)

4. ECG changes and finally angina occur later in the cascade

Label the sequence of events in myocardial ischemia: (8)

1. Duration of ischemia

2. Perfusion abnormalities

3. Diastolic dysfunction

4. Systolic dysfunction

5. ∆ ECG

6. Angina

7. Nuclear imaging/MRI

8. Echocardiography/MRI

Myocardial infarction: (2)

1. When a blockage occurs in one the coronary arteries and the blood supply to heart muscle is completely occluded causing irreversible damage

2. Same as “heart attack”

Symptoms and signs of myocardial infarction:

• Angina

• Chest heaviness, aching, pinching, squeezing, tightness or pressure

• Nausea, vomiting

• Numbness

• Dizziness/fainting

• Diaphoresis

• Palpitations

• Radiating arm, back, shoulder, jaw pain

• Dyspnea

• Heart failure (SOB, edema, cough)

• ECG changes

Causes of myocardial infarction: (3)

1. Rupture of atherosclerotic plaque

2. Spontaneous coronary artery dissection SCAD - more common in women

3. Coronary spasm

What is the leading cause of death in men and women?

Heart attack (myocardial infarction)

What do electrocardiograms show with MI? (2)

1. ST elevation with an acute MI

2. Q waves with an old MI

Acute infarction: (3)

1. Normal wall thickness

2. Reduced or absent endocardial motion and wall thickening

3. ST elevation on the electrocardiogram

Old myocardial infarction: (3)

1. Thinning and increased echogenicity due to scarring and fibrosis

2. Abnormal motion and absent wall thickening

3. Q waves on the electrocardiogram

Progression of MI: (2)

1. First, the heart muscle affected becomes hypokinetic or akinetic but the thickness remains normal

2. The heart muscle will become thin and scarred (fibrotic) over time and appear brighter on the echocardiogram

What does normal wall motion imply?

That there is no ischemia at the time images were acquired

Dressler’s syndrome: (3)

1. A form of pericarditis

2. A small pericardial effusion after a myocardial infarction

3. Usually 1 - 12 weeks post MI

What and why is the test of choice on a post MI patient with a murmur? (3)

Echo

1. Mitral regurgitation

2. Ventricular septal defect

3. Ventricular rupture with pseudoaneurysm

Ischemic mitral regurgitiation:

• Functional mitral regurgitation — the leaflets are normal — includes mitral regurgitation caused by ischemia and dilated cardiomypathy

• Caused by papillary muscle displacement and dilation of the annulus

• Most common complication of a MI

• Severe mitral regurgitation can occur with papillary muscle rupture

• Tenting of the mitral valve leaflets (normal closure is at the annulus)

What is ischemic mitral regurgitation caused by?

Papillary muscle displacement and dilation of the annulus

What is the most common complication of a myocardial infarction?

Ischemic mitral regurgitation

What can occur with severe papillary muscle rupture?

Severe mitral regurgitation

Ventricular septal defect: (4)

1. Rupture of part of the IVS

2. Evaluate using color Doppler looking for high velocity flow on the right side

3. Left to right flow

4. Obtain peak velocity using continuous-wave Doppler in multiple windows

Pseudoaneurysm:

• AKA contained rupture

• An aneurysm caused by a rupture

• Narrow neck (less than 0.5 cm) and lined with pericardium, not lined with myocardium

• May have thrombus - perform off-axis, magnified imaging (improved near-field resolution)

• Surgical repair recommended

What is a pseduoaneurysm lined with?

Pericardium

True aneurysm:

• Diastolic contour abnormality - outward bulging of the wall in a severely infarcted area

• Systolic dyskinesis - wall moves out while other walls contract in

• Most common locations are apical or inferobasal

• Lined by thin myocardium

• Smooth transition from normal myocardium to thinned area

• Wide neck (greater than 0.5 cm)

• May have thrombus - perform off-axis, magnified imaging

What is a true aneurysm lined with?

Thin myocardium

Pericardial effusion:

• Can occur after an MI - Dressler’s syndrome

• Nonspecific response

• Usually benign but could indicate pericarditis, possible dissection or LV rupture

• Sometimes can develop tamponade physiology

Right ventricular infarcation:

• Most often associated with an inferior MI

• Right ventricular hypokinesis

• Variable degrees of dilation

Left ventricular thrombi

Clotting information in areas of low flow

Low-flow examples that increase the likelihood of LV thrombi: (3)

1. Severely reduced akinetic area

2. An aneurysm

3. The appearance of spontaneous echo contrast (smoke)

LV thrombi; must perform careful imaging of the LV and apex…

• Can be small or large

• Can be confused with other structures - trabeculation, tendon, chord

• Use high-resolution settings for better near-field resolution

• Use off-axis imaging planes (short-axis apical views)

• Use multiple imaging planes

Electrocardiogram findings: (3)

1. ST depression - ischemia

2. ST elevation - acute MI

3. Q waves - old MI

Label the EKG (Ischemia ST depression): (9)

1. aVR (augmented vector right)

2. aVL (augmented vector left)

3. aVF (augmented vector foot)

4. V1

5. V2

6. V3

7. V4

8. V5

9. V6

What do the colors mean within the diagram?

• Blue- Lateral

• Yellow- Inferior

• Green- Septal

• Red- Anterior

What do the wall segments on echocardiography correlate with?

They correlate closely with the coronary artery territories

Label the coronary arteries: (11)

1. Left main

2. Left circumflex

3. Intermediate

4. Obtuse marginal

5. Left anterior descending

6. Posterior lateral

7. Posterior descending

8. Acute marginal

9. Right ventricular

10. Right coronary artery

11. Sinoatrial node

Label the coronary artery wall segments: (11)

1. LAD

2. LCx

3. LAD

4. RCA

5. LCx

6. LAD

7. LCx

8. RCA

9. LAD

10. LCx

11. LAD

Label the Apical 4-Chamber diagram: (6)

1. Apical septal (LAD)

2. Mid inferoseptal (RCA)

3. Basal inferoseptal (RCA)

4. Apical lateral (LCx)

5. Mid anterolateral (LCx)

6. Basal anterolateral (LCx)

Label the Apical 2-Chamber diagram: (6)

1. Apical inferior (RCA)

2. Mid inferior (RCA)

3. Basal inferior (RCA)

4. Apical anterior (LAD)

5. Mid anterior (LAD)

6. Basal anterior (LAD)

Label the Apical 3-Chamber diagram: (6)

1. Apical lateral (LCx)

2. Mid inferolateral (LCx)

3. Basal inferolateral (LCx)

4. Apical anterior (LAD)

5. Mid anteroseptal (LAD)

6. Basal anteroseptal (LAD)

Label the SAX MV level diagram: (6)

1. Anterior (LAD)

2. Anterolateral (LCx)

3. Inferolateral (LCx)

4. Inferior (RCA)

5. Inferoseptal (RCA)

6. Anteroseptal (LAD)

Label the SAX PAP level diagram: (6)

1. Anterior (LAD)

2. Anterolateral (LCx)

3. Inferolateral (LCx)

4. Inferior (RCA)

5. Inferoseptal (RCA)

6. Anteroseptal (LAD)

PAP

Label the SAX apical level diagram: (4)

1. Anterior (LAD)

2. Lateral (LCx)

3. Inferior (RCA)

4. Septal (LAD)

What will an occlusion of the left anterior descending artery result in?

A myocardial infarction and akinesis of the:

• Anterior septum

• Anterior wall

• Apex

What will an occlusion of the right coronary artery result in?

A myocardial infarction and akinesis of:

• Inferior septum - base and mid

• Inferior wall

What will an occlusion of the circumflex artery result in?

A myocardial infarction and akinesis of:

• Anterolateral wall

• Inferolateral wall

Parasternal long-axis view evaluates wall motion of: (3)

1. Basal and mid segments of the anterior septum

2. Inferolateral wall (posterior wall)

3. Right ventricular free wall

Parasternal short-axis view evaluates wall motion of: (6)

1. Anterior septum

2. Anterior wall

3. Anterolateral wall

4. Inferolateral wall

5. Inferior wall

6. Inferoseptal wall

Apical four-chamber view evaluates wall motion of: (2)

1. Anterolateral wall

2. Inferior septum

Apical five-chamber view evaluates wall motion of: (2)

1. Anterolateral wall

2. Anterior septum

Apical two-chamber view evaluates wall motion of: (2)

1. Anterior wall

2. Inferior wall

Apical long-axis view evaluates wall motion of: (3)

1. Basal and mid segments of the anterior septum

2. Inferolateral wall (posterior wall)

3. Right ventricular free wall

Two-dimensional imaging tips: (5)

1. Avoid foreshortening in the apical views

   • Endocardial definition may be difficult due to attenuation from lung

   • Change patient position

   • Respiratory maneuvers

2. Obtain extra views and different depths

3. Perform off-axis views of the apex when wall motion abnormalities are present

4. Magnify on the apex using high resolution to evaluate for thrombus

5. Use contrast:

   • Aid in endocardial defitinion

   • Presence of a thrombus especially when wall motion abnormalities are present

Qualitative evaluation of global and regional function of CAD: (3)

1. Visually assess global and regional wall motion and systolic function

2. Estimate (eyeball) the ejection fraction

3. Use all windows and many tomographic views

Semi-quantitive evaluation - Wall Motion Score Index: (4; numbers correlate with scores)

1. Normal - endocardial inward motion and wall thickening in systole

2. Hypokinetic - reduced endocardial motion and wall thickening in systole

3. Akinetic - absence of inward endocardial motion or wall thickening in systole

4. Dyskinetic - outward motion or “bulging” of the segment in systole, usually associated with thin, scarred myocardium

Other information about Wall Motion Score Index:

• Can be derived by dividing the sum of scores for each segment by the number of segments evaluated

• Must be able to visualize the endocardium

Quantitative evaluation of global and regional function in CAD: (4)

1. Bi-plane tracing of the endocardium at end-systole and end-diastole in the apical views

2. Must have optimal endocardial definition

3. Method of Discs - Simpson’s

4. More accurate and preferred method as long as there is good imaging of the endocardium

Can echo alone assess for coronary artery disease?

No

Stress echocardiography:

• Uses echocardiography (wall motion), rather than the electrocardiogram, to diagnose ischemia

• Either exercise or dobutamine (pharmacologic) is used to attempt to raise the heart rate to produce ischemia

• Observe LV wall motion before and after exercise or during pharmacologic exercise

• Segmental wall motion abnormalities will develop with ischemia - reduced oxygen to the area

• Need to evaluate wall motion during ischemia

Echocardiography in the Emergency Department:

• Echocardiography is used very often to evaluate patients suspected of having an MI or patients with chest pain

• Very easy to assess global and regional wall motion of the left and right ventricles

• Echocardiography is useful in determining the location and severity of the wall motion abnormality

• Echocardiography is also useful in re-evaluating global and regional function after a reperfusion procedure - CABG, Stent, balloon angioplasty

What do acute infarcts and ischemia usually have?

A wall motion abnormality with normal wall thickness

What do old infarcts have?

A wall motion abnormality with a thinning of the wall

End-stage ischemic cardiac disease:

• Global left ventricular dysfunction develops due to multiple infarcts with some regional variation in wall motion

• The presence of wall motion abnormalities will help distinguish CAD from a dilated cardiomyopathy

• Once the end stage is reached, becomes difficult to differentiate from dilated cardiomyopathy

• Dilated cardiomyopathy usually affects both ventricles

• Usually preserved function at the base - basal inferolateral wall and lateral wall move best

What does dilated cardiomyopathy usually affect?

Both ventricles

Ischemic disease (end-stage): (2)

1. Definite areas of akinesis or wall thinning

2. Normal right ventricular size and function, unless there was an infarct

Purpose of contrast:

• For use in patients with suboptimal echocardiograms

• To opacify the LV to improve the delineation of the LV endocardium

• To improve evaluation of LV systolic function

• To enhance visualization or delineation of LV thrombus

• To enhance tricuspid regurgitation Doppler jet for estimating PAP

• Unlike agitated saline, the microspheres pass the capillary beds and opacify the LV

• Helps answer questions; improves suboptimal images

Echo facts:

• Inexpensive

• Portable

• Not selective

• Ordered most often for LV function evaluation

• 25.7 million echocardiograms performed in 2006

• Estimate that 20% of echocardiograms are non-diagnostic

• Requires adequate delineation of endocardial borders

• Regional wall motion abnormalities are associated with abnormalities of thickening and endocardial motion

• Decreases the time needed to image technically difficult studies

• Reproducible and accurate: Measurement of LV function provides prognostic and diagnostic information in patients with cardiovascular disease, which is why the ASE strongly supports the use of contrast

• “See Better, Judge Better, Treat Better”

When to use contrast:

• It is the responsibility of the sonographer to determine the need for contrast by determining the quality of the echocardiogram

• Use contrast when unable to visualize two or more wall segments in the AP4C and AP2C views

• Want to be able to see thickening of the myocardium, not movement

• When less than 80% of endocardial border definition is visualized, contrast is strongly recommended

• Use when wall motion abnormalities are present to rule out thrombus

• Apical aneurysm, HCM

Possible complications after a myocardial infarction: (5)

1. Pericarditis

2. Dressler’s Syndrome

3. Pericardial effusion

4. Thinning and scarring of myocardium

5. VSD

Basic reasons to use contrast: (3)

1. To enhance suboptimal images

2. To enhance tricuspid valve regurgitation

3. To delineate a mass or thrombus

An ejection fraction over 75% is called?

Hyperkinesis