Echo Assessment and complications of CAD/MI Unit 3 Lesson 1

How common is CAD in adult cardiology in the U.S., and how many people per year die from its complications?

CAD is the most encountered problem in adult cardiology in the U.S., and about 700,000 people per year die from complications of CAD

List the 3 areas of CAD/MI knowledge that are helpful for diagnosis, management, and prognosis.

• Global and regional systolic function

• Diastolic function

• Complications

List the 5 main areas of echo assessment for CAD/MI.

• Systolic function

• 2D/M-mode features

• Doppler features

• Diastolic assessment

• Complications of CAD

List the 3 ways systolic function is assessed in CAD/MI.

• Global appearance

• Regional assessment

• WMSI

What are the normal LVEF ranges for females and males?

• Female: 54–74%

• Male: 52–72%

What does fractional shortening measure, and what is the normal range?

It measures the percent change in LV dimension with contraction.

25–45%.

What does regional systolic-function assessment evaluate?

The contractility of individual myocardial segments.

List the 5 ASE regional wall-motion grades.

1. Normal

2. Hypokinetic

3. Akinetic

4. Dyskinetic

5. Aneurysmal

Define ALL 5 ASE regional wall-motion grades.

1. Normal= Normal inward motion and endocardial thickening during systole & Endocardial thickening >40%

2. Hypokinetic= Reduced inward motion and endocardial thickening during systole & Endocardial thickening <30%

3. Akinetic = Absence of inward motion and endocardial thickening during systole & Endocardial thickening <10%

4. Dyskinetic= Paradoxical thinning/outward movement of the myocardial wall segment during systole, usually associated with thin wall segments and scarring.

5. Aneurysmal = Dilation and outward movement of the wall throughout the cardiac cycle, associated with thin wall segments and diastolic deformation.

What is WMSI used for?

To semi-quantitatively determine the extent of regional wall-motion abnormalities.

What is the WMSI equation?

WMSI = Sum of wall-motion scores ÷ Number of segments visualized

How does infarct size affect WMSI?

Larger infarcts have a higher WMSI.

What WMSI indicates normal regional function?

The slide lists WMSI <1.0 as normal regional function.

When should contrast echo be used to assess wall motion?

When you cannot visualize 2 or more wall segments.

What complication may contrast echo help delineate?

Aneurysms

List the 8 2D/M-mode findings that may be seen with CAD/MI.

1. Decreased LV or RV systolic function

2. Chamber enlargement

3. Segmental wall-motion abnormalities

4. Hyperkinesis of opposing walls

5. Thin echogenic akinetic region — scarring

6. Spontaneous echo contrast in infarcted region

7. Identification of complications

8. B bump on M-mode

List the 6 Doppler findings or assessments in CAD/MI.

1. Decreased SV, CO, and CI

2. Increased right-sided pressures

3. Severity of coexisting valve lesions

4. Grade of diastolic dysfunction

5. Decreased dP/dt

6. Increased LIMP and RIMP

What can IMP help predict?

Survival and symptoms.

What 3 time intervals are used to calculate IMP?

• IVCT

• IVRT

• Ejection time — ET

Where is ejection time measured when calculating IMP?

Through the LV or RV outflow tract.

What does LIMP assess versus RIMP?

• LIMP: Global LV performance

• RIMP: Global RV performance

List the 3 changes myocardial dysfunction causes that affect LIMP.

• Prolonged isovolumic intervals

• Shortened ejection time

• Increased LIMP

What does an increased LIMP indicate?

LV dysfunction

What is the normal LIMP value?

0.35 ± 0.05

List the 4 projected LIMP ranges for LV function.

• Normal LV function: <0.4

• Mild LV dysfunction: 0.4–0.5

• Moderate LV dysfunction: 0.6–0.9

• Severe LV dysfunction: >1.0

List the 3 changes associated with myocardial dysfunction and RIMP.

• Prolonged isovolumic intervals

• Shortened ejection time

• Increased RIMP

What does increased RIMP predict in pulmonary hypertension?

Decreased survival

What is the normal RIMP value?

0.28 ± 0.04.

What is the RIMP equation?

RIMP = (IVCT + IVRT) ÷ ET

How does myocardial ischemia affect diastolic function?

It alters diastolic function.

What is the most prominent initial diastolic abnormality in patients with ischemia?

Delayed relaxation.

List the 5 Doppler changes seen with delayed relaxation from ischemia.

1. Decreased E

2. Increased DT

3. Increased A

4. Decreased E/A ratio

5. Increased IVRT

Is there one specific mitral inflow pattern seen in all patients with MI?

No

List the 7 factors that can affect mitral inflow after an acute MI.

1. Relaxation abnormalities

2. Ventricular compliance

3. LA pressure

4. Loading conditions

5. Heart rate

6. Medications

7. Pericardial compliance

What is one of the most important parameters in determining restrictive filling?

Left atrial pressure — LAP.

What does a restrictive filling pattern after an MI suggest?

A greater likelihood of heart failure from severe LV dysfunction and a poor prognosis.

List the 10 complications of MI.

1. Contractile dysfunction

2. Arrhythmias

3. Myocardial rupture

4. Papillary muscle dysfunction

5. Pericarditis/pericardial effusion

6. Mural thrombus

7. RV infarct

8. Aneurysm

9. Infarct expansion

10. Sudden death

How is the degree of LV failure related to the size of an MI?

The degree of LV failure is proportional to the size of the MI.

List the 3 findings most often associated with LV failure after an MI.

• Hypotension

• Pulmonary congestion

• Pulmonary edema

What is cardiogenic shock after an MI?

Severe acute pump failure involving at least 40% of the LV.

What type of MI usually causes cardiogenic shock?

An anterior MI

List the 4 characteristics of cardiogenic shock.

1. Elevated filling pressure

2. Low cardiac output

3. Systemic hypotension

4. Vital-organ hypoperfusion

What is ischemic cardiomyopathy?

Chronic ischemic heart disease that causes progressive heart failure.

List the 2 reasons ischemic cardiomyopathy causes progressive heart failure.

• Severe obstructive CAD

• Exhaustion of compensatory hypertrophy of the non-infarcted myocardium

List the 3 previous conditions or treatments commonly associated with ischemic cardiomyopathy.

• Previous MI

• CABG

• Coronary intervention

How is ischemic cardiomyopathy diagnosed clinically?

By the gradual onset of CHF in a patient with a previous MI or angina.

List the 2 structural echo findings associated with ischemic cardiomyopathy.

• Dilated heart with secondary LVH

• Isolated echogenic areas of previous infarction

Why can an MI cause arrhythmias and sudden death?

MI causes disturbances in electrical activity and irritability of the myocardium.

What mechanism is hypothesized to cause post-MI arrhythmias?

Reentry caused by inconsistent electrical characteristics of ischemic myocardium

List the 6 arrhythmias associated with MI.

1. Sinus bradycardia/tachycardia

2. Various heart blocks

3. Asystole

4. PVCs

5. Ventricular tachycardia

6. Ventricular fibrillation

Why can myocardial rupture occur after an MI?

Because necrotic and inflamed myocardium becomes weakened.

List the 3 types of myocardial rupture. & Which type of myocardial rupture is the most common?

• Free-wall rupture

• Ventricular septal rupture

• Papillary muscle rupture

Free-wall rupture is the most common

How often is free-wall rupture seen in patients who die from MI?

About 10%

Why is free-wall rupture usually fatal?

It causes hemopericardium → cardiac tamponade.

What type and location of MI is commonly associated with free-wall rupture?

A transmural MI involving the LAD distribution

What is the most common site of free-wall rupture?

The anterior/lateral walls at the mid ventricle.

When does free-wall rupture usually occur after an MI?

Usually 5–7 days after the onset of MI, although it can occur at any time

Why is the myocardium especially weak around 5–7 days after an MI?

Because of:

1. Necrosis

2. Neutrophil infiltration

3. Lysis of connective tissue

List the 4 risk factors for free-wall rupture.

1. Age >60

2. Female sex

3. Hypertension

4. Lack of LVH before the MI

How common is ventricular septal rupture after an MI?

About 1–2% of patients who had an MI

What new murmur is associated with ventricular septal rupture?

A harsh holosystolic murmur heard at the left sternal border.

What echo technique is useful for detecting ventricular septal rupture?

2D echo with color-flow imaging

What happens with complete transection of a papillary muscle?

It is not tolerable because it causes torrential MR

List the 4 characteristics of partial papillary muscle rupture.

1. More common

2. Severe MR

3. More tolerable

4. Not immediately fatal

How often does papillary muscle rupture occur with small infarcts?

50% of the time.

What infarct usually causes posteromedial papillary muscle rupture?

An inferior-wall infarct

What infarct may cause anterolateral papillary muscle rupture?

An anterolateral MI

How common is rupture of the RV papillary muscles?

Rare

What usually causes papillary muscle dysfunction after an MI, and what can it lead to?

It is usually caused by ischemia of the underlying myocardium and papillary fibrosis and can lead to post-infarct regurgitation. Echo Assessment and complicatio…

What is post-MI pericarditis?

An epicardial manifestation of underlying myocardial inflammation.

What type of MI commonly causes pericarditis?

A transmural infarct.

When can pericarditis pain begin after an MI?

From 1 day to 6 weeks after the MI.

What usually happens to post-MI pericarditis over time?

It usually resolves.

What types of infarcts are most commonly associated with a pericardial effusion?

Anterior or larger infarcts

Do most post-MI pericardial effusions cause hemodynamic compromise?

No. The majority do not.

What condition may occur along with a post-MI pericardial effusion?

Pericarditis

What is Dressler’s syndrome, and when does it occur?

A post-MI syndrome occurring about 1–8 weeks after an MI.

List the 5 characteristics of Dressler’s syndrome.

1. Large pericardial effusion

2. Malaise

3. Fever

4. Leukocytosis

5. Elevated erythrocyte sedimentation rate

Is the cause of Dressler’s syndrome well defined?

No. Detection of antibodies suggests an immune response.

What is a mural thrombus?

A blood clot attached to the wall of a cardiac chamber.

Where does a mural thrombus commonly adhere after an MI?

To the wall overlying the MI.

What may happen to superficial pieces of a mural thrombus?

The slide states that they may break off, producing MI.

What is the prognosis when a mural thrombus develops early?

The patient has a higher mortality rate.

What is a laminated thrombus?

A thrombus made of multiple layers formed at different times.

List the 3 echo features suggesting potential embolization from a mural thrombus.

• Increased thrombus mobility

• Protrusion into the ventricular chamber

• Adjacent areas of akinesis and hyperkinesis

Is an isolated RV infarct common, and what MI does it usually accompany?

An isolated RV infarct is rare and usually accompanies an inferior LV MI.

List the 3 hemodynamic effects of an RV infarct.

• Marked decrease in overall cardiac function

• Elevated right-heart filling pressure/RAP

• Preserved LAP

What type of disease has hemodynamics similar to an RV infarct?

Pericardial disease

List the 4 hemodynamic findings associated with RV infarction.

• Increased RV filling pressure

• Square-root sign on catheterization

• Kussmaul’s sign

• Pulsus paradoxus

What does Kussmaul’s sign suggest when it is present with an inferior MI?

RV infarction

How common is a true aneurysm after an MI?

It occurs in <5% of patients who develop an MI.

How does a true ventricular aneurysm form?

The necrotic area heals into a thin scar, and intraventricular tension stretches the region, causing the wall to bulge

What layers are involved in a true aneurysm, and why does it usually not rupture?

It involves all 3 layers, and rupture does not usually occur because the wall is fibrotic.

List the 3 complications of a true aneurysm.

• Mural thrombus

• Arrhythmias

• Heart failure

What is a pseudoaneurysm?

An incomplete or contained rupture of the myocardium.

How does the pericardium help form a pseudoaneurysm?

The pericardium seals off the rupture, preventing development of a hemopericardium.

List the 3 structural/clinical characteristics of a pseudoaneurysm.

• Walls composed of thrombus and pericardium

• Narrow neck

• High rate of rupture

What is infarct expansion?

Acute dilation and thinning of the infarcted region that is not explained by additional necrosis

List the 3 causes of infarct expansion.

• Slippage of muscle bundles due to decreased myocytes in the region

• Disruption of normal myocytes

• Tissue loss in the region

How does pre-infarct wall thickness affect infarct expansion?

• Hypertrophy protects against expansion.

• Thin regions, especially the apex, are more vulnerable