Ischemic Heart Disease
Definition
A narrowing of the coronary artery(s) sufficiently to prevent adequate blood supply to the myocardium (ischemia). This narrowing may progress to a point where heart muscle is damaged (infarction).
Etiology
- Atherosclerosis
- Coronary artery spasm
- Embolus
Signs and Symptoms
- Angina pectoris (stable, unstable, Prinzmetal's)
- Myocardial infarction
- Sudden cardiac death
Cardiac Catheterization
- Coronary arteriogram is the gold standard for determining the presence and severity of coronary artery disease
- Intravascular ultrasound and 3-D ultrasound may supplement coronary arteriography
M-Mode
- Abnormal systolic wall motion, systolic wall thickening, and wall thickness
- Increased E-point septal separation of the mitral valve
- B "bump" or "notch" of the mitral valve
- May disclose left ventricular aneurysm
2-D
- Multiple views should be used
- Segmental wall motion abnormality
- Evaluate systolic wall motion, systolic wall thickening, and wall thickness
Note: Routine echocardiography tends to overlook coronary artery disease because the examination is performed while the patient is at rest, when the narrowed coronary arteries may still be able to provide adequate blood supply to the heart muscle. To better evaluate the presence and severity of coronary artery disease, a stress echocardiograrn should be performed
Complications of Myocardial Infarction:
- Pericarditis / pericardial effusion
- Dressler's syndrome
- Left ventricular true aneurysm
- Left ventricular false (pseudo-) aneurysm
- Left ventricular thrombus
- Ventricular septal defect
- Papillary muscle dysfunction
- Right ventricular infarction
Pericardial Effusion
It is a common acute response to acute myocardial infarction (about 30%). It may predict a more complex course.
Dressler's Syndrome
A delayed form of pericarditis: Post-infarction illness which manifests with fever, pericarditis, and pleuritis; may occur one week to several months after myocardial infarction. An autoimmune phenomenon- evaluate for pericardial effusion.
Left Ventricular True Aneurysm
Definition
A bulge that persists in diastole and systole with akinesia/ dyskinesia
Importance of Detection
- Higher mortality rate
- 2-D echocardiography aids in determining the amount of viable myocardium when aneurysmectomy is being considered
- Increased risk of thrombus formation
- Associated with ventricular arrhythmias
Differential Diagnosis
- Left ventricular diverticulum
- Herniation of the ventricle with a partial defect of the pericardium
Electrocardiogram
Persistent ST-T wave elevation
Chest X-ray
- Aneurysmal dilatation of left heart border
M-Mode
- Limited value
- Progressive widening of the body of the left ventricle with a scar from the aortic root to the left ventricular apex
2-D
- Thin walls with distorted shape that demonstrate akinesia/dyskinesia
- "Hinge" point where "good" left ventricular myocardium meets.
- Thrombus within the aneurysm possible
Doppler
- Mitral regurgitation
Important to Note
A true aneurysm takes two to four weeks to develop. A true aneurysm may affect the left ventricular apex, interventricular septum, or inferior wall of the left ventricle; most commonly seen following anterior myocardial infarction with the aneurysm affecting the apex and septum.
Pseudoaneurysm
Definition
The free wall of the left ventricle ruptures and a hemopericardium is confined by the pericardium
Etiology
- Usually myocardial infarction
- May also be caused by cardiac surgery, blunt trauma, or endocarditis
Importance of Detection
- Significantly increased risk of sudden death
- Increased risk of thromboembolism
- Associated with congestive heart failure
M-Mode
- Limited value
- Pericardial clear space
2-D
- A narrow perforation of the left ventricular free wall with a saccular/globular contour of the false chamber
- A clot may line the aneurysm
Doppler
- A to-and-fro turbulent flow noted at the orifice of the false aneurysm
Left Ventricular Thrombus
Types
- Layered (sessile)
- Mobile (pedunculated)
2-D
- Found most often at the apex of the heart
Important to Note
- Often associated with anterior myocardial infarction.
- Use a high-frequency, short-focus probe.
- Spin the probe 360° when investigating the cardiac apex
- Use a-black-on-white display.
- Prove the presence of the thrombus in at least two views
Ventricular Septal Defect
Definition
A rupture of the interventricular septum
M-Mode
- Limited
- Interruption of the inter-ventricular septal wall
2-D
- Allows direct visualization of the defect
Doppler
- A high-velocity, turbulent jet with left-to-right shunting
- Determine the systolic pulmonary artery pressure
- Determine the shunt ratio
Papillary Muscle Dysfunction
2-D
- Incomplete closure of the mitral valve leaflets where they fail to coapt to the level of the mitral annulus ("tenting")
- An area of wall motion abnormality around either papillary muscle implies dysfunction
- Fibrosis/calcification of the papillary muscle implies papillary muscle dysfunction
- Left ventricular dilatation interrupts the spatial orientation of the papillary muscles to the rest of the mitral valve apparatus, thus inducing papillary muscle dysfunction
- The most severe form of papillary muscle dysfunction is the rupture of a papillary muscle head or the muscle itself
Doppler
- Mitral regurgitation
Right Ventricular Infarction
Etiology
- Associated most often with inferior infarction
Signs and Symptoms
- Hypotension
- Normal to low pulmonary artery pressures
- Shock with clear lungs
2-D
- Right ventricular dilatation
- Segmental wall motion abnormality—look for associated wall motion abnormality of inferior wall and/or posterior septum (M-shaped infarct)
- Use multiple views (the right ventricle may be visualized in almost every standard 2-D echocardiographic view)
Doppler
- Tricuspid regurgitation (if present, pulmonary artery pressures should be unexpectedly low)
- Right-to-left shunting through a patent foramen ovale