2A: Cardiac Pathologies II Flashcards
What is the goal for treating CAD?
Halt progression and possible improvement with risk factor modification
What is the definition of an MI?
Ischemic event that may result in injury or irreversible tissue death at the myocardium
What are the three signs and symptoms of an MI?
- ECG changes
- Cardiac symptoms
- Elevation of cardiac enzymes
What are possible ECG changes with an MI?
- S-T segment elevation
- Inverted T wave
- Significant Q wave
How is an MI ruled in or out?
Must have 2/3 key symptoms
What are the three zones of infarct of MI?
- Zone of ischemia
- Zone of injury
- Zone of infarct
What is the zone of ischemia?
Tissue is viable and may not have any damage if infarct doesn’t extend
What is the zone of injury?
Viable as long as O2 delivery stays intact. Increasing O2 delivery can save the tissue
What is the zone of infarct?
Tissue is O2 deprived and has irreversible damage
What zones can intervention have an effect on?
Zone of ischemia and injury
What are the three main cardiac enzymes of interest with an MI?
- CPK-MB
- Troponin
- LDH-1
When will CPK-MB increase?
0-24 hrs after MI
Why is CPK-MB a marker for MI?
Because MB is an isoenzyme that is specific to cardiac tissue
When will troponin increase after an MI?
12 hrs - 4 days after
How does LDH-1 indicate MI?
Look at the ratio of LDH-1 to LDH-2. If it is greater than 1, suggests MI
What are the two main classifications of MI?
Transmural and Subendocardial
What is a transmural MI?
Goes into the wall of the myocardium, will see the most wall motion deficits
What is a hypokinetic transmural MI?
Decreased wall motion
What is a dyskinetic transmural MI?
Unorganized wall motion
What is an akinetic transmural MI?
No wall motion
What is a subendocardial MI?
Partial thickness infarct
How does a subendocardial MI present?
Wall motion may be normal and less EKG changes compared to transmural
What is the definition of cardiomyopathy?
Disease where contraction and relaxation of the cardiac muscles are impaired
What are possible causes of cardiomyopathy?
Collagen disorder, autoimmune, viral, idiopathic, neurotransmission
What are the three types of cardiomyopathy?
- Dilated cardiomyopathy
- Hypertrophy
- Restrictive
What is dilated cardiomyopathy?
Heart wall is floppy, similar to an aneurism
What does all cardiomyopathy lead to?
Decreased ejection fraction
What is hypertrophy cardiomyopathy?
Hypercontractile left ventricle
What does hypertrophy cardiomyopathy lead to?
Increased myocardial O2 demand, rapid ventricular emptying, decrease EF
What is restrictive cardiomyopathy?
Endocardial scarring that restricts the heart wall distention
What are the causes of right sided CHF?
Pulmonary HTN, right ventricular infarct
What are initial signs of right CHF?
Systemic edema with fluid accumulation in the abdomen, liver, and legs
What is the primary sign of right CHF, and what should you observe for?
LE edema - look for weight gain and jugular vein distension
What are causes of left CHF?
Resistance from systemic HTN, MV/LV dysfunction secondary to cardiomyopathy or infarct
How does left sided CHF initially present?
Pulmonary edema
What is the primary symptom of left CHF?
Dyspnea
What are three additional symptoms of left CHF?
- Tachypnea
- Mouth or lung crackles
- Orthopnea
How does CHF progress?
To both sides of the heart
What are signs that may indicate right or left sides CHF?
S3 heart sound, tachycardia, decreased activity tolerance, weight gain, pulmonary edema
Describe NYHA I
No limitation to physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, or shortness of breath
Describe NYHA II
Slight limitation of physical activity. Comfortable at rest. Ordinary physical activity results in fatigue, palpitation, shortness of breath, or chest pain
Describe NYHA III
Marked limitation of physical activity. Comfortable at rest. Less than ordinary activity causes fatigue, palpitation, shortness of breath, or chest pain
Describe NYHA IV
Symptoms of heart failure at rest. Any physical activity causes further discomfort
What is the result of CHF?
Low cardiac output (CO)
How does the cardiopulmonary system respond to low cardiac output?
As if it is a low blood volume problem
In what four ways does the body respond to low cardiac output?
- Retain fluid
- Vasoconstriction
- Increase stroke force
- Increase HR
Why is medical intervention necessary for CHF?
Control stroke force and reduce vascular pressure and excess fluid to decrease workload on the heart
What is a concern with left sided CHF and why?
Hypertrophy of the left ventricular wall - has the largest muscle mass with high O2 consumption making it vulnerable to ischemic attack
What happens to skeletal muscle and muscle fibers with CHF?
Skeletal muscle atrophy and decreased type I fibers leading to decreased endurance
Why do muscles have a decreased ability to work with CHF?
Decreased skeletal muscle blood flow
How does CHF impair skeletal muscle metabolism?
Decreased ability to break down O2 for use
What is pulmonary edema?
Fluid leaks from pulmonary and lymphatic systems interstitially and get into alveoli creating a barrier making gas exchange between capillaries and alveoli difficult
