Ischemic Heart Disease

Question 1

Heart failure

Answer 1

Heart is unable to pump blood sufficiently to meet the neds of tissue

• ventricle unable to fill with or eject blood
• “congestive heart failure”
• usually progressive condition with poor prognosis

Question 2

Systolic heart failure

Answer 2

deterioration of myocardial contraction

Question 3

Diastolic heart failure

Answer 3

Inability of heart chamber to relax, expand, and adequately fill during diastole

Question 4

Left sided heart failure
Causes
Effects
Signs and Symptoms

Answer 4

Causes:

1. Ischemia
2. Hypertension
3. Aortic/mitral valve disease
4. Nonischemic myocardial diseases

Effects:

1. Damming of blood in pulmonary circulation
2. Diminished peripheral blood flow

Signs and Symptoms:
-shortness of breath

Question 5

Right sided heart failure:
Causes
Effects
Signs and Symptoms

Answer 5

Causes: 
1. Left sided heart failure (#1 cause)
2. cor pulmonale-lung disease or primary pulmonary hypertension 
Signs and symptoms:
-peripheral edema, ascites

Question 6

What is stable angina pectoris?

Answer 6

-chronic stenosing coronary atherosclerosis (>75% reduction of lumen area)

1. increased cardiac demand and workload needs unmet
   - substernal chest pressure
2. physical activity, emotional excitement
   - relieved with rest
   - vasodilator-nitroglycerin

-ST segment depression-subendocardial ischemia

Question 7

What is unstable angina pectoris?

Answer 7

Atherosclerotic plaque disruption–>partially occluding thrombus

• thrombogenic plaque components, subendothelial basement membrane exposed
• platelet activation, aggregation
• vasospasm

Symptoms:
-frequent, less effort, at rest, longer duration

ST segment depression-subendocardial ischemia

Question 8

What makes plaques vulnerable?

Answer 8

1. lipid rich atheromas
2. thin fibrous caps
   inflammation
   moderately stenotic-50-75%

Question 9

What is prinzmetal variant angina?

Answer 9

coronary artery spasm
unrelated to physical activity, heart rate, or bp
-responds to vasodilators

ST segment elevation-transmural ischemia

Question 10

How does a myocardial infarction happen?

Answer 10

Plaque disruption
Platelet adhesion, aggregation activation 
Vasospasm
Coagulation 
-->occlusive thrombus formation

Question 11

TIme of infarction is reversible what time is irreversible?

Answer 11

30 irreversible, coagulative necrosis

Question 12

What are transmural vs. nontransmural infarcts?

Answer 12

transmural: occlusive thrombus
nontransmural: subendocardial infarct or microinfarcts

Question 13

0-4 hours

Answer 13

no gross or light microscopic changes

Question 14

4-12 hours

Answer 14

microscopic changes: coagulative necrosis
-start losing nuclei and eosinophilia

complications: arrhythmias

Question 15

12-24

Answer 15

Gross: dark mottling
Microscopic: ongoing coagulation necrosis
-pyknosis of nuclei

Question 16

1-3 days

Answer 16

gross: mottled
Microscopic: loss of nuclei and myocytes
-Neutrophil infiltrate

Question 17

3-7 days

Answer 17

• myocyte disintegration, phagocytosis of dead cells

- Macrophages

Question 18

7-10 days

Answer 18

well developed phagocytosis and early granulation tissue

Question 19

10-14 days

Answer 19

granulation tissue

Question 20

2-8 weeks

Answer 20

scar formation

Question 21

How do patients with an MI present?

Answer 21

• crushing substernal chest pain, dyspnea, diaphoresis
• tachycardia, pulmonary congestion and edema
• 10-15% silent : elderly, diabetic

Question 22

What labs do you look at?

Answer 22

myoglobin-peaks early but insensitive
CK-MB-goes down faster
Troponin-peaks lasts long time

Question 23

What does Triphenyltetrozolium chloride stain stain for?

Answer 23

Infarcted myocardium does not stain due to enzyme depletion

Question 24

What are the treatments to myocardial infarction?

Answer 24

Aspirin and other antiplatelet agents
Heparin
Thrombolytic therapy
Beta Blockers
ACE inhibitors
Nitrates
Oxygen

Question 25

What can happen with reperfusion?

Answer 25

reperfusion injury-restoration of blood flow leads to local myocardial damage

• free radical prodcution
• myocyte hypercontracture, increased Ca
• leukocyte aggregation–>proteases, elastases
• mitochondrial dysfuntion–>apoptosis

Question 26

What are some complications of myocardial infarction?

Answer 26

1. cardiogenic shock
   - severe pump failure
   - 10-15% of patients
   - large infarcts (>40% of ventricle)
2. Arrhythmias
   - conduction disturbances
   - myocardial irritability

3. myocardial rupture
3-7 days
-free wall-hemopericaridum, cardiac temponade
-ventricular septum
-papillary muscle  

4. Acute pericarditis
   - 2-3 days
   - transmural MI
5. Ventricular aneurysm
   - late complication
   - mural thrombus
6. progressive heart failure

Question 27

What is sudden cardiac death caused by?

Answer 27

lethal arrhythmia

-underlying structural heart disease: chronic severe atherosclerosis heart disease found in 80-90% of cases

• usually NOT acute infarct
• electrical irratibility of myocardium