alterations of the heart for week 10

Question 1

Presentation of CAD, ischemia and infarction depending on amount and rate of occlusion

Answer 1

• irreversible once collagen is laid down
• fatty streaks are reversible
• where the plaque is small, is nonocclusive thrombus, or occlusive thrombus will change the experienced symptoms

Question 2

Coronary Artery Disease (CAD)

Answer 2

• atherosclerosis of the coronary arteries may present in several clinical forms:
• angina pectoris (chest pain)
• chronic ischemic heart disease with congestive heart failure (CHF = cardiac insufficiency)
• acute myocardial infarction (MI - heart attack)
• sudden cardiac death
• Myocardial ischemia is the underlying mechanism in all forms (not getting enough blood supply to heart wall)

Question 3

Pathogenesis of “heart attacks”

Answer 3

• acute coronary syndromes (unstable angina, acute myocardial infarction, sudden cardiac death) often result from acute changes in chronic atherosclerotic lesions
• fissuring of the plaque with clotting
• plaque rupture with embolization
• thromboemboli

Question 4

Ischemic heart disease

Answer 4

• results from an imbalance between the myocardial oxygen demand and myocardial blood supply
• usually due to atherosclerosis of the coronary arteries
• as a result of coronary occlusion, myocardial cells:
• become hypoxic within 10 seconds
• lose ability to contract after several minutes
• die after 20 minutes
• worried about heart and brain and rest of body

Question 5

Hemodynamic factors contributing to conditions of reduced blood supply

Answer 5

• increased resistance in coronary vessels
• hypotension or shock
• decreased blood volume (such as hemorrhage)

Question 6

cardiac factors contributing to conditions of reduced blood supply

Answer 6

• decreased diastolic filling time
• increased heart rate (extreme cases)
• valvular incompetence
• valve issue (too stiff or too elastic)

Question 7

hematologic factors contributing to conditions of reduced blood supply

Answer 7

• oxygen content of the blood

- respiratory disorders, anemia, hemoglobin disorders

Question 8

other issues contributing to conditions of reduced blood supply

Answer 8

systemic disorders that reduce blood flow or the availability of oxygen, such as shock, anaphylaxis

Question 9

Conditions that increase oxygen demand

Answer 9

• high systolic blood pressure (heart needs to over work)
• increased ventricular volume
• increased thickness of the myocardium, increased systolic resistance, hypertension (heart can’t supply extra O2)
• increased heart rate
• exercise, stress, hyperthyroidism, anemia

Question 10

Pathophysiology of myocardial ischemia

Answer 10

• healthy coronary arteries are able to dilate to increase the flow of oxygenated blood to the myocardium (sitting -> exercise)
• narrowing of a major coronary artery by more than 50% impairs blood flow sufficiently to hamper cellular metabolism under conditions of increased myocardial demand

Question 11

Angina Pectoris

Answer 11

• sign of ischemia
• chest pain caused by myocardial ischemia
• transient discomfort of varying degrees
• effect of temporary ischemia is reversible (goes away by itself)
• pain is caused by buildup of lactic acid or abnormal stretching of the ischemic muscle
• pallor, profuse sweating, and dyspnea may be associated

Question 12

types of angina

Answer 12

• stable angina
• unstable angina
• prinzmetal angina

Question 13

stable angina

Answer 13

• caused by luminal narrowing and hardening of the arterial walls
• generally predictable

Question 14

unstable angina

Answer 14

• caused by a combination of vasospasm and atherosclerotic lesions
• unpredictable; often occur at rest

Question 15

prinzmetal angina

Answer 15

vasospasm occurs almost exclusively at rest with or without atherosclerosis

Question 16

the clinical presentation of ischemic disease depends on:

Answer 16

• extent of the occlusion
• anatomic location (which coronary artery and where in that artery)
• type of lesion (no one plaque is the same, fibrolipid plaques more likely to rupture and cause an acute event than fibromuscular plaques)
• speed at which the ischemia develops
• extent of disease in other coronary branches
• other diseases (hypertension, hyperthyroid)