MT2_5_Ischemic Heart Disease

Question 1

what falls under stable coronary disease?

Answer 1

• chronic stable angina

Question 2

what falls under acute coronary syndromes?

Answer 2

• unstable angina
• non-st elevation MI
• st elevation MI

Question 3

What is the most common cause of MI?

Answer 3

• coronary artery disease (atherosclerosis)..can be stable or unstable

Question 4

where are the arteries located, and why is diastole important?

Answer 4

arteries are on the epicardial surface, and diastole is important bc that is when coronary artery perfusion occurs.

Question 5

why does ischemia occur?

Answer 5

• when supply does not equal demand…for O2

Question 6

What are the three things that affect coronary blood flow, and O2 SUPPLY?

Answer 6

1. Coronary blood flow
   
   • vessel potency–obstruction
   • vasc. resistance of coronary arteries (dilatation)
   • heart rate (since arteries are perfused during diastole)
2. O2 carrying capacity
3. Collaterals (development of new blood vessels)

Question 7

What are the three things that affect myocardial oxygen DEMAND (MVO2)?

Answer 7

1. heart rate (need more atp)
2. contractility (contractile myocytes require atp)
3. wall tension/wall stress (preload and after load)

Question 8

How do we estimate MVO2?

Answer 8

• SBP times HR = rate pressure product

Question 9

What are the most common causes of diminished coronary artery blood flow?

Answer 9

1. **stable CAD +/- plaque rupture and atherothrombosis

2. coronary artery spasm (can occur w/o plaques)

Question 10

define artheroclerosis

Answer 10

• disease affecting arterial blood vessels, due to deposition and invasion of macrophages into arterial walls
• this results in narrowing of artery lumen
• reduced vascular reactivity (so stiffening and endothelial dysfunction)
• unstable plaques can rupture

Question 11

Define stable angina

Answer 11

• atherosclerosis leads to……
• diminished coronary artery lumen
• endothelial dysfunction
• reduced vessel compliance

resulting in a gradual reduction of coronary blood/O2 supply
= stable symptoms

Question 12

Define acute coronary syndrome

Answer 12

• the plaques rupture, leading to atherothrombosis, and a rapid loss of coronary blood/O2 supply

Question 13

Summarize the sequence of events of an atherosclerotic event

Answer 13

• plaque formation..chornic, leading to ischemia if MVO2 is INcreased
• plaque disruption (or vas-spasmes) due to a sudden change in pressure
• thrombus formation ( resulting in acute partial or complete obstruction of the artery)
• ischemia (which can occur even without an increase in MVO2 due to the decrease in supply) –> angina
• tissue necrosis (infarction) in a wavefront matter from the subendocardium to the epicardium

Question 14

What does ACS severity depend on?

Answer 14

• degree
• duration
• location
• collateral circualtion
• time to revascularization

Question 15

What system is activated during an acute infarction phase?

Answer 15

• neurohormonal systems (adrenenergic) which then worsen ischemia, expand infarct, and increase arrhythmic risk

Question 16

What are the initial assessment tools?

Answer 16

• Hx/chest pain differential (due to ischemia or stable/unstable?)
• ECG
• Cardiac Biomarkers (troponin I or T)

Question 17

How can we determine if it is angina?

Answer 17

1. Description of pain
   - Quality
   - Duration
   - Location
   - Radiation
2. Precipitating Factors?
   - exertion or stress (physical/emotional)
3. Relieving Factors
   - rest, NTG,

• pain scale, diaphoresis, dyspnea, weakness, nausea, fever

Question 18

What are the 3 main criteria for a typical angina? Atypical, and non-anginal chest pain?

Answer 18

1. substernal chest discomfort with quality and duration that is
2. provided by exertion or emotional stress
3. and relieved by rest or NTG

Atypical: 2/3
Non-anginal: 0-1 of criteria

Question 19

What is the difference between stable and unstable angina?

Answer 19

• stable is predictable and does not change in frequency, intensity, and duration
• unstable can be 1. at rest, 2. new onset w severe pain, and 3. pain that is more frequent, longer in duration, and pt has a lower threshold

Question 20

What does T wave inversion represent?

Answer 20

• myocardial ISCHEMIA

Question 21

What does ST segment depression represent?

Answer 21

• active myocardial ISCHEMIA, more sensitive to T wave inversion

Question 22

ST segment elevation represent?

Answer 22

• ACUTE INFARCT thus causing injury

- must be more than 1mm in 2 contiguous leads

Question 23

What does a Q wave represent?

Answer 23

• transmural infarct, can be old OR new…not diagnostic for an acute infarct

Question 24

Troponin T/I is a regulatory protein that is very specific to cardiac tissue, and is proportional to amount of damage. The peak sensitivity is ____ therefore absence does not rule out damage

What are the troponin levels?

Answer 24

• 8-12 hours
• less than 0.01 is normal
• 0.01-0.12 is “leak)
• more than .12 is positive for MI

Question 25

When is CK a diagnostic of an MI?

Answer 25

- CKMB fraction greater than 5% (with elevated CK) is a diagnostic for MI at 8-12 hours

Question 26

What are the 3 main things used to diagnose an acuity of an ischemia?

Answer 26

- CP history - ECG - Biomarkers

Question 27

For stable angina, CP History ECG Biomarkers

Answer 27

- CP: typical or atypical angina, does not meet criteria for unstable symptoms ECG: no change Biomarkers: no change

Question 28

Non-STE ACS CP eCG Biomarkers

Answer 28

CP: typical or atypical angina, meets criteria for unstable symptoms history ECG: may have acute T wave inversion, or ST depression Biomarkers: no change is UNSTABLE ANGINA acute rise is NSTEMI

Question 29

STEMI CP ECG Biomarkers

Answer 29

CP: typical or atypical, can be unstable ECG: ST elevation Biomarkers: acute rise, but can be normal in early stages of an MI

Question 30

What is considered an unstable angina?

Answer 30

- patients presenting with worsening angina, w/o evidence of ST elevation on ECG or elevated cardiac biomarkers

Question 31

STABLE angina is a ___state caused by ____ narrowing of the coronary arteries. Under normal conditions, patients will not experience symptoms, but when ___is increased, the symptoms of ischemia are present. So the goal is to ____and____O2 supply

Answer 31

chronic artherosclerotic MVO2 stabilize, balance

Question 32

In ACS, an atherosclerotic plaque has been compromised, leading to ___and ___ process. If left unchecked, a complete ___of the artery will result. Therefore, therapy must be more ___and agents are added to combat the thrombotic and inflammatory process to restore normal blood flow. How aggressively you manage the thrombotic aspect depends on the risk of further _____ Minority of the cases are due to ____ Symptoms can develop ___ of MVO2

Answer 32

prothormbotic and inflammatory occlusion aggressive myocardial damage vasospasms independent