(ACS) Acute Coronary Syndrome Flashcards
Acute Coronary Syndrome
Umbrella term for conditions where: Blood flow to the heart is suddenly blocked
ACS
- STEMI
- NSTEMI
- Unstable Angina
- all three involve plaque + platelet aggregation
- Only STEMI + NSTEMI include a thrombus
Angina types
- Printzmetal’s Variant Angina
(vasospasm)
-SUPPLY ISCHEMIA
-Not from atherosclerosis - Chronic Stable Angina
(fixed stenosis)
-DEMAND ISCHEMIA - Unstable Angina
(thrombus)
-SUPPLY ISCHEMIA
Prinzmetal Angina: Cause
Coronary artery spasm
-From endothelial dysfunction (damage)
Prinzmetal Angina: Characteristics
Unique Features
- CAD (Atherosclerosis) may or may not be present
- Onset timing: Rest, minimal exertion, night
- Elevated ST SEGMENT
ACS: Unstable Plaque
- Size of Lipid core?
- Large - Inflammation?
- Active - Smooth muscle cells?
- Proliferation into intima
Unstable Angina
Chest pain occurring for the first time
-Myocardial Ischemia
Chest pain more severe than usual with chronic angina
- New regions of the heart are undergoing myocardial ischemia
- First nitro doesn’t stop pain
EMERGENCY situation
Unstable Angina Characteristics
Ruptured plaque + thrombus formation
Why is there no infarction?
-Occlusion is PARTIAL OR thrombus DISSOLVES
ECG Changes:
-Might see ischemic changes, typically transient
Cardiac enzymes elevated?
-NO
Key characteristics of Plaque rupture
Large lipid core
Thin cap
Theory of plaque Rupture
INCREASED SNS ACTIVITY (exercise, stress, circadian rhythm) -Inc BP, HR, Force of contraction -Inc force of coronary artery blood flow -Inc force exerted against injured epithelium
PLAQUE RUPTURE
- platelets adhere to ruptured plaque
- release of substances
1. attract more platelets
2. contribute to vasospasm
THROMBUS FORMATION
ACS vs Stable Angina
Stable Angina: <15 mins
-treated w/rest
ACS: >20 mins
- more pain
- n/v, diaphoresis…
Signs of ACS: MEN
MEN:
- Discomfort or tingling in arms, back, neck, shoulder, or jaw
- Chest pain
- SOA
Signs of ACS: WOMEN
WOMEN:
- Fatigue
- Sudden dizziness
- Heartburn-like feeling
- Cold sweat
- N/V
Signs of MI
- Diaphoresis
- Dyspnea
- Extreme anxiety
- Levine’s sign (Fist to chest)
- Pallor
- Retrosternal crushing chest pain that radiates to shoulder, arm, jaw, or back.
- Weak pulses
What is an ACUTE MI?
Rupture of plaque and then thrombus formation
-Blood flow disruption is prolonged or totally stopped
ST-Elevation or not
Inc Troponin
ACUTE MI Definition
Acute coronary syndrome (ACS) with prolonged ischemia without recovery
Myocardial cells suffer irreversible ISCHEMIC NECROSIS
Either STEMI or NSTEMI
From Ischemia to Infarction
Ischemia causes lack of blood flow»> less O2»» less ATP production»> cells can’t work
Irreversible injury occurs in: 30min to 4hrs
(why REPERFSION should be done within 4hrs)
Tissue necrosis: by 4hrs
Necrotic tissue is cleared away by: 1-2 weeks
Tough fibrous scar tissue replaces necrotic tissue by:
6 Weeks
Ischemia, Injury, and Infarction: 3 zones of tissue damage
- Infarction (Necrosis)
- MI, dead cells
- No recovery for this tissue - Injury
- Some recovery possible
- can be reperfused
- Not dead yet… - Ischemic
- Full recovery possible
Do not want the patient to make it worse and extend the size of infarction
GOAL: Inc O2, Decrease heart’s demand
Acute MI: Extent of damage depends on 3 factors….
- LOCATION OR LEVEL of occlusion in the coronary artery
- LENGTH OF TIME that the coronary artery has been occluded
- Heart’s availability of COLLATERAL CIRCULTION
STEMI
ST-segment: Elevated QRS: Wide T wave: Peaked, then invert Troponin: Elevated Size of infarct: large Outcomes: Poor
NON-STEMI
ST-segment: Depressed or normal QRS: normal T wave: Inverted Troponin: Elevated Size of infarct: Smaller Outcomes: Better
LAD
Left Anterior Descending
- Supplies Left Ventricle
- Most common place for MI
WIDOW MAKER
ECG Tombstoning
Elevated ST segment With PEAKED Rounded T-wave (tombstone shaped)
-Indicates a large myocardial area is experiencing ischemia (POOR OUTCOME)
