Angina & MI Flashcards
CAD
- Coronary Artery Dz
- Accumulation of atherosclerotic plaque in the coronary arteries
-could lead to development of collateral circulation, angina, acute coronary syndrome, MI, dysrhythmias, HF, or death
MI
- caused by declining artery circumference or lack of blood supply
- increased demand for oxygen or decreased supply of oxygen
- usually occurs when a coronary artery is greater than 75% occluded (or stenosed)
- cardiac cells can sustain about 20 min of no O2 before necrosis
Collateral Circulation
- tiny vessels connecting the large coronary arteries
- often develops in the presence of atherosclerosis to allow for continued blood flow
- Alternative route for blood to flow from the aorta to the cardiac muscle tissue
Angina
- symptom not a dz (CP)
- chest pain resulting from reduced coronary blood flow
- imbalance between myocardial blood supply and demand
- 3 types of angina
Factors of Angina
- Physical exertion
- temp extremes
- anxiety/anger
- consumption of a heavy meal
- smoking
- sexual activity
- drugs
- dysrhythmias
Stable Angina
-predictable pattern of increased work of the heart resulting in chest pain and relieved by rest or nitrates
S/S:
- pain
- SOB
- N/V
- palpitations and weakness
Prinzmental Angina
- coronary artery vasospasm
- occurs unpredictably (not associated with physical activity)
- most often ocurrs at night while at rest
- unknown cause, though presumed to be caused by hyperactive sympathetic response, altered calcium flow, and reduced prostaglandins that promote vasodiation
Unstable Angina
- unpredictable pain without contributing factors
- at rest or during activity
- departing from the usual pattern
- may last more than 20 minutes
- marked by increasing frequency, severity, and duration of chest pain symptoms
Patient History
P: precipitating events
Q: quality of the pain
R: radiation of the pain
S: severity of the pain
T: timing when it began, with what activity?
Meds?
Risk factors? fam hx, stressors
ACS
Acute Coronary Syndrome
When the blood flow is significantly reduced but not fully occluded causing myocardial injury
Factors for ACS
-Rupture of atherosclerotic plaque resulting in a thrombus
formation
- Coronary artery vasospasm
- Increasingly occlusive atherosclerotic plaque
- Inflammation of coronary artery
- Diastolic and systolic dysfunction (heart failure)
Plaque rupture in ACS
- hemodynamic changes cause plaque to rupture….
- platelet aggregation….
- clot formation…..
- cell ischemia and injury….
- lactic acid production causes chest pain
Acute MI
- When blood flow to a portion of the cardiac muscle is completely blocked
- complete occlusion results in prolonged ischemia which kills cardiac cells permanently
- irreversible cell damage leads to poor cardiac functioning
AMI: Electrical changes
T wave will invert or the ST segment of the ECG tracing will become elevated
AMI: ST segment elevation
- greater than 0.04 seconds after J point
- greater than 1 mm in 2 or more contiguous chest leads
contiguous
limb leads that “look” at the same area of the heart or are numerically consecutive chest leads
Stages of Myocardial Insult
- Ischemia
- Injury
- Infarct