Flashcards in Chapter 5 Deck (138)
what is a chronic disease of the arterial system characterized by abnormal thickening and hardening of the vessel walls?
What is a form of arteriosclerosis in which the thickening and hardening of the vessel walls are caused by a buildup of fat-like deposits in the inner lining of large and middle-sized muscular arteries?
what is the usual cause of an acute coronary syndrome?
Rupture of an atherosclerotic plaque
Fatty streaks are thin, flat yellow lesions composed of lipids (mostly cholesterol) or smooth muscle cells that protrude slightly into the arterial opening. Do these cause a lot of problems?
NO! Fatty streaks do not obstruct the vessel and are not associated with any clinical symptoms
Progression from a fatty streak to an advanced lesion is associated with injured endothelium that activates the inflammatory response
how much of arterial stenosis should occur to produce angina symptoms?
70% stenosis of the vessel's diameter
what are the 3 vulnerable sites for plaque disruption within the coronary arteries?
1. the proximal portion of the LAD
2. near the origin of the marginal branch on the RCA
3. near the origin of the first obtuse marginal branc on the circumflex coronary artery
why is aspirin such a grand idea?
Aspirin blocks the formation of thromboxane A2 which is released by platelets. Thromboxane A2 causes vasoconstriction therefore reduced blood flow at the site - aspirin lowers the risk of complete blockage of a vessel
what's the most common cause of an MI?
acute plaque rupture
what can result from a partial (incomplete) blockage of a coronary artery?
- no clinical signs and symptoms (silent MI)
- unstable angina
- sudden death
What can result from a complete blockage of a coronary artery?
STEMI or sudden death
How does cocaine cause MI?
1. increasing myocardial oxygen demand by increasing heart rate, BP and contractility
2. decreasing oxygen supply via vasoconstriction
3. inducing a prothrombotic state by stimulating platelet activation and altering the balance between procoagulant and anticoagulant factors
4. accelerating atherosclerosis
which type of angina is the result of intense spasm of a segment of a coronary artery and may occur in otherwise healthy individuals?
Prinzmetal's angina AKA variant angina
when does Prinzmetal's angina usually occur?
it usually occurs at rest, often occurs between midnight and 8 am and may awaken the patient from sleep
also it can be precipitated by exercise, emotional stress, hyperventilation or exposure to cold
What does Prinzmetal's angina look like on EKG?
Prinzmetal's angina produces ST segment elevation during periods of chest pain
After the episode of chest discomfort is resolved, the ST usually returns to baseline
so you may see no change in ST if you don't have a pre-treatment EKG before you give nitroglycerin
what should you do when a patient presents with a possible ACS?
You should obtain a baseline 12-lead EKG before initiating treatment in any pt presenting with a possible ACS
what are the forms of acute coronary syndromes?
unstable angina, NSTEMI and STEMI
what is it called when chest discomfort occurs when the heart muscle doesn't receive enough oxygen
what is the term given for squeezing or tightening rather than pain?
describe ischemic chest discomfort
ischemic chest discomfort is usually not sharp, it's NOT worsened by deep inspiration, it's not affected by moving muscles in the area where the discomfort is localized nor is it positional
What angina is characterized by one or more of the following:
- symptoms that occur at rest and usually last for more than 20 mins
- symptoms that are severe and/or of new onset
- symptoms that are increasing in duration, frequency or both; and intensity in a patient with a history of stable angina
note that the discomfort associated with unstable angina may be described as painful
what are the subdivisions of the myocardium?
the innermost half of the myocardium is called the subendocardial area and the outermost half is called the subepicardial area
what areas of the heart are most vulnerable to ischemia?
the endocardial and subendocardial areas of the myocardial wall because they have a high demand for oxygen and they are fed by the most distal branches of the coronary arteries
what provides the strongest evidence for the early recognition of MI?
patients history and symptoms, cardiac biomarkers, and the presence of ST segment elevation
at what time of the day are peak incidence of acute cardiac events?
between 6 AM and noon
a patient presents with an acute coronary syndrome - what mnemonics are included in the targeted history?
- SAMPLE history
- OPQRST for pain presentation
What is included in the SAMPLE history?
Signs and symptoms
Past medical history
Last oral intake
Events leading to the incident
What is included in the OPQRST pain presentation?
What is the Levines signs?
When the patient describes their discomfort with a clenched fist held against the sternum
what are the typical symptoms with ACS?
discomfort typically lasts longer than 30 minutes and it may be constant or come and go, occasionally it may be relieved with belching