Cardiac Pathology Flashcards
What happens to the myocytes with unstable angina?
Reversible injury to the myocytes (cellular swelling)
What percent of stenosis of the arteries with atheromas does stable angina develop?
Greater than 70%
What are the s/sx of stable angina? How long does it last for?
Chest pain that lasts less than 20 minutes, and is brought on by exercise
How long does the chest pain last in stable angina? What is the significance of this time?
Less than 20 minutes How long that myocytes can tolerate reduced blood flow
Which cell layer of the heart is affected with myocardial ischemia? What are the characteristic EKG findings with this?
- Subendocardial layer
- ST segment depression
What is the MOA by which NTG relieves stable angina?
Decreases venous return (preload) via NO production
What are the characteristics of unstable angina?
Chest pain at rest due to rupture of an atherosclerotic plaque
What causes unstable angina?
Rupture of an atheroscleotic plaque with thrombosis and an incomplete occlusion of a coronary artery
Is the injury to the myocytes in unstable angina reversible?
Yes
What are the EKG changes with unstable angina?
ST segment depression
What is Prinzmetal angina?
Spasm of the coronary artery, causing chest pain that is unrelated to exertion
What are the EKG findings with Prinzmetal angina? Why?
- ST elevation
- Complete loss of blood supply to all layers of the myocardium
What are the meds that are used in Prinzmetal angina, and how do they relieve chest pain?
NTG- vasodilation
CCB- vasodilation + stop spasms
What is the cause of an MI?
Complete occlusion of a coronary artery by plaque or spasm
How long does the chest pain last with an MI?
Greater than 20 minutes
Is the chest pain with an MI relieved by NTG administration?
No
What is the most common artery that is occluded in an MI? What does this cause in terms of heart wall damage?
- LAD
- Anterior wall of the LV infarction
What is the artery that supplies the inferior wall of the ventricle?
RCA
What is the artery that supplies the left lateral wall of the LV?
LCX
Which layer of the heart is undergoes necrosis first in an MI? What will will the EKG show?
- Subendocardium
- ST depression
What is the most sensitive test for an MI? When does this rise, and for how long?
- Troponin I
- Rises 2-4 hours after infarction, peaking at 24 hours, and returning to normal at 7 days
What is the use of CK-MB?
Rises 4-6 hours, but returns to normal after 72 hours. Thus can be used to r/o a reinfarction after a recent MI
What is the treatment for an MI?
- ASA/heparin
- Supplemental O2
- Nitrates
- Beta blocker
- ACEI
What is the use of beta blockers in an MI?
Lower oxygen demand by decreasing contractility
Lower BP