Ischemic Heart Disease Flashcards
Biggest cause of ischemic heart disease?
Obstructive atherosclerotic lesions in the coronary arteries.
Four acute coronary syndromes (ACS)?
Angina pectoris Myocardial infarction Chronic IHD with heart failure Sudden cardiac death
68 y/o man experiences paroxysmal and recurrent attacks of substernal and precordial chest discomfort with running. Pain goes away with rest or vasodilation. What is his dx?
Stable Angina Caused by an imbalance of perfusions relative to myocardial demand, 75% occlusion.
Angina caused by coronary artery spasm unrelated to physical activity, HR, or BP. Relieved by vasodilators and calcium channel blockers.
Prinzmetal Angina
Type of angina seen in artery occlusion of 90% or greater. Pattern of increasingly frequent pain of prolonged duration even at rest.
Unstable Angina Warning of impending acute MI.
What is the sequence of development of an MI?
- Acute change of an atheromatous plaque exposes very thrombogenic contents 2. Platelets adhere to the exposed plaque and degranulate and initiate vasospasm 3. Tissue factor activates the coagulation cascade adding to the bulk of the thrombus 4. Thrombus completely occludes the lumen of the vessel
What percentage of myocardial infarcts occur without coronary vascular pathology? What are the etiologies?
10% 1. Vasospasm with/without atherosclerosis 2. Emboli 3. Ischemia without atherosclerosis or thrombosis
Timeline for injury in MI?
Reversible injury is ischemia lasting no more than 20-30 minutes. Loss of contractility within 60s. Necrosis is complete within 6 hours of onset.
Difference between transmural and subendocardial infarction?
Transmural: Full thickness necrosis. Subendocardial: Necrosis limited to the inner 1/3-1/2 of the ventricular wall. Due to reduction in coronary flow. Non-ST elevation infarcts.
Match the vessel to the location of the infarct: 1. Apex, anterior wall of LV, anterior 2/3 of ventricular septum 2. Posterior 1/3 of septum, RV free wall, posterobasal wall of LV 3. Lateral wall of LV
- Left Anterior Descending Artery (LAD)
- Right Coronary Artery (RCA)
- Left Circumflex Artery (LCA)
Name the stage of MI.
Coagulation Necrosis (1-2 days)
Karyolysis, karyorrhexis, pyknosis.
Removal of the nucleus.
Glycogen depletion.
Name the stage of MI.
Neutrophilic Stage (3-4 days)
Yellow pallor.
Neutrophilic infiltrate.
Name the stage of MI.
Granulation Stage (1-2 weeks)
Granulation tissue with fibroblasts, collagen, and blood vessels.
Macrophages.
Name the stage of MI.
Remote Scar (Months)
Scar not as strong as myocardium.
Can’t tell when the MI has occured after the remote scar has formed.
Name the clinical features of MI.
Rapid, weak pulse.
Diaphoresis.
Dyspnea.
Asymptomatic.
What are the three cardiac markers?
What are advantages of each?
Timeline for rise/peak?
Treatment for MI?
Aspirin
Heparin
Oxygen
Nitrates
Beta Blockers
ACE Inhibitors
Reperfusion (thrombolysis, angioplasty, stent placement, CABG)
What are complications of reperfusion?
Arrythmias
Myocardial hemorrhage with contraction bands
Irreversible cell damage superimpose on the original injury (reperfusion injury)
Microvascular Injury
Prolonged ischemic dysfunction (myocardial stunning)
Chronic IHD?
Progressive heart failure from ischemic myocardial damage.
Function decompensation of hypertrophied noninfarcted myocardium.
Pathophysiology of Sudden Cardiac Death?
Lethal arrhythmia normally triggered by myocardial ischemia.
Arrhythmia normally occurs at a site distant from the conduction system (adjacent to scars of previous MI).
