Myocardial Infarction CAT Flashcards
Etiology of MI
Poor coronary artery perfusion leads to ischemia, followed by necrosis of the cardiac tissue
What causes MI?
Thrombus, arterial blockage or atherosclerosis
Transmural MI
Full-thickness of the myocardium
Nontransmural MI
Involves the subendocardial area (inner 1/3 of myocardium)
Zones of injury to the myocardium
- Zone of infarct
- Zone of hypoxic injury
- Zone of ischemia
Which artery is the most common location of infarct?
- Anterior descending branch of the L coronary artery
- Affects the L ventricle
Thrombosis in the R coronary artery results the myocardium in whicch parts of the heart?
- Posteroinferior portion of the L ventricle
- Can potentially affect the R ventricle
Primary risk factors for MI
- Pt/family hx of heart disease
- Smoking
- Physical inactivity
- Stress
- Hypertension
- Elevated cholesterol
- DM
- Obesity
What time of day/year are MI more common?
- In the morning
- During the November-December holiday season
Prodromal symptoms for MI
- Unstable angina
- Shortness of breath
- Fatigue
S/s for MI
- Deep pain or pressure in substernal area
- Pain may or may not radiate into jaw and into L arm or back
- Pt cannot relieve pain w/ rest or nitroglycerin and it may last for hours
- Anxious, pale, sweating, fatigue, maybe nausea and vomiting
Lab/imaging to confirm diagnosis
- 12 lead ECG (inverted T wave, elevated ST segment for acute MI, depressed ST pending MI)
- Creatine phosphokinase, aspartate transferase, and lactic dehydrogenase can be dramatically altered during and after MI
Arrhythmias occur in what percentage of patients w/ MI?
~90%
Pharmacological management of MI
- Anticoagulants, beta-blockers, thrombolytic agents, angiotensin-converting enzyme inhibitors, vasodilators
- Surgical intervention
Exercise testing w/ MI
Takes place 3 days post-MI to establish baseline
