Cardio Exam 1 CBL Flashcards
What cardiac labs can be ordered?
Enzymes
- CK/CPK
- LDH
- Troponin T/I
- Glycogen phosphorylase isoenzyme BB
B-type natiuretic peptide (BNP)
CBC
Myoglobinemia/myoglobinuria
What is CK/CPK
Catalyses the conversion of creatine to create phosphocreatine and ADP
What are the three isoenzymes for CK/CPK
CK-MM: skeletal muscle
CK-MB: myocardium
CK-BB: brain
What are the normal CK/CPK values
60-400 IU/L
When are low levels of CK seen
Alcoholic liver disease
Rheumatoid disease
When are elevated CK levels seen
Muscle damage:
-rhabdo
-muscular dystrophy
-myositis
-malignant hyperthermia
-statin meds
Myocardial Infarction:
-peaks in 10-24 hours
-returns to normal in 2-3 days
What is LDH
Enzyme that catalyzes the conversion of pyruvate to lactate
Which is more specific, LDH or Troponin
Troponin
What are the 5 isoenzymes of LDH
LDH-1: heart and RBC’s*
LDH-2: Reiculoendothelial system (typically the predominant form)
LDH-3: Lungs
LDH-4: Kidneys, placenta, and pancreas
LDH-5: Liver and striated muscle
What is notable about LDH in MI
LDH-1 > LDH-2
Peaks in 3-4 days (72 hours)
Remain elevated for up to 10 days
What is notable about LDH in pleural effusion/pericardial effusion
Exudate: Ratio > 0.6 (Fluid LDH: Serum LDH)
Transudate: Ratio < 0.6
What is troponin
Most sensitive and specific test for myocardial damage; virtually undetectable in a healthy patient
What are the subtypes of troponin?
Troponin I
Troponin T
Troponin C
(I or T is measured, not both)
What does it mean if Troponin is elevated (cardiac)
Myocardial infarction
- released in 2-4 hours
- Peaks at 12 hours
- Remains elevated for up to 7 days
Severe tachycardia, heart failure, cardiomyopathy, defibrillation/cardioversion, cardiac surgery
What does it mean if troponin is elevated (non-cardiac)
Critical illness/sepsis (40%)
Chemotherapy agents
Toxins/Venoms
Pulmonary Embolism/Pulmonary HTN
What is myoglobin?
Iron and oxygen-binding protein in the muscle tissue; low specificity for MI and least used MI marker
What is the upside of myoglobin?
Responds the quickest - peaks in 2 hours
*also elevated in rhabdo
What is BNP - B-type natriuretic peptide
Secreted by the ventricle of the heart in response to excessive stretching of heart muscle
What are the effects of BNP?
Decrease in cardiac output - decrease in SVR
Decrease in blood volume - increase in natiuresis
What is BNP mostly used for?
Used in the diagnosis and screening of acute congestive heart failure (CHF)
What is an interesting fact about BNP
It is what makes you feel like to have to pee after getting into a bathtub or a pool
Why would you order a CBC if an MI is inspected
Rule out anemia which can decrease oxygen supply
Evaluate platelets if a thrombolytic is to be given if heparin was given recently
What does a WBC count have to do with an MI
Leukocyte count may be normal initially, but increases within 2 hours and peaks in 2-4 days
May remain elevated for 1-2 weeks
What is the AMA approved lipid panel used to evaluate the risk of coronary heart disease
LDL cholesterol
HDL cholesterol
Total cholesterol
Triglycerides
