Cardiac Function

Question 1

Describe what occurs when a patient has congestive heart failure.

Answer 1

Inability to pump effectively. Fluid accumulates within the lungs and causes a decreased cardiac output.

Question 2

What three organs does hypertension affect?

Answer 2

Kidney, brain and heart.

Question 3

What occurs in hypertensive heart disease?

Answer 3

Increased peripheral resistance and left ventricular workload.

Question 4

Describe what occurs in acute coronary syndrome.

Answer 4

Reduced blood flow to the heart.

Question 5

Describe what occurs in ischemic heart disease.

Answer 5

Obstruction of the blood supply resulting in lack of nutrients and oxygen.

Question 6

What are some risk factors for coronary syndrome?

Answer 6

Age, sex, family history, hyperlipidemia (increased LDL), smoking, hypertension, sedentary lifestyle, diabetes mellitus, and response to stress.

Question 7

Describe what occurs in acute myocardial infarction.

Answer 7

Blocked blood flow which leads to ischemia and tissue death.

Question 8

What is the function of Aspartate Aminotransferase (AST)?

Answer 8

The synthesis and degradation of amino acids.

Question 9

What is the clinical significance of AST?

Answer 9

Indicative of hepatocellular disorders (4X ↑ - cirrhosis; 50-100X ↑ - hepatitis), skeletal muscle disorders, acute myocardial infarction, and pulmonary embolism.

Question 10

AST > ALT is indicative of what?

Answer 10

Alcohol or drug related hepatic disorders.

Question 11

What is the function of Lactate Dehydrogenase (LD)?

Answer 11

Glycolysis; catalyzes the interconversion of lactic and pyruvic acid; hydrogen-transfer.

Question 12

How many isoenzymes are there for LD?

Answer 12

Five.

Question 13

What are the five different isoenzymes for LD, and where are they most prominent?

Answer 13

LD1 - Heart
LD2 - Kidney
LD3 - Lungs, spleen, pancreas, lymphs
LD4 - Liver, skeletal muscles
LD5 - Skeletal muscles

Question 14

What is the clinical significance of LD?

Answer 14

Highest levels occur during hemolytic anemia, pernicious anemia, shock, and hypoxia.

Moderate levels occur in myocardial infarction: LD1.

Question 15

What is the function of creatine kinase (CK)?

Answer 15

Catalyzes reversible phosphorylation-dephosphorylation; an enzyme found within the cytoplasm and mitochondria.

Question 16

What is the clinical significance of creatine kinase?

Answer 16

Myocardial infarction:

 - Rise ~ 4 - 8 hours
 - Peaks ~ 12 - 24 hours
 - Returns to normal ~48 to 72 hours

Question 17

What are the three isoenzymes for CK, and where are they located?

Answer 17

CK - MM : Muscle
CK - MB : Hybrid
CK - BB : Brain

Question 18

How do the cardiac proteins change with cardiac damage?

Answer 18

They increase.

Question 19

What is the clinical significance of Myoglobin?

Answer 19

2% of total muscle, found in striated skeletal and cardiac.

Question 20

When would myoglobin be increased?

Answer 20

Acute myocardial infarction and progressive muscular dystrophy.

Question 21

What are the three different isoenzymes for troponin?

Answer 21

T, I, and C.

Question 22

What is the function of Troponin?

Answer 22

To regulate muscle contraction.

Question 23

When can you find Troponin T & I increased?

Answer 23

Acute myocardial infarction and ischemic heart disease.

Question 24

Why is HS-CRP helpful to monitor heart disease?

Answer 24

It’s a liver protein that increases rapidly with inflammation; small increases predict vascular disease/cardiac events.

Question 25

Why is homocysteine helpful to monitor heart disease?

Answer 25

Increases cause disulfide bridging with proteins; causes a direct injury to vessels.

Question 26

What are other helpful serum markers to monitor during acute coronary syndromes?

Answer 26

Fibrinogen, D-Dimer, Ischemia-modified albumin, and Lp-PLA2

Question 27

Why would Brain-type Natriuretic Peptide (BNP) be helpful when monitoring heart disease?

Answer 27

It is a peptide hormone that is secreted by cardiac vesicles. BNP stimulates excretion of sodium by kidneys and increases urine flow. Elevated levels occur in diseases that expand fluid volume.