Cardiac Labs

Question 0

BNP values

Answer 0

B-type natriuretic peptide 
BNP Level (pg/mL)
Compensated CHF
100 – 199
Moderate CHF
200 – 400
Moderate to severe CHF
>400

Question 1

BNP definition

Answer 1

B-type natriuretic peptide.

• The main clinical utility of either BNP or NT-BNP is that a normal level rules out acute heart failure in the emergency setting.
• BNP is secreted by the ventricular myocardium and acts as a vasodilator when the heart senses volume overload resulting in excessive retention of sodium and water.
• In addition, BNP when released will attempt to suppress the reninangiotensin system and decrease sympathetic tone.
• It is often used to aid in the diagnosis of (CHF).
• Higher levels of BNP or NT-proBNP are often associated with a worse outlook (prognosis) for the person.
• Normal results indicate that the person’s symptoms are likely due to something other than heart failure.

Question 2

Cardiac Output definition

Answer 2

(Q or CO )

• Q ≈ (HR × SV) ≈ MAP / TPR(total peripheral resistance)
• Cardiac output is the measurement of the volume of blood pumped by the heart every minute.
• It is a function of heart rate and stroke volume.
• It is a very important measurement that Is commonly found on echocardiogram and is often used to assess cardiac dysfunction.
• increasing resistance decreases Q; conversely, decreased resistance increases Q.(vascular resistance)

Question 3

Cardiac Output value and reasons for high or low values

Answer 3

5L/min
High
Anemia, exercise, septic shock.
Low
Acute respiratory distress syndrome, anaphylaxis, cardiac tamponade, cardiogenic shock, dilated cardiomyopathy, hypovolemic shock, neurogenic shock.

Question 4

Ck-mb definition

Answer 4

Aka Creatinine kinase-MB, CPK-MBm
CK-MB is a marker for cardiac ischemia (myocardial infarction). There are 3 isoenzymes of CK distributed variably among muscle tissue (heart, skeletal muscle, brain), thus CKMB is not as specific for cardiac muscle as other cardiac markers such as troponins.
have now been largely replaced by the troponin test, which is more specific for damage to the heart. If a troponin test is not available, then the CK-MB test is still considered an acceptable substitute. Since CK-MB is also present in small quantities in skeletal muscle, significant damage to skeletal muscles can also increase the CK-MB level.

Question 5

Ck-mb value and how to interpret those findings

Answer 5

0-5 ng/ml
If CK-MB is elevated and the ratio of CK-MB to total CK (relative index) is more than 2.5–3, it is likely that the heart was damaged. A high CK with a relative index below this value suggests that skeletal muscles were damaged.

Question 6

What are the normal values of creatinine kinase for females and males?

Answer 6

30-135u/l female

55-175 U/L male

Question 7

What does high ck mean?

Answer 7

Alcoholism, extensive rhabdomyolysis, muscle trauma, mi, Tetnus, stroke, myocarditis. Plasma CK levels are helpful in diagnosing rhabdomyolysis, because objective clinical signs are often absent. Muscle trauma and burns also significantly elevate CK.

Question 8

What is the ck index?

Answer 8

Since CKMB is not specific for cardiac damage, CK Index is used to distinguish cardiac from non-cardiac elevations of CKMB. Combines total ck and comb into an index.

Question 9

What are the ck index values and how do you interpret it?

Answer 9

The equation for CK Index is (CKMB mass ng/mL)*100/(Total CK activity U/L)
* If the CKMB < 10 ng/mL and an index 10 ng/mL and an index >2.5 indicates cardiac damage. *CKMB >10 ng/mL and an index <2.5 indicates skeletal muscle damage

Question 10

What is ck?

Answer 10

Creatinine kinase
Creatine kinase is an enzyme that catalyzes the reversible phosphorylation of creatine by ATP. The end product, phosphocreatine, is a readily available energy source for cells. CK is present in many tissues but skeletal and heart muscles contain the highest concentrations. CK released from skeletal muscle accounts for almost all of the CK activity detected in the plasma of healthy individuals.

Question 11

What is ejection fraction and what does it mean?

Answer 11

Ejection fraction is a measurement of the percentage of blood that is ejected from the heart in a single cardiac cycle (heartbeat). Specifically it is the volume of blood in the ventricle at the end of diastole (EDV) divided by the volume in the ventricle at end of systole (ESV). EF is a very important marker used to assess cardiac function and can help deterermine the severity of heart failure

Question 12

What is a normal ejection fraction? How do you measure it?

Answer 12

> 55%

Echocardiograph usually

Question 13

What causes high and low ejection fraction?

Answer 13

High
Exercise, hypertrophic cardiac myopathy
Low
MI, left ventricular dysfunction, ischemic cardiac myopathy

Question 14

What are the equations used to get CO?

Answer 14

Q=HRXSV=MAP/TPR

Question 15

What is stroke volume?

Answer 15

It is the volume of blood pumped out by the heart in one beat.

Question 16

How is SV found?

Answer 16

Echocardiogram. It is calculated by subtracting the end systolic volume from the end diastolic volume.

Question 17

What factors effect stroke volume?

Answer 17

Age, gender, heart size, contractility, after load, preload, duration of contraction

Question 18

What is a normal stroke volume?

Answer 18

Approx. 70 ml. Both ventricles are generally equal

Question 19

What physiologic factor has a direct correlation to SV?

Answer 19

Preload, decrease venous return decreases SV

An increase in volume or venous return will increase preload

Question 20

What are troponins?

Answer 20

Troponins are proteins of cardiac muscle that give the most specificity of for cardiac injury. Elevated troponins are also associated with future adverse cardiac events.

Question 21

What do elevated troponins indicate?

Answer 21

Chf, myocardial injury, cardiac surgery, cardiac trauma, dilated cardiac myopathy, MI, myocarditis, prolonged SVT, unstable angina

Question 22

What is a normal value for troponin I?

Answer 22

<0.04ng/ml

Question 23

What is the normal level for troponin T?

Answer 23

<0.1ng/ml

Question 24

What is myoglobin?

Answer 24

Myoglobin is an oxygen binding protein found in skeletal and cardiac muscle. Therefore it is elevated in skeletal or cardiac muscle damage. It has low specificity for marking cardiac damage. Can be use to aid in mi recognition.