Laboratory Findings for Heart Disease Detection & Management

Question 1

What are the three types of natriuretic peptides and where are they found?

Answer 1

Atrial natriuretic peptide: 28-aa peptide found in the atrium of the heart

B-type natriuretic peptide: 32-aa peptide found mainly in the ventricles of the heart

C-type natriuretic peptide: 53- and 22-aa peptides found in the endothelium

Question 2

Which natriuretic peptide will be most useful to diagnose heart conditions?

Answer 2

B natriuretic peptide (BNP)

-released in response to stretch from incr. volume in ventricles

Question 3

BNP’s are useful for their specificity (if they’re normal, prob not HF). What non-related heart factors will increase BNPs?

Answer 3

BNP levels tend to be higher in women, elderly BNP levels elevated in renal insufficiency

*BNP is normally < 100 pg/ml

Question 4

Your patient is a 68 yo male with history of coronary artery disease (CAD), hypertension, tobacco use, 3 months of increasing shortness of breath (SOB), decreasing energy level and increasing edema.

Tests: Chest: Crackles one-third of way up posteriorly Cardiac: Regular rate and rhythm, S4 and S3 gallops, III/VI systolic murmur at apex radiating to axilla

Abdomen: Enlarged liver

Extremities: 2+/4 edema to knees

What is your diagnosis? Explain why with each of these symptoms?

Answer 4

Right and left-sided HF

• SOB: pulmonary hypertension (left sided failure)
• edema/ splenomegaly: right sided back up
• decreased energy: low CO
• crackles: pulmonary edema
• S4: stiff ventricle
• S3: abnormal due to age; dilated ventricles
• systolic murmur at apex: mitral regurg. (left side problems)

Question 5

What would you do next?

Answer 5

ECG and order blood tests, then echo

Question 6

Your patient is a 42 year old female: BP 98/60, HR 62, RR 18

Chest: clear to auscultation and percussion

CV: Regular rate and rhythm, II/VI systolic murmur at lower left sternal border and apex, II/VI early diastolic “rumble” murmur at apex

Explain what each PE finding means…

Answer 6

Syst. murmur @ lower left sternal border: tricuspid regurg.

systolic murmur @ apex: mitral regurg.

early diastolic rumble: mitral stenosis

Question 7

Again from last lecture, what are the typical steps of progression with coronary artery disease?

Answer 7

• Asymptomatic, non-obstructive CAD
• Ischemia

–Stable exertional angina

–Unstable angina

•Myocardial infarction (MI), cellular necrosis

Question 8

While doing an echo you see decreased movement with the anterior wall down to the apex. There is mostly likely problems with which coronary artery?

Answer 8

Left anterior descending

Question 9

So we know that troponins are proteins specific to heart released from myocyte necrosis..

But how long after injury until you can detect troponin in the blood?

How long until they peak?

Answer 9

• Myocardial necrosis leads to release of Troponin into blood within 3-12 hours, peaking in 18-24 hours
• Look for rise and fall in appropriate time frame (prolonged in renal failure)

Question 10

What are your findings on the ECG?

Answer 10

ST elevation in inferior leads (II, III, AVF) and V3

**Right coronary artery

Diagnosis: Acute ST elevation MI

Question 11

Your patient has Troponin of .01 (normal <.5) and creatinine of .9. Does he not have an MI? What additional info does this give you?

Answer 11

Troponin is normal because it was so soon and it hasn’t gotten into blood yet. Could still have MI

Creatinine is normal. So patient is good to go to cath lab. HURRY!