Cardiac Diagnostic Testing and Invasive Cardiology

Question 1

When are cardiac biomarkers used?

Answer 1

in the diagnosis and risk stratification of patients with cardiac symptoms. Not necessary for the diagnosis of patients who present with ischemic chest pain and EKGs with ST elevation

Question 2

What are the cardiac biomarkers?

Answer 2

Troponin, Creatinine Kinase, Myoglobin

Question 3

What is troponin?

Answer 3

Protein that is integral to muscle contraction. Troponin I and Troponin T are isolated proteins specific for cardiac muscle. Marker for cardiac muscle cell death

Question 4

Describe the troponin levels after cardiac insult

Answer 4

rises within 2-3 hours and may stay elevated for 10-14 days after event. “Wash out” after thrombolytics will cause significant rise in Troponins

Question 5

What is creatine kinase?

Answer 5

Enzyme found in muscle cells. Elevations can be indicative of injury, rhabdomyolysis, MI, myositis, myocarditis. in hypothyroidism when T3 is low, CK becomes elevated. statins can increase CK.

Question 6

What are the 3 isoenzymes of creatine kinase?

Answer 6

CK-MM (skeletal muscle and heart), CK-MB (Heart), CK-BB (Brain)

Question 7

Describe CK-MB levels after cardiac insult

Answer 7

Noted at 4-6 hours after onset of symptoms. Peaks at 24 hours and normalizes in 48-72 hours

Question 8

How does the CK-MB/CK relative index help determine cardiac vs skeletal muscle injury?

Answer 8

Calculated by the ratio of CK-MB to the total CK. Ratio less than 3 = skeletal muscle source. Ratio greater then 5 = cardiac source

Question 9

Describe myoglobin levels after cardiac insult?

Answer 9

rises 2-4 hours after onset of infarction. Peaks at 6-12 hours. Normalizes in 24-36 hours. Low sensitivity for AMI due to lack of cardioselectivity

Question 10

What lab tests are used for CV risk assessment?

Answer 10

lipid profile, hs-CRP, homocystine

Question 11

How is an elevated high sensitivity CRP interpretated?

Answer 11

2-3 times the risk of MI, stroke, sudden cardiac death and peripheral arterial disease. Stronger predictor of heart disease and stroke than LDL

Question 12

What is homocystine?

Answer 12

Amino acid acquired mostly from meat protein. Elevated levels of homocystine are related to low levels of B6, B12 and folate

Question 13

What disease processes have been linked to hyperhomocystinemia?

Answer 13

Prone to endothelial injury, Blood clots, Heart attack, Stroke, Miscarriage, Pre-eclampsia

Question 14

What is brain naturetic peptide?

Answer 14

Produced by the ventricles and atria in response to an increase in volume and pressure. Stimulates the release of atrial naturetic peptide (Na excretion to decrease body water volume)

Question 15

How is BNP used as a cardiac diagnostic test?

Answer 15

May be helpful in differentiating between CHF and lung disease. Do not use routinely to follow CHF

Question 16

What is AST (asprtate transaminase)?

Answer 16

Enzyme released into the blood when certain organs or tissues, particularly the liver and heart, are injured. Used for evaluation of liver disease

Question 17

What is LDH (lactate dehydrogenase)?

Answer 17

Found extensively in body tissues, such as blood cells and heart muscle and is released during tissue damage

Question 18

How is LDH-1 used as a cardiac diagnostic test?

Answer 18

Not useful for the diagnosis of MI. Elevated in hemolytic anemia (may check if a pt has valve disease and anemia)

Question 19

What are the different types of cardiac stress tests?

Answer 19

Regular exercise stress test (treadmill only). Nuclear stress test (Cardiac perfusion images plus treadmill). Stress echo (Cardiac images to assess wall motion plus treadmill). Pharm agents used for those who can’t excercise

Question 20

What are contraindications to stress testing?

Answer 20

acute MI, unstable angina, acute pericarditis, acute systemic illness, severe aortic stenosis, CHF exacerbation, severe HTN, uncontrolled arrhythmias

Question 21

What pharmacologic agents can be used for stress testing?

Answer 21

Adenosine* or persantine (potent vasodilators). Dobutamine (positive inotropic and chronotropic agent) and is only agent that can be used for a stress echo

Question 22

How are stress echos used?

Answer 22

Detect wall motion abnormalities, lack of thickening of the LV with stress, reduced EF with stress. Not great for existing LBBB. May be limited by obesity or hyperinflation of the lungs

Question 23

What information does an echo provide about cardiac structure and function?

Answer 23

Chamber size, muscle thickness, Ejection fraction, wall motion, Aortic root size, Valve structure and function, Intracardiac blood flow (shunts, pressures)

Question 24

When is a transesophageal echo used?

Answer 24

Intracardiac thrombus prior to direct current cardioversion, Valve function in ORs, Endocarditis

Question 25

What is the difference between a holter monitor and an event montor?

Answer 25

holter monitor is worn for 24 hrs. patient records activities and sx. event monitor worn for a month. patient triggers the monitor to record during sx.

Question 26

What are ambulatory cardiac monitors used to asses?

Answer 26

Palpitations, assess rate control or determine percent of atrial fibrillation, syncope, suspected bradycardia, suspected or known arrhythmias

Question 27

What are electrophysiologic studies (EPS)?

Answer 27

Records an internal EKG. Defines conduction system disease. Attempts to induce arrhythmias (SVT and VT). Measure response to pharmacologic and/or pacing device intervention

Question 28

What are electrophysiologic studies (EPS) indicated for?

Answer 28

Unexplained syncope, Survivors of sudden cardiac death that was not related to an ischemic event, Palpitations preceding syncope, Poorly tolerated episodes of SVT

Question 29

What is balloon angioplasty?

Answer 29

balloon catheter is advance through artery until the tip is beyond the narrowing. balloon is inflated and once plaque has been compressed it’s deflated and removed

Question 30

What is the post-op treatment plan for angioplasty?

Answer 30

with or without stent placement aspirin for life. with stent placement with also need Plavix for 6-12 months

Question 31

When is a transcutaneous pacemaker recommended?

Answer 31

for the initial stabilization of hemodynamically significant bradycardia until transvenous pacing or other therapies can be applied

Question 32

What are indications for a pacemaker?

Answer 32

Sick sinus syndrome, Symptomatic sinus bradycardia, Tachy-brady syndrome, Afib with slow ventricular response, 3rd degree heart block, Chronotropic incompetence (Inability to increase heart rate to match exercise), Prolonged QT syndrome

Question 33

When is a biventricular pacemaker recommended?

Answer 33

advanced heart failure. The combination of three leads creates a synchronized pumping of the ventricles. May increase EF

Question 34

When are the indications for ICDs?

Answer 34

Primary prevention in pt’s with EF less than 35%.

Secondary prevention for history of sudden cardiac death, VT or VF.

Question 35

What is pacemaker syndrome?

Answer 35

Patient feels worse after pacemaker placement and presents with progressive worsening of CHF symptoms due to loss of atrioventricular synchrony