Ischemic Heart Disease

Question 1

Define ischemic heart disease.

Answer 1

Imbalance between myocardial oxygen demand and supply

Question 2

During what phase of the cardiac cycle is there the lease resistance to coronary artery blood flow?

Answer 2

Diastole

Question 3

What is the most common site for coronary artery thrombosis?

Answer 3

LAD

Question 4

What regions does the LAD perfuse?

Answer 4

Anterior LV, anterior 2/3 IVS, apex

Question 5

What is the second most common site of coronary artery thrombosis?

Answer 5

RCA

Question 6

What regions does the RCA perfuse?

Answer 6

Posterior LV, posterior 1/3 IVS, RV, posteriormedial papillary muscle, SA/AV nodes

Question 7

What is the most common manifestation of IHD?

Answer 7

Angina pectoris

Question 8

What are the causes of stable angina?

Answer 8

Atherosclerotic CAD (most common), AV stenosis or HTN w/ concentric LVH, hypertrophic cardiomyopathy, cocaine induced coronary artery vasoconstriction

Question 9

What is the pathogenesis of stable angina pectoris?

Answer 9

Subendocardial ischemia; decreased coronary artery blood flow or concentric hypertrophy

Question 10

What are the clinical findings in stable angina?

Answer 10

Exertion induced substernal chest pain, often accompanied by SOB, diaphoresis

Question 11

What is the treatment for an acute episode of stable angina?

Answer 11

Nitroglycerin (0.3-0.6 mg SL q5min)

Question 12

What is the mechanism of action for nitroglycerin?

Answer 12

Decreases oxygen demand (dec. preload due to venoldilation)

Increased oxygen supply (inc. coronary perfusion and decrease vasospasm)

Question 13

In a patient with stable angina, what would be seen on ECG?

Answer 13

ST-segment depressions (>1mm)

Question 14

Prinzmetal (variable) angina is characterized by intermittent coronary artery vasospasm at rest or w/o superimposed CAD. What would a stress test show?

Answer 14

ST-segment elevations

Question 15

Define unstable angina.

Answer 15

Increased frequency and duration of angina episodes produced by less exertion or at rest; high frequency of progression of MI if untreated

Question 16

What diagnostic tests are helpful in diagnosis IHD?

Answer 16

Resting ECG, stress test, coronary angiography

Question 17

What drugs are used to treat IHD; how do they work; when would you use them?

Answer 17

Nitrates
Beta-blockers (decreas oxygen demand by decreasing HR and contractility) initial tx for all patients with stable angina)
Ca channel blockers (decrease preload, wall stress, contractility, HR, coronary vasospasm and increase coronary perfusion; variant angina)
Aspirin for all, clopidogrel if pt allergic to aspirin
Heparin+aspirin (unstable angina)
Ranolazine (decresaes late inward Na current; stable angina for pts refractory to other drugs)
Statins (inhibit HMG-CoA which decreases LDL and increases HDL, also anti-inflammatory; pts w/ dyslipidemia)

Question 18

What are the side effects of nitrates?

Answer 18

Headaches, hypotension, reflex tachycardia

Question 19

What are the side effects of beta blockers?

Answer 19

Excessive bradycardia, decreased LV contractile function (worsening of HF), bronchoconstriction, fatigue, impotence

Question 20

What are the side effects of Ca channel blockers?

Answer 20

Headache/flushing, decreased LV contraction, marked bradycardia, edema, constipation

Question 21

What are the adverse effects of Ranolazine?

Answer 21

Dizziness, headache, constipation, nausea

Question 22

What drug is used to prevent thrombosis in revascularization procedures?

Answer 22

Abciximab

Question 23

When is CABG indicated?

Answer 23

Left main coronary artery disease or symptomatic 3 vessel disease

Question 24

What graft is the best for CABG?

Answer 24

Internal mammary artery>saphenous vein

Question 25

What is the pathogenesis of a MI?

Answer 25

Plaque rupture, thrombosis, infarct

Question 26

What role does TxA2 play in formation of an MI?

Answer 26

Aids in platelet aggregation and acts as vasoconstrictor

Question 27

What are the types of of MI?

Answer 27

STEMI and NSTEMI

Question 28

What are the two therapeutic methods of reperfusion in MI?

Answer 28

PCI, fibrinolytic therapy

Question 29

Why is early reperfusion important in MI?

Answer 29

Increases early and long term survival

Question 30

When do contraction bands appear?

Answer 30

Reperfusion of irreversibly damaged cells that leads to the entry of Ca in to cytosol causing hypercontraction

Question 31

When does coagulation necrosis appear following an MI?

Answer 31

24 hours

Question 32

When do macrophages break down the necrotic tissue and what danger exists during this period?

Answer 32

3-7 days; danger of rupture

Question 33

What are the clinical findings of MI?

Answer 33

Sudden onset of severe retrosternal pain, usually longer than 30 min, not relieved by nitroglycerin, usually radiates, associated with sweating/anxiety/hypotension

Question 34

What is the most common cause of death in STEMI?

Answer 34

V-fib

Question 35

What are the complications of STEMI?

Answer 35

Cardiogenic shock, arrhythmias (ventricular most common), CHF, rupture, mural thrombus, pericarditis, ventricular aneurysm

Question 36

Detail the temporal sequence of CK-MB.

Answer 36

Appears in 4-8 hours, peaks at 24 hours, disappears in 3 days

Question 37

Detail the temporal sequence of cardiac troponins.

Answer 37

Appear 3-12 hours, peak at 24 hours, disappear in 10 days

Question 38

What serum biomarker can be used to diagnose reinfarction?

Answer 38

CK-MB

Question 39

What serum biomarker is the gold standard for diagnosis of MI?

Answer 39

Cardiac troponins