#10 - Ischemic Heart Disease (Brown)

Question 1

List the 4 ways ischemic heart disease can manifest clinically

Answer 1

• chest discomfort
• heart failure / shortness of breath
• abnormal EKG/ stress test
• arrhythmia

Question 2

What percentage of death due to cardiac disease are “sudden deaths”?

Answer 2

60%

Question 3

How many sudden deaths are instantaneous?

Answer 3

1/3

Question 4

How many sudden deaths occur outside the hospital?

Answer 4

70%

Question 5

Most sudden cardiac deaths are due to which type of arrhythmia?

Answer 5

ventricular fibrillation

Question 6

T/F: Most sudden cardiac deaths are caused by acute MIs.

Answer 6

False. Most are associated with atherosclerosis and remote MI’s but the majority are due to arrhythmias, NOT caused by acute MIs.

Question 7

T/F Most deaths due to MI are “sudden death” but most sudden deaths are not due to MI

Answer 7

True.

Question 8

What are the 4 direct determinants of myocardial oxygen DEMAND?

Answer 8

• intraventricular systolic pressure.
• ventricular cavity radius
• heart rate
• contractility in the muscle (more actin/myosin units- more energy)

NOTE: stroke volume is not a determinant of oxygen demand!

Question 9

T/F diastolic pressure is more important than systolic pressure for coronary artery blood flow.

Answer 9

True.
(Why?? during systole, when the ventricle contracts, it squeezes the arteries, closing them. Therefore they fill during diastole)

Question 10

What are the 3 main determinants of myocardial blood flow.

Answer 10

• perfusing pressure (diastolic more important than systolic)
• resistance to flow (arterioles, atheroclerosis,)
• right atrial pressure

Question 11

What are the 3 ways resistance in the coronary arteries can change?

Answer 11

• arterioles - they are in charge of normal autoregulation
• obstructions (atherosclerotic plaques/ coronary artery spasm
• myocardial wall tension compresses the intramural portion of the arteries during systole, occluding flow

Question 12

What are the 2 categories of causes of IHD?

Answer 12

• disease of increased oxygen demands

- diseases of the coronary arteries (atherosclerosis/spasm)

Question 13

Which diseases cause ischemic heart disease through increased oxygen demands.

Answer 13

aortic valve disease (stenosis/insufficiency) –> hypertrophy of the LV wall, with inadequate capillary growth to supply blood to new tissue –> ischemia.

Question 14

T/F- the diagnosis of ischemic heart disease depends on the coronary angiogram

Answer 14

FALSE. Diagnosis is based on the history.

Question 15

Describe the type of pain in angina

Answer 15

tightness, aching, squeezing, pressure or weight, or burning.

Question 16

List 5 things that can increase heart rate/BP and help to provoke a heart attack. (Hint: remember Netter picture).

Answer 16

• heavy meal
• cold temperature
• activity early in the day (higher HR)
• activity involving arms
• cigarrettes.

netter picture from the ppt: guy leaving restaurant in the cold, carrying heavy briefcase. he was also smoking.

Question 17

How long does angina last?

Answer 17

usually 3-5 minutes.
sometimes 5-15 min
rarely 15-20 min

Never more than 30 min after rest or nitroglycerin.

Question 18

What are the 3 criteria for clinical diagnosis of angina? How do tthey relate to typical angina, atypical angina, and noncardiac chest pain?

Answer 18

1) substernal chast discomfort with a characteristic quality and duration.
2) chest discomfort is provoked by exertion or emotional stress\
3) relieved by rest or nitroglycerin

Typical angina = all 3
Atypical (probable) angina = 2/3
noncardiac chest pain = 1 or none /3

Question 19

T/F: Physical exam is very useful for diagnosing stable angina.

Answer 19

False. It is often unrevealing, especially if the angina is not presently occurring. This is why they make people do the stress test.

Question 20

What are the 3 main tests used for diagnosis of ischemic heart disease?

Answer 20

• EKG (during rest doesn’t show much)
• Treadmill test (along with concurrent testing)
• coronary angiography (remember angiography doesn’t make the diagnosis by itself)

Question 21

When should (and shouldn’t) a treadmill test be used in the evaluation of ischemic heart disease?

Answer 21

It should be used for patients with stable, typical angina, or probable angina.

DO NOT order this test for someone with unstable angina or an acute MI - that person needs to be hospitalized!!

Question 22

What are the advantages of a treadmill test?

Answer 22

• it is most practical (most available and cheapest)

- correlates patient’s BP/HR with symptoms and ST depression on EKG

Question 23

Coronary angiography shows a patient with angina has vessels that are 40% occluded. What is the conclusion? Does this person have severe or mild disease?

Answer 23

Mild. This is likely not causing severe disease. Coronary arteries are twice as wide as they need to be, so the lumen must be

Question 24

Definition of MI

Answer 24

a more prolonged imbalance between blood flow and oxygen demand, which is documented to have produced myocardial necrosis.

Question 25

How do you make a diagnosis of MI?

Answer 25

Almost always, associated with angina. | However, EKG changes or biochemical changes (troponin) is necessary to make the diagnosis.

Question 26

How long does angina from an MI last?

Answer 26

usually 1/2 hour to several hours.

Question 27

Clinical presentation of an MI

Answer 27

BP and HR vary Fever may be present (reaction to necrosis) -angina, often accompanied by sweating nausea vomiting or weakness -almost all patients will have S4 gallop. S3 may be present -pericardial friction rub - 24 hrs after onset of pain

Question 28

What heart sound is almost always heard in an acute MI patient?

Answer 28

S4 gallop

Question 29

T/F: physical exam is very important in an Mi patient.

Answer 29

True.

Question 30

Which EKG changes are diagnostic of MI?

Answer 30

- pathological Q waves | - ST-T changes.

Question 31

What is the window for testing troponin for an MI?

Answer 31

it peaks at 6-8 hours but may remain normal for 1-2 weeks.

Question 32

What are the major complications of acute MIs?

Answer 32

1) arrhythmias of all types (PVCs, tachycardia, ventricular fibrillation) - remember that ventricular fibrillation is major cause of death from acute MI) 2) Heart failure. 3) hypotension

Question 33

How might heart failure due to an acute MI manifest?

Answer 33

at first, only the finding of an S3 gallow and persistent relative sinus tachycardia at rest.

Question 34

T/F: If there is no ST elevation in an MI (but positive troponin), there is likely a pathological Q wave present.

Answer 34

FALSE. Q waves tend to accompany ST changes. If ST elevation present, Q wave likely (not always) present. And vice-versa.

Question 35

Definition of unstable angina?

Answer 35

angina without stable, exertional pattern, without ST elevation on EKG or elevated troponin. This includes -new onset angina (even if exertional) -exertional angina but occurring with increasing frequency or with preipitation by lesser degrees of exertion -angina at rest or during sleep -prolonged angina of >20 -30 min duration

Question 36

Definition of stable angina

Answer 36

angina with a predictable exertional pattern which has been present for >1 month.

Question 37

What is the major mechanism for all the acute coronary syndromes?

Answer 37

unstable/ruptured atherosclerotic plaque.

Question 38

Which is NOT a determinant of myocardial oxygen demand? - intraventricular systolic pressure. - ventricular cavity radius - stroke volume - heart rate - contractility in the muscl

Answer 38

Stroke volume. Think of it this way: lowering your blood pressure means your heart would have a larger stroke volume with the same amount of energy output/o2 requirements. Stroke volume is dependent on more than the energy the heart is expending. On the contrary, the heart could be working its ass off, but b/c of atrial valve stenosis, get low stroke volume.

Question 39

What is a determinant of all 3: oxygen delivery, blood pressure, and myocardial demands?

Answer 39

Heart rate

Question 40

You see a patient who has angina at rest. Is this sufficient for a diagnosis of atypical angina?

Answer 40

Yes. Hospitalize that shit!