Chapter 11: Myocardial Infarction

Question 1

A cessation of normal cardiac contractions

Answer 1

Cardiac arrest (asystole)

Question 2

What is the most common cause of cardiac arrest?

Answer 2

V fib

Question 3

An actual necrosis of the heart muscle starved of blood/oxygen

Answer 3

Myocardial infarction

Question 4

What is the most sever consequence of CAD/CHD?

Answer 4

MI

Question 5

Full-thickness infarct from
endocardium to epicardium, usually from clot in major
coronary artery

Answer 5

Transmural infarct

Question 6

MI in which only part of wall undergoes necrosis

Answer 6

Subendocardial infarct

Question 7

Which muscles of the heart are typically involved in an MI?

Answer 7

Muscles of the L ventrical and septum (because they are thicker and require larger blood supply, have greater O2 requirements)

Question 8

Infarcts of the left anterior wall caused by L descending artery blockage are called what?

Answer 8

Widow-maker infarct

Question 9

What are the 4 basic mechanisms that trigger a heart attack (MI or cardiac arrest)?

Answer 9

1) Sudden blockage
2) Hemorrhage
3) Arterial spasm
4) Sudden greatly increased myocardial oxygen requirements.

Question 10

True or false: MI patients usually develop one or more complications.

Answer 10

True

Question 11

What is the 5 year survival rate following an MI?

Answer 11

80%

Question 12

What are the 3 major causes of death following an MI?

Answer 12

1. Fatal arrhythmia
2. Heart failure
3. Cardiac rupture with
   cardiac tamponade

Question 13

What percentage of MI’s begin with angina? What percentage occur without warning?

Answer 13

50%; 50%

Question 14

What is the most important blood enzyme test for MI dx?

Answer 14

Troponin T and troponin I

Question 15

In what percentage of cases can you dx an MI accurately with an EKG and troponin test?

Answer 15

99%

Question 16

How can angina pectoris be treated?

Answer 16

1) Rest

2) Vasodilator (e.g., nitroglycerin)

Question 17

What does temporary insufficient blood supply to the heart lead to?

Answer 17

Angina pectoris

Question 18

What does prolonged insufficient blood supply to the heart lead to?

Answer 18

MI

Question 19

True or false: Heart muscle damaged by an MI can regenerate functional tissue.

Answer 19

False; undergoes scar repair and becomes non-contractile.

Question 20

What are two causes of cardiac arrest?

Answer 20

1) asystole (less common)

2) Ventricular fibrillation

Question 21

In what two ways can a heart attack be manifested?

Answer 21

1) Cardiac arrest

2) MI

Question 22

What 4 basic mechanisms can lead to a heart attack?

Answer 22

1) Sudden CA blockage
2) Hemorrhage into an atheromatous plaque
3) Arterial spasm next to plaque in a CA
4) Sudden increase in myocardial oxygen need

Question 23

How do women’s MI symptoms differ from men?

Answer 23

Women are much less likely to have chest

pain, arm/jaw pain, nausea/vomiting, or strong anxiety.

Question 24

Inflammation of lining of the lungs and chest.

Answer 24

Pleurisy

Question 25

What are two conditions whose symptoms can mimic a a heart attack

Answer 25

1) Heartburn/indigestion 2) Pleurisy 3) Gall bladder attack 3) Muscle strain

Question 26

Partial necrosis caused by an MI

Answer 26

subendocardial necrosis

Question 27

Necrosis through all layers of the heart caused by an MI

Answer 27

transmural necrosis

Question 28

What two key test are able to accurately diagnose MI 99% of the time?

Answer 28

EKG and troponin levels

Question 29

What are the three groups for Acute Coronary Syndromes?

Answer 29

1) Severe unstable angina (ST depression, no rise in troponins or CK) 2) Minor myocardial damage (non-STEMI, elevated troponins and CK 3) Major myocardial damage (STEMI, elevated troponin and CK)

Question 30

How is severe unstable angina diagnosed? How is it treated?

Answer 30

1) ST depression, no rise in troponins or CK | 2) Drugs

Question 31

How is minor myocardial damage (non-STEMI) diagnosed? How is it treated?

Answer 31

1) ST depression, increased troponin (not CK) | 2) Angioplasty

Question 32

How is major Myocardial damage treated (STEMI)?

Answer 32

Total CA blockage; treated with angioplasty or thrombolytics ASAP.

Question 33

Within what time period must thrombolytics be given to given to prevent irrversible tissue infarction?

Answer 33

within 6 hours

Question 34

What is the very best treatment for an MI?

Answer 34

angioplasty (unblocks CA in 90% of patients)

Question 35

What device can be used to treat patients who are at high risk of v-fib?

Answer 35

implantable cardioverter defibrillator

Question 36

What implantable device senses v-fib and automatically shocks the heart?

Answer 36

cardioverter defibrillator

Question 37

What is the percentage of MIs that are survived if patients are hospitalized?

Answer 37

95%

Question 38

What percentage of MI deaths occur outside of the hospital?

Answer 38

1/3