CARDIAC LECTURE 1: Epidemiology & coronary heart disease

Question 1

Cardiac disease is the ____ cause of death in Canada

Answer 1

2nd

Question 2

What is the most common type of heart disease in Canada?

Answer 2

Ischemic

Question 3

What are 5 causes of heart disease?

Answer 3

1. Rupture
2. Obstruction
3. Improper flow (backward, diverted)
4. Failure to pump (contraction, emptying, relaxing)
5. Conduction defect

Question 4

What is the general term for diseases where insufficiency of oxygen leads to damage of the myocardium?

Answer 4

Coronary heart disease

Question 5

What are 2 ways cardiac myocytes initially adapt to hypoxia?

Answer 5

1. Generates anastomoses to bypass blockage
2. Vasodilation

Question 6

At what point are the effects of CHD felt?

Answer 6

When the vessel is about 70% occluded

Question 7

What are 2 main consequences of ATP depletion in a hypoxic state?

Answer 7

1. Na+/K+ pump cannot work, causing influx of Na+ and fluid (swelling)
2. Anaerobic metabolism, causing acidity

Question 8

What are 3 other consequences of ATP depletion in a hypoxic state?

Answer 8

1. Ribosome detachment
2. Decreased protein synthesis
3. Lipid deposition

Question 9

What is the mechanism behind angina?

Answer 9

Injured cells release chemicals that activate nociceptors

Question 10

Why is anginal pain often felt at other places than the heart?

Answer 10

Referred pain: Sensations from upper abdomen, shoulders, arms, neck, lower jaw travel along same pathways and enter spinal cord at same region

Question 11

What are 3 patterns of angina?

Answer 11

1. Stable angina
2. Vasospastic angina
3. Unstable/crescendo angina

Question 12

What kind of angina normally manifests when cardiac workload is increased, and reduces at rest?

Answer 12

Stable angina

Question 13

What is the mechanism behind stable angina?

Answer 13

Stenotic/atherosclerotic coronary vessels dilate poorly in response to increased demand

Question 14

What kind of angina is characterized by unpredictable attacks, predominantly at rest?

Answer 14

Vasospastic (Prinzmetal, variant) angina

Question 15

What are 3 possible mechanisms behind vasospastic angina?

Answer 15

1. Vascular smooth muscle hyperreactivity
2. ANS imbalance
3. Endothelial dysfunction

Question 16

What are 2 treatments for vasospastic angina?

Answer 16

1. CCBs
2. Nitro

Question 17

What kind of angina is characterized by increasingly frequent pain with progressively less exertion?

Answer 17

Unstable/crescendo angina

Question 18

What is the mechanism behind unstable angina?

Answer 18

Stenotic coronary artery is further blocked by a ruptured plaque or embolism and leads to a severe obstruction

Question 19

What are 2 possible outcomes for unstable angina?

Answer 19

1. Clot dissolves before myocardial tissue dies
2. Myocardial infarction

Question 20

What is the term for necrossi of cardiac muscle due to prolonged ischemia?

Answer 20

Myocardial infarction

Question 21

How long until ischemia leads to irreversible changes/necrosis?

Answer 21

20-30 minutes

Question 22

Why may the outside of the heart appear healthy despite necrosis occuring?

Answer 22

The epicardium is affected last by MI

Question 23

Which layer of the heart feels the effects of MI the most, and why?

Answer 23

Endocardium, as it is the farthest away from the blood supply

Question 24

What is the term for the plasma membrane of cardiomyocytes?

Answer 24

Sarcolemma

Question 25

What morphological changes occur in the heart after 6 hours post MI?

Answer 25

Coagulative necrosis

Question 26

What is the eventual end result of the necrotic area of the heart?

Answer 26

Becomes scar tissue

Question 27

What are 4 atypical symptoms of MI that may occur in females?

Answer 27

1. Breathlessness 2. Sweating 3. Nausea/vomiting 4. Anxiety, tireness

Question 28

On an ECG strip, where is the ST segment located?

Answer 28

The flat portion right after the peak (R)

Question 29

What are 2 ECG readings that are considered NSTEMI?

Answer 29

1. ST depression 2. T inversion

Question 30

What is the treatment for ST elevation MI?

Answer 30

Immediate reperfusion therapy

Question 31

What is the treatment for non-ST elevation MI?

Answer 31

Antiplatelet and anticoagulation therapy

Question 32

What is the best serum biomarker used to diagnose MI?

Answer 32

Troponin I and T

Question 33

How long does it take for troponin to build up in the blood?

Answer 33

A few hours

Question 34

How long will troponin levels remain elevated after MI?

Answer 34

Up to 2 weeks

Question 35

What are 3 other biomarkers used to diagnose MI?

Answer 35

1. Creatine kinase 2. Myoglobin 3. Lactate dehydrogenase

Question 36

What are the 5 steps in diagnosing MI?

Answer 36

1. Presentation 2. Working diagnosis (ACS) 3. ECG 4. Cardiac biomarkers 5. Final diagnosis

Question 37

The patient's ECG shows ST elevation, and they have positive biomarkers. What is the diagnosis?

Answer 37

STEMI

Question 38

The patient's ECG does not have ST elevation, and their biomarkers are negative. What is the diagnosis?

Answer 38

Unstable angina

Question 39

The patient's ECG does not have ST elevation, but their biomarkers are positive. What is the diagnosis?

Answer 39

NSTEMI

Question 40

What are 3 methods of immediate reperfusion treatment?

Answer 40

1. Percutaneous coronary intervention (PCI) 2. Fibrinolysis (clot busters) 3. Coronary artery bypass graft (CABG)

Question 41

What are possible consequences due to reperfusion?

Answer 41

1. Hemorrhage 2. Arrhythmias 3. Inflammation

Question 42

What histological changes may be observable in cardiac muscle tissue after reperfusion?

Answer 42

Contraction bands

Question 43

What is the underlying cause for arrhythmias following MI?

Answer 43

Dead cells block conduction pathways

Question 44

What would cause a patient to experience cardiogenic shock following MI?

Answer 44

A large region of the muscle in the left ventricle is destroyed

Question 45

What is the underlying cause for myocardial rupture following MI?

Answer 45

Damaged tissue is weakened until scar tissue forms

Question 46

What is the term for a complication of MI where there is underlying myocardial inflammation leading to scarring?

Answer 46

Pericarditis

Question 47

What is the term for a complication of MI where new necrosis develops next to the area of infarction?

Answer 47

Infarct extension

Question 48

What is the term for a complication of MI where weakness in the affected tissue leads to stretching, thinning, and dilation?

Answer 48

Infarct expansion

Question 49

What is the term for a complication of MI where thing scar tissue of the ventricular wall bulges with contraction?

Answer 49

Ventricular aneurysm

Question 50

Why is mural thrombus a possible complication following MI?

Answer 50

1. Abnormal contractility causes stasis 2. Damage to endocardium creates a thrombogenic surface

Question 51

Which muscles of the ventricles may experience dysfunction following MI, and what may this lead to?

Answer 51

Papillary muscles Lead to rupture and mitral valve regurgitation

Question 52

What is the term for unexpected death from cardiac causes, within 1 hour of onset of symptoms?

Answer 52

Sudden cardiac arrest/death

Question 53

What is the underlying cause of suddent cardiac death?

Answer 53

Ischemia produces V-fib

Question 54

What is the term for progressive heart failure caused by slow atrophy and death of cardiomyocytes from chronic ischemia?

Answer 54

Chronic ischemic cardiomyopathy

Question 55

How is chronic ischemic cardiomyopathy different from MI?

Answer 55

Dead cells are spread throughout the heart instead of localized