Acute Myocardial Infarction

Front 1

what is the number one cause of death in the USA?

Back 1

acute myocardial infarction

Front 2

what is the main reason that people die from an acute MI?

Back 2

tissue death causes an arrhythmia

Front 3

what is the major cause of acute MIs?

Back 3

a primary plaque ruptures resulting in a thrombotic occlusion of a coronary artery

Front 4

T or F: high grade stenoses are likely to cause infarction.

Back 4

false, they are likely to cause ischemia but not likely to rupture and cause infarction

Front 5

what percent of acute MIs are fatal? how long does it usually take these fatal MIs to cause death?

Back 5

- about 1/3 are fatal
- about 1/2 of those that are fatal cause death within the first hour of onset

Front 6

what is the major advantage of a cardiac CT over an angiogram?

Back 6

cardiac CT allows you to look inside the vessel and find the unstable plaques wherease angiogram only allows you to see the vessel caliber from the outside

Front 7

what is a stable plaque?

Back 7

this a plaque with a thick fibrous capsule surrounding the necrotic core. these are not likely to rupture and cause an acute MI

Front 8

what is a vulnerable or unstable plaque?

Back 8

this is a plaque with a thin fibrous capsule surrounding a large necrotic core. these are prone to rupture and cause acute MI

Front 9

what are the criteria to be in the plaque danger zone?

Back 9

- thin fibrous cap
- low smooth muscle cell count
- large lipid core
- high macrophage content (lots of inflammation)

Front 10

what is acute coronary syndrome (ACS)?

Back 10

a spectrum of disease.
- stable angina (least worrisome)
- unstable angina
- non-Q wave MI
- Q wave MI (most worrisome)

Front 11

what is Prinzmetal's angina?

Back 11

chest pain due to an intense vessel spasm

Front 12

a 22 year old male comes into the ED at 2 am complaining of chest pain. he is sweating profusely and has a heart rate of 185 beats/min. what is your first suspicion as to the cause? what test should you order next?

Back 12

- cocaine use; cocaine can cause intense vessel spasms and when you see chest pain in a young otherwise healthy person think cocaine use
- you would order a drug screen for cocaine

Front 13

how can you differentiate between a MI and an aortic dissection based on patient symptoms alone?

Back 13

patients most commonly describe pain from an MI as crushing or squeezing and they will most commonly describe pain from a dissection as tearing or ripping and very intense

Front 14

T or F: one way to test for coronary artery pain is to have the patient jump.

Back 14

true; coronary arteries will not hurt with movement. if they pain can be reproduced or exacerbated by movement it is not coming from the coronary arteries

Front 15

if a patient describes chest pain as being knife-like stabbing upon inspiration, where should you suspect the pain is originating?

Back 15

pleura

Front 16

if the patient describes chest pain as worse when they cough and radiating to the trapezius, where should you suspect the pain is originating?

Back 16

pericardium

Front 17

if the patient describes the chest pain as a severe tearing sensation that is boring through the back and into the lower extremity, where should you suspect the pain is originating?

Back 17

aortic dissection

Front 18

if the patient describes the chest pain as a burning sensation, where should you suspect the chest pain originating?

Back 18

esophageal or GI

Front 19

when do we tend to see the most MIs? why?

Back 19

- early morning
- because catecholamine levels are highest in the early morning hours

Front 20

T or F: pain is a marker for infarction.

Back 20

false; infarcted tissue is dead and does not feel pain. pain is a marker for ischemia

Front 21

which patient populations will often present with atypical stories when having an MI?

Back 21

- women
- elderly
- diabetics

Front 22

what is the Levine sign?

Back 22

commonly seen in patients that are having a MI, it is when the patient is clutching or rubbing the chest and have an anguished look

Front 23

what is the hallmark of an MI on EKG?

Back 23

ST elevation > 1 mm

Front 24

what does a Q wave on an EKG represent?

Back 24

an infarction

Front 25

what enzymes are elevated in a MI?

Back 25

- CK MB
- troponin

Front 26

describe the serum levels of CK-MB and troponin in a MI?

Back 26

- CK MB rises 3-12 hours after onset and persists elevated until 48 hours
- troponin rises 3-12 hours after onset and persists elevated for 4-10 days after onset

Front 27

describe the Killip Classification of mortality risk.

Back 27

- Class I: No CHF, good perfusion = 5% risk of mortality
- Class II: Mild CHF, good perfusion = 15% risk
- Class III: Moderate CHF = 35% risk
- Class IV: Cardiogenic shock = 80% risk

Front 28

what is the most common and worrisome complication of an MI?

Back 28

an arrhythmia

Front 29

T or F: in a patient with an anterior MI it is not unusual for them to have a heart block.

Back 29

false, it is unusual. it is not unusual for patients with an inferior MI to have a heart block

Front 30

what causes acute mitral insufficiency after a MI? when will it present?

Back 30

- infero-medial papillary muscle rupture
- presents 2-7 days after the MI

Front 31

you are examining a patient for a follow up from a MI that occurred 6 days ago. upon ausculation you hear a new harsh, loud, holosystolic murmur. upon palpitation you can feel a thrill. what is the most likely diagnosis? is this a complication of the MI? are you worried?

Back 31

- septal rupture
- occurs in about 2% of MIs
- yes, because they have a high mortality rate

Front 32

are left ventricle free wall ruptures common after a MI? when would one occur if the patient were to develop one?

Back 32

- occur in about 10% of patients
- will occur from 1 day to 3 weeks after the MI, most commonly 1-4 days

Front 33

how does a left ventricle free wall rupture after an MI usually cause death?

Back 33

these often heal over as a pseudo-aneurysm and cause sudden death due to a cardiac tamponade

Front 34

what leads do we see right ventricle infarcts best?

Back 34

II, III, and aVF

Front 35

a 55 year old obese man comes in with crushing substernal chest pain that radiates to his neck. you suspect an MI and give sublingual nitroglycerin while waiting for a EKG to be performed. after administration of the nitro you see a decrease in cardiac output and a sudden drop in blood pressure. what artery is most likely blocked?

Back 35

right coronary; a decreased cardiac output and sudden drop in blood pressure after nitro is commonly seen in right ventricle infarcts. the right ventricle is supplied by the right coronary artery

Front 36

what is Dressler's syndrome?

Back 36

malaise, fever, pericardial pain, elevated sed rate and pericardial effusion seen 1-8 weeks after an MI

Front 37

why is it important to relieve the patients pain during an MI (other than the obvious reason of not wanting the patient to be in pain)?

Back 37

pain causes an increase in HR which increases myocardial O2 demand. the myocardial O2 demand is already not being met so if we increase the demand it will create a larger insufficiency and possibly more myocardial death

Front 38

what is the treatment of choice in a patient with a coronary artery occlusion?

Back 38

percutaneous coronary intervention

Front 39

is it ok to give lytics and then go to the cath lab?

Back 39

yes

Front 40

under what circumstances should you give a patient lytics when having an MI?

Back 40

- a delay to the cath lab
- when they are not contraindicated
- EKG criteria
- if you can give them within 12 hours of onset of symptoms
- if the patient is not in shock of CHF

Front 41

what is the best prognostic indicator?

Back 41

left ventricular dysfunction