Myocardial Infarction and treatment of ACS

Question 1

What are the signs and symptoms of a myocardial infarction?

Answer 1

Symptoms: Chest/back pain, jaw pain, indigestion, clamminess, SOB, none (especially in diabetics or dementia) or death.
Signs: Tachycardia, distressed, heart failure (crackles/raised JVP), shock arrhythmia or none

Question 2

What are the investigations for a suspected MI?

Answer 2

ECG - Evidence of ST segment deviation
Bloods - Cardiac troponin
CXR and ECHO - evidence of acute heart failure/LV systolic dysfunction
Coronary angiogram

Question 3

What is troponin and the different types

Answer 3

• It is involved in the interaction between actin and myosin. It is released into the blood stream and indicated myocyte necrosis
  3 types - TnI, TnT and TnC

Question 4

What is the definition of an MI

Answer 4

Any elevation in troponin IN the clinicals setting consistent myocardial ischaemia (ECG changes or symptoms)

Question 5

What are the different types of myocardial infarctions?

Answer 5

• Type 1: Spontaneous MI due to a primary coronary event.
• Type 2: Increased oxygen demand or decreased oxygen supply (HF, sepsis, anaemia, arrhythmias, hypertension or hypotension) can have atherosclerotic coronaries or not.
• Type 3: sudden cardiac death,
• Type 4: alpha is MI associated with PCI, beta is MI stent thrombosis
• Type 5: MI associated with CABG

Question 6

What is required when a patient presents with cardiac chest pain?

Answer 6

• ECG and troponin done within 15mins
• HEART score preformed, if heart score is below threshold then do serial troponin at baseline, 3 hours and then 6 hours

Question 7

What is the HEART score?

Answer 7

Sore which correlates for a proposed management. It is based off:
- History
- ECG,
- Age,
- Risk factors (Hypercholesterolaemia, hypertension, DM, smoking, pos family history and obesity),
- Troponin.

Question 8

What are some causes of type 2 MIs?

Answer 8

• Acute presentation of heart failure,
• Tachy-arrhythmias,
• Pulmonary embolism,
• Sepsis,
• Apical ballooning syndrome,
• Anything that stresses the heart (critically unwell patient)

Question 9

What are the ECG changes that are diagnostic of a STEMI?

Answer 9

• ST elevation >2mm in adjacent chest leads.
• ST elevation > 1mm in adjacent limb leads
• New LBBB with chest pain or suspicion of MI

Question 10

What are some non-coronary causes of chronic elevated troponin?

Answer 10

• Renal failure,
• Chronic heart failure,
• Infiltrative cardiomyopathies (amyloidosis, hemochromatosis or sarcoidosis)

Question 11

What is unstable angina?

Answer 11

An acute coronary event without a rise in troponin. So a clinical presentation of an MI with ECG changes or tight narrowing’s on a coronary angiography

Question 12

What is the difference between an NSTEMI and a STEMI

Answer 12

NSTEMI - partial occlusion of coronary artery with ST depression.
STEMI - Complete occlusion of coronary artery with ST elevation

Question 13

What leads and artery represent the inferior myocardium?

Answer 13

Leads II, III and aVF.
Right coronary artery.

Question 14

What leads and artery represent the septal myocardium?

Answer 14

Leads V1-2.
Proximal LAD artery

Question 15

What leads and artery represent the anterior myocardium?

Answer 15

Leads V3-V4.
LAD artery

Question 16

What leads and artery represent the lateral myocardium?

Answer 16

Leads I, aVL, V5-6.
Left circumflex artery

Question 17

What leads and artery represent the posterior myocardium?

Answer 17

ST depression in leads V1-3/4.
Left circumflex or right coronary artery

Question 18

What leads are affected in a high lateral STEMI?

Answer 18

ST elevation in leads I and aVL

Question 19

What is the time limit for a PCI?

Answer 19

120mins

Question 20

What is the immediate management of a STEMI?

Answer 20

• ABC,
• Aspirin 300mg PO,
• Morphine 5-10mg IV with anti-emetics,
• Clopidogrel (In ambulance) 600mg for PPCI or 300mg if for thrombolysis,
• Ticagrelor 180mg (in hospital)

Question 21

Describe the benefits of a primary PCI over thrombolysis

Answer 21

• Improves survival, reduces risk of stroke reduces changes for further MI, reduces chance of further angina, speeds up recovery and shortens time in hospital

Question 22

What is the subsequent management for a MI

Answer 22

• Monitor in coronary care unit,
• Secondary prevention drugs: SAAB: Aspirin 75mg and second anti-platelet such as clopidogrel, ACE inhibitors, BB and statins for all. If diabetics and HF then give eplerenone too.
• ECHO to assess for LV function,
• Cardiac rehabilitation

Question 23

What are the complications of an MI

Answer 23

• Arrhythmias: VT/VF (DC cardioversion) or AF.
• Heart failure: Give diuretics, inotrophes and vasodilators.
• Cardiogenic shock,
• Myocardial rupture: Septal rupture, papillary muscle (can cause mitral regurg) or free wall rupture which can cause tamponade.
• Psychological (anxiety/depression - cardiac rehab)

Question 24

What is the subsequent management for an NSTEMI

Answer 24

• Monitor in coronary care unit for complications and give aspirin, clopidogrel and LMWH/fondaparinux
• Secondary prevention drugs: ACE inhibitors, BB and statins for all. If diabetics and HF then give eplerenone too.
• ECHO to assess for LV function,
• Cardiac rehabilitation

Question 25

What is the grace score?

Answer 25

It is used to determine whether patient should stay in hospital for coronary angiography or not.