AMI Flashcards
Classification of AMI?
- STEMI
- NSTEMI
- UA
Management of STEMI?
- Re-perfusion therapy
Characteristics of UA?
- Normal Troponin levels
- With or without ECG changes
- Increased myocardial O2 demand
- Coronary artery narrowing
- Chest pain at rest or minimal exertion
Characteristics of MI related to acute myocardial infarction?
Atherosclerotic plaque disruption with thrombosis
Classification of MI?
- AMI
- Myocardial injury related to acute myocardial ischaemia because of oxygen supply/demand imbalance
- Other causes of myocardial injury
Characteristics of Myocardial injury related to acute myocardial ischaemia because of oxygen supply/demand imbalance?
- Reduced myocardial perfusion, e.g.
Coronary artery spasm, microvascular dysfunction
Coronary embolism
Coronary artery dissection
Sustained bradyarrhythmia
Hypotensive or shock
Respiratory failure
Severe anaemia - Increased myocardial oxygen demand, e.g.
Sustained tachyarrhythmia
Severe hypertension with or without left ventricular hypertrophy
Characteristics of Other causes of myocardial injury?
Cardiac conditions, e.g.
Heart failure
Myocarditis
Cardiomyopathy (any type)
Takotsubo syndrome
Coronary revascularization procedure
Cardiac procedure other tan revascularization
Catheter ablation
Defibrillator shocks
Cardiac contusion
Systemic conditions, e.g.
Sepsis, infectious disease
Chronic kidney disease
Stroke, subarachnoid haemorrhage
Infiltrative disease, e.g. amyloidosis, sarcoidosis
Chemotherapeutic agents
Critically ill patients
Strenuous exercise
What is type (1) MI?
- Spontaneous MI
- Rise in troponin
- Ischaemic ECG changes
- Ischaemic chest pain
- Coronary thrombus on angiography
- New RWMA
What is type (2) MI?
- Imbalance between supply/demand
What is type (3) MI?
Cardiac death presumed to be due to MI when troponin not available
What is type (4a) MI?
myocardial infarction associated with percutaneous coronary intervention < 48hrs
What is type (4b) MI?
myocardial infarction related to stent thrombosis on angio or autopsy
What is type (4c) MI?
caused by restenosis associated with percutaneous coronary intervention
What is type (5) MI?
myocardial infarction associated to coronary artery bypass grafting < 48hrs
Classification of MI?
See image attached
Indication for dual anti-platelet in MI?
It is only indicated in type (1) MI
Distinguishing between Type 1 & 2 MI?
See image attached
What is MINOCA?
Myocardial infarction with non-obstructing coronary arteries. There is >50% stenosis is epicardial vessels
What is the role of anti-platelet agents?
- Prevent platelet adhesion
- Limits formation of white thrombose
Site of action of Clopidogrel, prasugrel and ticagrelor?
ADP receptors
Mechanism of action of Aspirin?
Inhibition of cyclo-oxygenase and synthesis of thromoxane A2
Mechanism of action of fibrinolytic agents?
- Lysis of red thrombose
- Not active against white thrombose
Mechanism of action of antithrombin agents? (Heparin)
- Limits thrombin activation
- Lysis of fibrin
- Lysis of red cell thrombose
- Paradoxical increase in thrombin activation
What is the pathophysiology of ischaemic necrosis?
- Cellular disruption
- Loss of function
- Thinning of affected myocardium
- Increase of ventricular compliance
What is the sequelae of Myocardial Infarction?
- Fibrosis
- Decreased compliance
- Extension of ischaemic segment
- Compensatory ventricular remodelling
Issues associated with MI?
- Cardiogenic shock - LV failure
- Papillary rupture & regurgitation
- Septal defect due to RWMA
- Acute free wall rupture
- RV failure with low CO state
- LV re-modelling & CCF
What is the effect of infarction size?
- LV systolic & diastolic function
- Decreased stroke volume
- Raised ventricular filling pressures
- Pulmonary congestion
- Hypotension
- Decrease coronary perfusion pressures
What are the main arteries of the heart ?
- LCA ( Anterior descending & circumflex)
- RCA
Characteristics of cardiogenic shock?
- > 40% of myocardium is lost before CS
What are the contributory factors to cardiogenic shock after MI?
- VSD
- Free wall rupture
- Papillary muscle rupture or dysfunction
- MR
What is the sequaele of cardiogenic shock?
See image attached
Steps to optimal management of patients with ACS?
- Suspected ACS
- Establishing diagnosis
- Risk stratification
- Optimal treatment
What are the differential diagnosis for MI?
- Aortic dissection
- PE
- Pericarditis
Immediate management of ACS?
- ECG within 10mins
- Monitoring
- Oxygen
- IV nitrate
- Sublingual Nitroglycerin 0.4mg/ PRN 5mins
- Aspirin 300mg + daily 100mg
- Beta-blockers - If no low BP or CCF
- Fibrinolysis or pPCI within 12hrs
What are the common side-effects of nitrates ?
- ## Bezold-Jarisch Reflex (Low BP & HR)
Contraindications to use of Nitrates in MI?
- Use of phosphodiesterase inhibitors - Risk of hypotension
- RV MI
List platelet P2Y12 receptor blockers?
- Clopidogrel
- Prasugrel
- Ticagrelor
Management of pulmonary oedema in MI?
- Upright position
- CPAP/NIV
- IV GTN
- Furosemide
Indications for rapid reperfusion therapy ?
- Ischaemic symptoms < 12 hrs
- Persistent ST elevation
Indication for pPCI in the absence of STE?
- Cardiogenic shock
- Chest pain refractory to medical Tx
- Arrhythmias or cardiac arrest
- Acute HF
- ST & TW changes
What are features synonymous with high risk MI patients?
- Acute HF
- CVS instability
- Size of infarct
- RV involvement
- LV dysfunction (EF < 35%)
Significance of a 4th heart sound on auscultation in MI?
Indicative of non-compliant LV
Clinical features of RV infarction?
- Elevated JVP
- Clear lungs
- Decreased filling pressures + Low BP
Review of ECG in AMI?
See image attached
What is the prognosis of patients with new RBBB?
Very poor
Infarct localization and ECG?
Review the attached image
Conditions in which STE is observed?
- Pericarditis
- LVH
- LV aneurysm
- Brugada syndrome
- PE (V1-V3)
- WPW syndrome
- Conduction defects
- Metabolic disturbances
- Drug toxicity
- SAH
- Takotsubo syndrome (Apical ballooning)
Characteristics of Takotsubo syndrome?
- Normal angio
- Apical ballooning
- Severe mental or physical stress
- ## Post-menopausal females
Troponin I detection in blood?
- Within 4-6 hours
- Peaks at 12-24 hrs
- Resolution within 7-14 days
Killips classification ?
Class (1)
- No heart failure
Class (2)
- Lung crackles
- 3rd heart sound
- Raised JVP
Class (3)
- Frank pulmonary oedema
Class (4)
- Cardiogenic shock or low BP
Composition of the GRACE scoring system? (Global registry for Acute Coronary Events)
- Age
- SBP
- Creatinin
- Killips class
- Cardiac arrest at presentation
- Raised biomarkers
- ST changes
Classification for mortality according to GRACE scoring?
- Score >140 - High risk inpatient mortality
- 109-140 - Intermediate risk
See image attached
What is the TIMI scoring system?
- Used to estimate 14 day mortality in NSTEMI or 30 days in STEMI
- MI
- Urgent revascularisation in pt with NSTEMI
What are the components of the TIMI (Thrombolysis in Myocardial Infarction) ?
- Age >65
- 3 risk factors for CHD
- H/O coronary stenosis of > 50%
- ST changes on admission
- Angina
- Aspirin use in the prior 7 days
Variables in the CRUSADE scoring system?
- Haematocrite
- Creatinine clearance
- Female sex
- Diabetes
- PVD
- Heart failure
- SBP
- HR
