Ischaemic heart disease

Risk factors for coronary atheroma

• BMI > 30

• Age > 65

• Diabetes mellitus

• Hypertension

• Increased LDL

• Relatives with coronary artery disease

Characteristics of stable angina

• stable Atherosclerotic plaque

• Pain develops on exertion

• Vessel is unable to dilate enough to allow adequate blood flow

• Subendochardial ischaemia

• ECG + troponin normal

Characteristics of unstable angina

• ruptured fibrous cap → exposes plaque → platelets accumulate → form thrombus

• Pain at rest

• Subendocardial Ischaemia

• Inverted T waves/ ST depression

• Normal troponin levels

Characteristic of an NSTEMI

• Subendochardial infarction

• Pain at rest

• Inverted T waves/ ST depression Normal

• Elevated troponin

** Ischaemia for longer than 30 mins can lead to infarction (cell death)

Characteristics of a STEMI

• Transmural infarction

• Complete occlusion of lumen * infarct of the entire thickness of the myocardium

• Pain at test

• Hyperacute T wave/ ST elevation

• Elevated troponin

clinical signs of a ischaemic cardiac chest pain

• discomfort/ pressure (dull, crushing) that lasts more than 2 mins

• Worsened by exercise

• Radiation to arm/jaw

• Sweating/nausea

Atypical clinical signs of a ischaemic cardiac chest pain

• pain that can be localised with 1 finger

• Constant pain lasting for days

• Pain reduced my movement/ palpitation

• No pain

Clinical features of a R ventricular MI

• jugular venous distinction (blood in SVC)

• Oedema of lower extremities (blood in IVC)

• Hepatomegaly

• Hypotension

• Ascites

• Clear lungs

• Bradycardia /AV block

Clinical features of a L ventricular MI

• pulmonary oedema

• Shortness of breath

• Hypotension

• S4 heart sounds

• Reflex tachycardia

MI complications at 0-24 hrs

• Sudden cardiac death: No ATP → Na/K pump doesn’t work → more positive ions outside → ventricular tachy→ ventricular fib → sudden cardiac death

• Acute heart failure: hypotension → shock

• Flash pulmonary oedema

MI complications at 1-3 days

• pericarditis caused by inflammation → frictional rub/ pericardial effusion

MI complications at 3-4 days

Rupture syndrome

• ventricular wall rupture → Ventricular septal defect

• Free wall rupture → cardiac tamponade

• Papillary muscle rupture → mitral regurgitation

MI complications at 14 days - months

Left ventricular aneurysm → increase risk of thrombus formation

Clinical signs of pericarditis

Retrosternal, sharp + localised chest pain

Pericardial rub heart sound on auscultation

Saddle shape ST elevation

What is cardiac catheterisation

Catheter passes through the Radial or femoral artery → to aorta → coronary arteries

Used for definite diagnosis of heart disease

What bio marker is released in an infarction

Myoglobin (released quickly, not specific)

Troponin I and T (increase in 24 hrs and remain high for a couple days)

CK-MB (increased for 6hrs post MI) → can also check if there were multiple MI

How can you use an ECG to determine which coronary artery is occluded?

Look for ST elevation

Lead I, AvL, V5, V6 ( Lateral leads) → circumflex, diagonal branch of LAD

V1, V2, V3, V4 (anterior leads) → LAD

Lead II, Lead III, aVF (inferior leads)→ right coronary artery

aVR → R side of the heart

Immediate Management of MI

MONA

Morphine

Oxygen (only with hypoxia)

Nitroglycerin

Asprin (inhibits platelet activation)

+ Beta blocker

Revascularisation: PCI (percutaneous coronary intervention)/ coronary angioplasty

Fibrinolytic therapy (lysis of the clot) if you cannot do PCI