Ischaemic heart disease Flashcards
Define ischaemic heart disease
Characterised by decreased blood supply to the heart muscle resulting in chest pain (angina pectoris)
May present as stable angina or acute coronary
syndrome.
ACS can be further subdivided into:
Unstable angina- chest pain at rest due to ischaemia but
without cardiac injury
NSTEMI
STEMI -ST elevation with transmural infarction
Summarise the epidemiology of ischaemic heart disease
COMMON
Prevalence: > 2 %
More common in males
Annual incidence of MI in the UK ~ 5/1000
Explain the aetiology of ischaemic heart disease
Angina pectoris = myocardial oxygen demand > oxygen supply (usually due to atherosclerosis)
Rarer causes of angina pectoris include coronary artery spasm (e.g. induced bycocaine), arteritis and emboli
Atherosclerosis pathophysiology - Endothelial injury -> migration of monocytes into the subendothelial space.
Monocytes become macrophages. Macrophages become foam cells from LDL. Foam cells release GFs that stimulate smooth muscle proliferation, production of collagen and proteoglycans -> atherosclerotic plaque
Explain the risk factors of ischaemic heart disease
Male Diabetes mellitus Family history Hypertension Hyperlipidaemia Smoking
Recognise the presenting symptoms of ischaemic heart
disease
ACS
Acute-onset chest pain
Central, heavy, tight, crushing pain
Radiates to the arms, neck, jaw or epigastrium
Occurs at rest
More severe and frequent pain that previously occurring stable angina
Associated symptoms: Breathlessness Sweating Nausea and vomiting SILENT INFARCTS - occur in the elderly and diabetics
Stable Angina - Chest pain brought on by exertion and relieved by rest
Recognise the signs of ischaemic heart disease on physical examination
Stable Angina - Check for signs of risk factors
ACS May be NO CLINICAL SIGNS Pale Sweating Restless Low - grade pyrexia Check both radial pulses to rule out aortic dissection Arrhythmias Disturbances of BP New heart murmurs
Signs of complications (e.g. acute heart failure, cardiogenic shock)
Identify appropriate investigations for ischaemic heart disease
FBC U&Es CRP Glucose Lipid profile Cardiac enzymes (troponins and CK-MB) Amylase (pancreatitis could mimic MI) TFTs AST and LDH (raised 24 and 48 hours post-MI, respectively)
ECG -
Unstable Angina or NSTEMI: possible ST depression or T wave inversion
STEMI: Hyperacute T waves, ST elevation (> 1 mm in limb leads, > 2 mm in chest leads)
New-onset LBBB
Later changes:
T wave inversion
Pathological Q waves
CXR - Check for signs of heart failure
Exercise ECG
Radionuclide Myocardial Perfusion Imaging (rMPI)
Echocardiogram
Pharmacological Stress Testing - Dipyridamole, Adenosine, Dobutamine
Cardiac Catheterisation/Angiography
Coronary Calcium Scoring
Generate a management plan for Stable Angina
Minimise cardiac risk factors
(e.g. blood pressure, hyperlipidaemia, diabetes)
All patients should receive aspirin 75 mg/day
unless contraindicated
Immediate symptom relief (e.g. GTN spray)
Long-term management
Beta-blockers Contraindicated in: Acute heart failure Cardiogenic shock Bradycardia Heart block Asthma
Calcium channel blockers
Nitrates
Percutaneous coronary intervention (PCI) - Performed in patients with stable angina despite maximal tolerable medical therapy
Coronary artery bypass graft (CABG) = Occurs in more severe cases (e.g. three-vessel disease)
Generate a management plan for Unstable Angina
Admit to coronary care unit
Oxygen, IV access, monitor vital signs and serial ECG
GTN
Morphine + Metoclopramide (to counteract the nausea caused by morphine)
Aspirin (300 mg initially, followed by 75 mg indefinitely)
Clopidogrel (300 mg initially, followed by 75 mg for at least 1 year if troponin positive or high risk)
LMWH (e.g. enoxaparin)
Beta-blocker (e.g. metoprolol)
Glucose- insulin infusion if blood glucose > 11 mmol/L
GlpIIb/IIIa inhibitors may also be considered (e.g. tirofiban) in patients: Undergoing PCI, At high risk of further cardiac events
If little improvement, consider urgent angiography with/without revascularisation
NOTE: the acute management of ACS can be remembered using the mnemonic
MONABASH
Morphine Oxygen Nitrates Anticoagulants (aspirin + clopidogrel) Beta-blockers ACE inhibitors Statins Heparin
STEMI Management?
Same as UAP/NSTEMI management except:
Clopidogrel - 600 mg if patient is going to PCI
300 mg if undergoing thrombolysis and < 75 yrs
75 mg if undergoing thrombolysis and > 75 yrs
MAINTENANCE: 75 mg daily for at least 1 year
If undergoing primary PCI: IV heparin (plus GlpIIb/IIIa inhibitor), Bivalirudin (antithrombin)
Primary PCI - Goal <90 min if available
Thrombolysis - Uses fibrinolytics such as streptokinase and tissue plasminogen activator (e.g. alteplase)
Only considered if within 12 hours of chest pain with ECG changes and not contraindicated
Rescue PCI - may be performed if continued chest pain or ST elevation after thrombolysis
Secondary Prevention - Dual antiplatelet therapy (aspirin + clopidogrel)
Beta-blockers ACE inhibitors Statins Control risk factors Advice - No driving for 1 month following MI
CABG
Considered in patients with left main stem or three-vessel disease
Identify the possible complications of ischaemic heart disease
Increased risk of MI and other vascular disease (e.g. stroke, PVD). Cardiac injury from an MI can lead to heart failure and arrhythmias
Early Complications (within 24-72 hrs) Death Cardiogenic shock Heart failure Ventricular arrythmias Heart block Pericarditis Myocardial rupture Thromboembolism
Late Complications Ventricular wall rupture Valvular regurgitation Ventricular aneurysms Tamponade Dressler's syndrome Thromboembolism
MNEMONIC for Complications of MI
Darth Vader
Death Arrhythmias Rupture Tamponade Heart failure Ventricular disease Aneurysm Dressler's syndrome Embolism Regurgitation
Summarise the prognosis for patients with ischaemic heart disease
TIMI score (0-7) can be used for risk stratification NOTE: TIMI = thrombolysis in myocardial infarction
High scores are associated with high risk of cardiac events within 30 days of MI
Killip Classification of acute MI can also be used: Class I: no evidence of heart failure Class II: mild to moderate heart failure Class III: over pulmonary oedema Class IV: cardiogenic shock
