Stable Ischaemic Heart Disease and Angina Flashcards
Causes of myocardial Ischaemia
- Obstructive coronary atheroma (very common)
- Coronary artery spasm (uncommon)
- Coronary artery inflammation/arteritis (very rare)
Uncommonly due to - Reduced O2 transport due to anaemia of any cause
- Pathologically increased myocardial O2 demand
Modifiable risk factors for coronary artery disease
Smoking Lifestyle (exercise/diet) Diabetes Mellitus Hypertension Hyperlipidaemia
Non-modifiable risk factors for coronary artery disease
Age
Gender (Male > female)
Creed
Family history/genetics
Exacerbating factors for stable angina
Excess myocardial demand
- Exertion/Exercise
- Cold Weather
- Emotional stress
- Heavy meal
Investigations for stable angina
Bloods CXR ECG ETT Myocardial Perfusion Imaging Invasive angiography (most invasive) Cardiac catheterisation/coronary angiography
Characteristics of angina pain
SITE: retrosternal
CHARACTER: tight band/pressure/heaviness
RADIATION: neck and/or into jaw
AGGREVATING FACTORS: exertional/emotional stress
RELIEVING FACTORS: rapid improvement with GTN or physical rest
Other symptoms include:
- Breathlessness on exertion
- Excessive fatigue on exertion for activity undertaken
- Near syncope on exertion
Treatment measures for stable angina
General measures: address risk factors: BP, DM, Cholesterol, lifestyle Drugs: -INFLUENCING DISEASE PROGRESSION 1. Statins 2. ACE inhibitors 3. Aspirin - FOR RELIEF OF SYMPTOMS 1. Beta-blockers 2. IK channel blockers 3. Nitrates (GTN) 4. Ca2+ channel blockers 5. K+ channel activators Revascularisation: - Percutaneous Coronary Intervention (PCI) - Coronary artery bypass grafting (CABG)
Acute coronary syndromes
Myocardial Infarction (STEMI/NSTEMI) Unstable angina pectoris
Chronic stable ischemia syndromes
Angina pectoris
Silent ischaemia
Two types of myocardial ischaemia
- Demand Ischaemia (on exertion)
2. Supply ischaemia (at rest)
Determinants of myocardial demand
Heart rate
Systolic blood pressure
Myocardial wall stress
Myocardial contractility
Determinants of myocardial supply
Coronary artery diameter and tone
Collateral blood flow
Perfusion pressure
Heart rate (duration of diastole)
Purpose of drug treatment
Relieve symptoms Halt disease progress Regression of disease process Prevent MI Prevent death
3 major determinants of myocardial oxygen demand (which beta-blockers decrease) are…
Heart rate
Contractility
Systolic wall tension
Contraindications for beta blockers
Asthma Peripheral vascular disease Raynaud's syndrome Heart failure (due to dependence on sympathetic drive) Bradycardia/Heart Block
Adverse drug reactions from beta blockers
Tiredness/fatigue Lethargy Impotence Bradycardia Bronchospasm
Contraindications for calcium channel blockers
Never use nifedipine immediate release
Evidence that rapidly acting CCBs (nifedipine) may precipitate acute MI or stroke
Post MI
Unstable angina
Adverse drug reactions for (calcium channel blockers)
Ankle oedema (15-20% of patients affected and does not respond to diuretics)
Headache
Flushing
Palpitation
Nitro-vasodilators
Glyceryl trinitrate (GTN)
Isosorbide mononitrate
Isosorbide dinitrate
Overcome tolerance of nitrates by
- Giving asymmetric doses of nitrates 8am and 2pm
2. Using sustained release preparation which incorporates a “free nitrate period”
Adverse drug reactions of nitrates
Headache - increase dose slowly
Hypotension - GTN syncope
Potassium channel openers
Nicorandil
Ivabradine
Antiplatelet tablets
Low dose aspirin (75-100mg)
Clopidogrel
Newer agents: prasugrel and ticagrelor
Cholesterol lowering agents
Simvastatin
Pravastatin
Atorvastatin
New approaches to myocardial ischaemia
Metabolic modulation
Sinus node inhibition
Late Na current inhibition
Preconditioning
