Ischaemic Heart Disease Flashcards
What is IHD?
Decreased blood supply to the heart ( heart supplied by coronary arteries)
What does IHD result in ?
Ischaemia or infarction of myocardium
What causes IHD?
ATHEROMA
EMBOLISM- AF makes blood more turbulent so little emboli get trapped in heart
THROMBOSIS
VASOSPASM - vessel spasm in smooth muscle causes temporary ischaemia, onset at night. Prizmetals angina
CORONAY ARTERITIS - autoimmune inflammation reaction in internal lining of vessel (SLE)
What is atherosclerosis?
Narrowing of lumen due to atheromatous plaque build up
Affects laminar flow
Describe atherosclerosis formation?
1) LDL accumulation, which get oxidised and create inflammatory response
2) Macrophages eat LDL and beomce foam cells
3) Foam macrophages accumulate and lyse, leaving dead cells and fat in the vessel
4) Fat in the vessel grows and the vessel tries to stretch but there is less compliance, creates inflammatory response
5) Surface of the fat fibrous plaque gets knocked off, activating clot formation on the atheroma, causing the plague to grow in size
At what point in atherosclerosis causes an acute attack of unstable angina?
When the surface of the plaque is knocked off
What are the 5 big risk factors for IHD?
Smoking Cholesterol Diabetes Hypertension Family history
What is the spectrum of IHD?
Stable angina
Acute coronary syndromes (ACS) - unstable angina and MI (STEMI and NSTEMI)
What are the clinical symptoms of IHD?
Central crushing chest pain Spreads to arm, neck, jaw, back Pale Sweaty Nausea and vomitting SOB Palpitations Syncope
Describe stable angina?
Induced by exercise, cold weather, heavy meals, stress
Relieved by the stimulus is removed or after GTN spray
Describe ACS?
Spontaneous onset
Not relieved by rest
Can lead to ischaemia of myocardium (unstable angina)
Can lead to infarction of myocardium (MI)
How do we diagnose and differentiate IHD?
Pain on exercise and relieved by rest - stable angina
Spontaneous pain not relieved by rest - ACS
Troponin in blood - MI
No troponin in blood - unstable angina
ECG - Increased ST phase - STEMI
ECG - no increase to ST phase - NSTEMI
Why do we look for troponin in blood?
Troponin is released by myocytes when they die (MI)
What does the ST phase correlate to?
QRS = ventricle contraction T = ventricle relaxation
What is angiography?
Diagnostic imaging to visualise the inside of vessels
What is functional imaging?
Exercise ECG - treadmill test
Stress echocardiogram - exercise or give dopamine
Myocaridal perfusion study - nuclear imaging with a radionucleotide tracer absorbed by healthy myocytes and lack of absorption in areas of tissue damage
What is the treatment for IHD?
MEDICAL
02, GTN, morphine, antiplatelets, Xa inhibitors, statins
INVASIVE (if already on best medical management)
PCI - percutaneous coronary intervention, within 90 mins
Thrombolysis - within 6 hrs, hard to reverse
CABG - using an artery from the leg
What is the relevance of IHD to dentistry?
Stress and pain increase myocardial demand so decrease appt times and delay treatment post MI for 6 months
LA with adrenaline can cause problems
Avoid GA
Medication side effects - calcium channel blockers cause gingival hyperplasia (verapamil, nifedipine, amlodipine)
What is heart failure?
Heart fails as a pump - doesnt meet 02 demand of the body.
Terminal and chronic although body slightly compensates
Body fails to maintain adequate circulation
Can be left or right sided heart failure
What is the term given when both sides of the heart fails?
Congestive cardiac failure
What are the causes of heart failure?
PUMP FAILURE - IHD, cardiomyopathy, IE
EXCESSIVE AFTERLOAD - hypertension, aortic stenosis
EXCESSIVE PRELOAD - fluid overload, mitral regurgitation
RESTRICTION - pericarditis, cardiac tamponade
HIGH OUTPUT FAILURE - severe anaemia, hyperthyroid
What % of blood should a healthy normal heart pump
55%
Describe the progression of left ventricular dilation?
Left ventricular dilation Left ventricular dysfunction Reduced ejection fraction Body compensatory mechanisms Fluid retention and vasoconstriction Ventricular remodelling Left ventricular dilation
What are the symptoms of left sided heart failure?
Pulmonary oedema - SOB, orthopnoea, PND, less exercise tolerance
Reduced organ perfusion - tiredness, confusion, fatigue, less kidney function, muscle wasting, weight loss
What are the symptoms of right sided heart failure?
Peripheral oedema - ankle swelling
Ascites
Hepatomegaly - liver dysfunction and enlargement
Increased JVP
What investigations are done for heart failure?
Chest X ray - pulmonary congestion
Plasma BNP - brain natriuretic peptide
ECG - shows left ventricular hypertrophy
Echocardiogram - see structural abnormalities
How do we manage heart failure?
DIURETICS - flurosemide to increase water and salt excretion
ACE INHIBITORS - ramopril
BETA BLOCKERS - bisoprolol to reduce demand, contractility and rate
DIGOXIN - to increase contractility
SPIRONOLACTONE increases potassium levels
What is the dental relevance of heart failure?
Avoid extraction
Orthopnoea means pt uncomfortable lying flat in chair
Drug interactions - careful with NSAIDS, digoxin interacts with macrolides
