Ischaemic Heart Disease

Question 1

What is IHD?

Answer 1

Decreased blood supply to the heart ( heart supplied by coronary arteries)

Question 2

What does IHD result in ?

Answer 2

Ischaemia or infarction of myocardium

Question 3

What causes IHD?

Answer 3

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)

Question 4

What is atherosclerosis?

Answer 4

Narrowing of lumen due to atheromatous plaque build up

Affects laminar flow

Question 5

Describe atherosclerosis formation?

Answer 5

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

Question 6

At what point in atherosclerosis causes an acute attack of unstable angina?

Answer 6

When the surface of the plaque is knocked off

Question 7

What are the 5 big risk factors for IHD?

Answer 7

Smoking
Cholesterol
Diabetes
Hypertension
Family history

Question 8

What is the spectrum of IHD?

Answer 8

Stable angina

Acute coronary syndromes (ACS) - unstable angina and MI (STEMI and NSTEMI)

Question 9

What are the clinical symptoms of IHD?

Answer 9

Central crushing chest pain
Spreads to arm, neck, jaw, back
Pale
Sweaty
Nausea and vomitting
SOB
Palpitations
Syncope

Question 10

Describe stable angina?

Answer 10

Induced by exercise, cold weather, heavy meals, stress

Relieved by the stimulus is removed or after GTN spray

Question 11

Describe ACS?

Answer 11

Spontaneous onset
Not relieved by rest
Can lead to ischaemia of myocardium (unstable angina)
Can lead to infarction of myocardium (MI)

Question 12

How do we diagnose and differentiate IHD?

Answer 12

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

Question 13

Why do we look for troponin in blood?

Answer 13

Troponin is released by myocytes when they die (MI)

Question 14

What does the ST phase correlate to?

Answer 14

QRS = ventricle contraction
T = ventricle relaxation

Question 15

What is angiography?

Answer 15

Diagnostic imaging to visualise the inside of vessels

Question 16

What is functional imaging?

Answer 16

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

Question 17

What is the treatment for IHD?

Answer 17

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

Question 18

What is the relevance of IHD to dentistry?

Answer 18

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)

Question 19

What is heart failure?

Answer 19

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

Question 20

What is the term given when both sides of the heart fails?

Answer 20

Congestive cardiac failure

Question 21

What are the causes of heart failure?

Answer 21

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

Question 22

What % of blood should a healthy normal heart pump

Answer 22

55%

Question 23

Describe the progression of left ventricular dilation?

Answer 23

Left ventricular dilation
Left ventricular dysfunction
Reduced ejection fraction
Body compensatory mechanisms
Fluid retention and vasoconstriction
Ventricular remodelling
Left ventricular dilation

Question 24

What are the symptoms of left sided heart failure?

Answer 24

Pulmonary oedema - SOB, orthopnoea, PND, less exercise tolerance
Reduced organ perfusion - tiredness, confusion, fatigue, less kidney function, muscle wasting, weight loss

Question 25

What are the symptoms of right sided heart failure?

Answer 25

Peripheral oedema - ankle swelling
Ascites
Hepatomegaly - liver dysfunction and enlargement
Increased JVP

Question 26

What investigations are done for heart failure?

Answer 26

Chest X ray - pulmonary congestion
Plasma BNP - brain natriuretic peptide
ECG - shows left ventricular hypertrophy
Echocardiogram - see structural abnormalities

Question 27

How do we manage heart failure?

Answer 27

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

Question 28

What is the dental relevance of heart failure?

Answer 28

Avoid extraction
Orthopnoea means pt uncomfortable lying flat in chair
Drug interactions - careful with NSAIDS, digoxin interacts with macrolides