Ischaemic Heart Disease Flashcards
Describe the primary symptom of a heart attack
Tightness, constriction or heaviness in the chest
Describe how a heart attack occurs with regards to coronary arteries
- Tear occurs in artery wall
- Fatty material is deposited in vessel walls
- Narrowed artery becomes blocked by a blood clot
- Part of heart becomes occluded
Describe 3 components of early atherosclerosis
- Circulating cholesterol-rich low-density lipoprotein (LDL) infiltrate arterial wall
- LDL is modified by oxidation and taken up by macrophages to form foam cells
- Foam cells accumulate to form fatty streaks the earliest atherosclerotic lesion
Describe 3 components of advanced atherosclerosis
- Oxidised LDL alters the arterial wall’s physical and biomechanical properties
- Circulating white blood cells infiltrate the expanding lesion
- Fibrous cap forms
What is the relation between atherosclerosis and cardiovascular disease?
Atherosclerosis is the pathological process which underlies cardiovascular disease
What 2 processes are central to initiation and promotion of atherosclerosis?
- Oxidation
2. Inflammation
Describe cardiovascular disease
- Umbrella term for all diseases of heart and circulation
- Quarter of all deaths in NI each year
- Death rates fallen from 1960s
- Aging population seeing numbers living with CVD increasing
What occurs when a fibrous cap covering plaque ruptures?
Acute coronary syndrome
What does ST elevation on an ECG indicate?
Coronary artery is completely occluded
Describe 4 things paramedics will do when arriving at the scene of an acute coronary syndrome
- ECG - Determine type of acute coronary syndrome
- Aspirin - Anti thrombosis
- IV access - Pain relief
- Urgent transfer to cardiac catheterization laboratory
What is the most likely cause of unresponsiveness and pulselessness following an acute coronary syndrome?
Ventricular fibrillation
Describe ventricular fibrillation
- Heart muscle is starved of blood and becomes unstable
- Normal electrical activity is disturbed
- Blood prevented from being pumped out of the heart
- Patient now said to be in cardiac arrest
What is the treatment for ventricular fibrillation?
Defibrillation
What is the function in moving the patient to a catheterization laboratory?
Open up the occluded artery
Describe 3 steps of how a stent is placed in a coronary artery
- Stent is passed through blockage on an uninflated balloon
- Balloon is inflated in the artery
- The artery is expanded along with the stent to hold walls apart, and the balloon removed
Describe the main risk of stents
Stent thrombosis
Describe 4 types of stent thrombosis
- Acute stent thrombosis - 0 hours to 24 hours
- Subacute stent thrombosis - 24 hours to 30 days
- Late stent thrombosis - 30 days to 1 year
- Very late stent thrombosis - Over 1 year
What is the main way to prevent stent thrombosis?
Anti platelet medication
Describe antiplatelet medication to prevent stent thrombosis
Dual action using both aspirin or P2Y 12 receptor antagonists e.g clopidogrel, prasugrel
Describe dual action antiplatelet therapy with regards to dental treatment
Do not stop for dental treatment before checking with the cardiologist
Describe QT intervals on an ECG
- Interval from start of ventricular depolarisation to end of ventricular repolarisation
- Depends on duration of action potential
- Rate is depending on heart rate
What prolongs the QT phase?
Repolarisation
Name 3 types of ECG patterns which cause long QT syndrome
- LQTS1
- LQTS2
- LQTS3
Describe LQTS1
- Caused by potassium current
- Decreased functional effect
- Triggered by exercise, emotional stress and sleep
Describe LQTS2
- Caused by potassium current
- Decreased functional effect
- Triggered by emotional stress, exercise and sleep
Describe LQTS3
- Caused by sodium current
- Increased functional effect
- Triggered by sleep, emotional stress and exercise
Name 2 key differences between LQTS1 and LQTS2
- LQTS1 is caused primarily by sleep and LQTS2 is cause primarily by emotional stress
- LQTS1 Q phase is singular large increase from S section of wave and LQTS2 Q phase is flat section followed two small increases
Describe the genetic pattern of prolonged QT syndrome
Autosomal inheritance
Describe 4 ways to prevent the likelihood of an acute QT collapse
- Avoid strenuous physical activity
- Avoid medications known to prolong QT interval
- B-blockers
- Implantable defibrillator
Why are B-blockers beneficial for patients with LQTS?
Reduce the risk of developing ventricular arrhythmias
What is a consideration with regards to LQTS and dentistry?
Adrenaline in LA cartridges can prolong the QT wave