Conditions - HF / Atherosclerosis / Syncope / stroke / shock Flashcards
What is congestive heart failure
inability of the heart to maintain adequate cardiac output
Often the end stage of cardiac conditions
Categories of HF
Acute vs Chronic
Right vs Left
Systolic vs Diastolic
High vs Low output
What is chronic heart failure
Progressive dysfunction
Can have acute attacks
Common causes of acute heart failure
Acute MI
Acute cardiac tamponade
Acute valvular tamponade
Acute infective endocarditis
Common causes of chronic HF
Aortic stenosis
Ischaemic diseases
Cardiomyopathy
arrhythmias
Which side HF causes pulmonary congestion and systemic hypotension
Left HF (left ventricular failure)
What does right Ventricular failure cause
Pulmonary hypoperfusion
Systemic congestion
Common causes of right sided heart failure
secondary to left sided HF
cor pulmonale
congenital disease
pulmonary valve disease
What is cor pulmonale
Pulmonary hypertension -> increases SVR -> harder for right ventricle to pump blood -> right ventricular hypertrophy and eventually RVF
Common causes of Left sided HF
cardiomyopathy
valvular disease
congenital diseases
What is it called when there is both right and left side heart failure
Congestive cardiac failure
What does high output HF mean
There is sufficient cardiac output but not enough for the body due to increased metabolic demands / reduced SVR / shunting
What does systolic HF mean
impaired contraction during systole
Ejection fraction formula
SV / EDV
What does ejection fraction measure
The proportion of EDV ejected
What causes preserved ejection fraction heart failure
Diastolic heart failure
What causes diastolic HF
Cardiomyopathy - stiffness of the heart (cannot stretch to fill)
Cardiac tamponade
Constrictive pericarditis
What type of cardiomyopathy cause systolic HF
thin, weak heart muscle
What conditions cause increase in metabolic demands which in turn causes high output HF
Pregnancy
Hyperthyroidism
What conditions cause very low SVR which in turn causes high output HF
Sepsis - causes vasodilation
Anaemia
thiamine deficiency
What are the consequences of left sided heart failure
Pulmonary congestion because blood cannot be pumped out so it backs up in pulmonary vessels
Systemic hypotension because blood not pumped out
Symptoms of LVF pulmonary congestion
Exertional dyspnea
Orthopnea
Paroxysmal nocturnal dyspnea
nocturnal cough
Clinical features of LVF pulmonary congestion
Pulmonary oedema - fluid in alveoli due to high blood pressure forcing fluid out
Tachycardia
3rd heart sound
Crackles on auscultation
Clinical Signs of systemic hypoperfusion
Prolonged capillary refill time
cyanosis
Pulsus alterans
What is the word for alternating strong and weak pulses
Pulsus alternans
How does LVF cause RVF
Pulmonary congestion -> pulmonary hypertension -> cor pulmonale
Symptoms of RVF (systemic congestion)
Oedema
weight gain
abdominal distention
Clinical signs of RVF
Elevated JVP Ankle / sacral oedema Ascites Hepatomegaly Tricuspid regurgitation - pansystolic murmur Pleural effusion
Diagnosis of HF
Blood tests
ECG
Imaging - echocardiogram / CXR
What do blood tests for HF measure
FBC - to exclude anaemia
U&Es - to exclude renal failure causing oedema
LFT - to check for hepatomegaly and exclude liver failure causing oedema
TFT - to exclude hyperthyoridism
BNP
What does elevated BNP indicate
Highly likely it is heart failure hence refer the patient to get echocardiogram
What does echocardiogram see
Any valvular abnormalities / contraction dysfunction
Measures ejection fraction - to see if EF is preserved or reduced
Normal ejection fraction value
50 - 70%
Below 40% + elevated BNP = HFrEF
Features of CXR that may be seen in HF
Cardiomegaly (due to hypertrophy)
Pulmonary oedema
Pleural effusion
Kerley B line
What is Kerley b line
It is a line normally at lung bases, extending transversely to touch the pleural margin.
It indicates pulmonary oedema
First line drug therapy for LVF
Diuretics - for relief oedema - loop (furosemide) is used - add thiazide if oedema is resistant ACEi + Beta Blockers AT inhibitor if ACE is not tolerated
What conditions contraindicate the use of beta blockers
Asthma
COPD
Bradycardia
Second line treatment for LVF
Spironolactone (aldosterone inhibitor)
Digoxin
Ivabradine
Vasodilators - hydralazine + nitrates
When can digoxin be used
Second line treatment of HF if patient has atrial fibrillation
Third line treatment of HF
Cardiac resynchronisation therapy
Transplantation
When is cardiac resynchronisation therapy used
Last line treatment for HF in patients with prolonged QRS
Treatment for acute HF
IV furosemide
IV dopamine
IV diamorphine
Drugs to treat angina
CCB Beta blockers Nitrates aspirin statin
Formation of atherosclerotic plaque
1) initial endothelial injury, increasing permeability of the vessel
2) LDL move into the intima layer. Monocytes move into the intima layer
3) Monocytes become macrophages and release free radicals that oxidise LDL -> OXLDL
4) Macrophage engulf OXLDL -> foam cell -> forms fatty streak
5) OXLDL also amplifies this inflammation process by attracting more macrophages
6) Release of inflammatory mediators causes proliferation of smooth muscle into intima layer
7) Recurrent injury and healing -> fibrosis -> collagen deposit in intima layer
8) Atherosclerotic plaque with fibrous cap and fatty core forms
Complications of atherosclerosis (STADEI)
Arteriole Stenosis Arteriole Thrombosis Aneurysm Dissection Embolism Ischaemia
Why do aneurysms form
Weakened tunica media layer, causing persistant dilation
List the different consequences of atherosclerosis in different arteries
Carotid artery - stroke / TIA
Renal artery - renal hypertension / renal failure
Coronary artery - MI / heart failure
Periphery artery - leg ischaemia / claudication
What increases risk of thrombosis
Virchow’s triad
- abnormal blood flow
- increased coagulability of blood
- injury to the vessel
Consequences of arterial thrombosis
MI
renal infarction
cerebral infarction
Gut infarction
What is dissection
Splitting of media layer by flowing blood, creating a false lumen
pregnancy and Marfan’s syndrome causes an increase in risk of which complication of atherosclerosis
Dissection
What are the risk factors for atherosclerosis
Obesity High cholesterol Smoking Type 1 diabetes Physical inactivity Hypertension
What is considered as hypertension
Anything above 140/90
What is considered as stage I hypertension
above 140/90 or
Ambulatory BP 135/85
What is considered as stage II hypertension
Above 160/100 or
>150/95 ambulatory BP
What is considered as stage III hypertension
Above 180/110 or
Ambulatory diastolic pressure 110
Normal range of pulse pressure
30 - 50
Formula for pulse pressure
Systolic BP - Diastolic BP
What conditions do hypertension increase the risk for
MI
stroke
Chronic kidney disease
What are the classifications of hypertension
primary vs secondary
benign vs malignant
What is defined as a malignant hypertension
When diastolic BP is > 130-140
Life threatening
Why is it important to still treat benign hypertension
Because it can eventually case
- Left ventricular hypertrophy
- HF
- atherosclerosis
- thickening of tunica media
- hypertensive arteriosclerosis
- hypertensive retinopathy
What can malignant hypertension cause
acute HF
cerebral haemorrhage (haemorrhagic stroke)
acute renal failure
fibrinoid necrosis in blood vessels
What drugs can cause hypertension
NSAID
Glucocorticoids
Oral contraceptives
Risk factors for hypertension
Age Family history of hypertension Obesity Alcohol Diabetes
What are the conditions that can cause secondary hypertension
Excess renin
hyperaldosteronism
Cushing’s syndrome
How would you diagnose hypertension
Blood tests to exclude secondary causes
Measure BP
Average of 2 ambulatory BP to confirm
Measure ASSIGN risk score
Management of hypertension
Stage I - lifestyle advice
Stage II and III - lifestyle advice + drug therapy
When is CCB used in hypertension management
First line if the patient does not have type 2
diabetes
What is the drug therapy for hypertension
First line - ACE inhibitors / CCB
Second line - ACEi + CCB/Diuretics or CCB + ACEi/Diuretics
Third line - ACEi + CCB + Diuretics
What is stroke
Acute onset of neurological symptoms and signs due to disruption of blood supply to the brain
Difference between TIA and stroke
TIA is a brief disruption, usually due to small blood clots and will resolve by itself
2 types of stroke
Ischaemic stroke
Haemorrhagic stroke
What is ischaemic stroke
Due to blood clot occluding the vessels that supply the brain
Can be due to thrombosis or embolism
Which part of the heart most commonly produce blood clots
Left atrium (atrial fibrillation usually occurs here)
What are the causes for ischaemic stroke
Thrombosis / atherothrombotic
Embolism
Hypoperfusion due to stenosed artery
What is haemorrhagic stroke
Stroke due to bleeding inside or around brain tissue, causing damage
Unmodifiable risk factors for stroke
Age family history of stroke previous history of stroke or TIA gender race
Modifiable risk factors of stroke
Hypertension Hyperlipidaemia AF Smoking Alcohol Diabetes HF
What is FAST score
Facial drooping Arm weakness Speech difficulties Time This helps identify those that need urgent referral to stroke center
Imaging for stroke
CT is better than MRI because CT is quicker
What should not be given to a person with haemorrhagic stroke
Antiplatelets and anticoagulants
What is the management of ischaemic stroke
Thrombolysis ror thrombolectomy
Treat underlying cause
4 types of shock
Hypovolaemic
Distributive
Obstructive
Cardiogenic
What is defined as shock
Abnormal circulatory system resulting in inadequate tissue perfusion due to low BP and CO
What is hypovolaemic shock
Shock due to loss in blood volume which can be haemorrhagic or non-haemorrhagic
How does loss in blood volume lead to hypovolaemic shock
Loss in blood volume -> decrease in venous return -> decrease in preload -> decrease in EDV -> decrease in SV hence CO
Loss in blood volume -> decrease in BP -> baroreceptor reflex + RAAS system -> vasoconstriction + tachycardia
Why are patients in hypovolaemic shock tachycardic and peripherally cool
Due to sustained decrease in blood volume activating baroreceptor reflex and RAAS
Baroreceptor reflex -> increase in sympathetic stimulation -> vasoconstriciton and increase in heart rate
RAAS -> vasoconstriction
Under what circumstances will the compensatory mechanisms fail to maintain BP
When the loss in blood is > 30% of total blood volume
What is cardiogenic shock
Shock due to cardiac dysfunction
What causes cardiogenic shock
Arrhythmias
Valvular pathologies
MI
What is obstructive shock
Shock due to pressure pressing against the heart or occlusion of vessels
What causes obstructive shock
Pneumothorax - air pressure pressing against the heart -> decrease in venous return
Cardiac tamponade - fluid pressing against the heart -> decrease in venous return
What is distributive shock
Shock due to peripheral vasodilation leading to abnormal distribution
What causes distributive shock
Septic shock
Anaphylactic shock
Neurogenic shock - excess parasympathetic stimulation causing vasodilation
How to manage septic shock
Septic 6 bundle - start within an hour
3 in - IV fluids / oxygen / antibiotics
3 out - blood culture / serum lactate / urine output
What is syncope
Transient loss of consciousness characterized by short duration due to hypotension causing short inadequate cerebral perfusion
What is the difference between syncope and stroke
Inadequate perfusion in syncope is only for a short duration
Hypotension in syncope is not sustained
Syncope is self-resolving
3 types of syncope
Postural hypotension
Reflex syncope
Cardiac syncope
3 types of reflex syncope
Vasovagal
Situational
Carotid sinus
What is reflex syncope
Syncope due to reflex response leading to cardioinhibition and vasodepression
What triggers vasovagal syncope
Prolonged standing
Heat
Stress
Prodromal symptoms + no signficant history is a typical example of
Vasovagal syncope
What triggers situational syncope
Coughing
Urination
Swallowing
What is carotid sinus syncope
Exaggerated response to carotid baroreceptors due to neck manipulation
What is cardiac syncope
An acute cardiac event causing sudden drop in CO and BP
What kind of cardiac events can cause cardiac syncope
Arrhythmias
Structural diseases - aortic stenosis / cardiomyopathy limiting blood flow
Why shouldn’t aspirin be used in asthmatics
Most people with asthma are allergic to aspirin
