Cardiology 1 and 2 Flashcards
What is acute coronary syndrome?
A spectrum of conditions
- Unstable angina
- NSTEMI
- STEMI
Reduction in blood flow through the coronary arteries - usually as a result of atherosclerotic plaque rupture
What is diagnosis of ACS based on?
Symptoms
ECG
Bloods
What does an ECG with sustained ST elevation indicate?
Full thickness ischaemia and necrosis
List some symptoms of ACS
Heartburn Chest pain - Radiates to neck or left arm Sweating Clammy Cold Grey pallor Nausea Vomiting LOC Arrest Anxiety
List the risk factors for ACS
HTN High cholesterol FH Smoking Male Obesity Diabetes
What score is used to predict the risk of death from MI after ACS?
GRACE 2 score
List the treatment aims of ACS
Reduce cardiac ischaemia
Reduce myocardial O2 demand
Prevent recurrence
How is cardiac ischaemia reduced
Revascularisation
Thrombolysis
Medical management
Describe revascularisation
Patient to catheter lab
Femoral/radial access
Angiography +/- Angioplasty +/- stenting (bare metal or drug eluting - dual antiplatelet therapy for up to 12 months - premature discontinuation leads to an increased risk of stent thrombosis)
Or coronary artery bypass graft
When is thrombolysis used to treat ACS?
Used in a STEMI
Which drugs are used in thrombolysis?
Alteplase
Reteplase
Streptokinase
Tenecteplase
When is thrombolysis contraindicated?
Recent bleeding/trauma (<1 month) Bleeding disorders Hemorrhagic stroke Ischaemic stroke/TIA (<6 months) On warfarin/DOAC
Describe the immediate management of ACS
Oxygen Nitrates Anti-emetics Antiplatelet loading Fondaparinux/LMWH
What long term management and secondary prevention would you expect an ACS patient to be discharged home with?
DAPT - aspirin, clopidogrel/prasugrel/ticagrelor ACE inhibitors/ARBs Beta blockers Statins GTN spray Lifestyle advice
What is the loading dose of aspirin?
300mg
What is the maintenance dose of aspirin?
75mg
What must aspirin be taken with?
Food
What is the loading dose of clopidogrel?
300 or 600mg depending on local guidelines
What is the maintenance dose of clopidogrel?
75mg OD
What is the loading dose of ticagrelor?
180mg STAT
What is the maintenance dose of ticagrelor?
90mg BD
What is the loading dose of prasugrel?
60mg STAT
What is the maintenance dose of prasugrel?
<60 Kg or >75years old - 5mg OD
>60 Kg 10mg OD
What is a common side effect of ticagrelor?
Shortness of breath
What is a common side effect of prasugrel?
GI bleeding
Describe the mechanism of action of beta blockers
Affect receptors in heart and blood vessels
Slow the SA node which initiates heart beat
Slows heart rate and allows time for the left ventricle to fill completely and lowers heart workload
Dilate arteries
Lower blood pressure
List the contraindications and cautions of beta blockers
2nd and 3rd degree heart block
Asthma and obstructive airways disease
Unstable heart failure
What are the side effects of beta blockers?
Fatigue Cold hands/feet Nightmares/sleeping disturbances Breathing difficulties in asthmatics Bradycardia
What can beta blockers mask the symptoms of?
Hypoglycaemia
What may happen if a patient suddenly stops taking beta blockers?
Rebound tachycardia
Describe the use of ACE inhibitors in ACS
Ventricular enlargement causes a poorer prognosis so these patients should have an ACEi 24 hrs post MI
Titrate up every 2 weeks to the maximum tolerated dose
Prevent cardiac remodelling
Continue indefinitely
Monitor renal function and electrolytes
What are common side effects of ACE inhibitors?
Dry cough
Loss of taste/appetite
Postural hypotension - advised to take at night time
Describe the mechanism of action of statins
HMGCoA reductase inhibitors - prevent the synthesis of cholesterol in the liver
Lowers LDL cholesterol but does not target dietary cholesterol
Stabilises atherosclerotic plaques in coronary blood vessels. Anti inflammatory effect upon blood vessels.
When should simvastatin and pravastatin be taken?
At night
How much can statins reduce the risk of another cardiac event by?
60%
What is the target total cholesterol?
<5
What is the target Non-HDL cholesterol?
<4
What is the target LDL cholesterol?
<3
What is the target HDL cholesterol?
> 1
What is the target triglycerides?
<2.3
List the side effects of statins
Muscle pain Headaches Nausea Vomiting Abdominal pain
What is angina pectoris?
Pian, discomfort or pressure typically located in the chest and caused by an insufficient supply of blood to the myocardium
Describe the effects of nitrates in angina pectoris
Dilation of veins and collaterals - decreased O2 consumption
Describe the effects of nitrates in heart failure
Dilation of conduit arteries and veins - reduced LVEDP, reduced wall stress and reduction of mitral regurgitation
Describe the effects of nitrates in ACS
Dilation of conduit arteries, collaterals and antiaggregant effects - increases O2 supply
Give some reasons for nitrate use
To relieve or prevent expected chest pain - GTN spray
To prevent regular chest pain (tablets/patches)
What are some side effects of nitrates
Flushing
Headache - will reduce over time and become less severe
Dizziness
Postural hypotension
Which drugs interact with nitrates?
Sildenafil
Vardenafil
Tadalafil
Cause significant drop in BP
Why must people be careful when driving and taking nitrate?
Causes dizziness
Should a person consume alcohol when taking nitrates?
No - may cause dizziness - Avoid directly after use
Describe the mechanism of action of nicorandil
Nitrate like action and K+ ATP channel opener
What are the side effects of nicorandil?
Dizziness
Nausea
Headache
Name the most common arrhythmia
Atrial fibrillation
Describe atrial fibrillation
Rapid atrial rate >300-600 beats per min followed by a rapid and irregular ventricular beat
AV node restricts conduction, giving ventricular rate < 200 bpm
List the symptoms of atrial fibrillation
Palpitations Chest pain Fatigue Dizziness Dyspnoea Syncope Low exercise tolerance
What is persistent AF?
> 48hrs after onset but may be cardioverted back to SR using either electrical or pharmacological cardioversion
What is paroxysmal AF?
Intermittent, self terminating or recurrent arrhythmia combined with normal SR. Main aim of treatment is to maintain SR for as long as possible because cardioversion is ineffective
What is permanent AF?
Chronic condition which is permanent for >48hrs
Cardioversion is either ineffective or unsuitable.
Aim of treatment is to maintain the HR by controlling the ventricular rate
Describe rate control
Slow conduction through the AV node
Patient remains in AF but a more controlled/slow rate
Describe rhythm control
Electrical by cardioversion - immediate or elective
Chemical cardioversion - drug therapy alone or as an adjunct to electrical cardioversion
What is ablation?
A technique where a small amount of energy is applied directly onto the area responsible for the abnormal electrical circuit within the heart - the energy creates scar tissue which blocks the electrical transmission in these areas
List the drug treatments for AF
Anticoagulants
Rate control - Beta blockers, rate lowering calcium antagonist (verapamil, diltiazem) and digoxin
Rhythm control - Structural heart disease (beta blocker or amiodarone), No structural heart disease (beta blocker)
Pill in the pocket - Flecainide and propafenone
Why is AF dangerous?
Most common cardiac disorder leading to stroke and thromboembolism
Where do thromboembolisms resulting from AF come from?
Left atria
What do AF strokes lead to?
High mortality and high levels of disability - larger strokes
How much does appropriate anticoagulation reduce the risk of stroke by?
2/3
Which drug class is commonly used to treat AF?
DOACs
Name some DOACS used to treat AF
Dabigatran
Rivaroxaban
Apixaban
Edoxaban
When do you avoid the use of DOACS
If Cr CL is <15ml/min
How often would you check U&Es after starting a DOAC?
1 year
On initiation of DOAC treatment what monitoring must be carried out?
Renal function
Patient weight
Liver function
Clotting screen
Describe the mechanism of action of warfarin
Vitamin K antagonist
Works on clotting cascade factors 2,7,9 and 10
What monitoring is needed when a patient is on warfarin?
Regular INR checks
How is warfarin dosed?
According to INR
What is warfarin licensed for use in?
AF PE DVT Recurrent DVT and PE Mechanical valves
Name a scoring system used to estimate the risk of stroke
CHA2DS2-VASc Score
Name a scoring system used to estimate the bleeding risk
HASBLED
List the components on the CHADVASC score
Congestive heart failure (1) Hypertension (1) Age >75 (2) Diabetes mellitus (1) Previous stroke, TIA or thromboembolism (2) Vascular disease (1) Age 65-74 (1) Sex (female = 1)
List the components on the HASBLED score
Hypertension (1) Abnormal renal and liver function (1 point each) Stroke (1) Bleeding (1) Labile INRs (1) Elderly - age >65 (1) Drugs or alcohol (1 point each)
Which drug is used in rhythm control?
Digoxin
Describe the mechanism of action of digoxin
Increases the force of contraction and reduces conductivity with the AV node
What is digoxin only effective for?
Controlling ventricular rate at rest
Which patient should digoxin be used in?
Monotherapy for sedentary patients
What should the dose of digoxin be determined by?
Ventricular rate at rest
HR should not fall below 60bpm
How is digoxin excreted?
Renally
What monitoring is required with digoxin?
The digoxin level
What is the ideal digoxin level?
0.5-2 micrograms/litre
How long after the dose are digoxin levels taken?
6 hrs
What can toxic levels of digoxin occur at?
> 1.5-3 micrograms/litre
What is digoxin toxicity increased by?
AKI
Hypokalemia
Hypomagnesaemia
Hypocalcaemia
List the signs of digoxin toxicity
Lethargy Confusion Vomiting Diarrhoea Visual changes
Are IV and PO digoxin doses equal?
No
Describe the loading dose of digoxin
750 micrograms - 1 mg in divided doses over 24 hours (reduce dose if elderly)
What is the adult maintenance dose of digoxin?
125-250 micrograms OD
How much amiodarone is required to load?
5-10g
Describe the loading dose of IV amiodarone
5mg/Kg given over 20-120 mins with ECG monitoring
Describe the loading dose of infusion amiodarone
1.2g/24hrs preferred central administration
Describe the loading dose and maintenance dose of oral amiodarone
200mg tds for 1 week, then 200 mg BD for 1 week and then maintenance dose of 200mg OD
Which bloods would you check if a patient was on amiodarone?
TFTs and LFTs
List the side effects of amiodarone
Cardiac - new/worsened arrythmia
Skin - sensitive to the sun and or blue grey discolouration
Eyes - corneal deposits in the eye - careful with driving
Thyroid - precipitate under active thyroid disease or overactive thyroid disease (blood test before starting and every 6 months)
Liver -rarely causes abnormal liver results (blood test before starting and at 6 months)
Lun - rarely causes inflammation of lining of alveoli
Altered taste and sleep disturbance
Name some calcium channel antagonist groups and state their effect
Dihydropyridine - antihypertensive effect
Non dihydropyridine - antiarrhythmic effect
Which food must patients avoid when taking calcium channel antagonists?
Grapefruit
Name some dihydropyridine CCBs
Felodipine Amlodipine Nimodipine Nifedipine Nicardipine
Name some non-dihydropyridine CCBs
Verapamil
Diltiazem
Describe the mechanism of action of monoamine oxidase inhibitors
Inhibit calcium ions from entering slow or voltage gated channels seen in vascular smooth muscle and the myocardium - increases myocardium oxygen delivery
List the side effects of MAOi
Constipation Facial flushing Headaches Ankle swelling Fatigue Dizziness
What is heart failure?
Clinical syndrome resulting in reduced cardiac output and/or elevated intracardiac pressure at rest or in times of stress
What is heart failure caused by?
Structural and/or functional abnormality in the heart
List the typical symptoms of heart failure
Breathlessness
Ankle swelling
Fatigue
List the typical signs of heart failure
Elevated jugular venous pressure
Pulmonary crackles
Peripheral oedema
Describe systolic heart failure
Heart failure with reduced ejection fraction - Fraction of blood ejected is <40%
Left ventricle can not contract adequately to eject the blood into the aorta. Lack oxygen rich blood to meet the bodys needs
What is systolic heart failure predominately caused by?
Coronary artery disease
Describe diastolic heart failure
Heart failure with a preserved ejection fraction - Fraction of blood ejected >50%
Heart muscles become stiff and do not relax properly resulting in an impaired filling process
What is diastolic heart failure predominately caused by?
Hypertension
Name a class system used to classify heart failure patients
New york heart association
List some causes of chronic heart failure
IHD HTN Valve disease Myocarditis Cardiomyopathy Arrhythmia ACS
Describe the treatment of systolic HF
ACEi/ARB/ARNi/BB
AA (or MRA)
Manage fluid status
Describe the treatment of diastolic HF
Manage fluid status
What are the goals of HF treatment?
Relieve signs and symptoms
Prevent hospital admission
Improve survival
Describe the physiological response to heart failure
Increase cardiac output
Increase catecholamine release
Activation of renin angiotensin system
Structural changes
Describe the compensatory mechanisms in heart failure
CO = SV x HR
Starling’s Law
Sympathetic Nervous System
Renin-Angiotensin-Aldosterone System
Endothelin, Nitric oxide and prostaglandins
Vasopressin
Stretch and pressure response (ANP and BNP)
What drugs are used to treat HF?
Diuretics ACEi/ARB (if ACEi not tolerated) Beta-blockers Mineralocorticoid receptor antagonists Ivabradine Nitrates Sacubitril/Valsartan
Describe the site and mechanism of action of thiazide diuretics
Distal convoluted tubule - Inhibition of sodium & water reabsorption.
Describe the site and mechanism of action of loop diuretics
Ascending loop of henle - Inhibition of sodium & water reabsorption
Describe the site and mechanism of action of mineralocorticoid receptor antagonists (aldosterone antagonists)
Collecting duct - Inhibition of aldosterone ie allows excretion of sodium & water: potassium retained
What is the first line treatment for all left ventricular HF?
ACEi and ARBs
Describe the dosing of ACE inhibitors and ARBs
Start at low dose and titrate upwards every 2 weeks until maximum tolerated dose.
When are angiotensin 2 receptor antagonists recommended first line?
In patients who can not tolerate ACE inhibitors
Name some angiotensin 2 receptor antagonists
Candesartan, losartan and valsartan
Describe ivabradine
Licensed for Chronic HF
5mg BD for 2 weeks then increase to maximum 7.5mg BD (Resting HR >50 bpm)
2.5mg BD if >75 years or unable to tolerate higher dose
NICE recommends it in combination with standard therapy when Beta blockers are not tolerated or contra-indicated
ESC recommends it for EF<35% in SR with resting HR ≥ 70bpm when Beta blockers are not tolerated or contra-indicated
List the side effects of ivabradine
slow heart rate,
headache,
dizziness,
vision disturbance.
List some lifestyle changes used in the treatment of heart failure
Monitor fluid intake Monitor breathlessness and oedema Smoking cessation Optimise BP Optimise diabetes management Diet and reduced salt intake Regular exercise providing condition is stable and doesn’t preclude this Flu vaccination Pneumococcal vaccination Compliance with medication