Chaper 2: Cardiovascular - Arrythmia Flashcards
What is an arrhythmia?
A problem with the rate or the rhythm of the heartbeat
What are the general symptoms of an arrhythmia?
Palpitations SOB Dizziness Fainting Chest pain Fatigue
What are the three types of supraventricular arrhythmias?
Atrial fibrillation
Atrial flutter
Paroxysmal supraventricular arrhythmia
What are the two types of ventricular arrhythmia
Ventricular tachycardia (e.g. torsades de pointes) Ventricular fibrillation
What are ectopic beats and how are they managed?
They are extra heartbeats that occur just before a regular heartbeat
They usually don’t require treatment
But if they are troublesome beta-blockers may help
What is atrial fibrillation?
An abnormally fast rhythm arising from or above the AV node
It is triggered by rapidly firing electrical impulses
When the AV node receives more impulses that it can conduct, an irregular ventricular rhythm results
What are the causes of atrial fibrillation?
Cardiovascular: CHF
Non-cardiovascular: infection, cancer, PE
Lifestyle: alcohol abuse, obesity
What is the main complication of atrial fibrillation and how is this managed?
Stroke
Managed using anticoagulants
E.g. warfarin, apixaban, rivaroxaban, dabigatran, edoxaban
But before initiating consider a patients risk of stroke vs risk of bleeding
Assessment tools can help with this
What are the three broad categories for managing atrial fibrillation?
Cardioversion
Rate control
Rhythm control
What is the first-line treatment for reversible atrial fibrillation?
Cardioversion
What drugs are used for pharmaceutical cardioversion?
Oral or IV amiodarone (preferred if there is structural heart disease)
Oral or IV flecainide
When is electrical cardioversion preferred?
When atrial fibrillation has been present for more than 48 hours
Anticoagulation and electrical cardioversion?
Patients should be anticoagulated for at least 3 weeks before electrical cardioversion
If this is not possible, use parenteral anticoagulation before cardioversion, then oral anticoagulation for at least 4 weeks afterwards
What are the two types of electrical cardioversion?
Direct current
Cardiac pacing
What drugs can be used for rate control?
Beta-blocker (not sotolol)
Rate-limiting CCB e.g. diltiazem, verapamil
Digoxin
When can digoxin be used in atrial fibrillation?
When the patient is predominantly sedentary (it is only effective when at controlling the ventricular rate when the heart is at rest)
For non-paroxysmal atrial fibrillation
For atrial fibrillation and heart failure
In atrial fibrillation, when mono therapy with one of the rate control drugs fails to control the ventricular rate, what do you do?
Consider cardioversion
Or use a combination of 2 drugs (beta-blocker, diltiazem or digoxin)
In atrial fibrillation, how to you select which beta-blocker to use
First choice is atenolol (cheapest)
Acebutolol, metoprolol, nadolol, oxprendolol and propranolol are also indicated in AF
In atrial fibrillation, when is rhythm control used
Post-cardioversion
In atrial fibrillation, what drugs can be used for rhythm control?
First line - standard beta-blocker
Other options include anti-arrhythmics e.g. amiodarone, flecainide, sotolol, propane ones
What do you do in the acute presentation of atrial fibrillation?
Life-threatening haemodynamic instability:
Electrical cardioversion
Non-life-threatening haemodynamic instability:
Consider cardioversion (remember to anticoagulate the patient for 3 weeks, prior to cardioversion offer rate control)
Less than 48 hours - rate or rhythm control
Over 48 hours - rhythm control
What is paroxysmal atrial fibrillation and how is it managed?
Intermittent AF - it begins suddenly and stops on its own within 7 days
Manage with a standard beta-blocker
Or consider an oral anti-arrhythmic e.g. amiodarone, flecainide, sotolol, dronedarone, propafenone
In some patients, the ‘pill in pocket’ approach may be considered
What is the pill in pocket approach and when can it be used in atrial fibrillation?
It is when patients can self-treat when an episode occurs
It can be used in paroxysmal atrial fibrillation, where there are infrequent episodes
Drug options include oral flecainide or propafenone
What are the risk factors for stroke in atrial fibrillation?
Prior ischaemic stroke, TIA or thromboembolic events
Other heart conditions e.g. HF, LVSD
Other CV conditions e.g. diabetes, hypertension
Patient factors e.g. over the age of 65, female
What are the signs of haemodynamic instability?
Rapid pulse (>150 beats per minimum) Low blood pressure (systolic BP <90mmHg Ongoing chest pain Increasing breathlessness Severe dizziness
Describe the two screening tools to determine whether anticoagulation should be initiated in atrial fibrillation
CHADSVAS - stroke risk C - CHF/LVSD (1) H - Hypertension (1) A - Age >75 (2) D - Diabetes (1) S - Stroke/TIA/systemic arterial embolism (2) V - Vascular disease (precious MI, aortic plague (1) A - Age 65-74 (1) S - Sex, male 0, female 1
HASBLED H -Hypertension (1) A - Abnormal liver function (1) A - Abnormal renal function (1) S - Stroke (1) (Major) Bleeding history (1) L - Labile INR E - Elderly (>65) Drugs and alcohol (Drugs includes anticoagulants and NSAIDS (1), alcohol abuse (1))
What oral anticoagulants can be used for stroke prevention in atrial fibrillation?
Vitamin K antagonists:
Warfarin
Apixaban, rivaroxaban, edoxaban, dabigatran
What is atrial flutter and how does this differ from atrial fibrillation?
Atrial flutter is when the atria beat faster than the ventricles, causing for the heart rhythm to be out of sync
In atrial fibrillation, the atria beat irregularly. In atrial flutter that beat regularly but faster than usual and more often than the ventricles
How is atrial flutter managed?
First, rate control
Beta-blockers, rate-limiting CCB, digoxin
Note, IV is preferred if a rapid rate control is required
Then conversion of sinus rhythm by:
Electrical cardioversion (preferred if the atrial flutter has been present for more than 48 hours)
Pharmacological cardioversion
Catheter ablation
Remember, fully anticoagulate for 3 weeks prior to cardioversion
How do you manage paroxysmal supraventricular tachycardia?
First, reflex vagal stimulation
If this is not adequate or if symptoms are severe, use IV adenosine
IV verapamil is an alternative to IV adenosine, but avoid in patients recently treated with beta-blockers
In patients who are haemodynamically unstable or do not respond to either of the above do electrical cardioversion
Prophylaxis can include verapamil, diltiazem, beta-blockers, flecainide, propafenone
What can be used to treat an arrhythmia after an MI?
Lidocaine
Disopyramide
How do you manage ventricular tachycardias?
Pulseless patients:
Defibrillation
Sustained ventricular tachycardia and haemodynamically unstable: Electrical cardioversion (direct current)
Sustained ventricular tachycardia and haemodynamically stable:
IV anti-arrhythmics e.g. amiodarone
Non-sustained ventricular tachycardia and haemodynamically stable:
Beta-blocker
Most patients will require maintenance therapy, e.g. beta-blocker, or beta-blocker and amiodarone
What is torsades de pointes?
A form of ventricular tachycardia that is associated with a long QT interval syndrome
How is torsades de pointes managed?
IV magnesium sulfate
Beta-blocker
Avoid anti-arrhythmics as these also prolong the QT interval and so can worsen the condition
Which drugs can be used to manage which types of arrhythmia s?
Supraventricular arrhythmia:
Digoxin, adenosine, verapamil
Ventricular arrhythmia:
Lidocaine
Both:
Everything else
What are the class I anti-arrhythmics?
Lidocaine (IA)
Disopyramide (IB)
Flecainide (IC)
Propafenone (IC)
What are the class II anti-arrhythmics?
Beta-blockers
What are the class III anti-arrhythmics?
Amiodarone
Dronedarone
What are the class IV anti-arrhythmics?
CCBs e.g. verapamil
What is a side-effect of most anti-arrhythmic drugs?
Arrhythmia
Hypokalaemia can enhance this effect
What is lidocaine indicated for and how is it administered?
Arrhythmia in MI
IV
What should you do if both flecainide and amiodarone are given?
Reduce the flecainide dose by half
Which is preferred in pregnancy/breastfeeding out of amiodarone and flecainide for arrhythmia?
Flecainide
Should propafenone be taken with or without food?
With food
What is the dose of amiodarone in arrhythmias?
Oral
200mg TDS for 1 week, then 200mg BD for 1 week, then a maintenance dose of 200mg OD
IV
5mg/kg, to be given over 20-120 minutes
Maximum 1.2g
What is the dose of amiodarone for ventricular fibrillation, or pulseless ventricular tachycardia refractory to defibrillation?
Only considered after the administration of adrenaline
IV injection
300mg in a pre-filled syringe or 20ml glucose
Then 150mg if required
IV infusion
900mg over 24hours
What are the contraindications of amiodarone?
Thyroid dysfunction
Iodine sensitivity
Sinus node disease
Sino-atrial block
Sinus bradycardia
Severe conduction disturbances
With IV use
Severe arterial hypotension, severe respiratory failure
Bolus - CHF, cardiomyopathy
What should you consider if you see an amiodarone prescription in the elderly?
STOPP criteria
What should you consider with regards to amiodarone and it’s interactions?
It’s long half life
There is a potential for drug interactions for weeks/months after amiodarone has been stopped
What are 10 side effects of amiodarone
Hyperthyroidism Hypothyroidism Nausea Vomiting Hepatic disorders Corneal deposits Bronchospasm Respiratory disorders Arrythmia Skin reactions Delirium Pancreatitis Photosensitivity reactions Headache Erectile dysfunction Constipation Sleep disorders Altered smell or taste Thrombocytopenia, neutropenia, agranulocytosis
Can amiodarone be given in pregnancy or breastfeeding?
Avoid in pregnancy unless essential
Avoid in breastfeeding
What are the monitoring requirements of amiodarone?
Before treatment:
Chest X-ray
Serum potassium concentration
6 monthly
During treatment
T4 and TSH
LFT
Patient counselling with amiodarone?
Phototoxocity - during and after treatment
May affect driving and skilled tasks
What is the risk of the concurrent use of amiodarone and sofobusir, and what symptoms should patients look out for?
Heart block and severe bradycardia
Symptoms include: SOB light-headedness Palpitations Fainting Fatigue Chest pain
Can amiodarone be given to patients with Wolff-Parkinson-White syndrome?
Yes
What is the indication for adenosine?
Paroxysmal supraventricular arrhythmia
For rapid conversion to sinus rhythm (including those associated with accessory conducting pathways e.g. Wolff-Parkinson-White syndrome)
What is the indication of sotalol?
Maintenance of sinus rhythm following cardioversion of atrial fibrillation or atrial flutter
Treatment of non-sustained ventricular Arrythmia
Prophylaxis of paroxysmal atrial fibrillation
Life-threatening arrhythmias
It is no longer indicated in Angina Hypertension Thyrotoxicosis Secondary prevention after an MI
What is the dose of sotalol?
Initially 80mg daily in 1-2 divided doses
Increased gradually to 160-320mg daily in 2 divided doses
What effect does sotalol have on the QT interval?
QT interval prolongation
What are the symptoms of digoxin toxicity?
Nausea, vomiting
Neurological symptoms e.g. confusion
Increased heartbeat
Reduced appetite
How do you manage digoxin toxicity?
Withdraw digoxin and correct electrolyte abnormalities
Administer digoxin-specific antibody fragments
What should the ventricular rate at rest be above whilst on digoxin?
60 beats per minute
Is digoxin used for rapid control of heart rate?
No, it has a long half life.
Do electrical cardioversion
Can digoxin be administered orally, by IV, by IM and by SC?
Oral and IV - yes
IM and SC - no
Do patients with heart failure and are in sinus rhythm require a loading dose?
No - their levels will be satisfactory in about a week
How often is digoxin given?
Usually OD
Can sometimes be BD e.g. due to nausea
What concentration of digoxin is more likely to be toxic?
1.5-3mcg/L
What is the risk of hypokalaemia for patients on digoxin and how is this managed?
It predisposes the patient do digoxin toxicity
Manage with a potassium sparing diuretic or potassium supplements
How do you give digoxin to a patient with thyroid disease?
Reduce the dose in hypothyroidism
May need to increase the dose in hyperthyroidism
Thyrotoxicosis
Reduce the dose until it is in control
What are the indications and doses for digoxin
Maintenance of atrial fibrillation or atrial flutter
125-250mcg OD
Heart failure (for patients in sinus rhythm) 62.5-125mcg OD
Rapid digitalisation of atrial fibrillation or atrial flutter
0.75-1.5mg in divided doses
Given over 24 hours
Emergency loading dose for atrial fibrillation or atrial flutter
0.75-1.5mg in divided doses
Given over at least 2 hours
When should the dose of digoxin be reduced?
Elderly
Renal impairment
Concurrent use of amiodarone, dronedarone, quinine (reduce by half)
If another cardiac glycosides has been given in the preceding 2 weeks
When switching from IV digoxin to oral digoxin, how much should the dose be increased by in order to maintain the same digoxin-plasma concentration?
20-33%
What are the contraindications and cautions of digoxin?
Contraindications
Ventricular tachycardia or fibrillation, heart block, myocarditis
Cautions Hypercalcaemia Hypokalaemia, hypomagnaesia Hypoxia Recent MI Elderly (STOPP criteria?)
What are 8 side-effects of digoxin?
Arrythmias Dizziness Diarrhoea Vomiting Skin reactions Vision changes (yellow vision) Thrombocytopenia Depression Nausea Increased appetite Confusion Malaise GI disorders Headache
What are the monitoring requirements for digoxin?
Monitor digoxin-plasma concentration and serum electrolytes in renal impairment
Monitor digoxin-plasma if digoxin toxicity is suspected
When doing a plasma-digoxin concentration assay, take blood 6 hours after a dose
Heart rate (should be maintained over 60 beats per minute)
Which class of medication for atrial fibrillation does verapamil interact with, and what is the consequence?
Beta-blockers
Increased risk of severe hypotension and bradycardia
AVOID
What is a shared contraindication for digoxin and verapamil?
Arrythmia associated witch conduction pathways s.g. WPW syndrome
Which LFT in particular do we monitor to assess for amiodarone liver toxicity?
Transaminases
Which drugs are interact with amiodarone by increasing the risk of Tordades de pointes?
Sotalol Co-trimoxazole Erythromycin Chlorpromazine Haloperidol Amisulpride Amitripyline Anti-malarials
What is the rescue drug for severe bradycardia following IV amiodarone being administered too quickly?
Atropine
In which groups of patients should flecainide and propafenone not be used in?
Asthma
COPD
Structural/ischaemic heart disease
What can cause QT interval prolongation and therefore Torsades de Pointes?
Drugs
Hypokalaemia
Bradycardia
Does amiodarone cause hypo or hyperkalaemia?
What is the problem with this?
Hypokalaemia
This increases the pro-arrythmic effect of amiodarone
For paroxysmal supraventricular tachycardia, when might IV verapamil be preferred over IV adenosine?
Asthma or COPD
Why does hypokalaemia need to be corrected before starting soltolol?
Both hypokalaemia and sotolol can prolong the QT interval and increase the risk of arrhythmias
How can digoxin toxicity affect vision?
It can cause yellow vision
What is valvular AF?
AF + artificial heart valve
Valvular AF - warfarin
Non-valvular AF - warfarin or DOACs
