Arrhythmias Flashcards
What are the Class I anti arrhythmias?
Na+ blockers
Disopyramide
Lidocaine
Flecainide/propafenone
When is flecainide contraindicated?
Asthma
Severe COPD
When should you avoid propafenone?
In structural/ischaemic heart disease
What are class II anti arrhythmics?
Beta blockers
What are Class III antiarrhythmics?
K+ channel blockers
Amiodarone
Sotalol
Dronedarone
When should amiodarone be used in order to increase the chances of success?
4 weeks before and 12 weeks after electrical cardioversion
What are the main side effects of dronedarone?
Hepatotoxicity
Heart failure
What are the class IV antiarrhythmics?
Rate limiting CCBs
Verapamil
Diltiazem
When is digoxin used in arrhythmias?
For sedentary patients with non-paroxysmal atrial fibrillation
Associative congestive heart failure
What is atrial fibrillation?
Rapid and irregular heartbeat
What are the symptoms of atrial fibrillation?
Heart palpitations
Dizziness
SOB
Tiredness
What are the complications of atrial fibrillation?
Stroke
Heart failure
What is paroxysmal atrial fibrillation?
Episodes stop within 48 hours without treatment
What is persistent atrial fibrillation?
Episodes last > 7 days
What is permanent AF?
Episodes present all the time
What is rate control?
Controls ventricular rate
What is rhythm control?
Restores and maintains sinus rhythm
What is cardioversion?
Type of rhythm control
- Electrical
- Pharmacological
Which of the following is most appropriate when there is acute new-onset presentation of atrial fibrillation and life threatening haemodynamic instability?
A) electrical cardioversion B) flecainide C) verapamil D) digoxin E) sotalol
A) electrical cardioversion
Which of the following is most appropriate when there is acute new-onset presentation of atrial fibrillation without life threatening haemodynamic instability and it is less than 48 hours since onset of presentation
A) electrical cardioversion B) bisoprolol C) verapamil D) digoxin E) sotalol
A) electrical cardioversion
Or amiodarone/flecainide
Which of the following is most appropriate when there is acute new-onset presentation of atrial fibrillation without life threatening haemodynamic instability and it is more than 48 hours since onset of presentation
A) electrical cardioversion B) Amiodarone C) verapamil D) digoxin E) Flecainide
C) Verapamil
Or beta blocker
What is the first line treatment for atrial fibrillation?
- Rate control - B-blockers (not sotalol), rate limiting CCB, digoxin. Monotherapy - dual therapy - rhythm control
- Rhythm control - beta blockers/amiodarone/flecainide/propafenone/dronedarone
What are the treatments for paroxysmal and symptomatic atrial fibrillation?
Ventricular or rhythm control - beta blocker or oral antiarrhythmic
Pill in pocket - flecainide or propafenone
What tool is used to calculate bleeding risk in atrial fibrillation?
ORBIT
Older (75+) Reduced Hb or history of anaemia Bleeding history Insufficient kidney function Treatment with antiplatelet
What is the tool used to determine risk of stroke in atrial fibrillation?
CHA2-DS2-VASc
Chronic heart failure Hypertension Age 75+ Diabetes Stroke Vascular disease Age 65-74 Sex female
Anticoagulant if 2 or more
For new onset atrial fibrillation what anticoagulant would you give for stroke prevention?
Parenteral anticoagulant
For diagnosed atrial fibrillation what anticoagulant would you give?
Warfarin or DOAC
DOAC in non valvular + 1 or more risk factors
How would you treat pulseless v.tach (ventricular tachycardia)?
Immediate defibrillation + CPR
Amiodarone refractory to defibrillation
How would you treat unstable sustained v.tach?
Direct current cardioversion
Failure then IV amiodarone and repeat
How would you treat stable sustained v. Tach?
IV anti arrhythmic (amiodarone preferred)
How would you treat non-sustained v. Tach?
Beta blocker
What is the first line treatment for maintenance after v.tach?
Cardioverter defibrillator implant
Some require drug too - sotalol, beta blocker, beta blocker + amiodarone
What is the treatment for prolonged QT interval?
Magnesium sulphate
What causes prolonged QT interval (torsades de pointes)?
Sotalol
Other drugs
Hypokalaemia
Bradycardia
What is the treatment pathway for paroxysmal supraventricular tachycardia?
- Spontaneously terminates or reflex vagal nerve stimulation
- IV adenosine
- IV verapamil
What is amiodarone?
Class III anti arrhythmic
Used for supraventricular arrhythmias and ventricular arrhythmias
What is the dosing schedule for amiodarone?
200mg TDS for 7/7
200mg BD for 7/7
200mg OD maintenance
What are the side effects of amiodarone?
Corneal microdeposits Optic neuropathy Phototoxicity Slate grey skin Peripheral neuropathy Pneumonitis Pulmonary fibrosis Hepatotoxicity Hyperthyroidism Hypothyroidism
What are the counselling points for amiodarone?
Night time glares when driving
Stop if impaired
Shield skin from light during and after stopping
Numbness, tingling hands and feet, tremors
Shortness of breath, dry cough
Jaundice, nausea, vomiting, malaise
What would be the action plan for amiodarone induced hyperthyroidism?
Give carbimazole if necessary
Withdraw amiodarone
What would be the action plan for hypothyroidism cause by amiodarone?
Start levothyroxine without withdrawing amiodarone if essential
What are the monitoring requirements for amiodarone?
Annual eye test Chest X-ray before treat,met LFTs every 6 months Thyroid function BP and ECG Serum potassium - causes hypokalaemia
What are the interactions for amiodarone?
Long T1/2
Grapefruit juice - increases amiodarone concentration
Warfarin, phenytoin, digoxin - increases plasma concentration of these drugs
Statins - myopathy
Beta blockers, rate limiting CCBs - bradycardia
Quinolones, macrolides, TCAs, SSRIs, lithium, quinine, hydroxychloroquine, antimalarials, antipsychotics - QT prolongation
What is the ideal serum concentration of digoxin?
1-2 mcg/L (Cp 6 hours after dose)
Regular monitoring not required unless toxicity suspected or renal impairment
What is digoxin?
Cardiac glycosides
What is the mechanism of action of digoxin?
Increases force of myocardial contraction
Reduces conductivity in the AV node
Is a loading dose required for digoxin?
Yes as long half life
What is the maintenance dose of digoxin?
Atrial flutter and non paroxysmal AF in sedentary patients - 125-250mcg
Worsening or severe heart failure - 62.5-125 mcg
What are the signs of digoxin toxicity?
Slow and sick
Bradycardia Nausea and vomiting Blurred or yellow vision Confusion Delirium
Risk of toxicity in: Hypo K+, Hypo Mg2+, Hyper Ca2+, hypoxia, renal impairment
What is the treatment for digoxin toxicity?
Withdraw and correct electrolytes
Digoxin specific antibody
What are the interactions of digoxin?
CRASED
CCB (verapamil) Rifampicin Amiodarone St Johns Wort Erythromycin Diuretics
Which drugs cause hypokalaemia when given with digoxin?
Diuretics
B2 agonists
Steroids
Theophylline
What drugs increase plasma digoxin concentration?
Amiodarone
Rate limiting CCB
Macrolides
Ciclosporin
What drugs decrease the plasma digoxin concentrations?
St Johns Wort
Rifampicin
What drugs cause reduced renal excretion and lead to digoxin toxicity?
NSAIDS
ACEi
