Arrhythmias - Atrial Fibrillation Flashcards
ESSENCE
Supraventricular tachyarrhythmia secondary to uncoordinated atrial contractions
What rhythm is caused
Irregularly irregular rhythm (non-repetative pattern in PR interval)
Cardiac consequences
Maybe reduced cardiac output and result in thrombus formation in atrium
What is most common site of origin for ectopic foci (abnormal pacemaker)
Pulmonary veins
PATHOGENESIS
- Usually due to an underlying cause
- eg atrial enlargement and inflammation or infiltrative disease affecting atrium
AETIOLOGY
5 most common causes
- Remember AF affects mrs SMITH
- Sepsis
- Mitral valve pathology (stenosis or regurgitation)
- Ischaemic heart disease
- Thyrotoxicosis
- Hypertension
EPIDEMIOLOGY
What is most common arrhythmia
Atrial fibrilation
CLINICAL FEATURES
Symptoms
- Asymptomatic
- In symptomatic cases
- Palpitations
- Shortness of breath (suggestive of heart failure)
- Lightheadedness
CLINICAL FEATURES
Signs
- Irregularly irregular pulse
- Focal neurological deficit if results in embolic stroke
- In cases where AF leads to HF
- Elevated JVP
- Bibasilar rates on pulmonary auscultation
- Peripheral oedema
The 2 differentials for irregularly irregular pulse
AF
Ventricular ectopics
INVESTIGATIONS
First choice
- ECG
- If arrhythmia not captured then Holter monitoring in outpatient setting or telemitry in inpatient setting
- Transthoracic echocardiogram (TTE)
- Lab testing
- TFT
- U&Es
ECG findings
- Absent P waves
- Narrow QRS complex tachycardia
- Irregularly irregular ventricular rhythm
DIFFERENTIALS
- Multifocal atrial tachycardia
- Premature atrial contractions
- Atrial flutter
- Wolff-Parkinson-White syndrome
MANAGEMENT
What does management depend on
Haemodynamically stable or not
MANAGEMENT
Haemodynamically unstable
Synchonised cardioversion
MANAGEMENT
General principles
- Slowing on ventricular rate short term
- Long term management
- Rate and rhythm control
- Anticoagulation to prevent stroke
MANAGEMENT
When should patients not have rate control
- Reversible cause for AF
- AF new onset (within last 48 hours)
- AF causing heart failure
- remain symptomatic despite being effectively rate controlled
MANAGEMENT
Options for rate control
- Beta-blocker
- CCB - not preferable in heart failure
- Digoxin - only in sedentary people, needs monitoring due to toxicity risk
MANAGEMENT
Indications for rhythm control instead of rate control
- Reversible cause of AF
- New onset (<48 hours)
- AF causing heart failure
- Remain symptomatic despite being effectively rate controlled
2 different kinds of cardioconversion
- Immediate cardioconversion
- AF been present <48 hours or severely haemodynamically unstable
- Delayed cardioversion
- AF present >48 hours and stable
What should be done in delated cardioconversion in regards to medication
Should be anticoagulated for minimum of 3 weeks before cardioconversion
2 options for cardioconversion
Pharmacological
Electrical
First line for pharmacological cardioconversion
- Flecanide
- Amiodarone - drug of choice in patients with structural heart disease
Lines for long term medical rhythm control
- Beta blockers
- Dronedarone
- Amiodarone - with heart failure or left ventricular dysfunction
What does choice of anticoagulant depend on
CHA2DS2-VASc score
Describe CHA2DS2-VAS2 score
- CHA2DS2-VAS2
- Congetive heart failure - 1 point
- Hypertension - 1 point
- Age =>75 - 2 points
- Diabetes - 1 point
- Stroke/TIA/Thromboembolism - 2 points
- Vascular disease - 1 point
- Age 65-74 - 1 point
- Sex female - 1 point
- Coagulation choice for CHA2DS2-VASc score
- 0 or 1
- 2 or more
- 0 or 1
- Aspirin
- Conservative monitoring
- 2 or more
- Dabigatran
- Rivaroxaban
- Apixaban
- Warfarin
What can reverse anticoagulation effects in uncontrolled/life-threatening bleeding
- Andexanet alfa (apixaban and rivaroxaban)
- Idarucizumab (monoclonal antibody against dabigatran)
COMPLICATIONS
- Atrial thombi emboli to cerebral vessels causing ischaemic stroke or TIA
- Atrial thombus to common iliac artery
- Renal infarction
What tool is used to establish patients risk of major bleeding whilst on anticoagulation
HAS-BLED
What is HAS-BLED score based on
- HAS-BLED
- Hypertension
- Abnormal renal and liver function
- Stroke
- Bleeding
- Labile INRs (whilst on warfarin)
- Elderly
- Drugs or alcohol
