Arrhythmias Flashcards
Define AF
Suprventricular tachyarrhythmia characterised by un-coordinated atrial electrical activity
Predisposes risk of thrombus formation
- Stroke
- Ischaemic limbs/ organs.
Define AF
Suprventricular tachyarrhythmia characterised by un-coordinated atrial electrical activity
Predisposes risk of thrombus formation
- Stroke
- Ischaemic limbs/ organs.
AF classifications
Paroxysmal
- Spontaneous occurrence, resolves within 7 days
Persistent
- Lasts >7 days
Permanent
- > 7 days, and refractory to cardioversion, sinus rhythm not maintained/ restored.
AF risk factors
IHD
Hypertension
Valvular heart disease
Heart failure
Lung disease: COPD, pneumonia
Genetic- cardiomyopathy, channelopathies
DM
OSA
Advanced age
Pericarditis, alcohol
Pathophysiology of AF
Fibrosis and atrial muscle remodelling/ degeneration causes new entries of electrical impulse.
Causes of atrial disease
- Ageing
- Dilation (cardiomyopathy, heart failure)
- Inflammation
- Genetic
AF management
- Haemodynamically unstable
- Acute onset <48 hours
Haemodynamically unstable
- Direct current cardioversion
Acute onset, <48 hrs= rhythm control, maintain sinus rhythm
- Normal heart
1. Felcainide/ sotalol
Abnormal heart
1. Amiodarone
Investigations for AF
Bloods
- U+E: K+, low Mg
Cardiac enzymes (CK, trop)
- Ischaemia (cause or consequence)
TFT
- Thyrotoxicosis
Imaging
- Echo: heart failure, atrial thrombus, structural disease.
- CXR: lung disease, cardiomegaly
AF management
- Haemodynamically unstable
- Stable, acute onset <48 hours
Haemodynamically unstable
- Direct current cardioversion
Pharmacological cardioversion
- Normal heart
1. Felcainide/ sotalol
Abnormal heart
1. Amiodarone
Acute onset, <48 hrs= rhythm control, main sinus rhythm
- Beta blocker (atenolol)
- Amiodarone (heart failure)
AF management
- Acute onset >48 hours
Rate control
Normal heart
1. Beta-blocker
- Atenolol, propranolol, metoprolol, bisoprolol
- Diltiazem, verapamil
- Add digoxin
Abnormal heart
1. Amiodarone/ digoxin
2. Amiodarone.
AF management
- Paroxysmal/ permanent
Rate control
- CCB/ Beta-blocker
- Add digoxin
Anticoagulation in AF
Indicated if CHA2DS2VASc >2
Warfarin or DOAC (dabigatran, apixaban, rivaroxaban)
CHA2DS2VASc score
Risk of stroke in AF patients
C- Congestive heart disease/ LV systolic dysfunction
H- Hypertension
Age- >75 = 2 points
D- Diabetes
S- Previous thromboembolic event= 2 points
V- vascular disease
A- Age 65-74
Sc- Female= 1
> 2= anticoagulation
HASBLED score
Score for risk of bleeding in pts on anticoagulation.
H- Hypertension
A- abnormal renal/ liver function
S- Stroke
B- Bleeding
L- Labile INR
E- Elderly (>65)
D- Drugs/ alcohol
> 3= high risk
Loading dose for warfarin in anticoagulation
If <65, >60kg
- 8mg for first 2 days
- Check INR on 3rd day
If >65, <60kg
- 6mg for first 2 days
Maintenance dose of warfarin for anticoagulation
If INR 4+ = with-hold warfarin
If INR 3+
- 1/4 of loading (i.e. 2mg)
INR 2.5+
- 1/3
INR 2+
- 1/2
