Atrial Fibrillation Flashcards
define atrial fibrillation?
A form of supraventricular tachycardia with uncoordinated atrial electrical activation causing ineffective atrial contraction
define atrial flutter?
type of supraventricular tachycardia caused by re-entry circuit within the right atrium-> leads to continuous atrial depolarisation atrial rate of 200-400bpm
AV node responds intermittently hence an irregular ventricular rate
what are the causes of AF?
Idiopathic
Coronary artery disease
Thyroid
COPD
Electrolyte disturbance
Pneumonia
summarise the epidemiology of AF?
VERY COMMON in the elderly Present in 5% of those > 65 years May be paroxysmal
what happens to cardiac output in AF?
drops by 10-20% as ventricles aren’t primed reliably by atria
what are the presenting symptoms of AF?
often ASYMPTOMATIC palpitations syncope ( if low output)- dizzy, faints symptoms of the cause of AF with underlying MI-> Chest pain, dyspnoea
what are the signs of AF on physical examination?
irregularly irregular pulse difference in apical beat and radial pulse- apical is greater than radial 1st heart sound of variable intensity signs o LVF check for wings of thyroid disease and valvular disease Elevated JVP
what does atrial flutter look like on an ECG?
narrow complex tachycardia->, saw tooth pattern flutter waves loss of isoelectric baseline- absence of p waves
what can be seen on the ECG for AF?
uneven baseline with absent p waves irregular intervals between QRS complexes
describe bloods in AF?
cardiac enzymes- MI may cause or precede AF
TFT- thyrotoxicosis may present with AF
lipid profile
U and Es , Mg2+, Ca2+-> because there is increased risk of dioxin toxicity with hypokalaemia, hypomagneaemia and hyeprcalcaemia
describe what can be seen on the Echo in AF?
mitral valve disease
left atrial dilatation
left ventricular dysfunction
structural abnormalities
what are the complications of AF?
- Thromboembolism
- Worsened heart failure
what are the key components of AF management?
in AF-> there are randomised atrial contractions-> lead to fast ventricular contractions Rate control- restores ventricular rate to normal range. This leads to slow AF Rhythm control- restores sinus rhythm anticoagulation
Outline the management of AF?
outline the management for atrial flutter?
If unstable => synchronised cardioversion (<50J)
Metoprolol (B-blocker) or diltiazem (CCB) or verapamil (CCB)
AND
Heparin or enoxaprin + warfarin (or NOACs)
AND
Amiodarone or defotilide or sotalol
Consider catheter ablation of cavotricuspid isthmus if antiarrhythmic drugs have failed
where do the points from the CHA2DS2 come from?
