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Atrial fibrillation (AF) and flutter (Aetiology (Neoplastic Atrial…
Atrial fibrillation
(AF) and flutter
Definition
Cardiovascular disorder of
irregularly irregular pulse
due to chaotic atrial activity
Epidemiology
AF is commonest arrhythmia
Elderly
Pathophysiology
AF
Low CO as ventricles not effectively filled
by the atria following fibrillation
Acute (onset last 48h) or chronic (>48h)
Some impulses conducted by AVN producing
an irregular ventricular response
Chaotic ineffective atrial contraction
at 300-600bpm
Flutter
Fluttering ineffective contraction, atrial rate typically 300bpm
with every second beat conducted (ventricular rate 150bpm)
Often associated with AF
Often caused by a re-entry circuit in the atria
Aetiology
Neoplastic
Atrial myxoma
Lung cancer
Metabolic
Hypo-K
Hypo-Mg
Haemachromatosis
Infection/inflammation
Endocarditis
Pericarditis
Pneumonia
Sepsis
Endocrine
Thyrotoxicosis
Vascular
MI, HTN, HF
Valve disease
PE, cardiomyopathy
Sick sinus syndrome
Drugs
Alcohol
Caffeine
Iatrogenic
Post op
Autoimmune
Sarcoidosis
Clinical
presentation
Asymptomatic
Palpitations
Syncope
SOB
Fatigue
Diagnosis
Examination
Cardio - irreg irreg pulse, signs of cause
(murmurs, oedema etc)
Consider resp, thyroid exam if appropriate
Investigations
Bloods
FBC (infection), CRP/ESR (inflamm)
U+E, LFT, TFT (thyrotoxicosis)
Cardiac enzymes (troponins), D-dimer
Imaging
CXR - signs of HF, infection
ECHO - valve disease, function,
check mural thrombi before cardioversion
Bedside
Obs - fever if infection
ECG - irregularly irregular, no p waves (AF)
sawtooth pattern (flutter)
History
HPC - SOB, syncope, palpitations
PMH - IHD, HTN, valve disease
DH - alcohol, caffeine, anti-arrhythmics
FH - cardiac disease
SH - smoking, alcohol, illicit drugs
Management
Initial ABCDE
Definitive
Acute AF
(<48h)
Anticoagulation
Indication: persisting unstable
rhythm or embolic risk factors
LMWH
Indication: 1L low risk
E.g. enoxaparin
Warfarin
Indication: 1L if high risk
(stroke, PVD, CAD, valve disease etc.)
Rate control
Indication: all patients
B-blocker
E.g. bisoprolol
Rate-limiting CCB
E.g. verapamil
Digoxin
Indication: 2L
Amiodarone
Indication: 2L
Rhythm control
Indication: unstable patient
Pharmacological cardioversion
MOA: chemical conversion to SR
E.g. amiodarone, flecainide
Electrical DC cardioversion
MOA: electrical stimulation to SR
CI: onset >48h (risk mural thrombus)
Chronic AF
(>48h)
Rate control
Indication: all patients
B-blocker
Indication: 1L (OR CCB)
E.g. bisoprolol
CCB
Indication: 1L (OR B-blocker)
E.g. verapamil
Digoxin
Indication: add on; sedentary pts
Amiodarone
Indication: add on
Rhythm control
Indications: symptomatic,
CCF, <65y, first time,
corrected cause
Electrical DC cardioversion
MOA: electrical stimulation to SR
NB. Need ECHO first (LV thrombi)
and anticogulate for 3wk before
Pharmacological cardioversion
MOA: chemical conversion to SR
E.g. sotalol, flecanide;
amiodarone if structural heart disease
Surgical options
AVN ablation
Pacing
Anticoagulation
NOAC
E.g. rivoroxaban
Warfarin
Indication: >65y, risk factors
CI: low Plt, bleeding disease, severe HTN
Aspirin
Indication: <65y lone AF, warfarin CI
Flutter
Per AF; ablation of
re-entry circuit can cure
Complications
Embolic stroke
Embolic limb ischemia