Arrhythmias Flashcards
define atrial fibrillation (AF)
a condition of uncoordinated atrial contraction due to delayed AV node impulses
- it is the most common sustained cardiac arrhythmia
triggers of AF
PIRATES get AF:
pulmonary embolism ischaemia respiratory disease atrial enlargement thyroid disease ethanol sepsis/sleep apnoea
types of AF
acute - lasts >48hrs
paroxysmal - lasts < 7 days + intermittent
persistent - lasts > 7 days but responds to cardioversion
permanent - lasts > days and is not amenable to cardioversion
clinical features of AF
chest pain
palpitations
dyspnoea
dizziness
signs of AF
irregularly irregular pulse
single JVP waveform due to a-wave loss
apical - radial pulse deficit
variable intensity S1
describe fast AF
a ventricular rate of >100bpm
management of fast AF
unstable: immediate DC cardioversion
stable: rate + rhythm control or electric cardioversion
rate control management in AF
beta-blocker (e.g. bisoprolol) OR rate-limiting calcium channel blocker (e.g. dilitiazem)
if cardiac failure or hypotensive: digoxin
if young with paroxysmal AF: oral flecainide
rhythm control management in AF
achieved either via electrical cardioversion or pharmacological cardioversion
requirements for anticoagulation in AF
provided if CHADS2VASc score >1 (in men) or >2 in women
and no major risk of bleeding according to ORBIT score
use of DOACs in AF
e.g. edoxaban, apixaban, rivaroxaban and dabigatran
- 1st line
- less bleed risk than warfarin
use of Warfarin in AF
- requires LWMH cover for 5 days prior to initiation + regular INR monitoring
- used in cases of valvular AF
common appearance of AF on ECG
absence of P waves
narrow and irregular QRS complexes
investigations of AF
bloods (FBC, U+Es, LFTs, TFTs and glucose)
ECG
BP
define atrial flutter
a condition arising due to aberrant macro-circuit within the right atrium cycling @ ~300bpm
common causes of atrial flutter
COPD obstructive sleep apnoea pulmonary emboli pulmonary hypertension alcohol sepsis
clinical features of atrial flutter
patients are often asymptomatic but may present with:
palpitations
chest pain
dizziness
investigations of atrial flutter
bloods (FBC, U+E, TFTs, glucose)
ECG
common ECG findings of atrial flutter
regular rhythm tachycardia
saw tooth baseline of 300bpm
narrow QRS complexes
management of atrial flutter in haemodynamically unstable patients
urgent direct current synchronised cardioversion
management of atrial flutter in haemodynamically stable patients
fluid resus rate control (e.g. beta-blocker or calcium-channel blocker)
management of atrial flutter if unresponsive to treatment
catheter ablation of aberrant pathway
define ventricular fibrillation (VF)
an irregular broad complex tachycardia with accompanying pulseless rhythm
presentation of VFib
syncope
cardiac arrest
ECG presentation of VFib
irregular, broad and polymorphic QRS complex
management of V-Fib
- ABCDE approach and commence CPR
- administer unsynchronised cardioversion (200J biphasic)
- restart CPR
- after 3rd shock, 1mg adrenaline + 300mg amiodarone
- adrenaline administered every 3-5 mins following 3rd shock
define ventricular tachycardia (VT)
a thing
common causes of VT
MI
cardiomyopathy
metabolic abnormalities
long QT syndrome
clinical features of VT
palpitations
chest pain
syncope
common ECG appearance of VT
tachycardia
absent P waves
monomorphic regular broad QRS complex
signs of VT
hypotension
varying S1
occasional canon A-waves on JVP
management of pulseless VT
unsynchronised DC shock
CPR for 2 mins
IV adrenaline + 300mg amiodarone after 3rd shock
adrenaline every 3-5mins after 3rd shock
management of VT in patient with pulse (adverse features)
synchronised DC shock
if > 3 shocks:
- IV 300mg amiodarone (over 10-20mins followed by 900mg over 24hrs)
management of VT with pulse and no adverse features
300mg amiodarone IV over 20-60 mins, followed by 900mg over 24hrs
define Torsades de Pointes
a polymorphic ventricular tachycardia caused by prolonged QT interval
common causes of TdP
congenital long QT syndrome
drugs (e.g. antiarrhythmics)
MI
renal/liver failure
management of TdP in haemodynamically unstable patient
urgent synchronised DC shock
300mg IV amiodarone
management of TdP in haemodynamically stable patients
IV magnesium sulphate (2g over 10 mins)
stop offending drugs and manage electrolyte imbalances
