Arrhythmias Flashcards
1st degree heart block ECG feature
Prolonged PR interval
>0.2s
Subtypes of heart block
1st degree
2nd degree
3rd degree
Subtypes of 2nd degree heart block
Mobitz type 1
Mobitz type 2
Mobitz type 1 ECG feature
Progressive PR interval prolongation until a QRS complex is missed
Mobitz type 2 ECG feature
Every *th QRS complex is missed
3rd degree heart block ECG feature
No QRS complexes
> 60bpm is what type of arrhythmia
Bradycardia
<100bpm is what type of arrhythmia
Tachycardia
Treatment of Bradycardia
Atropine
Supraventricular tachycardia treatment
1st - vagal manoeuvres (pop ears)
2nd - carotid massage
3rd - adenosine IV
4th - verapamil, diltiazem, beta-blockers
what is Paroxysmal AF
lasts <48hrs
what is Persistent AF
lasts >48hrs
what is Permanent AF
lasts >48hrs + CANNOT be cardioconverted to normal rhythm
What would a typical ECG of a patient with AF look like
No p waves
QRS is rapid + irregular
An irregular irregular rhythm is associated with?
AF
ACUTE Treatment of AF
Amiodrone OR flecainide (if haem stable) DC cardioversion (if harm unstable)
If cardioversion isn’t possible within 24-48hrs then put on warfarin for 6-8wks then bring back to cardiovert.
Long-term treatment of AF
Beta-blockers
Ca2+ channel blocker (verampil)
Digoxin
What arrhythmia is associated with AF?
Atrial flutter
“saw-tooth” waves on ECG
Atrial flutter
Treatment of Atrial flutter
Electrical cardioversion
Treatment of recurrent Atrial flutter
1st - radio frequency ablation
2nd - amiodrone
What drugs can cause Bradycardia?
Beta-blockers
verapamil
Treatment of Bradycardia
treat underlying cause
atropine
pacing if haemodynamically compromised (CHF, angina, collapse, hypotension)
What arrhythmia does sick sinus syndrome cause?
Bradycardia
Athletes may have what arrhythmia?
Bradycardia
What arrhythmia is generally well tolerated?
Bradycardia
What would a typical ECG of a patient with ventricular Tachycardia look like?
Broad, abnormal QRS
Acute treatment of ventricular Tachycardia
haem unstable = emergency DC cardioversion
haem stable = IV Lidocaine/lignocaine OR amidrone
Symptoms of ventricular Tachycardia
pre-syncope, hypotension, cardiac arrest
Patient is pulseless and becomes rapidly unconscious, what arrhythmia do they have
V.fib
What would a typical ECG of a patient with ventricular Fibrillation look like?
shapeless, rapid oscillations, no organisation
toddler’s scribble
Acute treatment of V. Fib
Defib
Long-term treatment of V.Fib
Implantable cardioverter Defib
Most common cause of death following an MI
V.fib
ECG is shapeless, rapid oscillations, no organisation
toddler’s scribble
V.Fib
ECG has Broad, abnormal QRS
V.tach
ECG has No p waves and QRS is rapid + irregular
AF
What is Long QT syndrome?
ventricular repolarisation is greatly prolonged.
Torsades de pointes is associated with?
Long QT syndrome
where do SVT originate from
above the ventricle
includes: atrial muscle, av node,
what are the 2 types of SVT
AF
Atrial flutter
what are the 3 types of ventricular arrhythmias
V.tach
V.fib
asystole
what are the 2 types of AV node arrhythmias
AV block (3 subtypes) AVN re-entry tachycardia
what are ectopic beats
beats or rhythms that originate in places other than the SA node
what is re-entry
requires more than 1 conduction pathway with different speed of conduction and recover of excitability
how can ectopics cause tachycardia
may cause single beats or a sustained run of beats that is faster than sinus rhythm take over the intrinsic rhythm
how can re-entry cause tachycardia
triggered by an ectopic beat it results in a self perpetuating circuit
symptoms of arthymias (general)
palpitations "pounding heart" SOB dizzy loss of consciousness/faintness sudden death
investigations of arrhythmias (general)
ECG (12 lead, stress, 24hr)
CXR
echocardiogram
what is an 12 lead ECG used for
assess rhythm
signs of previous MI or pre-excitation
what is an exercise ECG used for
assess for ischaemia
to look for exercise induced arrhythmia
what arrhythmia does an exercise ECG look for
exercise induced arrhythmia
what arrhythmia does a 24hr ECG look for
paroxysmal arrhythmia
what are the physiological causes of tachycardia
anxiety
fever
hypotension
anaemia
treatment of sinus tachycardia
b-blockers
acute management of SVT
haem stable: increase vagal tone via carotid massage
slow conduction in AV node via IV adenosine or Verapamil
haem unstable: cardioversion
long-term management of SVT
b-blockers
ablation
causes of heart block
old age MI myocarditis drugs (b-blockers, Ca2+ channel blockers) genetic
what drugs can cause heart block
b-blockers
Ca2+ channel blockers
treatment of 1st degree heart block
none
monitor
what is lone/idiopathic AF
absence of any HR disease and no evidence of ventricular dysfunction
could be genetic
what causes AF (physiology)
multiple waves of re-entry
what is the atrial rate in AF
> 300bpm
what drugs are used in rate control in AF
digoxin
B-blockers
Ca2+ channel blockers
how is normal sinus rhythm achieved in AF
pharmacological cardioversion (e.g. amidarone) direct current cardioversion (DCCV)
what is the main mutation in long QT syndrome
potassium channel KCNQ1
what ECG changes are observed in long QT syndrome
QT prolongation:
males >440ms
females>460ms
what is the main mutation in brugada syndrome
cardiac sodium channel mutation SCNSA
treatment for brugada syndrome
implantable cardiac device (unless asymptomatic without FHx)
what arrhythmia is most commonly linked to sudden cardiac death
Long QT syndrome
long term treatment of ventricular Tachycardia
revascularisation (correct ischemia)
implantable cardiovertor defibs
VT catheter ablation
what is the treatment for 2nd degree heart block
ventricular pacing
what is the treatment for 3rd degree heart block
ventricular pacing
