Arrhythmias Flashcards
What are the shockable rhythms?
Ventricular tachycardia
Ventricular fibrilation
What are the non-shockable rhythms?
Pulseless electrical activity
Asystole
Describe pulseless electrical activity
all electrical activity except VF/VT, including sinus rhythm with no pulse
What is the treatment of tachycardia in an unstable patient?
Consider up to 3 synchronised shocks
Consider Amiodarone infusion
Describe tachycardia treatment in stable patient with narrow complex tachycardia
AF- rate control with BB or diltiazem
Atrial flutter- control rate with BB
Supraventricular - treat with vagal manoeuvres and adenosine
Describe tachycardia treatment in stable patient with wide complex tachycardia
Ventricular - amiodarone infusion
if know SVT with BBB - treat as normal SVT
If irregular may be AF variation -seek expert help
How does atrial flutter appear on an ECG?
150bpm ventricular contraction
sawtooth appearance on ECG with P wave after p wave
What conditions are associated with atrial flutter?
hypertension
Ischaemic heart disease
cardiomyopathy
thyrotoxicosis
What is the treatment of Atrial flutter?
Rate/ rhythm control
treat reversible underlying condition
radio frequency ablation
anticoagulation based of Chad2ds2vasc score
What causes supraventricular tachycardia?
the electrical signal re-entering the atria from the ventricles.
How does SVT appear on an ECG?
Narrow complex tachycardia. It looks like a QRS complex followed immediately by a T wave, QRS complex, T wave and so on
What are the 3 main types of SVT?
Atrioventricular nodal re-entrant tachycardia
Atrioventricular re-entrant tachycardia
Atrial tachycardia
Describe the acute management of stable patients with SVT
Continuous ECG monitoring Valsalva manoeuvre Carotid sinus massage Adenosine verapamil direct current cardioversiom
What leads to Wolff-Parkinson White syndrome?
An extra electrical pathway connecting the atria and the ventricles.
What are the ECG changes in WPW syndrome?
Short PR (<0.12 seconds) Wide QRS complex (>0.12) "delta wave" which is a stirred upstroke on the QRS complex
Describe Torsades de Pointes
a polymorphic ventricular tachycardia. It looks like normal VT but there is an appearance of the QRS twisting around the baseline. The height of the QRS complexes progressively get smaller.
Occurs in patients with a prolonged QT interval
What are the causes of prolonged QT?
Long QT syndrome (inherited)
Medications (antipsychotics. citalopram, flecainide, sotalol, amiodarone, macrolide antibiotics)
Electrolyte disturbances (hypokalaemia, hypomagnesaemia, hypocalcaemia
What is the acute management of torsades de pointes?
Correct the cause
MAgnesium infusion
Defibrilation if VT occurs
what is the long term management of prolonged QT syndrome?
Avoid QT prolonging meds Correct electrolyte disturbances beta blockers (not sotalol) Pacemakers or implantable defib
What are ventricular ectopics?
Premature ventricular beats caused by random electrical discharges from outside the atria
What is the management of ventricular ectopics?
Check bloods for anaemia, electrolyte disturbance and thyroid abnormalities
Reassurance in the healthy
seek advice for patients with heart disease
Describe first degree heart block
Occurs when there is delayed AV conduction. Despite this, every atrial impulse leads to a ventricular contraction meaning every p wave leads to a QRS complex
How does first degree heart block present on an ECG?
PR >0.2 seconds
Describe second degree heart block
where some of the atrial impulses do not make it though the AV node to the ventricles. This means there are instances when the p waves do not lead to QRS complexes
Describe mobitz type 1
The atrial impulses become gradually weaker until it no longer conducts to the ventricles.
How does mobitz type 1 present on an ECG?
increasing PR interval until the p wave no longer conducts to the ventricles. The cycle repeats
Describe mobitz type 2
Intermitted failure or interruption of SV conduction. This results in missing QRS complexes. Usually a set ratio of P waves to QRS complexes. The PR intervall remains normal. There is a risk of asystole
Describe third degree heart block
complete heart blokc
NO observable relationship between p waves and QRS complexes. There is a significant risk of asystole
How should stable bradycardia be managed?
observation
How should unstable or mobitz type 2 / type 3 heart block be treated?
Atropine 500mcgIV
then up to 6 doses of atropine
Other inotropes such as noradrenalin
Transcutaneous cardiac pacing
What options are available to patients with a high risk of asystole?
Temporaty transvenous cardiac pacing
permanent implantable pacemaker
what are the side effects of atropine
Inhibits parasympathetic system
pupil dilatation, urinary retention, dry eyes and constipation
