Adult tachycardia algorithm: initial steps
A-E
ECG
Identify reversible causes (4Ts + 4Hs)
Any adverse signs?
What are the adverse signs in tachycardias?
Shock
Syncope
MI
Heart failure
What do you do when there are adverse signs in a tachycardia?
Pt unstable Synchronised DC shock Amiodarone 300mg over 10-20 mins Repeat shock Amiodarone 900mg over 24hrs
What to do if there are no adverse signs in a tachycardia?
Assess whether tachycardia is broad, narrow, regular or irregular
What to do with a broad, regular tachycardia?
If VT or unsure:
Amiodarone 300mg over 24hrs then 900mg over 24hrs
If SVT w/ BBB: treat as regular narrow complex (Vagal)
What to do with a broad, irregular complex?
Seek help!! AF w/ BBB
What to do with a narrow, regular tachycardia?
Vagal manouvres (vasalva, carotid sinus massage, blowing into syringe) Adenosine 6mg rapid IV - if no effect give another 12mg, then another 12mg
What happens after treating a narrow, regular tachycardia?
If sinus rhythm achieved = probably re-entry paroxysmal SVTIf not achieved = could be atrial flutter - control with BB
What to do with a narrow, irregular tachycardia?
Probably AF - treat rate with BB or dilitiazem
Digoxin or amiodarone in HF
Assess thrombosis risk
Management of a polymorphic VT (eg Torsades de Point)?
Magnesium 2g
When is amiodarone used?
Broad complex QRS arrhythmias
ECG findings for VF
Small fib waves
Management of AVRT + AVNRT (stable vs unstable)
If stable - vagal then adenosineIf unstable, synchronised cardioversion then amiodarone
What is AVNRT?
Electrical activity circuits around the AV node
Caused by fast + slow fibres
What is AVRT?
AV re-entrant tachycardia
Due to accessory pathway between ventricles + atria
Signal is conducted back to atria so atria contract before SAN sends next impulse
Causes fast heart rate
EG Wolff Parkinson White - accessory pathway is bundle of Kent
What is SVT?
Narrow complex
Any impulse beginning above the bundle of His - any tachycardia that is not ventricular in origin (AF/ flutter/ AVRT)
How can you distinguish between different forms of tachycardias on ECG?
Broad or narrow? Broad irregular = AF with BBB Broad regular = VT or SVT with BBB Narrow Reg: VT, SVT Irregular: AF
Types of ventricular tachycardia
Monomorphic VT = short circuit coming from 1 place in the heart
Polymorphic VT = Torsades de Point, due to long QT interval
S+S of AVNRT
Palpitations, dizziness, light headedness, SOB
Sudden onset
AVNRT on ECG
Sudden onset, following atrial premature beat, spontaneous termination with AV block in absence of premature atrial beat
Loss of P waves
Management of AVNRT
Stable = vagal maneuvres, adenosine, then verapamil, diltiazem, metoprolol or digoxin
Unstable = cardioversion
Long term = BB, diltiazem, digoxin
2nd line = flecainide, propafenone
Bradycardia guidelines - initial step
Assess using A-E approach Any adverse features: Shock Syncope Myocardial ischaemia HF
Bradycardia guidelines - what to do if adverse features are present?
Atropine 500mcg IV
If satisfactory response - move onto assessing risk of asystole
If not, consider interim measures: Atropine 500mcg IV repeat to max of 3mg OR Transcutaenous pacing OR Isoprenaline 5mcg min IV Adrenaline 2-10mcg min IV
Ultimately - arrange transvenous pacing!!
Bradycardia guidelines: what to do if there are no adverse features?
Assess risk of asystole: Recent asystole Mobitz II AV block Complete heart block w/ broad QRS Ventricular pause >3s
Bradycardia guidelines: what to do if there is no risk of asystole?
Continue obs
Bradycardia guidelines: what to do if there is a risk of asystole?
Consider interim measures: Atropine 500mcg IV repeat to max of 3mg OR Transcutaenous pacing OR Isoprenaline 5mcg min IV Adrenaline 2-10mcg min IV
Ultimately - arrange transvenous pacing!!
Types of bradycardias
Sinus bradycardia Sinoatrial block Sinus arrest AV block Junctional rhythm Idioventricular rhythm
Types of regular narrow complex tachycardias
Sinus tachycardia Atrial tachycardia Junctional tachycardia AVNRT AVRT Atrial flutter
Types of regular wide complex tachycardias
SVT with BBB
VT
AVRT
Types of irregular narrow complex tachycardias
AF
Atrial flutter with variable block
Premature atrial contraction
Types of irregular wide complex tachycardias
AF with BBB
Atrial flutter with variable + BBB
Polymorphic VT (Torsades de Point)
Premature ventricular contraction
Management of sick sinus syndrome
Atropine
What are the types of premature beats?
Premature atrial contraction
Junctional premature beat - originates from vicinity of AV nodes
Describe WPW
Congenital defect of Bundle of Kent causing AVRT + AF
ECG changes in WPW
PR interval <120
Slurred upstroke of QRS (delta wave)
Widened QRS
Describe AF in WPW
> 200 blm ventricular rate - AF is conducted through bypass tract
What are the types of AVRT?
Orthodromic = stimulus from premature complex travels up bypass tract + down AV node with narrow complex Antidromic = signal goes up AV node + down bypass tract, causes wide + abnormal QRS
Management of AVRT
Same as AVNRT except avoid digoxin + verapamil
Long term = ablation
What is a premature ventricular contraction?
Usually benign but can be significant if consecutive or multiform, or if falling on T wave of previous beat
ECG changes for premature ventricular contraction
ARS >120
No P wave
Bizarre QRS
What is an accelerated idioventricular rhythm?
Ectopic ventricular rhythm with rate 50-100
Occurs in acute MI or heart disease
What is Torsades de Point?
Variation of polymorphic VT that occurs with baseline QT prolongation
QRS complexes twist around baseline
What drugs predispose to Torsades?
Anything that prolongs QT: Quinidine Sotalol TCAs Erythromycin Quinolones Antihistamines
What electrolyte disturbances can cause Torsade de Point?
Hypokalaemia
Hypomagnesemia
Management of Torsades de Point?
Magnesium, temporary pacing, isoproterenol
What is a pre-excitation syndro,e?
AVRT + symptoms of tachyarrhythmia
eg WPW or LGL
What is ortho vs antidromic?
Orthodromic = impulse goes down AVN up accessory pathway Anti = impulse goes down accessory pathway and up AVN - dangerous because its uncontrolled