Arrhythmia Management - tachycardia Flashcards
What is the initial mx for tachyarrhythmia and bradycardia with adverse signs
Tachy - synchronised DC cardioversion
Brady - atropine +/- pacing
What are the adverse signs to look out for in an arrhythmia
- Shock - SBP <90
- Syncope
- MI - chest pain or on ECG
- Heart failure
What to do initially in all arrhythmias
Apply 3 lead cardiac monitoring
Identify and treat cause
- electrolyte abnormalities
- ACS
- hypoxaemia
- sepsis
- thyroid dysfunction
- drug toxicity
Review ECG
- Tachycardia >100bpm
- —— Narrow complex (QRS <120ms or 3 ss)
- —— Broad complex (QRS >120ms or 3 ss)
What to do for regular narrow complex tachycardias
- Vagal manoeuvres
- Adenosine* 6mg rapid IV bolus - 12mg - 12mg and monitor ECG continuously
- if SR achieved - then probable re-entry paroxysmal SVT - record 12-lead ECG in NSR
- if SVT recurs treat again and consider anti-arrhythmic prophylaxis
- if SR not achieved –> seek expert help
- — possible atrial flutter and rate control required i.e. with beta blocker
*can’t use adenosine in asthma - verapamil instead
What to do for irregular narrow complex tachycardias
Probable AF
- control rate with beta blocker or diltiazem
- if in heart failure consider digoxin or amiodarone
- assess thromboembolic risk and consider anticoagulation (based on CHADS2VASC)
What to do for regular broad complex tachycardias
If VT or uncertain rhythm
- amiodarone 300mg IV over 20-60 mins
- then amiodarone 900mg IV over 24H
If known to be SVT with bundle branch block:
- treat as for regular narrow complex tachycardia
What to do for irregular broad complex tachycardias
Seek expert help
Possibilities include:
- AF with bundle branch block - treat as per narrow complex
- Pre-excited AF - consider amiodarone
What to do if arrhythmia with adverse features
Synchronised DC shock - up to 3 attempts
- conscious patients require sedation or GA for CV
Seek expert help
Amiodarone 300mg IV over 10-20 mins
Repeat shock
Amiodarone 900mg IV over 24H
What are the causes of a narrow complex tachycardia
Caused by supra ventricular tachyarrhythmias
Sinus - treat cause
Paroxysmal SVT
- AV Nodal Re-entry Tachy (AVNRT)
- —— due to entire re-entry conduction circuit in the AV node
- —— ECG: regular, often no P waves as buried in QRS
- AV re-entry tachy (AVRT) i.e. WFW syndrome
- —– due to accessory pathway allowing conduction re-entry between atrium and ventricle
- —– ECG as per AVNRT - may see retrograde P waves (notch in T wave)
- Ectopic atrial tachycardia - due to depolarising focus in atria
Atrial fibrillation / flutter
- Flutter - regular saw-tooth baseline
- Fib - irregular with no P waves
How is AF and AFl managed
Rate or rhythm control and therapeutic anticoagulation (CHADS2VASC)
Rate - >65y AND has IHD/no sx/unsuitable for CV
- B-blocker - bisoprolol
- Rate-limiting CCB - diltiazem
- Digoxin - if acute HF/hypotension/sedentary lifestyle
Rhythm
- acutely if clear onset <48H
- or after 4 weeks therapeutic anticoagulation AND rate control
- electrical or pharmacological* CV
- amiodarone if structure or IHD
- flecainide if not
What causes a broad complex tachycardia
May be caused by ventricular tachycarrhythmias or supra ventricular tachyarrhythmias with abnormal conduction
Ventricular tachys:
- VT - amiodarone
- Torsades de pointes - magnesium sulphate
Broad complex tachycardias of SV origin - treat as VT if any doubt
How to manage a bradycardia
A-E approach
Adverse features present (SBP<90, MI, syncope, HF)
1. atropine 500mcg IV
If there is a satisfactory response - consider if there is a risk of asystole*
- If no risk - observe
- If risk continue as if no satisfactory response
If not a satisfactory response to atropine - consider interim measures:
- Atropine 500mcg IV repeat to maximum of 3mg (6 doses)
- OR transcutaneous pacing
- OR isoprenaline 5mcg / min IV / adrenaline 2-10 mcg/min IV / alternative drugs**
After/during interim measures - seek expert help to arrange transvenous pacing
- Asystole risks
- recent asystole
- mobitz II AV block
- complete heart block with broad QRS
- ventricular pause >3s
- *alternative drugs
- aminophylline
- dopamine
- glucagon (if bradycardia caused by B-blocker or CCB)
- glycopyrrolate - may be used instead of atropine
What differentials to consider in a bradycardia
Sinus bradycardia - may be caused by:
- Drugs - b-blockers, digitalis
- Neurally mediated syndromes i.e. carotid sinus hypersensitivity, vasovagal syncope
- Hypothermia
- Hypothyroidism
SA node dysfunction (sick sinus syndrome)
AV node dysfunction (2nd degree or complete heart block)
What drugs to memorise for arrhythmias
Adenosine 6mg IV
- can be followed by 12 mg then another 12mg if unsuccessful
- flushed quickly wide bore cannula in antecubital fossa
Amiodarone 300mg IV over 20-60 minutes through large vein
- Followed by 900mg IV over 24H via central venous line
Atropine 500mcg IV
- repeat every 3-5 minutes to max of 3mg if required
Magnesium sulphate 2mg IV over 10-15 mins
Placement of 3 lead cardiac monitoring
Ride Your Green Bicycle (from R shoulder)
- Red - right anterior shoulder
- Yellow - left anterior shoulder
- Green - left ASIS
- Black - right ASIS (not present on defibrillator machine)
