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Please use current guidelines available on the UHNM intranet for patient treatment
Please use current guidelines available on the UHNM intranet for patient treatment
RECOGNITION AND ASSESSMENT
- Treat patient first and arrhythmia second.
- Accurate diagnosis is not possible without a 12-lead ECG
Symptoms (in order of increasing severity/urgency)
- Palpitation
- Dyspnoea
- Chest pain
- Dizziness
- Syncope
- Cardiac arrest
Signs
- Heart rate <60 or >100 beats/min
- Hypotension (systolic BP<100 mmHg)
- Hypoperfusion
- Jugular venous pressure (JVP) elevated
- Cannon waves or flutter waves in internal jugular vein
- Variable intensity of first heart sound
- Signs of heart failure
Investigations
- 12-lead ECG unless patient unconscious with no pulse, when resuscitation takes priority - see Cardiopulmonary resuscitation - life support procedure. A single-lead rhythm strip is an inferior alternative, but better than no ECG at all
- Urgent U&E
IMMEDIATE TREATMENT
- Atrial fibrillation - follow Atrial fibrillation guideline
- Continuous ECG recording
- If arrhythmia causing hypotension, cardiac failure, chest pain, shock or requiring pacing, seek urgent advice from cardiology team
Potassium
- Correct any abnormalities of potassium - see Hypokalaemia/Hyperkalaemia guidelines
Is the arrhythmia?
Bradycardias
- Sinus bradycardia may need no treatment - if symptomatic, give atropine 500 microgram IV, and repeat once after 5 min if necessary or consider isoprenaline
- Sinus pauses and sino-atrial block - if episodes prolonged and symptomatic, consider isoprenaline or pacing: contact cardiology team
- Sino-atrial disease manifest as tachycardia-bradycardia - seek urgent advice from cardiology team
- Atrio-ventricular (AV) conduction block
- first degree: no treatment necessary
- second and third degree: consider isoprenaline or pacing and contact on-call cardiology SpR
- Intraventricular conduction block/bundle branch block - contact cardiology team to consider pacing if:
- new appearance of bifascicular block (right bundle branch block and left axis deviation) or alternating left and right bundle branch block
- bifascicular block/trifascicular block with otherwise unexplained syncope
Tachycardias
Clinical significance
- Accurate diagnosis requires 12-lead ECG (paper speed 25 mm/sec, 40 msec = 1 small square)
- Narrow (<120 msec) QRS complexes originate from sinus node, atrium or AV junction
- Broad (>120 msec) QRS complexes should be considered ventricular in origin unless or until proved otherwise
- If diagnosis in doubt, try carotid sinus massage (CSM) first
- recent CVA/TIA, or known established carotid disease are contraindications to CSM
- If CSM unsuccessful, unless there is a history of wheezing, give adenosine 3 mg IV over 2 sec via a large bore cannula into antecubital fossa vein with sodium chloride 0.9% flush
- NB: in patients taking dipyridamole (which decreases adenosine metabolism), initial dose of adenosine should be 1 mg IV and subsequent doses should be halved
- if no response after 1-2 min, give adenosine 6 mg IV over 2 sec. If no response after a further 1-2 min, give 12 mg IV over 2 sec
- NB: in patients taking theophylline (which antagonises the anti-arrhythmic effect of adenosine), higher doses will usually be necessary (CAUTION with adenosine in these patients as adenosine can cause bronchospasm)
- obtain rhythm strip
- following adenosine, atrial tachycardias should be revealed (P waves with AV block) or junctional re-entrant tachycardias terminated; ventricular tachycardias will be unaffected
Initial treatment
- If tachycardia associated with hypotension, shock, or cardiac failure, before giving any anti-arrhythmic drug IV, seek urgent advice from cardiology team to discuss DC cardioversion (or overdrive pacing for selected tachycardias)
- If patient with pathological tachycardia haemodynamically stable with no overt heart failure or impaired ventricular function, an anti-arrhythmic drug may be given by slow IV injection provided full resuscitation facilities are available, preferably on CCU. Seek urgent cardiology team advice
Specific rhythms
Is the tachycardia:
- Sinus tachycardia is usually physiological - identify and treat cause (e.g blood loss, heart failure, thyrotoxicosis, anaemia)
- if no obvious underlying cause, cardiac function adequate, and tachycardia inappropriate and distressing, consider oral atenolol 50 mg daily
- Atrial tachycardia arises from atrial myocardium – seek urgent cardiology team advice about giving beta-blockers or calcium blockers etc.
- Wolff-Parkinson-White can present as AF – QRS complexes will be pre-excited (i.e. wide and bizarre) and ventricular response very fast with a tendency to degenerate to ventricular flutter and fibrillation (VF). NEVER give digoxin/beta-blockers/amiodarone or verapamil but seek urgent advice of cardiology team with a view to restoring sinus rhythm with flecainide if patient stable or DC cardioversion if patient unstable
- Junctional re-entry tachycardia usually involves AV node in re-entry circuit and is likely to be terminated by AV nodal blockade. Unless there is a history of wheezing, give adenosine 3 mg IV over 2 sec via a large bore cannula into antecubital fossa vein with sodium chloride 0.9% flush
- NB: in patients taking dipyridamole (which decreases adenosine metabolism), initial dose of adenosine should be 1 mg IV and subsequent doses should be halved
- if no response after 1-2 min, give 6 mg IV over 2 sec. If no response after a further 1-2 min, give 12 mg IV over 2 sec
- NB: in patients taking theophylline (which antagonises the anti-arrhythmic effect of adenosine), higher doses will usually be necessary
- If not responsive, seek urgent cardiology team advice about giving verapamil 5 mg IV over 2 min (3 min if patient >65 yr), repeated if necessary at 5-10 min intervals to total 10 mg
Do not give verapamil if patient already taking a beta-blocker
- Ventricular tachycardia arises from ventricular myocardium. Haemodynamic consequences are related to ventricular rate and underlying left ventricular function
- seek urgent cardiology team advice, with a view to DC cardioversion if patient unstable or consider IV procainamide or amiodarone if patient stable
- Torsade de pointes (polymorphic VT) usually self-terminating, but often produces haemodynamic collapse - seek urgent cardiology advice
- stop any precipitating drugs (call Medicines Information)
- do not give further anti-arrhythmic drugs
- correct serum K+ to >4.5 mmol/L. Give sodium chloride 0.9%. 500 mL with potassium chloride 20 mmol IV, as commercially prepared pre-mixed bag, over 2 hr, with continuous ECG monitoring
- if not given earlier, give magnesium sulphate 2 g (equivalent to 8 mmol Mg++) made up to 50 mL with sodium chloride 0.9% by IV infusion over 10-15 min
- consider beta-blocker/pacing
- If sustained, leads to cardiac arrest and must be treated by immediate DC cardioversion (when patient unconscious)
- Seek urgent cardiology team advice to consider the following:
- if arrhythmia fails to terminate or recurs, consider and deal with possible trigger factors:
- electrolyte abnormalities (hypokalaemia, hypocalcaemia, hypomagnesaemia)
- anti-arrhythmic or anti-psychotropic drug toxicity
- underlying relative bradycardia (temporary pacing will be necessary)
- acute MI - consider urgent revascularisation by angioplasty - for recurrent episodes, try lidocaine (with ECG monitoring) by IV infusion 4 mg/min for 30 min, then 2 mg/min for 2 hr, then 1 mg/min - reduce concentration further if continued beyond 24 hr
- for electrical storm (e.g. recurrent VF), maintain plasma K+ > 4.5 mmol/L, give sodium chloride 0.9% 500 mL with potassium chloride 20 mmol IV (as commercially prepared pre-mixed bag) over 2 hr, with continuous ECG monitoring
- give IV magnesium sulphate 2 g (equivalent to 8 mmol Mg++) made up to 50 mL with sodium chloride 0.9% by IV infusion over 10-15 min, repeated once if necessary and atenolol 2.5 mg IV at rate of 1 mg/min, repeated at 5 min intervals to a maximum of 10 mg
- in peri-arrest situation, give IV amiodarone 300 mg as bolus injection
- in patients with ventricular tachycardia or VF occurring ≥48 hr after acute MI or with no obvious reversible factors, consider implantable cardioverter defibrillator
- 24-hr tape for patients with impaired LV function and IHD - if non-sustained VT present, refer to electrophysiology service for assessment for ICD implant.
- if arrhythmia fails to terminate or recurs, consider and deal with possible trigger factors:
- If intracardiac electrophysiological studies or ablation therapy contemplated, send formal referral to cardiac electrophysiology department
MANAGEMENT AFTER STABILISATION
- If recurrent arrhythmias, seek urgent advice from cardiology team
General
- After any emergency treatment to revert or stabilise a patient's heart rhythm, further assessment should include:
- accurate identification of arrhythmia - a 12-lead ECG during the arrhythmia will give the diagnosis in most cases, sometimes with the addition of specific manoeuvres, such as carotid sinus massage/adenosine, or by comparison with ECG in sinus rhythm. Electrophysiological testing may be required where there is doubt
- diagnosis of cause - ECGs in sinus rhythm, troponin T, thyroid function tests, chest X-ray
- definition of underlying heart disease - echocardiography, cardiac catheterisation where appropriate
- identification of precipitating/contributing factors - electrolytes (including Ca2+, Mg2+), ECG monitoring
- provocation testing where necessary (e.g. exercise testing, tilt testing, carotid sinus pressure, drug challenge, invasive electrophysiologic testing)
- for most patients with SVT/atrial tachycardia/atrial flutter, radiofrequency ablation - refer to cardiology SpR for out-patient review with electrophysiologists
Do not use amiodarone as a first-line agent for long-term treatment because of the risk of serious adverse effects
DISCHARGE AND FOLLOW-UP
- Refer patients with recurrent arrhythmias requiring prophylactic anti-arrhythmic treatment to a cardiologist
- Make appropriate arrangements with anticoagulation management service for follow-up of patients with AF who are anticoagulated