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
  • Sinus pauses and sino-atrial block – if episodes prolonged and symptomatic, consider 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: 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 (<110 msec) QRS complexes originate from sinus node, atrium or AV junction
  • Broad (>110 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
    • obtain rhythm strip
    • following adenosine, atrial tachycardias should be revealed (P waves with AV block) and junctional re-entrant tachycardias terminated; ventricular tachycardias will be unaffected, though retrograde conduction will be blocked

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 flecainide 2 mg/kg IV (up to 150 mg) over 20 min
    • flecainide is contraindicated in angina, MI and heart failure, consider amiodarone for acute management
  • Wolff-Parkinson-White syndrome 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 or verapamil but seek urgent advice of cardiology team with a view to restoring sinus rhythm with flecainide or sotalol, or DC cardioversion
  • 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 – give lidocaine 100 mg (50 mg if patient is or estimated to be <50 kg, or whose circulation is severely impaired) IV over 2 min, repeated only once if necessary after 10 min
  • seek urgent cardiology team advice, with a view to DC cardioversion under general anaesthesia
  • 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) made up to 50 mL with sodium chloride 0.9% by IV infusion over 10–15 min
    • consider beta-blocker/pacing
  • Ventricular Fibrillation (VF)
  • if sustained, leads to cardiac arrest and must be treated by immediate electrical defibrillation (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 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

Alert

  • 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

© 2022 The Bedside Clinical Guidelines Partnership.

Created by University Hospital North Midlands and Keele University School of Computing and Mathematics.

Research and development team: James Mitchell, Ed de Quincey, Charles Pantin, Naveed Mustfa