Tachycardia

Adult ED Management – RCUK 2025

Treat the patient, not the rate

Sinus tachycardia is usually compensatory — identify and treat the cause. Do NOT cardiovert sinus tachycardia.

INITIAL ASSESSMENT

ABCDE

Cardiac monitor
BP and SpO₂
12-lead ECG
IV access
Bloods as clinically indicated: FBC
U&E / Mg²⁺ / Ca²⁺
glucose
troponin where indicated
other investigations directed by likely cause
Give oxygen only if SpO₂ <94%, unless an alternative target is appropriate.

Think WHY the patient is tachycardic?

Sepsis/Hypovolaemia/Haemorrhage
Pain/Anxiety
Hypoxia
Fever
PE
ACS/Heart failure
Thyrotoxicosis
Drugs/Withdrawal
Pregnancy

Do not attempt to normalise an appropriate sinus tachycardia with anti-arrhythmics or electrical cardioversion.

SIMPLE ED RULE

SICK? → SHOCK

WELL? → WIDTH + REGULARITY

  • Narrow + regular: Vagal → Adenosine → Verapamil / beta-blocker → Shock
  • Narrow + irregular: AF pathway / rate control
  • Broad + regular: VT until proven otherwise → Cardioversion / procainamide
  • Broad + irregular: Pre-excited AF / polymorphic VT → expert help

      UNSTABLE?

      LIFE-THREATENING FEATURES

      > SHOCK: Hypotension with evidence of impaired tissue perfusion.
      > SYNCOPE: Especially with severe or ongoing hypotension.
      > MYOCARDIAL ISCHAEMIA: Ongoing chest pain and/or significant ischaemic ECG changes.
      > SEVERE HEART FAILURE: Particularly pulmonary oedema.
      > IMMEDIATELY POST-ROSC

      DC-Cardiversion (SYNC) RCUK 2025

      > AF → Maximum defibrillator output
      > Flutter / SVT → 70–120 J
      > VT with pulse → 120–150 J

      Escalate subsequent shocks where appropriate.

      STABLE

      Regular  – Sinus Tachycardia, AVNRT (SVT), Atrial flutter with regular block, AVRT (WPW)

      • Sinus Tachycardia – Look for the cause ?infection ?pain ?anaemia ?hypovolaemia ?anxiety ?drugs
      • SVT – Stepwise treatment until NSR regained (ensure cardiac monitoring): –
        • Vagal Manoeuvres – Lie flat and head down, Carotid sinus massage (ensure no bruit 1st), Blow into 50ml syringe
        • Adenosine –  6mg, 12mg, 18mg boluses (not in severe Asthma/Allergy/Heart transplant)
        • Not reverted – call for expert help
      • Atrial Flutter with 2:1 block (150bpm) – consider rate controlling drugs
      • AVRT (WPW) – get expert help (DO NOT give Adenosine)

      PDF: Arrhythmia Clinic referral form (Print and Fax OR can email – use fill and sign function to enter details)

      PDF: Patient Info

      Irregular – likely AF (Follow AF Pathway)

      Assume VT until proven otherwise

      Particularly in:

      • older patients
      • previous MI
      • structural heart disease
      • cardiomyopathy

      Stable monomorphic VT

      Electrical cardioversion is an appropriate first-line strategy

      • Especially where structural heart disease is present or cannot be excluded.
      • SYNCHRONISED CARDIOVERSION For VT with a pulse: 120–150 J initially, escalating if required

      If sedation / anaesthesia presents significant risk

      Drug treatment may be considered:

      • Procainamide 10–15 mg/kg IV over 20 minutes Maximum 1 g OR
      • Amiodarone 300 mg IV over 10–60 minutes followed by: 900 mg IV over 24 hours
      • If ineffective: SYNCHRONISED CARDIOVERSION WITH EXPERT ADVICE

      STOP — HIGH-RISK RHYTHM

      Consider:

      • 1. AF WITH BUNDLE BRANCH BLOCK
      • 2. PRE-EXCITED AF / WPW
      • 3. POLYMORPHIC VT

      Seek senior / cardiology support early.

      PRE-EXCITED AF

      Think pre-excitation when there is:

      • very rapid irregular broad-complex tachycardia
      • varying QRS morphology
      • ventricular rates sometimes >200 bpm
      • known WPW / previous delta wave

      DO NOT GIVE AV-NODAL BLOCKING DRUGS

      Avoid the following as these may increase conduction through the accessory pathway and precipitate VF:

      • Adenosine
      • Beta-blockers
      • Verapamil
      • Diltiazem
      • Digoxin

      Treatment

      • Procainamide OR
      • Synchronised cardioversion

      If polymorphic VT occurs with QT prolongation:

      Magnesium: Mg²⁺ 8 mmol IV over 10 minutes

      Also:

      • Correct K⁺ / Mg²⁺ abnormalities.
      • Stop QT-prolonging drugs.
      • Treat reversible causes.
      • Seek expert help.

      For recurrent pause-dependent torsades consider increasing the heart rate with:

      • Isoprenaline OR
      • Temporary pacing

      ❌ AVOID AMIODARONE because it may further prolong the QT interval.

      ⚠️ PITFALLS

      FAST ≠ ARRHYTHMIA

      Do not treat physiological sinus tachycardia as an arrhythmia.

      BROAD + REGULAR = VT UNTIL PROVEN OTHERWISE

      Do not delay appropriate treatment while attempting to prove SVT.

      BROAD + IRREGULAR ≠ ROUTINE AF

      Always consider pre-excited AF.

      ADENOSINE IS NOT FOR IRREGULAR BROAD-COMPLEX TACHYCARDIA

      DO NOT GIVE AMIODARONE FOR TORSADES / LONG-QT POLYMORPHIC VT

      Give magnesium and correct the underlying problem.

      CARDIOVERSION REQUIRES SYNC

      Confirm the machine is marking the R waves before delivering the shock.

      Re-check SYNC after each shock — some defibrillators automatically revert out of synchronised mode.

      DISPOSITION

      Consider admission / cardiology assessment for:

      • VT
      • broad-complex tachycardia of uncertain cause
      • syncope associated with tachyarrhythmia
      • significant structural heart disease
      • ACS / myocardial ischaemia
      • heart failure
      • recurrent arrhythmia despite treatment
      • pre-excitation
      • significant electrolyte disturbance
      • drug-induced arrhythmia
      • prolonged QT / torsades
      • haemodynamic instability
      • arrhythmia requiring electrical cardioversion

      Patients with uncomplicated successfully terminated SVT may be suitable for discharge following senior review, appropriate investigation and follow-up depending on the clinical circumstances.

      GUIDANCE

      Based primarily on:

      • Resuscitation Council UK — Guidelines 2025: Adult Advanced Life Support
      • Resuscitation Council UK — Adult Tachyarrhythmia Algorithm, current version March 2026
      • Current atrial fibrillation guidance

      EMbeds clinical quick guide

      Last evidence review: September 2026
      Suggested next review: September 2027

      This is a clinical support guide and does not replace clinical judgement, current CHFT medicines guidance or specialist advice.

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