Tachycardia (Peri-Arrest) Management
Resuscitation Council UK Adult Advanced Life Support Guidelines. Published: Oct 2025.
Changes made to this article:
- Link to the latest 2025 Resuscitation Guidelines updated
- A few changes were made to the guideline, see the overview section for comparison
Date: 04/12/25
Overview of New 2025 Guideline vs Old 2021 Guideline
| Scenarios | Old 2021 guideline | New 2025 guideline (key changes) | |
|---|---|---|---|
| Unstable | After 3x synchronised DC shocks → IV amiodarone | After 3x synchronised DC shocks → IV amiodarone or procainamide | |
| Stable | Narrow QRS + regular | No changes | |
| Narrow QRS + irregular |
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| Board QRS + regular |
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Patients with structural heart disease → synchronised DC shock is recommended
If there is high sedation / anaesthesia risk → antiarrhythmics
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| Board QRS + irregular |
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In addition, “immediately post-ROSC” has been introduced as a new life-threatening feature in peri-arrest management.
NB The latest guidelines on stable tachyarrhythmias have become increasingly complex, particularly for broad-complex, regular rhythms. It is therefore unlikely that examinations will test detailed nuances of this algorithm.
For example, in a question on the management of a stable, broad-complex, regular tachyarrhythmia, it is unlikely that both DC cardioversion and procainamide would be presented as options. More likely, the correct answer would be one of these, alongside clearly inappropriate distractors (e.g. magnesium, atropine, bisoprolol).
In contrast, it is more important to be familiar with the management of unstable tachyarrhythmias, as these pathways are more straightforward, high-yield, and clinically relevant. Consistent with clinical practice, the guidelines emphasise on expert input when managing stable tachyarrhythmias.
Background Information
Cardiac Arrest vs Peri-Arrest
This article covers the algorithm for peri-arrest tachycardia, meaning in the presence of a pulse.
If there is no pulse, that is cardiac arrest, the ALS algorithm should be used.
Approach to Tachycardia (Classification and Causes)
Any tachycardia could be approached with the following method. This is not an exhaustive list, but it includes the most important ones.
| QRS duration | Rhythm | Common arrhythmias |
|---|---|---|
| Narrow QRS (<120 ms) | Regular |
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| Irregular |
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| Broad QRS (>120 ms) | Regular |
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| Irregular |
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Management
The first step is to check for ANY of the life-threatening features:
- Shock – hypotension (SBP < 90 mmHg) and/or features of sympathetic compensation
- Syncope – due to ↓ cerebral blood flow
- Myocardial ischaemia – chest pain and/or 12-ECG findings
- Heart failure – pulmonary oedema (LV failure) and/or raised JVP (RV failure)
- Immediately post-ROSC
The timing of adverse features must be current (i.e. present at the time of evaluation) to prompt consideration of immediate synchronised cardioversion. Past episodes of instability do not, by themselves, justify urgent cardioversion unless instability recurs or persists during clinical assessment.
Important: the adult tachyarrhythmia algorithm is for peri-arrest tachyarrhythmia of abnormal origin. It is NOT for sinus tachycardia.
Sinus tachycardia is defined as a heart rate >100 bpm originating from the sinus node, typically in response to physiological stressors (e.g., fever, hypovolemia, pain, anaemia, hypoxia). Sinus tachycardia is generally a sympathetic compensatory mechanism, rather than a primary arrhythmia. To manage sinus tachycardia, treat underlying cause, do NOT use antiarrhythmics and cardioversion to normalise the heart rate.
Typical ECG features of sinus tachycardia: 1) heart rate 100-150 bpm 2) identifiable and upright P wave in leads I, II and aVF.
Life-Threatening Feature(s) Present (Unstable)
Immediate management: synchronised DC shock up to 3 attempts, under sedation or anaesthesia (regardless of the rhythm)
- For atrial fibrillation: initial shock at maximum defibrillator output is reasonable
- For other rhythms: use a stepwise approach (use a lower initial energy level and increase in a stepwise manner)
If DC shock is unsuccessful in restoring sinus rhythm, and the patient remains unstable:
- First, attempt pharmacological cardioversion
- Amiodarone 300mg IV over 10-20 min, or
- Procainamide 10-15 mg/kg over 20 min
- If pharmacological cardioversion failed → re-attempt synchronised DC shock
No Life-Threatening Features (Stable)
The management algorithm depends on the likely tachyarrhythmia, based on 1) QRS duration and 2) rhythm.
Narrow QRS (<120 ms)
Regular Rhythm
In the context of regular narrow complex tachycardia, SVT or atrial flutter is most likely
Step up accordingly if there is an inadequate response:
- Step 1: vagal manoeuvres
- Step 2: adenosine IV bolus (6mg → 12mg → 18mg)
- Step 3: beta blocker or verapamil
- Step 4: synchronised DC shock
Adenosine contraindications as per the BNF: [Ref]
- Asthma & chronic obstructive lung disease (can cause bronchospasm) → can safely use all other interventions besides beta-blockers/adenosine
- Decompensated heart failure
- Long QT syndrome
- 2nd / 3rd degree AV block and sick sinus syndrome (unless a pacemaker is fitted)
- Severe hypotension
Irregular Rhythm
In the context of irregular narrow complex tachycardia, AF is most likely.
Offer rate control with:
- Beta blocker, or
- Digoxin, or
- Rate-limiting CCB (verapamil or diltiazem) (avoid in heart failure or ↓ LVEF)
Anticoagulation is necessary if the duration of the arrhythmia has lasted >24 hours
For detailed management of atrial fibrillation (non-acute), see the Atrial Fibrillation (AF) article.
Rate-limiting CCBs (verapamil and diltiazem) should be avoided if there is heart failure or an ejection fraction <40%. Beta blocker or digoxin should be used instead.
This is because rate-limiting CCBs (specifically non-DHP CCBs) have a strong -ve inotropic and -ve chronotropic effects, which can depress myocardial contractility, worsening heart failure, and potentially triggering cardiac arrest.
Broad QRS (>120ms)
Regular Rhythm
Regular broad complex tachycardia is VT until proven otherwise, but it could also be SVT with aberrancy.
VT is likely if ANY of the following are present:
- Known case of VT
- Vagal manoeuvres and adenosine failed
- Known / suspected heart disease
- Uncertain mechanism of arrhythmia
Management approach:
- Patients with structural heart disease (or unclear whether there is underlying heart muscle damage) → synchronised DC shock (under sedation / anaesthesia) is recommended
- If there is high sedation / anaesthesia risk OR certainly no structural heart disease → antiarrhythmics
- 1st line: IV procainamide 10-15 mg/kg over 20 min
- 2nd line (if procainamide is unavailable or contraindicated): IV amiodarone 300 mg over 10-60 min, then 900 mg over 24 hours
- If antiarrhythmics are ineffective → synchronised DC shock up to 3 attempts
Procainamide contraindications:
- Severe heart failure
- Acute myocardial infarction
- End-stage renal disease
Irregular Rhythm
In the context of irregular broad complex tachycardia, polymorphic VT or AF with aberrancy is most likely
- Torsades de pointes (i.e. polymorphic VT) →
- IV magnesium 8 mmol (equivalent to 2g) over 10 min
- Avoid amiodarone
- Consider isoprenaline or temporary pacing to increase the heart rate
- AF with pre-excitation (e.g. WPW) → procainamide / cardioversion