Electrical Storm (Recurrent VT/VF)

Related Subjects: |Electrical Storm (Recurrent VT/VF)

⚡ Introduction

• Electrical storm (also called ventricular electrical storm or arrhythmic storm) is defined as ≥3 episodes of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) within 24 hours, separated by ≥5 minutes, requiring termination by intervention (e.g., cardioversion, defibrillation, antitachycardia pacing, or antiarrhythmics).^1,2
• It reflects profound myocardial electrical instability and is a life-threatening emergency with high short-term mortality (up to 14–40% acutely/in-hospital if untreated).^1,3

🔎 Causes / Triggers

• Structural heart disease: Ischaemic cardiomyopathy (post-MI scar re-entry), non-ischaemic dilated cardiomyopathy, hypertrophic cardiomyopathy.
• Acute ischaemia: STEMI/NSTEMI (especially early phase).
• Inherited/channelopathies: Long QT syndrome, Brugada syndrome, catecholaminergic polymorphic VT.
• Metabolic/electrolyte: Hypokalaemia (<4.0–4.5 mmol/L), hypomagnesaemia, hyperkalaemia, acidosis, digoxin toxicity, QT-prolonging drugs.
• Iatrogenic/device-related: Proarrhythmic drugs (class Ic, sotalol), ICD lead malfunction, inappropriate shocks triggering further instability.
• Other: Thyrotoxicosis, sepsis, acute heart failure exacerbation.

🩺 Clinical Features

• Recurrent sustained VT/VF → repeated defibrillation/shocks or haemodynamic collapse.
• Symptoms: Syncope, chest pain (if ischaemic trigger), dyspnoea, or sudden cardiac arrest.
• Signs: Hypotension/shock, pulmonary oedema (if LV dysfunction), or repeated ICD shocks causing severe pain/anxiety.
• Psychological impact: Repeated shocks often lead to severe distress, anxiety, depression, or PTSD in ICD patients.

🧪 Investigations

• Bloods: FBC (target Hb >90–100 g/L), U&Es (target K⁺ >4.5 mmol/L, Mg²⁺ >1.0–1.2 mmol/L), troponin, thyroid function, digoxin level if relevant.
• ECG: Document VT morphology (mono/polymorphic), ischaemic changes, Brugada pattern, QTc, or epsilon waves.
• Imaging: CXR (cardiomegaly/oedema), urgent echo (LV function, structural issues, effusion).
• Advanced: Coronary angiography (if ACS/ischaemia suspected), cardiac MRI (scar/substrate assessment in selected cases).

🚑 Management (Involve senior cardiology / electrophysiology ± ICU early)

• Immediate resuscitation: Follow ALS protocol — external DC cardioversion/defibrillation (biphasic 120–200 J for VT with pulse; unsynchronised for VF/pulseless VT). Deep sedation or general anaesthesia for conscious patients to enable safe cardioversion and reduce sympathetic surge.^1,2
• Supportive: High-flow O₂/ventilation, IV access, analgesia/sedation, arterial line, correct reversible causes (electrolytes, ischaemia, proarrhythmics).
• Antiarrhythmics & sympathetic suppression (key: suppress catecholamines first):
  • IV β-blockers (preferred first-line in most cases): Propranolol (non-selective)oral and IV, esmolol (short-acting), or metoprolol — reduce sympathetic drive and ischaemia-related triggers.^1,2
  • IV Amiodarone: Often with beta blockers or alone. Bolus 150 mg then 0.5–1 mg/min infusion — most commonly used, especially in structural heart disease.^1,2
  • IV Lidocaine: 1–1.5 mg/kg bolus then 1–4 mg/min — particularly useful in acute ischaemia/post-MI VT.¹
• Revascularisation: Urgent coronary angiography ± PCI if ischaemia/ACS is the trigger (primary PCI for STEMI).
• Refractory cases:
  • Deep sedation/general anaesthesia + mechanical ventilation to minimize catecholamines. Benzodiapepines, Propofol, Opioids
  • Short-term mechanical circulatory support (IABP, Impella, ECMO/VA-ECMO) if cardiogenic shock persists (may be considered in drug-refractory cases with shock).^1,2
  • Percutaneous stellate ganglion block (left ± bilateral) — effective adjunct for sympathetic modulation in drug-refractory storm (supported by STAR trial and meta-analyses; high efficacy in reducing VA burden with low complication rate).^4,5
  • Catheter ablation — for monomorphic VT substrate (often after stabilisation).^1,2
• Long-term / secondary prevention: GDMT for heart failure (β-blocker, ACEi/ARNI, MRA, SGLT2i), ICD optimisation/reprogramming (e.g., ATP zones, avoid oversensing), treat underlying substrate (e.g., ablation, sympathetic denervation in select cases).

💡 Key teaching pearl: Electrical storm signals an unstable myocardium — treat both the rhythm acutely (defibrillation + antiarrhythmics and sedation) and the underlying trigger (ischaemia, electrolytes, sympathetic overdrive, scar). Early electrophysiology input is critical; refractory cases often benefit from sympathetic modulation (β-blockers ± stellate ganglion block) before advanced interventions.^1,2

References

1. Lenarczyk R, et al. Management of patients with an electrical storm or clustered ventricular arrhythmias: a clinical consensus statement of the European Heart Rhythm Association of the ESC—endorsed by the Asia-Pacific Heart Rhythm Society, Heart Rhythm Society, and Latin-American Heart Rhythm Society. Europace. 2024;26(4):euae049. doi:10.1093/europace/euae049
2. Zeppenfeld K, et al. 2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Eur Heart J. 2022;43(40):3997-4126. doi:10.1093/eurheartj/ehac262
3. Jentzer JC, et al. Multidisciplinary Critical Care Management of Electrical Storm: JACC State-of-the-Art Review. J Am Coll Cardiol. 2023;81(22):2189-2206. doi:10.1016/j.jacc.2023.03.424
4. Savastano S, et al. Electrical storm treatment by percutaneous stellate ganglion block: the STAR study. Eur Heart J. 2024;45(10):823-833. doi:10.1093/eurheartj/ehae021
5. Motazedian P, et al. Efficacy of stellate ganglion block in treatment of electrical storm: a systematic review and meta-analysis. Sci Rep. 2024;14:24719. doi:10.1038/s41598-024-76663-9