A 52-year-old woman with dilated cardiomyopathy (EF 30%) and recurrent syncope is referred for risk stratification. She has no prior myocardial infarction. On 12-lead ECG, there is a QRS duration of 155 ms with left bundle branch block morphology. Electrophysiology study shows inducible sustained monomorphic ventricular tachycardia. What is the most appropriate next step in management?

Explanation

## Clinical Context: Secondary Prevention of SCD **Key Point:** This patient has **secondary prevention indications for ICD**: prior syncope due to VT in the setting of severe LV dysfunction (EF 30%). **High-Yield:** Inducible sustained monomorphic VT on EPS in a patient with haemodynamically significant arrhythmias is a Class I indication for ICD implantation regardless of the underlying cardiomyopathy aetiology (ischaemic or non-ischaemic). ## ICD Indications in Cardiomyopathy | Indication | EF Threshold | Requirement | Class | |-----------|-------------|-------------|-------| | **Secondary prevention** | ≤40% | Prior VT/VF or syncope | **I** | | **Primary prevention (non-ischaemic)** | ≤35% | EPS-inducible VT or prior syncope | **IIa** | | **Primary prevention (ischaemic)** | ≤35% | No requirement for EPS | **I** | | **Primary prevention (any)** | ≤30% | No EPS needed | **IIb** | **Clinical Pearl:** The presence of **inducible sustained monomorphic VT on EPS** in a patient with prior syncope and EF 30% is a strong predictor of future arrhythmic events and sudden cardiac death. ICD is the definitive therapy. ## Management Algorithm ```mermaid flowchart TD A[Dilated cardiomyopathy, EF 30%]:::outcome --> B{Prior syncope or VT/VF?}:::decision B -->|Yes - Secondary prevention| C[ICD indicated]:::action B -->|No - Primary prevention| D{EPS-inducible VT?}:::decision D -->|Yes| E[ICD indicated]:::action D -->|No| F[Medical therapy + risk stratification]:::action C --> G[Implant ICD + beta-blocker/ACE-I]:::action E --> G G --> H[Consider amiodarone if recurrent ICD therapies]:::action ``` **High-Yield:** Amiodarone monotherapy (without ICD) has been shown in the GESICA and CHF-STAT trials to **reduce mortality by ~25% but NOT prevent sudden cardiac death** in non-ischaemic cardiomyopathy. ICD is superior for secondary prevention. **Mnemonic:** **"SCD-HeFT Rule"** = Systolic dysfunction + Cardiomyopathy → Defibrillator (if EF ≤35% and NYHA II–III, or prior arrhythmia).