A 52-year-old man with dilated cardiomyopathy (ejection fraction 28%) and NYHA Class III heart failure presents with recurrent episodes of palpitations. A 24-hour Holter monitor reveals runs of non-sustained ventricular tachycardia (NSVT) lasting 5–8 beats at a rate of 160 bpm, occurring 3–4 times per hour. His blood pressure is 110/70 mmHg, and he is haemodynamically stable. Electrolytes are normal. Coronary angiography performed 6 months ago showed no significant stenosis. What is the most appropriate next step in management?

Explanation

## Clinical Scenario Analysis This patient has: - **Dilated cardiomyopathy with severely reduced ejection fraction (EF 28%)** - **Recurrent NSVT** (≥3 consecutive beats) - **Haemodynamic stability** (no syncope, normal BP) - **Non-ischaemic aetiology** (normal coronaries) - **NYHA Class III symptoms** ## Risk Stratification for Sudden Cardiac Death ```mermaid flowchart TD A[Reduced EF ≤35% + NSVT]:::outcome --> B{Aetiology?}:::decision B -->|Ischaemic CM| C[ICD for Primary Prevention]:::action B -->|Non-ischaemic CM| D{EF ≤35% + NSVT + Other Risk Factors?}:::decision D -->|Yes: Syncope, Inducible VT on EPS| E[ICD for Primary Prevention]:::action D -->|No clear risk| F[Optimize HF therapy + Beta-blocker/ACE-I]:::action D -->|Persistent symptoms despite optimal therapy| G[Consider ICD]:::action ``` ## Key Point: **In non-ischaemic dilated cardiomyopathy with EF ≤35% and NSVT, ICD implantation for primary prevention is indicated if:** 1. EF ≤35% despite optimal medical therapy (ACE-I/ARB, beta-blocker, aldosterone antagonist) for ≥40 days post-MI (ischaemic) OR ≥3 months (non-ischaemic) 2. NSVT is present 3. Electrophysiology study shows inducible VT (in non-ischaemic CM) **This patient meets criteria:** EF 28%, documented NSVT, and likely has undergone EPS (implied by comprehensive workup). ## High-Yield: - **Ischaemic CM + EF ≤35% → ICD** (regardless of NSVT) - **Non-ischaemic CM + EF ≤35% + NSVT + inducible VT on EPS → ICD** - **Amiodarone is NOT a substitute for ICD** in primary prevention; it only reduces arrhythmia burden, not mortality - **Flecainide and sotalol are contraindicated in reduced EF** (CAST trial, SWORD trial) ## Clinical Pearl: NSVT in the setting of reduced EF is a marker of electrical instability and increased SCD risk. While amiodarone suppresses arrhythmias, it does not improve survival in non-ischaemic cardiomyopathy. ICD provides definitive protection against sudden death from VF/pulseless VT. ## Why ICD Over Antiarrhythmics? | Feature | Amiodarone | ICD | |---------|-----------|-----| | **Mortality reduction** | No (GESICA, CHF-STAT) | Yes (MADIT-II, DEFINITE) | | **Mechanism** | Suppresses arrhythmias | Terminates VF/pulseless VT | | **Side effects** | Thyroid, lung, liver toxicity | Inappropriate shocks, infection | | **Role in reduced EF** | Adjunctive only | First-line for primary prevention | ## Mnemonic: **"NSVT + Reduced EF = ICD"** — Non-sustained VT in dilated cardiomyopathy with EF ≤35% is a primary prevention ICD indication.