A 52-year-old man presents with exertional chest pain and dyspnea. On examination, a late systolic murmur is heard at the apex, preceded by a mid-systolic click. Echocardiography confirms mitral valve prolapse with mild regurgitation. Which investigation is most appropriate to assess the risk of sudden cardiac death and guide management in this patient?

## Clinical Context Mitral valve prolapse (MVP) with regurgitation carries a small but real risk of ventricular arrhythmias and sudden cardiac death, particularly in symptomatic patients with palpitations or syncope. ## Investigation of Choice: 24-Hour Holter Monitoring **Key Point:** Holter monitoring detects occult ventricular arrhythmias (premature ventricular contractions, non-sustained ventricular tachycardia) that correlate with sudden cardiac death risk in MVP. **High-Yield:** In MVP patients with: - Palpitations or syncope - Echocardiographic evidence of regurgitation - Redundant/thickened leaflets Holter monitoring is the standard initial investigation to stratify arrhythmia risk and guide beta-blocker or antiarrhythmic therapy. **Clinical Pearl:** The presence of complex ventricular ectopy on Holter (frequent PVCs, couplets, or NSVT) in MVP is an independent predictor of adverse outcomes and may warrant ICD consideration in high-risk subsets. ## Why Holter Monitoring? | Feature | Relevance | |---------|----------| | Detects arrhythmias | MVP-related arrhythmias are paroxysmal; Holter captures them over 24 hrs | | Non-invasive | Safe, repeatable, no contrast or radiation | | Guides therapy | Presence/absence of arrhythmias determines need for beta-blockers or antiarrhythmics | | Risk stratification | Arrhythmia burden predicts SCD risk | ## Other Investigations in MVP | Investigation | Role in MVP | |---|---| | **Transoesophageal echo** | Better visualisation of posterior leaflet; not for risk stratification | | **Cardiac MRI** | Assesses myocardial fibrosis; not standard in uncomplicated MVP | | **Coronary angiography** | Indicated only if ischaemic chest pain or positive stress test; not for MVP risk assessment | | **Exercise stress test** | May be used if exertional symptoms; Holter is primary for arrhythmia detection | **Mnemonic:** MVP risk assessment = **HAREM** - **H**olter monitoring (arrhythmia detection) - **A**cute syncope / palpitations (symptoms prompting Holter) - **R**egurgitation severity (echo finding) - **E**chocardiography (baseline structural assessment) - **M**yxomatous changes (leaflet redundancy on echo)