Unmasking hidden risk: echocardiographic and electrocardiographic markers of arrhythmic risk in pediatric mitral valve prolapse

Background

Mitral valve prolapse (MVP) is a common valvular condition characterized by systolic displacement of the mitral valve leaflets. Although often benign, a subset of patients faces increased risk of serious arrhythmias and sudden cardiac death; an entity called "arrhythmogenic MVP". Risk stratification is crucial for prevention. Evaluation involves 12-lead Electrocardiogram (ECG), echocardiography, and Holter ECG monitoring for identifying high-risk individuals.

Purpose

To determine the prevalence and type of arrhythmia in pediatric MVP using Holter monitoring and to identify ECG and echocardiographic predictors of arrhythmia, comparing these findings between primary MVP and Marfan-associated MVP.

Methods

In this cross-sectional study 56 MVP patients (51 primary MVP, 5 Marfan-associated) and 56 age- and sex-matched controls were enrolled. All underwent ECG, echocardiography, and 48-hour Holter monitoring. Statistical analysis used standard tests (p≤0.05 significant).

Results

Pediatric MVP patients had a significantly higher arrhythmic burden than controls, with premature ventricular contractions (PVCs) present in up to 40% of cases and significantly increased supraventricular ectopy. The Marfan-associated MVP showed extreme structural severity, universally featuring thick leaflets, bileaflet MVP, and a high prevalence of moderate/severe mitral regurge (MR). Remodeling was pronounced with elevated left atrial volume index (LAVI ≥40 mL/m²) seen exclusively in 60% of Marfan-associated MVP patients, and increased left ventricle end-diastolic diameter (LVEDD), with Z-score ≥+2 in 40% of the Marfan subgroup (Table 1).

Structural severity strongly predicted arrhythmic risk: Bileaflet MVP was associated with higher PACs and atrial couplets, and indicated autonomic dysregulation, characterized by lower mean SDNN. Moderate to severe MR correlated with high PACs and markedly low mean SDNN. T-wave inversion identified severe remodeling and autonomic dysfunction (100% abnormal SDNN; p = 0.024). Primary MVP patients demonstrated a shift toward sympathetic predominance (High LF/HF ratio >2 in 54.2% vs. 16.7% controls). PVCs, though common, were not morphology-specific but tended to occur with mitral annular dilation (higher Z-score ≥+2 in 17.6% of the PVC group vs. 5.1% in the non-PVC group) (Table 2).

Conclusion

Pediatric MVP, especially in the Marfan and bileaflet subtypes, is strongly linked to an increased arrhythmic burden and autonomic dysregulation. Integrating echocardiographic and electrocardiographic markers with Holter findings enables early, practical risk stratification to identify children at highest arrhythmic risk and guide tailored follow-up strategies.Table 1Table 2