Wearable cardioverter defibrillator for transient arrhythmic risk and sudden cardiac death prevention: a systematic review and updated meta-analysis.

Background: Sudden cardiac death (SCD) is a common cause of cardiovascular mortality, often triggered by ventricular arrhythmias in the setting of myocardial vulnerability. The wearable cardioverter-defibrillator (WCD) offers temporary protection against SCD, particularly when an implantable device is contraindicated or premature.

Objectives: We conducted a comprehensive meta-analysis to assess the effectiveness of the WCD in appropriately terminating life-threatening arrhythmias such as sustained ventricular tachycardia (VT) and ventricular fibrillation (VF), preventing sudden cardiac death.

Methods: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we systematically reviewed 40 studies comprising 59 647 adults fitted with a WCD for primary or secondary SCD prevention. Random-effects meta-analysis, subgroup analysis, meta-regression and sensitivity analyses were performed.

Results: The pooled incidence of appropriate WCD intervention was 3% (95% CI 2% to 3%), with substantial heterogeneity (I²=88.9%). The prediction interval ranged from 1% to 8%, indicating that future studies conducted in selected high-risk populations may observe significantly higher WCD intervention. Life-threatening arrhythmias were higher during early follow-up (≤60 days). An appropriate daily WCD wearing time significantly influenced the results. Gender, age, ejection fraction and study design were not significant modifiers. No publication bias was detected.

Conclusions: The WCD represents an effective strategy for preventing SCD in early high-risk settings, with its benefit closely linked to adherence and appropriate patient selection.