Patients with newly diagnosed non-ischemic cardiomyopathy (NICM) typically undergo a period of medical therapy optimization before decisions regarding primary prevention implantable cardioverter-defibrillator (ICD) implantation. During this period, patients may remain at risk for sudden cardiac death (SCD) due to malignant ventricular arrhythmias. The wearable cardioverter-defibrillator (WCD) has been used as a temporary protective strategy.A systematic review and meta-analysis published in the Heart evaluated the risk of SCD in patients with newly diagnosed NICM using WCD monitoring.

Medline, Embase, and the Cochrane Library were searched through March 2025. Studies were eligible if they included adults aged ≥18 years with newly diagnosed NICM (≤90 days) who received a WCD. Study selection, quality assessment, and data extraction were performed independently by two reviewers. Outcomes included appropriate WCD shocks, representing sustained ventricular arrhythmia, inappropriate shocks, and subsequent ICD implantation.

Fifty observational studies including 10,066 patients with NICM were analyzed. The pooled proportion of appropriate WCD shocks was 1% (87/7708; 95% CI 1% to 2%). Subgroup analyses showed appropriate shock rates of 2% in myocarditis, 3% in peripartum cardiomyopathy, 2% in Takotsubo syndrome, and 1% in congenital/inherited or genetic cardiomyopathy. Inappropriate shocks occurred in 0-1% of patients. At follow-up, ICD implantation occurred in 6% of patients with Takotsubo syndrome and up to 43% of those with congenital/inherited or genetic cardiomyopathy.

Patients with newly diagnosed NICM experienced documented ventricular arrhythmias during medical therapy optimization. WCD monitoring provided recorded evidence of arrhythmic events during this high-risk period.