Key result
Primary-prevention S-ICD in advanced CKD yields only ~5% appropriate therapy, outnumbered by inappropriate shocks.
Why the study?
Prospective data on the subcutaneous implantable cardioverter-defibrillator (S-ICD) for primary prevention in patients with chronic kidney disease stage 3-5 and LVEF <= 35% were lacking.
What is the rate of appropriate ICD therapy with the subcutaneous implantable cardioverter-defibrillator (S-ICD) for primary prevention in adults with CKD stage 3-5 and LVEF ≤ 35%?
What is the rate of appropriate ICD therapy with the subcutaneous implantable cardioverter-defibrillator (S-ICD) for primary prevention in adults with CKD stage 3-5 and LVEF ≤ 35%?
In patients with CKD stage 3-5 and LVEF ≤35% receiving a primary-prevention S-ICD, appropriate ICD therapy was infrequent (5.1%) and outnumbered by inappropriate shocks (12.8%) and non-arrhythmic mortality (7.7%), highlighting the need for cautious patient selection and device filter monitoring.
Low appropriate therapy rates question S-ICD benefit for primary prevention in advanced CKD; leaves open optimal arrhythmia strategy amid competing mortality.
BACKGROUND: Prospective data on the subcutaneous implantable cardioverter-defibrillator (S-ICD) in chronic kidney disease (CKD) are lacking. We estimated the rate of appropriate ICD therapy with the S-ICD in CKD stage 3-5 with left ventricular ejection fraction (LVEF) ≤ 35%. METHODS: In this single-arm exploratory study, adults with CKD stage 3-5 and a guideline-based primary-prevention indication received an EMBLEM MRI S-ICD at eight Korean centers. The primary endpoint, appropriate ICD therapy, was hypothesized at 18% versus a historical rate of 7.8% (α = 0.05, 80% power, planned N = 77; exact binomial test). RESULTS: ; 71.8% had CKD stage 5 and 69.2% were on hemodialysis. Over a median follow-up of 361 days, appropriate ICD therapy occurred in 2 patients (5.1%; 95% CI, 1.4-16.9), significantly below the hypothesized 18% (p = 0.036). Inappropriate shocks occurred in 5 patients (12.8%; 95% CI, 5.6-26.7; 8 shocks), a proportion 2.5 times that of appropriate therapy, from external electromagnetic interference (2 patients), multiple counting after automatic SMART Pass deactivation (2), and supraventricular misclassification (1). Three deaths (7.7%) occurred, none device-related or documented as arrhythmic (one undetermined); all hospitalizations were for heart failure, and no systemic device infection occurred. CONCLUSIONS: In this exploratory single-arm study, appropriate ICD therapy was infrequent and exceeded by inappropriate shocks, while non-arrhythmic competing mortality dominated the clinical course. These hypothesis-generating findings support cautious patient selection, verification of filter status during follow-up, and larger comparative studies. TRIAL REGISTRATION: Clinical Research Information Service (CRIS), Republic of Korea; identifier KCT0005596.
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Chung et al. (2026) studied Chronic kidney disease stage 3-5 with LVEF ≤ 35%. Subcutaneous implantable cardioverter-defibrillator (EMBLEM MRI S-ICD) vs. Historical control rate (7.8%) was evaluated on Appropriate ICD therapy (95% CI 1.4-16.9, p=0.036). Primary-prevention S-ICD in CKD stage 3-5 yielded a 5.1% (95% CI 1.4-16.9) rate of appropriate therapy, significantly below the hypothesized 18% (p=0.036) and exceeded by inappropriate shocks (12.8%).
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