Key result
Subcutaneous ICDs in hypertrophic cardiomyopathy patients were associated with a lower 5-year risk of appropriate ICD interventions compared to transvenous ICDs (HR 0.32; 95% CI 0.15-0.65; P=0.002).
Why the study?
Although S-ICD avoids transvenous leads and may reduce complications, it lacks bradycardia pacing and ATP, leaving its comparative clinical course in HCM patients unclear.
Does a subcutaneous ICD reduce ICD interventions, complications, and mortality compared to a transvenous ICD in patients with hypertrophic cardiomyopathy?
Cohort (n=427)
Does a subcutaneous ICD reduce ICD interventions, complications, and mortality compared to a transvenous ICD in patients with hypertrophic cardiomyopathy?
Effect estimate: HR 0.32 (95% CI 0.15-0.65)
p-value: p=0.002
In patients with hypertrophic cardiomyopathy, S-ICDs are associated with fewer appropriate and inappropriate shocks and fewer major lead-related complications compared to transvenous ICDs, with no difference in mortality at 5 years.
S-ICDs were associated with fewer appropriate interventions in HCM; hypothesis-generating and leaves open preference over transvenous devices pending RCTs.
AIMS: The implantable cardioverter-defibrillator (ICD) is a life-saving therapy in patients with hypertrophic cardiomyopathy (HCM) at risk of sudden cardiac death. Implantable cardioverter-defibrillator complications are of concern. The subcutaneous ICD (S-ICD) does not use transvenous leads and is expected to reduce complications. However, it does not provide bradycardia and anti-tachycardia pacing (ATP). The aim of this study was to compare appropriate and inappropriate ICD interventions, complications, disease-related adverse events and mortality between HCM patients implanted with a S- or transvenous (TV)-ICD. METHODS AND RESULTS: Consecutive HCM patients implanted with a S- (n = 216) or TV-ICD (n = 211) were enrolled. Propensity-adjusted cumulative Kaplan-Meier curves and multivariate Cox proportional hazard ratios were used to compare 5-year event-free survival and the risk of events. The S-ICD patients had lower 5-year risk of appropriate (HR: 0.32; 95%CI: 0.15-0.65; P = 0.002) and inappropriate (HR: 0.44; 95%CI: 0.20-0.95; P = 0.038) ICD interventions, driven by a high incidence of ATP therapy in the TV-ICD group. The S- and TV-ICD patients experienced similar 5-year rate of device-related complications, albeit the risk of major lead-related complications was lower in S-ICD patients (HR: 0.17; 95%CI: 0.038-0.79; P = 0.023). The TV- and S-ICD patients displayed similar risk of disease-related complications (HR: 0.64; 95%CI: 0.27-1.52; P = 0.309) and mortality (HR: 0.74; 95%CI: 0.29-1.87; P = 0.521). CONCLUSION: Hypertrophic cardiomyopathy patients implanted with a S-ICD had lower 5-year risk of appropriate and inappropriate ICD therapies as well as of major lead-related complications as compared to those implanted with a TV-ICD. Long-term comparative follow-up studies will clarify whether the lower incidence of major lead-related complications will translate into a morbidity or survival benefit.
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Francia et al. (2023) conducted a cohort in Hypertrophic cardiomyopathy (n=427). Subcutaneous ICD (S-ICD) vs. Transvenous ICD (TV-ICD) was evaluated on Appropriate ICD interventions (HR 0.32, 95% CI 0.15-0.65, p=0.002). Subcutaneous ICDs in hypertrophic cardiomyopathy patients were associated with a lower 5-year risk of appropriate ICD interventions compared to transvenous ICDs (HR 0.32; 95% CI 0.15-0.65; P=0.002).
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