February 24, 2025Open Access
Subcutaneous Implantable Defibrillators in Young Patients: Arrhythmias, Complications, and Physical Activity
Key Result
Highly active lifestyles in young subcutaneous implantable cardioverter defibrillator recipients were not associated with an increased risk of arrhythmia- or device-related complications compared to inactive subjects.
Study Design
Type
Cohort (n=602)
Multicenter
Yes
Structured PICO
Does moderate to high physical activity or recreational sports participation increase S-ICD-related complications or shocks in young S-ICD recipients?
P
Population
602 young-adult (15–65 years) subcutaneous implantable cardioverter defibrillator (S-ICD) recipients, mean age 46±14 years, 77% men, from 19 Italian centers. Common diagnoses included hypertrophic cardiomyopathy (24%), ischemic heart disease (20%), and idiopathic dilated cardiomyopathy (17%).
I
Intervention
Moderate to high physical activity and recreational sports participation (assessed via International Physical Activity Questionnaire and Sport Questionnaire).
C
Comparator
Inactive lifestyle or non-participation in sports.
O
Outcome
Composite of (1) cardiac arrest or externally resuscitated tachyarrhythmia caused by shock failure, incessant ventricular arrhythmia, or postshock pulseless electric activity, (2) failure of the first maximum-energy shock to defibrillate, (3) any lead malfunction or system inability to provide reliable sensing requiring system revision or explant, and (4) any lead- or device-related complication requiring surgical reintervention.safety
Young S-ICD recipients can safely engage in moderate to high physical activity and recreational sports without an increased risk of device-related complications or shocks.
Main Result
Effect estimate: HR 0.88 (95% CI 0.28-2.73)
Absolute Event Rate: 4.4% vs 5.6%
p-value: p=0.83
Limitations
- Retrospective design with potential selection biases
- Local adjudication of endpoints without centralized analysis
- Self-reported exercise levels without objective measures
- All White population limits generalizability to other ethnicities
- Long mean time from implantation prevents analysis of early data
Abstract
BACKGROUND: The safety of subcutaneous implantable cardioverter defibrillator (S-ICD) recipients who lead active lifestyles and engage in recreational sports is unknown. We aimed to evaluate the association between lifestyle and recreational sports and the occurrence of arrhythmia- and device-related complications, appropriate and inappropriate shocks in S-ICD recipients. METHODS: We assessed a cohort of young-adult (15–65 years) S-ICD patients, evaluated their physical activity with IPAQ (International Physical Activity Questionnaire), and assessed the association between lifestyle and recreational sports on S-ICD safety and shocks. RESULTS: We enrolled 602 S-ICD recipients (77% men; age, 46±14 years). According to the IPAQ, patients were categorized as inactive subjects (26.4%), moderately active subjects (45.2%), or highly active subjects (28.4%). Among moderately/highly active subjects, 163 (27.1%) were recreational athletes. During follow-up (47.3 interquartile range, 27.0–67.6 months), 23 patients (3.8%) reached the safety end point of arrhythmia- or device-related complications, with moderately and highly active subjects showing in multivariate analysis similar incidence compared with inactive subjects ( P =0.59 and P =0.83, respectively). Forty-four patients had 87 appropriate shocks. In multivariate analysis, moderately and highly active subjects showed a nonsignificantly lower incidence of appropriate shocks compared with inactive subjects ( P =0.12 and P =0.11, respectively). Consistently, there was a nonsignificant lower incidence of appropriate shocks in athletes versus nonathletes ( P =0.06). Thirty-nine patients had 46 inappropriate shocks. Moderately and highly active subjects had similar incidence of inappropriate shocks compared with inactive subjects ( P =0.92 and P =0.88, respectively). CONCLUSIONS: Young S-ICD patients often lead active lifestyles and participate in sports. Higher activity levels were not associated with increased implantable cardioverter defibrillator–related complications or increased risk of implantable cardioverter defibrillator shocks.