Background Subcutaneous implantable cardioverter defibrillators (S-ICDs) are considered an alternative to conventional transvenous ICDs (TV-ICDs) in patients not requiring pacing.

Methods We searched MEDLINE and EMBASE for studies evaluating efficacy and safety outcomes in S-ICD patients. Outcomes were pooled across studies.

Results Sixteen studies were included with 5380 participants (mean age range 33–56 years). Short-term follow-up data were available for 1670 subjects. The most common complication was pocket infection, affecting 2.7%. Other complications included delayed wound healing (0.6%) and wound discomfort (0.8%). 3.8% of S-ICDs were explanted, most commonly for pocket infection. Mortality rates in hospital (0.4%) and during follow-up (3.4% from 12 studies reporting) were low. Incidence of ventricular arrhythmia varied from 0% to 12%. Overall shock efficacy exceeded 96%. Inappropriate shocks affected 4.3% and was most commonly caused by T-wave oversensing.

Conclusions Although long-term randomised data are lacking, observational data suggest similar shock efficacy and short-term complication rates between the S-ICD and TV-ICD.