Twiddler syndrome and Reel syndrome in patients with subcutaneous implantable cardioverter-defibrillator (S-ICD): a meta-summary of case reports

J Interv Card Electrophysiol. 2026 Jun;69(4):537-541. doi: 10.1007/s10840-026-02331-9. Epub 2026 Apr 15.

Abstract

BACKGROUND: Twiddler and Reel syndrome are mechanical complications of transvenous devices and are rarely reported in subcutaneous ICD (S-ICD) recipients. METHODS: We reviewed published cases and report Reel syndrome in a 15-year-old patient with an S-ICD, the youngest described. RESULTS: Ten cases were identified. The most common clinical presentation was inappropriate shocks due to altered sensing vectors. Diagnosis was confirmed by device interrogation and chest radiography. Risk factors are similar to those observed in transvenous devices. CONCLUSIONS: Twiddler and Reel syndrome can occur in S-ICDs and should be considered in the differential diagnosis of inappropriate shocks or device malfunction.

Keywords: Inappropriate shock; Lead dislodgement; Reel syndrome; Subcutaneous defibrillator; Twiddler syndrome.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Adolescent
  • Defibrillators, Implantable* / adverse effects
  • Equipment Failure
  • Foreign-Body Migration* / diagnostic imaging
  • Foreign-Body Migration* / etiology
  • Humans
  • Prosthesis Failure
  • Syndrome