Evaluation of body weight as a predictive factor for transvenous ventricular defibrillation characteristics

Cardiac defibrillation therapy for at risk patients with systemic right ventricular dysfunction secondary to atrial redirection surgery for dextro-transposition of the great arteries

AIM

To review techniques of implantable cardioverter-defibrillators (ICD) in patients after Mustard surgery for arterial transposition.

METHODS AND RESULTS

Retrospective analysis of all Mustard patients receiving ICDs at our institution. Five patients (median age 24 years, range 19-35, 3 male) with systemic right ventricular dysfunction (sRV) dysfunction and New York Heart Association (NYHA) II and III, received ICDs. Implantation was performed transvenously in three patients, epicardial patches and subcutaneous arrays at surgery in two patients. Two patients required lead extraction and baffle stent angioplasty before ICD implantation. Defibrillation vectors incorporating the anterior sRV mass [i.e., sub-pulmonary left ventricle (pLV) to generator can, and between epicardial defibrillator patches], consistently achieved a minimum 10 joule(J) safety margin during defibrillation threshold (DFT) testing. Subcutaneous arrays and endocardial vectors that included a superior vena cava (SVC) electrode were less effective. One patient developed pulmonary oedema post-procedure. At a median 20 months, all patients were alive and in NYHA class II. Follow-up over 24 months documented multiple non-sustained ventricular tachycardia (VT) in the group and one patient had recurrent VT with aborted device therapy.

CONCLUSION

Defibrillator implantation in Mustard patients is challenging. Sub-optimal defibrillation should be anticipated and can be overcome using vectors which integrate the RV mass and high-energy devices. A staged procedure involving pre-implant interventions or separate DFT tests, where indicated, may be better tolerated by patients.