Can we predict sudden cardiac death in long-term survivors of atrial switch surgery for transposition of the great arteries?

OBJECTIVE: This study aims to identify predictors of sudden cardiac death (SCD) in patients with transposition of the great arteries (TGA) who have undergone atrial baffle surgery with the Mustard or Senning operation.

BACKGROUND: Patients with TGA and previous atrial baffle surgery are known to be at increased risk of SCD. Despite this, indications for insertion of an implantable cardiac defibrillator for primary prevention have not been established.

METHODS: Eighty-nine patients with a diagnosis of TGA and previous Mustard or Senning repair were identified. Medical records were reviewed for SCD, aborted SCD, implantation of cardiac defibrillator (ICD), and use of cardiac medications. Clinically significant events (heart failure admissions, documented arrhythmias, and insertion of a pacemaker) were ascertained, and results of echocardiograms were explored.

RESULTS: There were five SCDs in our population, and five patients underwent a primary prevention ICD insertion, with no subsequent sustained ventricular arrhythmia or aborted SCD. Patients who suffered SCD had undergone surgery at an older age (median 53 months vs. 14 months) in a slightly earlier era (median year of operation 1971 vs. 1975). Atrial arrhythmias requiring treatment were documented in 100% of the SCD and in 29% of the no SCD patients.

CONCLUSIONS: Criteria for insertion of primary prevention implantable cardiac defibrillators postatrial baffle surgery remain to be established. In the SCD subgroup, surgery at an older age, earlier era of surgical repair, and history of atrial arrhythmia appear to convey an increased risk of sudden death.