Subcutaneous implantable cardioverter defibrillator in complex adult congenital heart disease. Results from the S-ICD "Monaldi Care" registry

Background: Implantable cardioverter defibrillators (ICD) are widely accepted therapy in congenital heart disease (CHD) patients at risk of life-threatening ventricular arrhythmias or sudden cardiac death (SCD). Initial experience with subcutaneous ICD (S-ICD) systems has shown a high efficacy. However, the use of S-ICD in complex ACHD (adult congenital heart disease) implies some specific considerations, as the safety for these patients in unknown and recommendations among physicians may vary widely. Methods: We review the data and studied the indications for S-ICD in complex ACHD and discuss its usefulness in clinical practice. Results: From a large cohort of 297 patients enrolled in the S-ICD "Monaldi care" registry, that encompass all the patients implanted in the Monaldi Hospital of Naples, we considered 14 consecutive complex ACHD patients (aged 35.9 +/- 16.7 years) who underwent S-ICD implant from February 2015 to June 2020. Mean follow-up was 23 +/- 19.5 months. All the patients showed a good compliance to the device system with no complications (infections or skin erosions). Four patients (1 M/3F aged 38.2 +/- 11.3) were listed for heart transplantation (HTX). Two of these underwent HTX, one died for refractory heart failure (HF) and one is still on the waiting list. Conclusions: There might be a conceivable benefit from an extended use of the S-ICD in selected patients with CHD, especially in those with life-treating ventricular arrhythmias and complex anatomy or patients awaiting HTX. S-ICD appears to be a safe alternative to a transvenous system when a transvenous ICD cannot be implanted and pacing is not required.