Contemporary outcomes of implantable cardioverter defibrillator patients on amiodarone

Patients with implantable cardioverter defibrillators (ICDs) frequently experience shocks due to arrhythmias. Current treatment options include ventricular tachycardia (VT) ablation, clinical follow-up, and antiarrhythmic medications like amiodarone. However, outcomes for patients initiated on amiodarone with an ICD in place remain unclear.

This study aims to evaluate the clinical outcomes of ICD patients who are treated with amiodarone for arrhythmia management.

We conducted a retrospective review of all patients who received a cardiac implantable electronic device (CIED) at our institution from January 1, 2007, to December 30, 2023. Patients who were on amiodarone and had documented VT were selected for analysis. Comorbidities and clinical outcomes, including arrhythmia recurrence and complications, were extracted from the electronic medical records (EMR).

A total of 487 patients with ICD-capable devices were identified as having ventricular tachycardia (VT) and being treated with amiodarone. 287 patients had both one-year follow-up and a complete dataset (mean age 71±10, 294 male). 88 patients had cardiac resynchronization therapy capable device with an average ejection fraction of 20% ± 18%. Of these patients, 214 (58%) had ischemic heart disease, and 63 (17%) initiated amiodarone therapy due to VT storm. Furthermore, 92 patients (32%) underwent VT ablation (RF or radio-ablation). Average duration of amiodarone therapy was 56 months (range 1 – 244 months). 177 (61%) patients had recurrent VT requiring ATP or shock after amiodarone initiation. Beta-blockers were used by 335 patients, flecainide by 1, mexiletine by 5, and sotalol by 23. At the one-year follow-up, 85 (29%) patients had discontinued amiodarone.

Patients with ICDs initiated on amiodarone for VT management are likely to remain on the medication at the one-year mark, indicating limited discontinuation despite potential side effects and alternative treatment options. Further investigation is warranted to explore factors influencing long-term amiodarone use in this population.