Long-term Clinical Outcomes of Implantable Cardioverter Defibrillator Recipients in New Zealand

Abstract

The long-term clinical outcomes of implantable cardioverter defibrillator (ICD) recipients across New Zealand are unknown. This study provides a detailed analysis of long-term clinical outcomes of ICD recipients in New Zealand over the past decade. All patients with an ICD implant between 2010 and 2019 were identified using the National Minimum Dataset, which collects all public hospital admissions in New Zealand using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD10-AM) procedure coding. There were 4,261 patients with a mean follow-up of 4.85±2.76 years. There were 1,739 (40.8%) primary prevention and 2,522 (59.2%) secondary prevention ICD recipients. The median age was 62 years and 78.9% were male. There was no significant difference in all-cause mortality between primary prevention or secondary prevention ICD recipients (21.7% vs 21.9%, p=0.99). In the primary prevention ICD group, heart failure (HF) hospitalisation more frequently occurred (32.7% vs 26.1%, p<0.001) but hospitalisations with ventricular arrhythmia (VA) were less common (16.7% vs 27.1%, p<0.001). Compared with ICD recipients with non-ischaemic aetiology for HF, those with ischaemic HF had higher all-cause mortality (30.0% vs 16.1%, p<0.001), HF hospitalisation (38.0% vs 22.4%, p<0.001), and hospitalisation with VA (27.9% vs 19.4%, p<0.001). In New Zealand ICD recipients, there was no difference in all-cause mortality between primary prevention and secondary prevention ICD implants. However, ICD recipients with ischaemic aetiology for HF had significantly higher all-cause mortality, HF hospitalisation, and hospitalisation with VA.