Temporal trends in the primary prevention of implantable cardioverter-defibrillator selection and long-term outcomes in patients with non-ischaemic dilated cardiomyopathy and ischaemic cardiomyopathy

The effect of primary prevention ICD (ppICD) in non-ischaemic dilated cardiomyopathy (DCM) remains debated. We investigated long-term outcomes and the incidence of ppICD therapy in patients with DCM and ischaemic cardiomyopathy (ICM), comparing implants before and after 2017.

We prospectively included ppICD patients from the multicentre IMPROVE study (2014–2022) with DCM and ICM. All underwent ECG and echocardiography at baseline. The primary outcome was appropriate ICD therapy; the secondary outcome was all-cause mortality. Outcomes were compared pre- and post-2017 in DCM and ICM patients. Among 393 ppICD patients (median age 66, 15% female), 115 had DCM (66 post-2017, 49 pre-2017) and 278 had ICM (165 post-2017, 113 pre-2017). DCM post-2017 patients were younger (54 vs. 64 years, P < 0.01) and had a higher left ventricular ejection fraction (LVEF) (33% vs. 24%, P < 0.001) compared to DCM pre-2017 patients. Nevertheless, ICD therapy [4.0 vs. 3.1/100 person-years (PY), P = 0.57] and all-cause mortality rates (2.0 vs. 4.7/100 PY, P = 0.09) were similar. ICM post-2017 patients had a slightly higher LVEF (31% vs. 29%, P = 0.04), fewer ICD therapies (3.1 vs. 6.2/100 PY, P = 0.01), and similar mortality rates (6.3 vs. 8.3/100 PY, P = 0.18) compared to pre-2017.

Patient selection for ppICD in DCM changed post-2017, with a shift towards younger patients and better LVEF compared to those implanted pre-2017; however, appropriate ICD therapy and all-cause mortality rates remained unchanged. In ICM, lower ICD therapy rates post-2017 may reflect improvement in revascularization and heart failure treatments.

ClinicalTrials.gov Identifier: NCT02286908