Implantable cardioverter-defibrillator therapy among patients with non-ischaemic vs. ischaemic cardiomyopathy for primary prevention of sudden cardiac death

The magnitude of benefit related to implantable cardioverter defibrillator (ICD) therapy for primary prevention of sudden cardiac death (SCD) in non-ischaemic cardiomyopathy (NICM) and ischaemic cardiomyopathy (ICM) has not been evaluated extensively in clinical practice.

Of the 5539 consecutive patients enrolled in the multicentre Défibrillateur Automatique Implantable–Prévention Primaire (DAI-PP) study (2002–12), 5485 patients (with information on underlying heart disease) were included in the present analysis: 2181 (39.8%) had NICM and 3304 (60.2%) had ICM. ICM patients were older (63.7 ±10.3 vs. 60.6 ± 12.2 years, P < 0.0001), with a higher ejection fraction [27% (25–30) vs. 25% (20–30), P < 0.0001], narrower QRS (37.3% vs. 21.4% with QRS <120, P < 0.0001), and higher prevalence of sinus rhythm (77.3% vs. 74.0%, P = 0.009). During a mean follow-up of 3.1 ± 2.2 years, 814 patients died, giving a mortality incidence of 48.6 per 1000 person-years [95% confidence interval (CI) 45.2–51.9], higher among ICM patients (52.3, 95% CI 47.8–56.7) than in NICM patients (42.4, 95% CI 37.3–47.6; P = 0.008) (adjusted hazard ratio 1.31, 95% CI 1.06–1.61, P = 0.01). The increase in mortality among ICM patients was mainly due to non-cardiovascular mortality (P = 0.0002), whereas incidences of cardiovascular mortality (including ICD-unresponsive SCD) were similar in the two groups. Incidences of appropriate ICD interventions (anti-tachycardia pacing, shocks) were similar, but inappropriate therapies were more frequent in NICM (7.94 vs. 5.96%; P = 0.005).

NICM and ICM patients had a same rate of ICD therapy for primary prevention of SCD in everyday practice. But, ICM patients more often died of a non- cardiovascular cause of death.

NCT 01992458.