Arrhythmia and Survival Outcomes among Black and White Patients with a Primary Prevention Defibrillator.

Background: Black Americans have a higher risk of non-ischemic cardiomyopathy (NICM) than White Americans. We aimed to evaluate racial disparities in the risk of tachyarrhythmias among patients with an implantable cardioverter defibrillator (ICD).

Methods: The study population comprised 3,895 ICD recipients enrolled in the U.S. in primary prevention ICD trials. Outcome measures included first and recurrent ventricular tachy-arrhythmia (VTA) and atrial tachyarrhythmia (ATA), derived from adjudicated device data, and death. Outcomes were compared between self-reported Black vs. White patients with a cardiomyopathy (ischemic [ICM] and NICM).

Results: Black patients were more likely to be female (35% vs 22%) and younger (57±12 vs 62±12) with a higher frequency of comorbidities. Blacks patients with NICM compared with Whites patients had a higher rate of first VTA, fast VTA, ATA, appropriate-, and inappropriate-ICD-therapy (VTA≥170bpm: 32% vs. 20%; VTA≥200bpm: 22% vs. 14%; ATA: 25% vs. 12%; appropriate 30% vs 20%; and inappropriate: 25% vs. 11%; p<0.001 for all). Multivariable analysis showed that Black patients with NICM experienced a higher risk of all types of arrhythmia/ICD-therapy (VTA≥170bpm: HR=1.69; VTA≥200bpm: HR=1.58; ATA: HR=1.87; appropriate: HR=1.62; and inappropriate: HR=1.86; p≤0.01 for all), higher burden of VTA, ATA, ICD therapies, and a higher risk of death (HR=1.86; p=0.014). In contrast, in ICM, the risk of all types of tachyarrhythmia, ICD therapy, or death was similar between Black and White patients.

Conclusions: Among NICM patients with an ICD for primary prevention, Black compared with White patients had a high risk and burden of VTA, ATA, and ICD therapies.

Clinical Perspective: Black patients have a higher risk of developing non-ischemic cardiomyopathy (NICM) but are under-represented in clinical trials of implantable cardioverter defibrillators (ICD). Therefore, data on disparities in the presentation and outcomes in this population are limited.This analysis represents the largest group of self-identified Black patients implanted in the U.S. with an ICD for primary prevention with adjudication of all arrhythmic events. In patients with a NICM, self-identified Black compared to White patients experienced an increased incidence and burden of ventricular tachyarrhythmia, atrial tachyarrhythmia, and ICD therapies. These differenced were not observed in Black vs White patients with ischemic cardiomyopathy (ICM).Although Black patients with NICM were implanted at a significantly younger age (57±12 vs 62±12 years), they experienced a 2-fold higher rate of all-cause mortality during a mean follow up of 3 years compared with White patients.These findings highlight the need for early intervention with an ICD, careful monitoring, and intensification of heart failure and antiarrhythmic therapies among Black patients with NICM.