Long-Term Outcomes Among a Nationwide Cohort of Patients Using an Implantable Cardioverter-Defibrillator: UMBRELLA Study Final Results

BACKGROUND: Large-scale studies describing modern populations using an implantable cardioverter-defibrillator (ICD) are lacking. We aimed to analyze the incidence of arrhythmia, device interventions, and mortality in a broad spectrum of real-world ICD patients with different heart disorders. METHODS AND RESULTS: The UMBRELLA study is a prospective, multicenter, nationwide study of contemporary patients using an ICD followed up by remote monitoring, with a blinded review of arrhythmic episodes. From November 2005 to November 2017, 4296 patients were followed up. After 46.6 +/- 27.3 months, 16 067 episodes of sustained ventricular arrhythmia occurred in 1344 patients (31.3%). Appropriate ICD therapy occurred in 27.3% of study population. Patients with ischemic cardiomyopathy (hazard ratio [HR], 1.51; 95% CI, 1.29-1.78), dilated cardiomyopathy (HR, 1.28; 95% CI, 1.07-1.53), and valvular heart disease (HR, 1.94; 95% CI, 1.43-2.62) exhibited a higher risk of appropriate ICD therapies, whereas patients with hypertrophic cardiomyopathy (HR, 0.72; 95% CI, 0.54-0.96) and Brugada syndrome (HR, 0.25; 95% CI, 0.14-0.45) showed a lower risk. All-cause death was 13.4% at follow-up. Ischemic cardiomyopathy (HR, 3.09; 95% CI, 2.58-5.90), dilated cardiomyopathy (HR, 3.33; 95% CI, 2.18-5.10), and valvular heart disease (HR, 3.97; 95% CI, 2.25-6.99) had the worst prognoses. Delayed high-rate detection was enabled in 39.7% of patients, and single-zone programming occurred in 52.6% of primary prevention patients. Both parameters correlated with lower risk of first appropriate ICD therapy, with no excess risk of mortality. The rate of inappropriate shocks at follow-up was low (6%) and did not differ among type of ICD but was lower in SmartShock-capable devices. CONCLUSIONS: Irrespective of the cause, contemporary ICD patients with heart failure-related disorders had a similar risk of ICD life-saving interventions and death. Current ICD programming recommendations still need to be implemented.

Automated summary

Large-scale studies on modern populations with implantable cardioverter-defibrillators (ICDs) are lacking. The UMBRELLA study analyzed the incidence of arrhythmia, device interventions, and mortality in a diverse group of real-world ICD patients with different heart disorders. Results showed that patients with certain heart conditions had higher risks of appropriate ICD therapies, while patients with other conditions had lower risks. Regardless of the cause, contemporary ICD patients with heart failure-related disorders had a similar risk of ICD life-saving interventions and death.