UMBRELLA: Risk for ICD shock delivery, death may vary across disease subtypes
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Among patients with an implanted cardioverter defibrillator, risk for appropriate ICD interventions and death varied by disease subtype, according to findings from the UMBRELLA study.
“This contemporary nationwide study involved a broad ICD population with long-term follow-up,” Sem Briongos-Figuero, MD, European Heart Rhythm certified cardiac device specialist at the Servicio de Cardiología at the Hospital Universitario Infanta Leonor in Madrid, and colleagues wrote. “We observed a decrease in the incidence of sustained ventricular arrhythmias, appropriate ICD therapies, inappropriate shock and death compared with previous observational and randomized studies. Patients with myocardial substrate derived from an impaired LVEF were at higher risk of appropriate ICD interventions and death than those with channelopathies and hypertrophic cardiomyopathy.”
The UMBRELLA study was a prospective, multicenter, nationwide study of 4,296 contemporary patients who received an ICD and followed up via remote monitoring that evaluated the incidence of arrhythmia, device interventions and mortality among patients with varying cardiac disorders.
During an average follow-up of 46.6 months, 31.3% of the cohort experienced episodes of sustained ventricular arrhythmia, and appropriate ICD therapy occurred in 27.3% of the study population.
The cumulative incidence of sustained ventricular arrhythmia was 23% at 1 year (95% CI, 22-24), 34% at 3 years (95% CI, 33-35) and 54% at 6 years (95% CI, 53-55), according to the study.
Appropriate ICD therapy was delivered in 85.7% of episodes of sustained ventricular arrhythmia among 1,173 patients. In addition, 58.4% of episodes of the untreated sustained ventricular arrhythmia occurred in a monitor zone and the remaining 41.6% of episodes terminated before delivery of the programmed therapy.
All-cause death was 13.4% at follow-up.
Greater risk for appropriate ICD therapy was observed among patients with ischemic cardiomyopathy (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).
Individuals with hypertrophic cardiomyopathy (HR = 0.72; 95% CI, 0.54-0.96) or Brugada syndrome (HR = 0.25; 95% CI, 0.14-0.45) were found to have a lower risk for therapy delivery.
Moreover, patients with ischemic cardiomyopathy (HR = 3.09; 95% CI, 2.58-5.9), dilated cardiomyopathy (HR = 3.33; 95% CI, 2.18-5.1) and valvular heart disease (HR = 3.97; 95% CI, 2.25-6.99) had the worst prognoses for survival compared with patients with other heart diseases.
“A better sudden cardiac death risk stratification is necessary in primary prevention ICD patients with channelopathies and inherited cardiomyopathies,” the researchers wrote. “A strategy based on delayed high-rate detection and single-zone programming still needs to be implemented in modern-era patients using an ICD.”
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