A novel marker of repolarization may identify patients with cardiomyopathy who would benefit from an implanted cardioverter defibrillator, according to a European research study presented at the annual congress of the European Society of Cardiology and published simultaneously in The Lancet.
High periodic repolarization dynamics were linked to substantial reductions in mortality in a prespecified substudy of the EU-CERT-ICD (European Comparative Effectiveness Research to Assess the Use of Primary Prophylactic Implantable Cardioverter Defibrillators).
The degree of periodic repolarization dynamics correlated with reductions in mortality in the 1,371 patients, 968 of whom had ICD implantation and 403 of whom were treated conservatively, in the prospective, nonrandomized controlled cohort study conducted at 44 centers in 15 countries within the European Union. At a median follow-up of 2-7 years, the ICD group had a mortality rate of 14%; at a follow-up of 1-2 years, the control group had a mortality rate of 16%, resulting in a 43% overall reduction in mortality for the ICD group.
Low periodic repolarization dynamics were associated with a low reduction in ICD-related death, whereas high periodic repolarization dynamics were linked to substantial reductions in mortality. In 199 patients with periodic repolarization dynamics of 7.5% or higher, ICD implantation resulted in a 75% reduction in death, compared with controls. Periodic repolarization dynamics also served as reliable predictors of appropriate shocks in patients with ICDs as well as death in controls.
Because of the link between high periodic repolarization dynamics and greater benefits, cardiologists may be able to use the measure as a marker to individualize treatment decisions about the use of ICDs, said Axel Bauer, MD, director of University Hospital for Internal Medicine III, Cardiology and Angiology at Medical University Innsbruck, Austria, and coauthors. “Better patient selection could lead to a reduced number of devices needing to be implanted to save a life.
“Our results should help patients to make decisions about their treatment that take into account individual circumstances and preferences,” the researchers noted.