The natural history of multifocal atrial rhythms in elderly outpatients: insights from the "Ikaria study".

Background: Multifocal atrial tachycardias confer an adverse prognosis in hospitalized patients. We assessed the prognostic impact of multifocal atrial rhythms (MARs-either chaotic atrial rhythm or multifocal atrial tachycardia/bradycardia) in very elderly outpatients.

Methods: One hundred ten subjects aged 60-74 years, 112 aged 75-89 years, and 61 over 90 years old, were enrolled and prospectively evaluated. Several demographic and clinical characteristic were recorded in all individuals.

Results: A high prevalence of MARs was detected in the study population (namely, 6%), which in subjects >90 years was even higher (15%). Individuals with MARs were older, more often female and less active. In multivariate analysis, independent predictors of MARs were age (OR = 1.07, 95% CI: 1.02-1.13, P = 0.01) and female sex (OR = 4.77, 95% CI: 1.23-18.48, P = 0.02). The mortality rate during the follow-up period was 8.4% without differences between age groups (P = 0.209). In particular, mortality rate was 6% in individuals with MARs and 9% in those without (P = 0.72). Mortality was associated with age (OR 1.07, 95% CI: 1.02-1.12, P = 0.005) and history of cardiovascular disease at baseline (OR 4.57, 95% CI: 1.87-11.2 P = 0.001).

Conclusions: Contrary to hospitalized individuals with multifocal atrial tachycardias, MARs were not associated with increased mortality in elderly outpatients in this study.