Excessive atrial ectopic activity as an independent risk factor for ischemic stroke

Abstract

Background: Excessive atrial ectopic activity (EAEA) has been related with an increased risk of atrial fibrillation (AF) and stroke but different cutoff values have been used. We aimed to determine the association between EAEA and stroke, AF and overall death.

Methods: Consecutive 24-hour Holter monitoring performed between 2005 and 2010 in a single center was evaluated. Patients with a previous diagnosis of stroke or AF were excluded. The number of premature atrial contractions (PACs) during 24h was analyzed in 2480 subjects and according to that 3 sub-groups were defined: >97PACs/h (above the top 5th percentile of the population) (EAEA+); intermediate value of PACs/h (below the top 5th percentile but above 30PACs/h) (EAEA+/-) and <30PACs/h (EAEA-).

Results: After adjusting for risk factors, laboratory findings and medication, EAEA+ was associated with ischemic stroke (hazard ratio [HR] 2.83; 95% confidence interval [CI], 1.65-4.84, p<0.001). Both EAEA+ and EAEA+/- were independently associated with AF (HR 2.05; 95% CI 1.31-3.23, p=0.010 for EAEA+ and HR 1.90; 95% CI 1.10-2.78, p=0.020 for EAEA+/-) and overall death (HR 2.17; 95% CI 1.48-3.28, p=0.031 for EAEA+; HR 2.01; 95% CI 1.06-2.52, p=0.029 for EAEA+/-).

Conclusion: In this population, having >30PACs/h was independently associated with a higher risk of AF and overall death but only subjects with >97PACs/h had a higher risk of ischemic stroke. In the majority of subjects with stroke and EAEA+, AF has not been detected before stroke event.

Keywords: Atrial fibrillation; Excessive atrial ectopy; Ischemic stroke.