Troponin-I Is a Predictor of a Delayed Diagnosis of Atrial Fibrillation in Acute Ischemic Stroke and Transient Ischemic Attack

Abstract

Prolonged cardiac monitoring detects higher rates of atrial fibrillation (AF) in ischemic stroke and transient ischemic attack (TIA) but is costly and has practical implications. The use of admission troponin-I (TnI) level to identify patients at high risk of delayed AF detection was investigated. Consecutive ischemic stroke and TIA cases presenting to our institute over a 13-month period were identified from the Irish Stroke and TIA Register. Electronic databases and case notes were examined. "Delayed" AF was diagnosed after a sinus rhythm admission electrocardiogram and no documented history. Group comparisons were made by AF status. The association between TnI and AF was investigated using a multivariate regression model. A total of 185 cases (130 ischemic stroke) were analyzed. Mean age (standard deviation) was 73.3 (13.9) years, 47% female. Sixty-two cases (33.5%) had AF. The first documented presentation of AF was found in 21 cases, on admission electrocardiogram (n = 11) or inpatient telemetry (delayed, n = 10). TnI was higher in those with delayed AF than in those without AF (W = 194; P = .036). A higher proportion of those with an elevated TnI (30%) than those with a normal TnI (6.1%) had delayed diagnosis of AF (χ(2) = 6.41, P = .011). Having an abnormal TnI was a significant independent predictor of delayed AF detection (odds ratio, 5.8; P = .037). TnI elevation is associated with a higher likelihood of subsequent AF diagnosis. Identification of these higher risk stroke and TIA cases for more intensive cardiac monitoring may improve stroke secondary prevention practices.