Subclinical atrial fibrillation in patients with recent transient ischemic attack

Atrial fibrillation (AF) is a major risk factor of stroke, but the association between AF and transient ischemic attack (TIA) is less clear. Despite this, patients with TIA are included in stroke trials.

To determine the 1-year incidence of AF in TIA patients using an insertable cardiac monitor (ICM); second, to determine factors associated with incident AF in these patients.

Prospective cohort study of patients with TIA with normal standard electrocardiogram (ECG) and 72-hour Holter monitoring (HM). Exclusion criteria were as follows: age < 18 or > 81 years; prior AF/stroke; ongoing oral anticoagulation therapy or contraindication for it; significant carotid artery stenosis; uncertain TIA diagnosis. Eligible patients received an ICM and were followed for 12 months.

From November 2013 to October 2015, 809 patients were diagnosed with TIA. In total, 235 patients were eligible. Nine (3.8%) of these had AF on standard ECG or HM. Of the remaining patients, 121 refused ICM implantation. In total, 105 patients (median age 65.4 years [range 27.1-80.8], 46% males) received an ICM, which revealed AF in 7 (6.7%). Factors associated with new-onset AF were a history of recurrent TIA (odds ratio [OR] 11.5, 95% confidence interval [CI] 2.1-63.6) and heart failure (OR 12.7, 95% CI 1.71-96.83).

The 1-year incidence of AF in TIA patients with normal ECG and HM was 6.7% using an ICM. Factors associated with development of AF were recurrent TIA and heart failure.