Abstract WP255: Can Normal Electrocardiogram Rule Out Newly Diagnosed Atrial Fibrillation in Ischemic Stroke Patients

Abstract

Introduction: Electrocardiogram (ECG) findings of premature atrial contraction and prolonged PR interval are associated with risk of onset atrial fibrillation (AF) in cryptogenic stroke. We sought to see if normal ECG and AF incidence is incompletely understood. Methods: From a prospective single-hospital stroke registry from 2018, we identified ischemic stroke patients who had ECG done on admission for review. We excluded patients with AF on admission ECG, history of AF, and implanted device with cardiac monitoring capability. Normal ECG was interpreted based on the standardized reporting guidelines for ECG studies evaluating risk stratification of emergency department patients. Stroke subtype was diagnosed according to the TOAST classification: large artery atherosclerosis (LAA), small vessel occlusion (SVO), cardioembolism, others/undetermined and embolic stoke of undetermined source (ESUS) criteria. We compared the incidence of newly diagnosed AF during hospitalization and from outpatient cardiac event monitoring between normal and abnormal ECG. Results: Of the 558 consecutive acute ischemic stroke patients, we excluded 135 with AF on admission ECG or history of AF and 9 with implanted devices. Of the remaining 414 patients that were included in the study, ESUS (31.2%) was the most frequent stroke subtype, followed by LAA (30.0%), SVO (14.0%), others/undetermined (15.7%), and cardioembolism (9.2%). Normal ECG was observed in 125 patients (30.2%). Cardioembolic subtype was less frequent in the normal versus abnormal ECG group (1.6% vs. 12.5%, p<0.001). New AF was detected in 17/414 patients (4.1%) during hospitalization. Of these 17 patients, none had normal ECG (0/125) and all had abnormal ECG (17/289, 5.9%) (p=0.002). After discharge, of 111 patients undergoing 4-week outpatient cardiac monitoring, new AF was detected in 16 (14.4%). Of these 16 patients, only 1 had a normal ECG (1/35, 2.9%) while 15 had abnormal ECG (15/76, 19.7%) (p=0.02). Conclusions: Normal ECG at admission for acute ischemic stroke is associated with low likelihood of detection of new atrial fibrillation in either the inpatient or outpatient setting.