Detection of Occult Paroxysmal Atrial Fibrillation in Stroke Patients Using High Resolution Electrocardiography

Background: Paroxysmal atrial fibrillation (AF) is highly prevalent in patients with ischemic stroke, but the diagnosis is often difficult. Methods: This study consisted of 61 stroke patients in sinus rhythm without a history of paroxysmal AF. All patients underwent P-wave signal-averaged electrocardiography (P-SAECG), echocardiography, 24-hour Holter monitoring, and measurement of plasma B-type natriuretic peptide (BNP) concentrations at admission. Results: An abnormal P-SAECG was found in 33 of 61 stroke patients. In the follow-up period of 11±3 months, paroxysmal AF developed in 19 patients (AF group). The remaining 42 patients were divided into non-AF group. An abnormal P-SAECG and frequent premature atrial contractions (PACs, 100 or more/24 hour) were detected more frequently in patients with AF group than non-AF group (89.5% vs 35.7%; p<0.001, 84.2% vs 26.2%; p<0.001, respectively). However, there were no significant differences in age, left atrial dimension, BNP concentrations between both groups. Cox proportional hazards analysis revealed that an abnormal P-SAECG (hazard ratio 21.3; p=0.003) and frequent PACs (hazard ratio 4.6; p=0.046) had significant correlation to the development of paroxysmal AF. Conclusions: An abnormal P-SAECG and frequent PACs may be novel predictors of paroxysmal AF in stroke patients. P-SAECG should be considered in stroke of undetermined etiology.