Usefulness of P wave-triggered Signal-averaged Electrocardiogram for the Estimation of Paroxysmal Atrial Fibrillation Risk in Cryptogenic Stroke

초록

Backgrounds: Detection of atrial fibrillation(AF) is important especially in cryptogenic stroke. The P wave-triggered signal-averaged electrocardiogram(signal ECG) is useful method for identifying paroxysmal AF risk. However, signal ECG study in stroke patients remains limited. We investigated the role of signal ECG in stroke patients by comparison between cryptogenic stroke and stroke with determined etiology. Methods: We prospectively recruited the acute ischemic stroke patients who admitted from June to September 2012, and underwent routine work up and signal ECG. Patients with known AF at the time of study were excluded. In signal ECG, P wave duration(PWD) and root mean square voltages for the last 20ms (RMS20) were measured. The criteria of RMS20≤3.5&#61549;V and PWD>120ms was defined as atrial late potential. We analyzed the difference in signal ECG between the patients with cryptogenic infarct and those with known stroke etiology. Results: A total of 160 subjects were enrolled. Patients with cryptogenic stroke (n=66) had significantly longer PWD (140&#61617;16ms) and lower RMS20 (2.50&#61617;1.91&#61549;V) compared to the subjects with known etiology (n=94; PWD 123&#61617;17ms, RMS20 3.36&#61617;2.11&#61549;V; P<0.01, respectively). Also the cryptogenic stroke patients showed more frequent atrial late potential than the other patients (80% vs 43%, P<0.01). The atrial late potential group (n=84) was more likely to have stroke involving right insular cortex (16%) than the other group (6%, p=0.05). During follow-up period of 1 & 1/2 year, AF newly appeared in 9.7% in the atrial late potential group and 4.5% in the others.