Signal-averaged P-wave ECG discriminates between persistent and paroxysmalatrial fibrillation

Atrial fibrillation (Afib) has been associated with abnormal signal-average d P wave (SAPW) parameters but whether SAPW is associated with the time cou rse of these arrhythmias (persistent vs. paroxysmal, frequent vs. rare epis odes) remains unknown. This article assesses the significance of SAPW durat ion in distinguishing patients with paroxysmal from those with persistent A fib. SAPW electrocardiogram was performed with a "double triggering" softwa re system for acquisition and analysis of data. SAPW total duration (TD), X , Y, and Z leads magnitudes and vector signal magnitudes were measured offl ine. Optimal cutoff value between control and patient groups was deter mine d by using a receiver operator characteristic curve. Data were analyzed to compare controls with patients groups and between patient groups according to time course of the arrhythmic history. Fifteen age-matched patients with out a history of Afib and 55 patients with a history of Afib (33 with parox ysmal and 22 with persistent arrhythmia) were studied off antiarrhythmic dr ugs. Patients with history of persistent arrhythmia were studied within 2 d ays after electrical cardioversion to sinus rhythm. SAPW TD was the only pa rameter consistently associated with Afib. SAPW TD was 98 +/- 6 ms (mean +/ - SD) in the control group, 127 +/- 19 ms in the pooled patients group (P = .0001); 122 +/- 20 ms for paroxysmal and 133 +/- 17 ms for the persistent Afib group (P = .04). Analysis of other SAPW parameters were not statistica lly significant. SAPW duration is a simple method to identify patients with history of Afib. A significantly longer SAPW TD characterizes patients wit h a history of persistent as opposed to paroxysmal Afib. Prolongation of SA PW TD possibly reflects more advanced electrophysiological changes, creatin g a more stable substrate that leads to persistence of the arrhythmia.