PREDICTION OF TRANSITION TO CHRONIC ATRIAL-FIBRILLATION IN PATIENTS WITH PAROXYSMAL ATRIAL-FIBRILLATION BY SIGNAL-AVERAGED ELECTROCARDIOGRAPHY - A PROSPECTIVE-STUDY

Background It is well known that paroxysmal atrial fibrillation (PAF) often precedes the establishment of chronic atrial fibrillation (CAF). However, there have been no definite methods to predict the transitio n from PAF to CAF. The purpose of this report was to determine prospec tively whether P-wave-triggered signal-averaged ECG (P-SAE) is useful for the prediction of the transition to CAF in patients with PAF. Meth ods and Results One hundred twenty-two consecutive patients with PAF w ere prospectively followed after P-SAE, echocardiography, and 24-hour Holter monitoring at study entry. The duration (Ad) and root-mean-squa re voltage for the last 30 ms (LP30) of the filtered P wave were measu red in P-SAE. The abnormality of P-SAE for the prediction of transitio n to CAF was defined as Ad greater than or equal to 145 ms and LP30 <3 .0 mu V. Twenty-three (19%; group 1) of the patients had the abnormali ty of P-SAE, whereas the others (group 2) did not. During the follow-u p period (mean, 26+/-12 months), 10 patients (43%) in group 1 acquired CAF, whereas the transition to CAF was observed in only 4 patients (4 %) in group 2. Kaplan-Meier analysis revealed that the transition to C AF was significantly observed more often in group 1 than in group 2 (l og-rank test, P<.0001). The Cox proportional hazards regression model identified that the variables most significantly associated with the t ransition to CAF were Ad (chi(2)=8.6, P=.003) and LP30 (chi(2)=5.1, P= .02), although significant differences in the left atrial dimension (4 0.8+/-5.3 versus 37.3+/-5.5 mm, P<.01) and the number of atrial premat ure contractions (3641+/-4524 versus 1489+/-2895 beats/d, P<.05) were observed between groups 1 and 2. Conclusions These results indicate th at P-SAE could be useful to identify patients at risk for the transiti on from PAF to CAF.