Clinical usefulness of the atrial double potential at the intereaval region in the right atrium - A new index for inducibility of atrial fibrillation in electrophysiologic studies

The second deflection of the atrial double potential (DP) recorded at the intercaval region is considered to reflect the far-field potential of the left atrium. The conduction via the upper interatrial connection was evaluated utilizing this DP and the relationship between atrial fibrillation (AF) and the conduction via the interatrial connection evaluated. In 30 consecutive patients with the DP at the intercaval region, prolongation in the left atrial activation time during the right atrial extra stimulation was measured at the intercaval region (DeltaDP) and the coronary sinus (DeltaCS). The difference between DeltaDP and ACS (DeltaDP-DeltaCS) was used as an index of inhomogeneity in interatrial conduction. The patients were divided into AF (n-13) and non-AF (n=17) groups in accordance with the inducibility of AF in the electrophysiologic study. The max DeltaDP and the max DeltaCS were greater in the AF group than in the non-AF group, i.e., max DeltaDP (43 +/- 19 vs 27 +/- 17 ms. P = 0.021), max DeltaCS (35 +/- 15 vs 21 +/- 14 ms, P = 0.029). The max \DeltaDP-DeltaCS\ was also greater in the AF group than in the non-AF group (19 +/- 12 vs 9 +/- 8 ms, P = 0.019). In accordance with the indices of the interatrial conductions, the delayed or inhomogeneous conductions during the atrial extra stimulation via interatrial connections were more prominent in the AF group than in the non-AF group. Analysis of the DP at the intercaval region might provide a useful index to evaluate the inducibility of AF.