Please click here to obtain permission to reproduce this image.
Click on image to view larger version.
Figure 2 Assessment of PV ERP by Programmed Stimulation
(Top) Fluoroscopic view of the catheter setting during a programmed stimulation of a left superior pulmonary vein (LSPV). The circumferential mapping catheter (Lasso [LS]) is placed at an ostial position of the LSPV while the ablation catheter (Map) is placed distally from the Lasso catheter within the LSPV. (Middle and bottom) Intracardiac tracings of the programmed stimulation within the LSPV after the exposure to atrial fibrillation (catheter setting as mentioned above). Stimulation is conducted through the ablation catheter (Map). The stimulation is performed with a basic drive cycle length of 440 ms, and a single extrastimulus is automatically decremented in steps of 10 ms until reaching the ERP. (1) At a coupling interval of 280 ms, the delay between S2 and the atrial farfield potential (AFF) is 140 ms. This delay continuously increases with further shortening of the extrastimulus coupling interval with a maximal increment of 300 ms induced by programmed stimulation with the shortest coupling interval with local capture of the PV musculature (S1/S2 to 110 ms). Of note, the S2 to PV potential interval also increases with shortening of the coupling interval. The ERP of the LSPV is reached at a coupling interval of 100 ms, which is markedly shorter as compared with the ERP before the atrial fibrillation exposure (250 ms). CS = coronary sinus; HRA = high right atrium; PVP = pulmonary vein potential; II, III, and V1 = surface electrocardiogram leads; other abbreviations as in Figure 1.
|
