Fig. 3.
Complete absence of LDCAE in AF dogs during isoproterenol infusion. (A) Isoproterenol response of normal dogs. In normal dogs, isoproterenol increased the heart rate and shifted the leading pacemaker site to the superior SAN with robust LDCAE (arrows). (B) Isoproterenol response of AF dogs. The LDCAE was complete absent in AF dogs during isoproterenol infusion. (a) RA Vm isochronal map. (b) Cai tracings from superior (S), mid (M), and inferior (I) SANs. (c) SAN LDCAE isochronal map. The unit of numbers on RA Vm isochronal map is ms. The earliest activation of RA was considered as 0 ms. This figure was reproduced with permission from Joung, et al.32,33 SAN, sinoatrial node; AF, atrial fibrillation; RA, right atrium; LDCAE, late diastolic Cai elevation.