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. Author manuscript; available in PMC: 2019 Jun 7.
Published in final edited form as: Circ Arrhythm Electrophysiol. 2018 Mar;11(3):e005659. doi: 10.1161/CIRCEP.117.005659

Figure 4. Optical mapping and postpacing spontaneous focal discharges (SFDs) in a Langendorff-perfused 8-d left atrial myocardial infarction ovine heart.

Figure 4.

A, Left atrial photographic snapshot (left) and corresponding RH237-fluorescence background snapshot (right) delineating the nonischemic zone (NIZ) and ischemic zone (IZ). B, Left atrial appendage (LAA) electrogram during sinus rhythm (SR), 10-s pacing at 175 ms cycle length and post-pacing (red line). The movie recording was started ≈1 s before the end of the 10-s pacing train. In this representative example, the pacing train elicited 4 postpacing SFDs: 1 from the LAA IZ-border and 3 from the posterior left atrial (PLA) IZ region. C, Simultaneous membrane voltage and calcium transients (Vm/Cai) single-pixel time sequence at the site of onset of a representative LAA IZ SFD. During pacing, the Ca2+ transient follows Vm. However, the SFD Ca2+ transient precedes Vm. D, Top, Average number of postpacing SFDs before and after isoproterenol (ISO) and before and after dantrolene in 7 hearts. Bottom, Rate dependency of SFDs. Most of the SFDs occurred at the pacing interval of 175 ms. At the 150-ms interval, the pacing often induced atrial fibrillation. E, Sequential Vm snapshots of the LAA IZ SFDs onset. The IZ origin of the SFD is best seen at 0, 8, 16, and 22 ms. Vm/Cai: Membrane voltage and calcium transients. *P<0.05.