The ectopy-triggering ganglionated plexuses in atrial fibrillation

Figures

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  Fig. 1. Intracardiac electrograms of synchronised HFS at a GP site. Pacing and HFS were delivered from Map distal. A) Pacing before the onset of HFS did not cause Wenckebach (620 ms). HFS was delivered after the fourth paced beat. There was a progressive RR prolongation during HFS until 3.9 sec asystole. RR interval recovered after cessation of HFS. No atrial ectopy or arrhythmia was observed. Therefore, this site was tagged as “AVD-GP”. B) Pacing before the onset of HFS did not cause Wenckebach (528-536 ms). There was a progressive RR prolongation during HFS until it reached 1066 ms; almost twice as long as the RR interval before HFS. An atrial ectopy was triggered after the 7th train of HFS. Therefore, this site was tagged both as “ET-GP” and “AVD-GP”. C) Continuation from the trace in B). AV block continued in 2:1 block fashion after the initial ectopy in B). Another ectopy was triggered after the 20th train of HFS, which induced AF. However, this second ectopy and AF induction may have been secondary to HFS capturing the myocardium due to shortening of the atrial refractory period following the initial atrial ectopy triggered in Fig. 1C. D) Sequential PV ectopy activation with ET-GP…

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  Fig. 2. Intracardiac electrograms of the range of responses to HFS at ET-GP. All examples are from one patient. Map distal was used to pace and deliver HFS. Its positions in the LA at the time of stimulation are shown in the PA views of the CARTO™ geometry. The PV catheter was in the lower branch of the left common PV for all three ET-GP sites. A) The Map catheter was positioned in the mid-roof, near to the posterior wall of the LA. After the first paced beat, the subsequent trains were synchronised HFS. The earliest ectopy activation was in PV 13–14. There were just two beats of the same ectopy before stopping both HFS and pacing. B) The Map catheter was positioned near the anterior ostium of the upper branch of the left common PV. After the first paced beat, the subsequent trains were synchronised HFS. Again, the earliest ectopy activation was seen in PV 13–14. The PV rapidly fired causing few seconds of AF that regularised towards the end then terminated. C) The Map catheter was positioned at the posterior ostium of the lower branch of the left common PV. This trace shows the first paced beat followed by one synchronised HFS train which triggered ectopy. The earliest ectopy activation…

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  Fig. 3. Intracardiac recordings of ET-GP response reproducibility with synchronised HFS. A and B are from the same patient. C and D are from two different patients. In all the examples, pacing and HFS are delivered from the Map catheter. A) In the left panel, a second train of HFS produced a PV ectopy which repeated itself after two further HFS. This response was reproducible upon re-testing the same site with HFS in the right panel. The PV ectopy in the right panel has different activation pattern to the left panel PV ectopy. The Map catheter was in the left side of the mid-posterior wall. The PV catheter was in the LIPV. B) In the same patient as A), a different site was tested with HFS in the left panel. This produced a PV ectopy after the 4th train of HFS, which repeated after 2 further HFS trains. Upon re-testing the same site with HFS, the right panel shows an early PV ectopy in PV 17–18 which initiated rapid PV discharges, causing 3.5 s of AF. The Map catheter was near the base of the LIPV in the posterior wall, 10 mm superior to the Map position from A). The PV catheter was in the LIPV. C) In a different patient to A/B), a PV ectopy initiated after several trains of HFS which…

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  Fig. 4. The probability distribution atlas of ET-GPs. The probabilities are between 0 and 45%, white to dark purple. “High probability ET-GP sites” were defined as >30% in probability, labelled with yellow dots on the atlas. This corresponds to the upper third probability (30–45%) of ET-GP. The highest probability of finding ET-GPs were in the roof and around the PV ostia. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)