Catheter Ablation -> SVT/AVNRT/WPW/AT: -> Mapping & Imaging D-PO05 - Poster Session V (ID 39) Poster

D-PO05-174 - Sinoatrial Conduction In Humans With Structural Heart Disease: Impact Of Overdrive Suppression On Arrhythmogenesis From An Endocardial-epicardial Perspective (ID 1294)


Background: The 3-dimensional nature of SAN function has not previously been characterised in the intact human heart
Objective: To characterise the 3-dimensional nature of SAN function (including activation and conduction patterns and signal complexities) in patients with SHD undergoing cardiac surgery using simultaneous endocardial-epicardial phase mapping
Methods: Simultaneous intra-op endo-epicardial SAN mapping was performed during sinus rhythm at baseline (SRbaseline) and post-overdrive suppression at 600ms (SRpostpace 600) and 400ms (SRpostpace 400) using two HD Grid catheters (16 electrodes, 3mm inter-electrode spacing). Uni- and bipolar EGM’s were exported for analyses. Dynamic phase maps were analyzed to determine activation exits and wavefront propagation and EGM fractionation between endocardial and epicardial surfaces were compared during the three rhythms
Results: Sixteen patients with SHD were included. Majority of activations exited cranially from the sinus node region at baseline (87.5%). With overdrive suppression, the frequency of caudal exits increased compared to baseline (SRpost-pace 600: Endo 12.5%, p=0.146; Epi: 31.2%, p <0.0001, SRpost-pace 400: Endo 18.8%, p=0.009, Epi: 31.2%, p <0.0001), wavefront activation sequence was more frequently asymmetrical (SRpost-pace 600: 17.9 vs 12.5%, p=0.006; SRpost-pace 400: 23.9 vs 12.5%, p<0.0001) and EGM’s were more frequently fractionated. All activations were unifocal at baseline and with overdrive suppression.
Conclusion: Sinus node mapping at baseline and post overdrive suppression showed unicentric activation, asymmetric wavefront propagation with preferential caudal activation exits and EGM fractionation in patients with SHD. These functional characteristics provides mechanistic insights for arrhythmogenesis in this cohort.