Key result
Proximal coronary sinus involvement in typical atrial flutter was identified in 8 of 20 patients, who exhibited more fragmented CS atrial potentials (106 vs 58.5 ms; P<0.001) than those without.
Why the study?
Is the proximal coronary sinus involved in the circuit of typical atrial flutter?
Observational (n=20)
Is the proximal coronary sinus involved in the circuit of typical atrial flutter?
The proximal coronary sinus is involved in the typical atrial flutter circuit in a subset of older patients with right atrial scar and fragmented CS atrial potentials, potentially acting as a secondary circuit.
AIM: It is commonly conceived that coronary sinus (CS) participates in atrial flutter (AFL) circuit but limited to the fibers surrounding its ostium. We evaluated the involvement of proximal CS in typical AFL. METHODS: Twenty AFL patients underwent entrainment mapping using postpacing interval minus AFL cycle length (PPI-AFL CL) including CS where a decapolar catheter was positioned with proximal bipole 1 cm from the ostium. RESULTS: We compared patients with proximal CS within the circuit (group 1, PPI-AFL CL ≤ 20 ms + concealed entrainment) and those without (group 2, PPI-AFL CL > 20 ms). Group 1 patients were older, 77.5 ± 4 vs 71 ± 12 years (P < 0.05). No difference was found in AFL CL, PPI-AFL CL at cavotricuspid isthmus (CTI) entry, plateau, and septal site. Group 1 patients had shorter PPI-AFL CL at proximal CS (9 ± 3 vs 40 ± 15 ms; P < 0.001) and fragmented mesodiastolic CS atrial potentials (APs) (106 ± 27 vs 58.5 ± 22 ms; P < 0.001). A mid-septal unexcitable scar was found in five of eight group 1 patients vs one of 12 group 2 patients (P < 0.05). All were ablated at CTI. A patient had AFL recurrence and underwent a second attempt: PPI-AFL CL was 60 ms at CTI entry and less than or equal to 20 ms at septal CTI and proximal CS; AFL was terminated 1 cm inside CS, applying RF at a fragmented AP. CONCLUSION: Proximal CS appears to be involved in a substantial subset of typical AFL patients, in whom advanced age, fragmented CS APs, and the presence of right atrial scar are prevalent. Proximal CS might be considered as an un-"innocent by-stander," but able, in rare cases, to generate a second AFL circuit.
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Sisti et al. (2018) conducted an observational in Typical atrial flutter (n=20). Proximal coronary sinus within the circuit vs. Proximal coronary sinus not within the circuit was evaluated on Fragmented mesodiastolic CS atrial potentials (APs) (p=<0.001). Proximal coronary sinus involvement in typical atrial flutter was identified in 8 of 20 patients, who exhibited more fragmented CS atrial potentials (106 vs 58.5 ms; P<0.001) than those without.
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