Background: The influence of inter-electrode spacing (IES) on complex fractionated atrial electrograms (CFAEs) and dominant frequency (DF) detection was assessed.
Methods: Bipolar electrograms were recorded via an octapolar catheter (2-mm electrode spacing) from left atrial CFAEs sites in 17 atrial fibrillation patients. The CFE-mean was calculated at IES of the electrode pairs 1-2, 1-3, 1-4, 1-5, and 1-6. The DF, regularity index (RI), and organization index (OI) were simultaneously analyzed.
Results: The CFE-mean decreased as the IES increased (from 71 ± 15 ms of IES 1-2 to 61 ± 8 ms of IES 1-3, 57 ± 6 ms of IES 1-4, 57 ± 8 ms of IES 1-5, and 58 ± 9 ms of IES 1-6, respectively; IES 1-2 vs. 1-3 to 1-6, P < 0.01). The DF was unchanged (6.6 ± 1.6 Hz for all; P > 0.99). However, the RI decreased as the IES increased (from 0.30 ± 0.11 to 0.26 ± 0.11, 0.23 ± 0.11, 0.22 ± 0.12, and 0.20 ± 0.12; IES 1-2 vs. 1-3 to 1-6, P < 0.01), as did the OI (from 0.39 ± 0.14 to 0.34 ± 0.12, 0.32 ± 0.13, 0.29 ± 0.13, and 0.28 ± 0.13; IES 1-2 vs. 1-3 to 1-6, P < 0.01).
Conclusions: A wider IES might detect dyssynchronous activations, leading to a reduced CFE-mean and RI and OI. Therefore, bipolar signals recorded with a narrower IES might be preferable to more precisely localizing CFAEs and DF sites.