RESUMO
BACKGROUND: Left atrial scarring is recognised as a critical component in the maintenance of atrial fibrillation and is associated with the failure of interventional treatment. Diminished bipolar voltage (LV) has been proposed as a useful tool for left atrial scar quantification. We hypothesised that, due to its anatomic location, signals on the coronary sinus catheter might be used to predict the amount of left atrial low voltage. METHODS AND RESULTS: A total of 124 patients (42% women, average age 66 ± 9 years) were included. Forty-one with paroxysmal and 83 with persistent atrial fibrillation. Left atrial low-voltage (<0.5 mV, measured during sinus rhythm) area size and distribution varied considerably among the included patients (mean: 34.9%; maximum: 94.6%; minimum: 0.4%). Spearman correlation revealed a strong negative correlation between bipolar voltage of the signals on the coronary sinus catheter and the amount of left atrial scarring (R = -0.778, p < .0001). The optimal CS voltage cut off for prediction of left atrial low-voltage size of ≥50% was 1.9 mV with an area-under-the receiver-operating-characteristic (ROC) curve of 0.982, a sensitivity of 97% and a specificity of 98%. CONCLUSIONS: There is a strong negative correlation between the size of left atrial low-voltage areas (LVA) and coronary sinus signal amplitude. With increasing left atrial LVA size, CS signal amplitudes decrease, and vice versa. On the basis of these findings, average CS signal amplitudes of ≤1.9 mV can be used as a predictor for a left atrial low-voltage size of ≥50%.
RESUMO
AIMS: In persistent atrial fibrillation (AF), left atrial low-voltage areas and complex fractionated atrial electrograms (CFAEs) have been thoroughly discussed as critical substrate points for AF perpetuation. Thus, in patients undergoing pulmonary vein isolation, these sites are often considered additional ablation targets. Currently, mapping techniques for these substrate indicators are still under discussion. The aim of this study was to evaluate the impact of different mapping catheters on the detection of low-voltage areas and CFAE. METHODS AND RESULTS: Two bipolar voltage maps and two CFAE left atrial maps were obtained each in 30 patients undergoing catheter ablation of AF using the following two different catheters: A four-pole ablation catheter (MAP, mapping and ablation catheter) (electrode size: tip: 4 mm, band: 1 mm; inter-electrode spacing: 0.5-5-2 mm) and a 10-pole circular pulmonary vein mapping catheter (CMC) (electrode size: 1 mm; inter-electrode spacing: 7-7-7 mm). Successively, low-voltage and CFAE area sizes were then compared between the two catheters. Areas with a bipolar voltage of <0.5 mV were significantly smaller when obtained with the CMC compared with the MAP (8.9 ± 8.9 vs. 17.4 ± 11.7 cm², P < 0.001). This was also significantly different for a bipolar voltage of <0.2 mV (2.3 ± 4.6 vs. 6.2 ± 9.6 cm², P < 0.001). Complex fractionated atrial electrogram area sizes were significantly larger when obtained with the CMC compared with the MAP group (14.6 ± 10.9 vs. 19.4 ± 9.4 cm², P = 0.011). CONCLUSION: Low-voltage and CFAE area size varies significantly between different mapping catheters. Mapping electrode settings have to be taken into consideration for the assessment of electroanatomical substrate of AF.