ABSTRACT
Objective:To explore the value of using bipolar electrogram to guide target selection in patients with frequent premature ventricular contractions in the right ventricular outflow tract (RVOT-PVC).Methods:The clinical data of 115 patients with idiopathic and frequent RVOT-PVC from October 2018 to January June 2020 in Guangzhou First People′s Hospital were retrospectively analyzed. The number of PVCs in Holter 24 h before ablation was 19 802.6±4916.7, and the load was (20.3±5.0)%. The Johnson & Johnson Carto 3.0 system was used to guide RVOT-PVC radiofrequency ablation, and the morphological characteristics of the bipolar electrogram in the cavity of the successful ablation target were observed. According to whether the starting part of the bipolar electrogram of the distal ablation catheter showed a steep negative shape recorded by the Carto 3.0 system, the patients were divided into positive group and negative group. The differences in ablation success rate, effective discharge time, total ablation time and other indicators of the two groups were compared.Results:Steep negative wave was recorded in the initial part of the effective target site of 87 patients (75.7%). The ablation success rate of the patients was 95.4%(83/87) based on the excitation mapping and unipolar morphology combined with the above initial part of the bipolar electrogram. Compared with the negative group, the PVC disappeared faster in patients of positive group [(6.9±2.3)s vs (10.2±2.9)s, P<0.05] and the total ablation time was shorter [(187.5±35.7)s vs (267.3±54.1)s, P<0.05]. Ambulatory electrocardiogram (ECG) was rechecked at 3 months. At 3 months, there was 1 case recurrence in the positive group and 1 case recurrence in the negative group, and there was no significant difference in the long-term recurrence rate between the two groups ( P=0.422). Conclusions:On the basis of traditional mapping, the bipolar electrogram combined with the steep negative shape of the initial part can be used as an alternative RVOT-PVC ablation strategy.
ABSTRACT
Although 3D-complex fractionated atrial electrogram (CFAE) mapping is useful in radiofrequency catheter ablation for persistent atrial fibrillation (AF), the directions and configuration of the bipolar electrodes may affect the electrogram. This study aimed to compare the spatial reproducibility of CFAE by changing the catheter orientations and electrode distance in an in-silico left atrium (LA). We conducted this study by importing the heart CT image of a patient with AF into a 3D-homogeneous human LA model. Electrogram morphology, CFAE-cycle lengths (CLs) were compared for 16 different orientations of a virtual bipolar conventional catheter (conv-cath: size 3.5 mm, inter-electrode distance 4.75 mm). Additionally, the spatial correlations of CFAE-CLs and the percentage of consistent sites with CFAE-CL<120 ms were analyzed. The results from the conv-cath were compared with that obtained using a mini catheter (mini-cath: size 1 mm, inter-electrode distance 2.5 mm). Depending on the catheter orientation, the electrogram morphology and CFAE-CLs varied (conv-cath: 11.5±0.7% variation, mini-cath: 7.1±1.2% variation), however the mini-cath produced less variation of CFAE-CL than conv-cath (p<0.001). There were moderate spatial correlations among CFAE-CL measured at 16 orientations (conv-cath: r=0.3055±0.2194 vs. mini-cath: 0.6074±0.0733, p<0.001). Additionally, the ratio of consistent CFAE sites was higher for mini catheter than conventional one (38.3±4.6% vs. 22.3±1.4%, p<0.05). Electrograms and CFAE distribution are affected by catheter orientation and electrode configuration in the in-silico LA model. However, there was moderate spatial consistency of CFAE areas, and narrowly spaced bipolar catheters were less influenced by catheter direction than conventional catheters.