Background Left atrial (LA) conduction velocity (CV) is an electrical remodeling parameter of atrial fibrillation (AF) substrate. However, the pathophysiological substrate of LA-CV and its impact on outcomes after catheter ablation for AF have not been well evaluated. Methods We retrospectively evaluated 119 patients with AF who underwent catheter ablation and electroanatomical mapping during sinus rhythm. To measure regional LA-CV, we took triplet sites (A, B, and C) on the activation map and calculated the magnitude of the matched orthogonal projection vector between vector-AB and vector-AC, indicating two-dimensional CV. The median of the LA-CVs from four triad sites in both the anterior and posterior walls was set as the ‘model LA-CV’. We evaluated the impact of the model LA-CV on recurrence after ablation and relationship between the model LA-CV and LA-low voltage area (LVA) of < 0.5 mV. Results During the 12-month follow-up, 29 patients experienced recurrence. The LA-CV model was significantly correlated with ipsilateral LVA. The lower anterior model LA-CV was significantly associated with recurrence, with the cut-off value of 0.80 m/s having a sensitivity of 72% and specificity of 67%. Multivariable analysis revealed that the anterior model LA-CV (hazard ratio, 0.09; 95% confidence interval, 0.01–0.94; p = 0.043) and anterior LA-LVA (hazard ratio, 1.06; 95% confidence interval, 1.00–1.11; p = 0.033) were independently associated with AF recurrence. The anterior LA-LVA was mildly correlated with the anterior model LA-CV (r = -0.358; p < 0.001), and patients with both lower LA-CV and greater anterior LA-LVA based on each cut-off value had the worst prognosis. However, decreased LA-CV was more likely to be affected by the distribution pattern of the LVA rather than the total size of the LVA. Conclusion Decreased anterior LA-CV was a significant predictor of AF recurrence and was a useful electrical parameter in addition to LA-LVA for estimating AF arrhythmogenicity.

Percutaneous coronary intervention (PCI) requires multiple staff members, including interventional cardiologists, with the physical burden of heavy protective measures to minimize radiation exposure. Here, we aimed to investigate the safety of task sharing with clinical engineers (CEs) working as 1st assistant during ad hoc PCI. We retrospectively included 286 patients who underwent ad hoc PCI following diagnostic catheterization for coronary artery disease between April 2019 and March 2021. Procedural complications including coronary perforation or rupture, myocardial infarction, cerebral embolism, cardiovascular death, decreased kidney function, and radiation parameters were compared between the two clinical settings [CE group, CEs as the 1st assistant from the beginning of diagnostic coronary angiography to the end of PCI vs. doctor (DR) group, others]. There was no increase in the ratio of procedural complications in the CE group (1.7%) versus the DR group (1.2%). Fluorescence time and radiation exposure dose were significantly reduced in the CE group {25 min [interquartile range (IQR), 19–35 min] vs. 28 min (IQR, 20–39 min), P = 0.036; 908 mGy (IQR, 654–1326 mGy) vs. 1062 mGy (IQR, 732–1594 mGy), P = 0.049}. The median amount of contrast medium was significantly reduced in the CE group [100 mL (IQR, 80–119 mL) vs. 110 mL (IQR 90–140 mL), P < 0.001]. After propensity matching, fluorescence time, radiation exposure dose, and contrast medium amount were similar between groups. Task sharing with CEs as the 1st assistant during ad hoc PCI could contribute to clinical safety in patients with coronary artery disease.

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