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Introduction and objectives: Pulmonary vein isolation (PVI) technique has become the cornerstone of atrial fibrillation (AF) catheter ablation. The objective of this study was to assess the efficacy and safety of extended antrum ablation based on electrophysiological substrate mapping plus PVI in AF patients who underwent cryoballoon ablation. Methods: In this observational study, a total of 121 paroxysmal AF patients and 80 persistent AF patients who did not achieve the procedure endpoint after cryoballoon ablation received extra extended antrum ablation (EAA) based on electrophysiological substrate mapping via radiofrequency ablation (EAA group). As a control group (PVI group), among paroxysmal AF and persistent AF patients, we conducted a propensity score-matched cohort, in whom only PVI was completed. Results: The average follow-up time was 15.27±7.34 months. Compared with PVI group, paroxysmal AF patients in the EAA group had a significantly higher rate of AF-free survival (90.1% vs. 80.2%, p=0.027) and AF, atrial flutter, or atrial tachycardia (AFLAT) -free rate survival (89.3% vs. 79.3%, p=0.031). Persistent AF patients in the EAA group also had a significantly higher rate of AF-free survival (90.0% vs. 75.0%, p=0.016) and AFLAT-free survival (88.8% vs. 75.0%, p=0.029) than PVI group. Complication rates did not significantly differ between both groups, in either paroxysmal AF or persistent AF patients. Conclusion: Our findings demonstrate that extra extended antrum ablation based on electrophysiological substrate mapping is effective and safe. Moreover, the strategy can improve the outcome of AF cryoablation. Resumo: Introdução e objetivos: A técnica de isolamento das veias pulmonares (IVP) tornou-se a pedra angular da ablação por cateter da fibrilhação auricular (FA). O objetivo deste estudo consistiu em avaliar a eficácia e a segurança da ablação antral alargada com base no mapeamento do substrato eletrofisiológico, para lá do IVP em doentes com FA, submetidos a crioablação. Métodos: Neste estudo observacional, 121 doentes com FA paroxística e 80 doentes com FA persistente que não alcançaram o objetivo do procedimento após a crioablação foram submetidos a ablação antral alargada com base no mapeamento do substrato eletrofisiológico, através de ablação por radiofrequência (grupo de Ablação Antral Alargada, grupo AAA). Como grupo controlo (grupo do Isolamento das Veias Pulmonares, grupo IVP), em doentes com FA paroxística e com FA persistente, realizámos um score de propensão agrupado, no qual só foi efetuado o IVP. Resultados: O tempo médio de seguimento foi 15,27±7,34 meses. Quando comparados com o grupo IVP, os doentes com FA paroxística no grupo AAA apresentaram uma taxa significativamente mais elevada de sobrevivência livre de FA (90,1% versus 80,2%, p=0,027) e de sobrevivência livre de AFLAT (FA, flutter auricular ou taquicardia auricular) (89,3% versus 79,3%, p=0,031). Os doentes com FA persistente no grupo AAA também apresentaram uma taxa significativamente mais elevada de sobrevivência livre de FA (90,0% versus 75,0%, p=0,016) e de sobrevivência livre de AFLAT (88,8% versus 75,0%, p=0,29) do que no grupo de IVP. As taxas de complicações não diferiram significativamente entre dois grupos, tanto nos doentes com FA paroxística como nos com FA persistente. Conclusão: Os nossos resultados demonstraram que a ablação antral alargada com base no mapeamento de substrato eletrofisiológico é eficaz e segura. Além disso, a estratégia pode melhorar os resultados da FA por crioablação.

ABSTRACT The objective of this study was to investigate the effects of the method and dose of cyclophosphamide (CPA) administration on cashmere shedding. Thirty-two castrated Liaoning cashmere goats were randomly allotted to four groups, with eight replicates in each group. Goats in the four groups were injected intravenously or intramuscularly with CPA at doses of 20 or 25 mg kg−1 body weight (BW), respectively. Feed intake and BW were recorded, and erythrocyte count, hemoglobin content, and cashmere weight were determined. It was found that the CPA administration method had no significant effect on feed intake or BW of cashmere goats. Cyclophosphamide injection can significantly decrease the erythrocyte count and hemoglobin content of cashmere goats, but the effects are dependent on injection method and CPA dose. The injection method and dose did not significantly influence cashmere weight, but the method had significant effects on time to initiate shedding and regrown hair length. Regrown hair was longest by intramuscular injection with 20 mg kg−1 BW, which also caused the least erythema on the epidermis during the days after shedding. The results indicate that the CPA administration method can significantly influence cashmere shedding. Intramuscular injection of CPA at a dose of 20 mg kg−1 BW was found to be relatively beneficial for hair removal and regrowth in cashmere goats.