BACKGROUND The number of atrial premature depolarisations (APDs) is a known risk factor for atrial fibrillation (AF) recurrence in humans. OBJECTIVES To evaluate if the number of APDs over a 24-h period 5 days post cardioversion predicts AF recurrence within 1 year in horses, taking the multifactorial nature of AF into account. STUDY DESIGN Retrospective case series. METHODS Eighty horses met these inclusion criteria: first AF episode, no AF recurrence within 5 days post cardioversion, cardioversion by transvenous electrical cardioversion (TVEC), 24-h ECG recording and echocardiographic examination 5 days post cardioversion, no antiarrhythmic treatment during the ECG recording and follow-up of minimum 1 year. To compare the APD burden between the recurrence and non-recurrence group a Mann-Whitney U test was used. A multivariable survival model was built to identify additional risk factors for AF recurrence. RESULTS The patient population mainly consisted of Warmbloods (93%). Twenty-six horses (33%) experienced AF recurrence within 1 year. The number of APDs (median [range]) was significantly higher (P = 0.01) in the recurrence group (15 [1-152]) compared with the non-recurrence group (7 [0-304]). In the multivariable survival model, APDs ≥25/24 h (hazard ratio [HR] 2.9, 95% confidence interval [CI] 1.2-6.8, P = 0.02), mitral regurgitation (HR 8.6, 95% CI 2.6-28.9, P<0.001), left atrial active fractional area change ≤9.6% (HR 2.6, 95% CI 1.0-6.5, P = 0.04) and lower body weight (HR 0.99, 95% CI 0.98-0.99, P = 0.001) were significantly associated with AF recurrence. MAIN LIMITATIONS This study did not evaluate early AF recurrence within 5 days. The results cannot necessarily be extrapolated to other treatment methods, as only horses converted by TVEC were included. CONCLUSIONS The APD burden 5 days post cardioversion could be a useful predictive value for AF recurrence within 1 year in horses. However, other factors such as mitral regurgitation and atrial contractile function must also be taken into account.

中文翻译：

---

电复律后五天的心房过早去极化与马的心房颤动复发风险有关。

背景技术心房过早去极化（APD）的数量是人类心房颤动（AF）复发的已知风险因素。目的 评估复律后 5 天 24 小时内 APD 的数量是否能预测马在 1 年内的 AF 复发，同时考虑到 AF 的多因素性质。研究设计回顾性案例系列。方法 80 匹马符合以下纳入标准：首次 AF 发作，复律后 5 天内无 AF 复发，经静脉电复律 (TVEC) 复律，复律后 5 天进行 24 小时心电图记录和超声心动图检查，心电图记录期间未进行抗心律失常治疗并至少随访 1 年。为了比较复发组和非复发组之间的 APD 负担，使用了 Mann-Whitney U 检验。建立了一个多变量生存模型来确定 AF 复发的其他​​危险因素。结果 患者人群主要由温血型 (93%) 组成。26 匹马 (33%) 在 1 年内经历了 AF 复发。与非复发组 (7 [0-304]) 相比，复发组 (15 [1-152]) 的 APD 数量 (中位数 [范围]) 显着更高 (P = 0.01)。在多变量生存模型中，APDs ≥25/24 h（风险比 [HR] 2.9，95% 置信区间 [CI] 1.2-6.8，P = 0.02），二尖瓣关闭不全（HR 8.6，95% CI 2.6-28.9，P <0.001)、左心房活动分数变化≤9.6% (HR 2.6, 95% CI 1.0-6.5, P = 0.04) 和较低的体重 (HR 0.99, 95% CI 0.98-0.99, P = 0.001) 显着相关伴有 AF 复发。主要局限 本研究未评估 5 天内的早期 AF 复发。结果不一定可以外推到其他治疗方法，因为仅包括 TVEC 转换的马匹。结论 复律后 5 天的 APD 负担可能是马 1 年内 AF 复发的有用预测值。然而，其他因素，如二尖瓣关闭不全和心房收缩功能也必须考虑在内。