To investigate the clinical and echocardiographic presentation of dogs with persistent atrial standstill (PAS), identify variables measured at first presentation that could predict their survival, and document the progression of the disease after pacing. Retrospective study of medical records of dogs diagnosed with PAS at three referral hospitals of the United Kingdom over seven years. Twenty-six dogs were diagnosed with PAS during the study period. Median age of the population was three years (range: seven months–12.5 years). The most common clinical sign was syncope (14/26). Twenty-four dogs received artificial pacemakers (PM). Major complications after PM implantation were observed in four dogs (four/24). Serial echocardiographic examinations showed that cardiac dimensions of PAS dogs with left atrial or left ventricular dilation at first presentation did not return to reference range after pacing. Further dilation of the cardiac chambers, recurrence of congestive heart failure (CHF), or development of new episodes of CHF were documented in seven, four, and 10 PAS dogs, respectively, despite pacing. Median survival time for cardiac-related deaths after PM implantation was 1512 days (18–3207). Neither CHF nor echocardiographic variables at presentation predicted survival after PM implantation in PAS dogs. Persistent atrial standstill (PAS) is an uncommon bradyarrhythmia, occurring in young adult dogs. Affected dogs were often presented with syncope. Whilst syncope resolved, cardiac remodeling persisted after PM implantation. Long-term survival was favorable after PM implantation and was not predicted by congestive status or cardiac chamber size at first presentation.

中文翻译：

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英国持续性心房停搏犬的临床表现、治疗和生存

为了调查持续性心房停搏 (PAS) 犬的临床和超声心动图表现，确定首次表现时测量的可预测其生存的变量，并记录起搏后疾病的进展。对英国三所转诊医院七年来诊断患有 PAS 的狗的医疗记录进行回顾性研究。在研究期间，有 26 只狗被诊断患有 PAS。人口的中位年龄为 3 岁（范围：7 个月至 12.5 岁）。最常见的临床症状是晕厥 (14/26)。 24 只狗接受了人工起搏器 (PM)。在四只狗（四/24）中观察到 PM 植入后的主要并发症。系列超声心动图检查显示，首次就诊时左心房或左心室扩张的 PAS 狗的心脏尺寸在起搏后并未恢复到参考范围。尽管有起搏，但分别记录了 7 只、4 只和 10 只 PAS 狗的心室进一步扩张、充血性心力衰竭 (CHF) 复发或新的 CHF 发作。 PM 植入后心脏相关死亡的中位生存时间为 1512 天 (18-3207)。就诊时的 CHF 和超声心动图变量均不能预测 PAS 狗植入 PM 后的存活率。持续性心房停搏（PAS）是一种罕见的缓慢性心律失常，发生在年轻的成年犬身上。受影响的狗经常出现晕厥。虽然晕厥得到缓解，但植入 PM 后心脏重塑仍然存在。 PM植入后的长期生存是有利的，并且不能通过首次就诊时的充血状态或心室大小来预测。