This case report concerns a 1-day-old, full-term Quarter Horse colt presented due to a progressive inability to rise and nurse. Besides the general weakness, a marked bradycardia was evident, which was caused by a third-degree atrioventricular (AV) block. Subsequently, the diagnosis of acute nutritional myodegeneration (NMD) was made based on clinical signs, elevated muscle enzymes, ECG findings, as well as low serum selenium and vitamin E values. Despite intensive care and supportive therapy, the foal´s condition deteriorated, and euthanasia was elected. Necropsy confirmed the diagnosis of NMD and revealed diffuse necrosis and inflammatory infiltration of the skeletal and myocardial musculature, as well as the cardiac conduction system which might have resulted in complete AV block.

中文翻译：

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患有营养性肌变性的新生儿马驹的完全 AV 阻滞

本病例报告涉及一头 1 天大的足月季马小马，由于逐渐无法站立和哺乳而出现。除了全身无力外，还有明显的心动过缓，这是由三度房室 (AV) 传导阻滞引起的。随后，根据临床症状、肌酶升高、心电图检查结果以及低血清硒和维生素 E 值做出急性营养性肌变性 (NMD) 的诊断。尽管进行了重症监护和支持治疗，但小马驹的病情恶化了，最终选择了安乐死。尸检证实了 NMD 的诊断，并显示骨骼和心肌组织以及可能导致完全 AV 阻滞的心脏传导系统的弥漫性坏死和炎性浸润。