Introduction

Although transient deep and giant negative T waves (NTWs) may develop during myocardial injury (MI) in humans, no data exist on this repolarization abnormality in canine MI. Therefore, this study aimed to describe the occurrence of transient deep/giant NTWs in dogs with MI.

Animals, Materials and Methods

Medical records were retrospectively searched to identify dogs with MI and transient deep/giant NTWs. Signalment, history, and selected diagnostic test results were reviewed. Data analysis was descriptive.

Results

Six cases were diagnosed with MI associated with deep (n = 1) and giant (n = 5) transient NTWs. Myocardial injury was classified as acute in all cases and was due to snake envenomation (n = 3), sepsis (n = 2), and systemic inflammatory response syndrome (n = 1). At the time of deep/giant NTWs identification, all dogs had elevated cardiac troponin I and ≥1 echocardiographic abnormality of the left ventricular structure and/or function. Moreover, all dogs with giant NTWs had prolonged QT intervals. After the MI resolution, T-wave polarity and QT-interval duration became normalized in all dogs. Moreover, left ventricular morphological and functional parameters were completely normalized in four dogs. In contrast, ventricular echogenicity remained heterogeneous in two dogs, despite otherwise normalized ventricular parameters. Five dogs were still alive at the conclusion of the study.

Conclusions

Transient deep/giant NTWs may develop in dogs with acute MI and T-wave polarity changes seem to occur synchronously with the evolution of myocardial damage. Moreover, transient deep/giant NTWs seem associated with a favorable prognosis in canine MI.

中文翻译：

---

心肌损伤犬的一过性深和巨大负 T 波

介绍

尽管在人类心肌损伤 (MI) 期间可能会出现短暂的深部和巨大负 T 波 (NTW)，但没有关于犬 MI 中这种复极异常的数据。因此，本研究旨在描述 MI 犬中短暂的深部/巨大 NTWs 的发生。

动物、材料和方法

回顾性搜索医疗记录以识别患有 MI 和短暂深部/巨大 NTW 的狗。审查信号、历史和选定的诊断测试结果。数据分析是描述性的。

结果

6 例被诊断为与深 (n = 1) 和巨大 (n = 5) 短暂 NTW 相关的 MI。心肌损伤在所有情况下都被归类为急性，是由于蛇毒（n = 3）、败血症（n = 2）和全身炎症反应综合征（n = 1）所致。在识别深部/巨大 NTW 时，所有犬的心肌肌钙蛋白 I 均升高，左心室结构和/或功能有≥1 处超声心动图异常。此外，所有具有巨大 NTW 的狗都有延长的 QT 间期。在 MI 消退后，所有狗的 T 波极性和 QT 间期持续时间变得正常。此外，四只狗的左心室形态和功能参数完全正常化。相比之下，尽管心室参数正常化，但两只狗的心室回声仍然不均匀。

结论

急性 MI 犬可能会出现短暂的深部/巨大 NTW，T 波极性变化似乎与心肌损伤的演变同步发生。此外，短暂的深/巨大 NTW 似乎与犬 MI 的良好预后相关。