Introduction

Large breed (LB) dogs develop dilated cardiomyopathy (DCM) and myxomatous mitral valve disease (MMVD). Echocardiography is required for definitive diagnosis but not always available. Our objective was to assess clinical utility of thoracic radiographs alone, and in combination with physical examination and electrocardiography findings, for prediction of clinically important DCM or MMVD in LB dogs.

Animals

Four hundred fifty-five client owned dogs ≥20 kg with concurrent thoracic radiographs and echocardiogram.

Materials and Methods

Medical records were reviewed and stored thoracic radiographs and echocardiographic images were measured to classify dogs as normal heart size (NHS), preclinical DCM, clinical DCM, preclinical MMVD (with cardiomegaly), clinical MMVD, or equivocal. Dogs with preclinical MMVD without cardiomegaly were classified as NHS. Vertebral heart size (VHS) and vertebral left atrial size (VLAS) were measured. Receiver operating characteristic curves and prediction models were derived.

Results

Prevalence of MMVD (39.3%) was higher than prevalence of DCM (24.8%), though most MMVD dogs (67.0%) lacked cardiomegaly and were classified as NHS for analysis. Area under the curve (AUC) for VHS to discriminate between NHS versus clinical DCM/MMVD or versus preclinical DCM/MMVD was 0.861 and 0.712, respectively, while for VLAS it was 0.891 and 0.722, respectively. Predictive models incorporating physical examination and electrocardiography findings in addition to VHS/VLAS increased AUC to 0.978 (NHS vs clinical DCM/MMVD) and 0.829 (NHS vs preclinical DCM/MMVD).

Conclusions

Thoracic radiographs were useful for predicting clinically important DCM or MMVD in LB dogs, with improved discriminatory ability when physical examination abnormalities and arrhythmias were accounted for.

中文翻译：

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使用临床、放射照相和心电图变量的组合预测大型犬没有超声心动图的临床重要获得性心脏病

介绍

大型犬 (LB) 患上扩张型心肌病 (DCM) 和粘液性二尖瓣病 (MMVD)。超声心动图是明确诊断所必需的，但并不总是可用的。我们的目标是单独评估胸片的临床效用，并结合体格检查和心电图检查结果，预测 LB 犬临床上重要的 DCM 或 MMVD。

动物

455 只客户拥有的狗 ≥20 公斤，同时进行胸片和超声心动图检查。

材料和方法

审查医疗记录并存储胸片和超声心动图图像，以将狗分类为正常心脏大小 (NHS)、临床前 DCM、临床 DCM、临床前 MMVD（心脏肥大）、临床 MMVD 或模棱两可。患有临床前 MMVD 而没有心脏肥大的狗被归类为 NHS。测量椎体心脏大小（VHS）和椎体左心房大小（VLAS）。接受者操作特征曲线和预测模型被推导出来。

结果

MMVD 的患病率 (39.3%) 高于 DCM 的患病率 (24.8%)，尽管大多数 MMVD 狗 (67.0%) 缺乏心脏肥大并被归类为 NHS 进行分析。VHS 区分 NHS 与临床 DCM/MMVD 或临床前 DCM/MMVD 的曲线下面积 (AUC) 分别为 0.861 和 0.712，而 VLAS 分别为 0.891 和 0.722。除 VHS/VLAS 外，结合体格检查和心电图结果的预测模型将 AUC 增加到 0.978（NHS 与临床 DCM/MMVD）和 0.829（NHS 与临床前 DCM/MMVD）。

结论

胸片可用于预测 LB 犬临床上重要的 DCM 或 MMVD，当考虑到体格检查异常和心律失常时，其鉴别能力有所提高。