Myocardial injury in dogs: a retrospective analysis on etiological, echocardiographic, electrocardiographic, therapeutic, and outcome findings in 102 cases

Introduction: In dogs, myocardial injury (MI) is a poorly characterized clinical entity; therefore, this study aimed to provide a detailed description of dogs affected by this condition. Animals, materials, and methods: Dogs diagnosed with MI according to the concentration of cardiac troponin I (cTnI) were retrospectively searched. Signalment, diagnostic, therapeutic, and outcome data were retrieved. Dogs were divided into six echocardiographic (dilated cardiomyopathy phenotype; hypertrophic cardiomyopathy phenotype; hypertrophic cardiomyopathy phenotype with systolic dysfunction; abnormal echogenicity only; endocarditis; and no echocardiographic abnormalities suggestive of MI), four electrocardiographic (abnormalities of impulse formation; abnormalities of impulse conduction; abnormalities of ventricular repolarization; and no electrocardiographic abnormalities suggestive of MI), and nine etiological (infective; inflammatory; neoplastic; metabolic; toxic; nutritional; immune-mediated; traumatic/mechanical; and unknown) categories. Statistical analysis was performed to compare cTnI values among different categories and analyze survival. Results: One hundred two dogs were included. The median cTnI value was 3.71 ng/mL (0.2-180 ng/mL). Echocardiographic and electrocardiographic abnormalities were documented in 86 of 102 and 89 of 102 dogs, respectively. Among echocardiographic and electrocardiographic categories, the dilated cardiomyopathy phenotype (n = 52) and abnormalities of impulse formation (n = 67) were overrepresented, respectively. Among dogs in which a suspected etiological trigger was identified (68/102), the infective category was overrepresented (n = 20). Among dogs belonging to different echocardiographic, electrocardiographic, and etiological categories, cTnI did not differ significantly. The median survival time was 603 days; only eight of 102 dogs died due to MI. Conclusions: Dogs with MI often have an identifiable suspected trigger, show various echocardiographic and electrocardiographic abnormalities, and frequently survive to MI-related complications.