Characterization of arrhythmias, evaluation of cardiac biomarkers and their association with survival in calves suffering from foot-and-mouth disease

Abstract Introduction Foot-and-mouth disease (FMD) causes mortality in calves due to myocarditis; however, the effects of FMD virus on cardiac arrhythmogenesis and Purkinje cells are unknown. Identifying diagnostic and prognostic markers in FMD affected calves may be useful in disease management in the endemic countries. Materials and Methods A total of 81 FMD affected calves were prospectively monitored till death or recovery. Foot-and-mouth disease was diagnosed by serology and reverse transcriptase–polymerase chain reaction (RT-PCR). Electrocardiography was recorded and serum cardiac biomarkers were measured. Histopathological examination of the ventricular myocardium was done in the calves that died of FMD (n=33). Apparently healthy calves (n=15) served as control. Results Serology and RT-PCR consistently revealed that the FMD was caused by serotype O virus. Arrhythmias occurred in 62/81 (76.5%) of the FMD affected calves, of which, ventricular premature complexes (VPC) were the most common type (22%). The combined mortality rate due to ventricular tachycardia, polymorphic VPCs and atrial fibrillation was 27.6%. Receiver operating characteristic (ROC) curve analysis revealed that cardiac troponin I (cTnI) concentrations of ≥ 1.3 ng/mL were diagnostic of myocarditis with a sensitivity and specificity of 90% and 100%, respectively. Similarly, serum cTnI concentrations of Conclusions FMD induces cardiac arrhythmias and Purkinje cell pathology in the calf. Portable ECG coupled with assay of serum cTnI would help in predicting survival in FMD affected calves.