Echocardiographic alterations after administration of azithromycin in donkeys: An experimental crossover study

Abstract

Cardiotoxicity and impairment of cardiac function are mostly diagnosed by echocardiography and based on objective metrics of cardiac function. The aim of the present study is to investigate the effect of azithromycin on the echocardiographic characteristics in healthy donkeys. Ten healthy donkeys were enrolled in a prospective crossover study. The study included two groups: (1) a placebo (normal saline, NaCl 0.9%), and (2) azithromycin (at a dose of 5 mg/kg body weight). A 2.0-3.9 MHz phased-array transducer was used for echocardiographic examination. Echocardiographic examinations were performed for donkeys before treatment (T0) and at 15, 30, 60, 90, 120, 180, and 240 min after azithromycin administration. In the azithromycin group compared to Placebo, the drug induced a significant increase in interventricular septal thickness in end-diastole (IVSTd) and interventricular septal thickness in end-systole (IVSTs) (P < 0.05), but it induced a significant decrease in left ventricular internal diameter (LVID) at end diastole (LVIDd) and at end systole (LVIDs) (P < 0.01). There was also a significant (P < 0.05) decrease in left ventricular posterior wall thickness at the end of diastole (LVPWd) and at the end of systole (LVPWs) compared with placebo. Left ventricular volume increased significantly (P < 0.05) at the end diastole (EDV), and at the end systole (ESV). Fractional shortening (FS%) decreased significantly (P < 0.05) in donkeys receiving azithromycin compared to placebo. In conclusion, azithromycin in healthy donkeys induces transient and mild effects on echocardiographic parameters with fewer overt clinical signs. Further studies are needed to evaluate the efficacy of this drug, specifically in equines with underlying cardiac disease.