Preliminary study on the effects of pergolide on left ventricular function in the horses with pituitary pars intermedia dysfunction

J Vet Sci. 2021 Sep;22(5):e64. doi: 10.4142/jvs.2021.22.e64.


Background: Pituitary pars intermedia dysfunction (PPID), a neurodegenerative disease leading to reduced dopamine production, is a common disease in aged horses. The treatment is based on administration of the dopamine agonist pergolide. This drug has been related to valvular fibrosis in humans, but the cardiovascular effect of this drug has not yet been investigated in horses.

Objectives: To determine whether pergolide induces valvular disease in horses or affects the cardiac function.

Methods: Standard, tissue Doppler (TDE) and two-dimensional speckle tracking (STE) echocardiography were performed in horses with diagnosed PPID based on adrenocorticotropic hormone dosage. Measurements taken in horses treated with pergolide were compared with those from untreated horses with nonparametric t-tests. Furthermore, measurements from follow-up examinations performed at least three months after the initial exam were compared with a Wilcoxon signed rank test for repeated measurements in each group.

Results: Twenty-three horses were included. None of the 12 horses under treatment developed valvular regurgitation. Furthermore, no differences in the measurements of the left ventricular systolic or diastolic function could be seen between the group of horses with treatment and those without treatment. Measurements taken in the follow-up exam did not differ compared to those taken in the initial exam in both groups.

Conclusions: No changes of the left ventricular function assessed by TDE and STE could be shown in a small population of horses with confirmed PPID. Treatment with pergolide did not affect the ventricular function nor induce valvular disease.

Keywords: Ultrasonography; equine Cushing syndrome; heart; horses; speckle tracking; tissue Doppler echocardiography.

MeSH terms

  • Adrenocorticotropic Hormone / therapeutic use
  • Animals
  • Dopamine Agonists / pharmacology*
  • Horse Diseases / drug therapy*
  • Horses
  • Pergolide / pharmacology*
  • Pituitary Diseases / drug therapy
  • Pituitary Diseases / veterinary*
  • Pituitary Gland, Intermediate / drug effects*
  • Pituitary Gland, Intermediate / pathology
  • Ventricular Function, Left / drug effects*
  • Ventricular Function, Left / physiology


  • Dopamine Agonists
  • Pergolide
  • Adrenocorticotropic Hormone