Echocardiographic assessment of left ventricular systolic function in colic horses

Background: Echocardiography has not been reported to study hemodynamic disturbances in colic horses.
Objectives: To non invasively assess the impact of colic-related endotoxin shock on equine cardiac function.
Animals: Fifty horses admitted in clinic on emergency for colic.
Methods: A shock score from 1 to 4 was established for each horse based on clinical evaluation, non invasive systolic blood pressure and blood tests measurements. Left ventricular echocardiographic and Doppler parameters were compared between the 4 groups according to the shock score (1 = no or discrete signs of shock, n=11; 2 = mild shock, n=17; 3 = moderate shock, n=12; 4 = severe shock, n=10) using a multivariable analysis. Horses with a score shock of 1 were considered as control. Significance was set at P < 0.05.
Results: The stroke volume, stroke index, ejection time, ejection time index corrected for heart rate, aortic velocity time integral, aortic flow acceleration time and aortic flow deceleration time were significantly lower whereas acceleration rate of aortic flow ejection and heart rate were significantly higher in shocked horses than in controls. Cardiac output was not significantly different between groups.
Conclusions and Clinical importance: Even if those results are difficult to interpret because of the shock-induced changes in loading conditions of the heart, they suggest that alterations in some indicators of systolic function can be quantified by Doppler echocardiography in horses with colic-induced endotoxemic shock. Ultrasonographic monitoring of cardiovascular function could thus be of interest in equine intensive care.