ABSTRACT This study aimed to evaluate the impact of minimally invasive partial pericardiotomy on echocardiographic variables of morphometry and function in healthy horses. Minimally invasive pericardiotomy was performed in six healthy horses. Echocardiographic evaluation was executed in different moments: prior to the surgical procedure (M0); 24 hours post procedure (M1); 72 hours post procedure (M2) and 28 days post procedure (M3). The following variables were measured: Right ventricular internal diameter in diastole and systole (RVd and RVs), interventricular septum thickness in diastole and systole (IVSd and IVSs), left ventricular internal diameter in diastole and systole (LVd and LVs), left ventricular free wall thickness in diastole and systole (LVFWd and LVFWs), aortic root diameter (Ao) and left atrial diameter (LA). From this data, the following variables were calculated: fractional shortening (FS%), fractional thickening of the interventricular septum (IVS%), fractional thickening of the left ventricular free wall (LVFW%) and the relationship between left atrial and aortic diameters (LA/Ao). After 28 days, a new thoracoscopy was performed for inspection of the thoracic cavity. In M1 and M2 ECO evaluations, a statistically significant change in LVFW and a decrease in RVd, LVd, LVFWs, LA, LVs, FS% and IVS was documented. Pericardiotomy is a promising technique in horses, with minor postoperative complication. The variations in the echocardiographic parameters were transient and did not cause hemodynamic damage to the animals.