[The effectiveness of romifidine on myocardial function in horses with and without heart disease, evaluated with M-mode echocardiography and PW-tissue Doppler imaging].

The research examines how the drug romifidine impacts the function of the heart muscle in horses, particularly those with heart disease, using M-mode echocardiography and PW-tissue Doppler imaging.

Overview of the Study

• The study was conducted to ascertain the effects of sedation with romifidine on the myocardial function in horses, particularly those suffering from heart disease. This was measured using PW-tissue Doppler (PW-TDI).
• The study involved 45 horses split into three groups. Group 1 had no heart disease, Group 2 had heart disease without increased heart dimensions, and Group 3 had heart disease with increased heart dimensions.
• The researchers used M-mode and TDI measurements to track heart activity before and after the horses were given romifidine.
• The velocity variations of the radial myocardial movement in the left and right ventricular walls were evaluated with PW-TDI.

Results of the Study

• The study found that after being given romifidine, all groups showed significant decreases in heart rate and fractional shortening (FS), a measure of the heart’s pumping efficiency.
• The isovolumic contraction time (IVC), systolic velocity (S), as well as the early (E) and late diastolic maximal velocities, were also significantly decreased.
• There was a significant difference in left ventricular isovolumic contraction times between the groups, most notably between horses with heart disease and increased heart dimensions, compared to those with heart disease but no increased dimensions.

Conclusion of the Study

• The study concluded that PW-TDI is an effective imaging technique for assessing the effects of romifidine on myocardial function in horses.
• The significant percentage change after the application of romifidine for TDI measurements compared to M-mode parameters indicates that myocardial velocity measured with TDI is the most sensitive parameter for documenting romifidine-induced changes on the heart muscle.