A Clinical Trial about the Efficacy of Pimobendan in Comparison to Enalapril in Dogs with Mitral Valve Endocardiosis. Part 2: Echocardiographic Results
*Tierklinik Am Sandpfad, Dr. Walla & Partner
Wiesloch, Baden-Württemberg DE
The echocardiographic examination was performed to compare the effects of the two drugs on heart chamber size and wall motion. Of special interest was the development or the increase of a hyperkinetic wall motion pattern in the Pimobendan group compared to the Enalapril group. Please refer also to Part 1.
The echocardiographic parameters measured on day 0, 7 and 28 of the study consisted of left atrial to aortic ratio, left ventricular wall thickness and diameters (LVID) and calculations from these values i.e., FS (fractional shortening) and ESVI (end systolic volume index). Please refer also to Part 1.
Within the Pimobendan group no significant difference in the echocardiography parameters were seen. On the other hand we found significant enlargements (p < 0,05) of LVIDd, LVIDs and ESVI within the Enalapril group after 28 days. The comparison between the groups showed significantly larger (p < 0,05) LVIDd and ESVI on day 7 and significantly larger (p < 0,05) LVIDd and LVIDs on day 28 in the Enalapril group. The FS calculations showed no significant changes within or between the groups (Enalapril group: Day 0: 44,4 %, day 28: 40,9 %; Pimobendan group: Day 0: 47,1 %, day 28: 46,7 %; ns)
According to our echocardiographic data treatment with Enalapril lead to a significant increase of the left ventricular diameters. This effect did not occur in the Pimobendan group. Treatment with Pimobendan on the other hand did not lead to an increase of the fractional shortening nor occurred a hyperkinetic wall motion pattern, the related parameters showed no significant changes. Also from this echocardiographic data, it can be concluded, that Pimobendan is a safe and efficacy drug for the treatment of patients with mitral valve endocardiosis.
The increase of left ventricular diameters (LVID) in the Enalapril group may be caused by the slower heart rate in this group allowing a longer filling period. But it could also be interpreted as a sign of left ventricular compensation for the mitral regurgitation that does not occur with Pimobendan treatment.