[B-mode, M-mode and Doppler sonographic findings in mitral valve insufficiency of horses].

The research study focuses on using B- and M-mode echocardiography, supplemented with pulsed-wave Doppler echocardiography, to diagnose mitral valve insufficiency (MVI) in horses, while also investigating its potential impact on the animals’ prognosis.

Study Overview

• The researchers used B- and M-mode echocardiography on 38 horses, 34 of which had systolic heart murmurs focused over the mitral valve.
• Of these, 17 were also studied using pulsed-wave Doppler echocardiography.

Findings and Diagnosis

• A mitral valve insufficiency was diagnosed in 26 patients with cardiac murmur and 4 patients without cardiac murmur using echocardiography.
• In 8 horses with systolic murmur over the mitral valve, M- and B-mode evaluation did not reveal a hemodynamic importance of the murmur.
• MVI diagnosis was based on dilation of the left atrium, with or without additional dilation of the left ventricle, alongside the regurgitation of blood into the left atrium as observed by pulsed-wave doppler.
• In certain cases, especially in hearts that were extremely dilated, a “real” ostium of regurgitation could be directly detected via B-mode echocardiography.

Correlating with Autopsy Measurements

• The researchers observed that echocardiographically evaluated changes of heart dimensions correlated well with autopsy measurements, backing the viability of their diagnosis technique.

The Effect on Prognosis

• The prognostic implications of their findings suggested that horses with systolic murmurs coinciding with dilatation of the left atrium and left ventricle, regurgitation of blood into the left atrium, or a high degree of dilation of the left atrium without changes of left ventricle chamber size, typically had a poor prognosis.
• In horses with little to medium dilated left atrium without changes of left ventricle dimension and additional regurgitation into the left atrium, the prognosis was denoted as at least cautious.

Proposed Utility of Echocardiography

• The study reinforced the importance of echocardiography as a useful diagnostic tool in understanding the impact of systolic murmurs on the mitral valve, especially when supplemented by pulsed-wave doppler.