6.3.1 Clinical signs
6.3.1 Clinical signs

A murmur compatible with a diagnosis of TR is a common finding in Thorracehorses which show no signs of clinical abnormality and in which athletic performance is normal. In horses presented for poor performance, TR should only be considered to be the likely cause after a thorough examination to rule out other possible conditions and, ideally, an echocardiographic examinaunless it is obviously severe.

Moderate and severe TR may result in a reduction in athletic performance. Severe TR can lead to right-sided failure, with prominent jugular pulsation. The pulsation results from the force of ventricular systole ejecting blood in a retrodirection into the right atrium (RA) and great veins. If the RA becomes dilated as a result of the volume overload, it may predispose to the development of atrial fibrillation.

Degenerative disease of the TV is uncommon. Occasionally rupture of the chordae tendineae of the valve is seen. TR is most often accompanied by proof the valve leaflets which may be seen on echocardiography. Prolapse of the TV is often regarded as clinically insignificant by the author and may rule out other possible conditions and, ideally, an echocardiographic examination, unless it is obviously severe.

Moderate and severe TR may result in a reduction in atheletic performance. Severe TR can lead to right side failure, with prominent jugular pulsation. The pulsation resulta from the force of ventricular systole ejecting blood in a retro-grade direction into the right atrium (RA) and great veins. If the RA becomes dilated as a result of the volume overload, it may predispose to the development of atrial fibrillation.

Degenerative disease of the TV is uncommon. Occasionally rupture of the chordae tendineae of the valve is seen. TR is most often accompanied by prolapse of the valve leaflets which may be seen on echocardiography. Prolapse of the TV is often rearded as clinically insignificant by the author and may apparently resolve on later examinations; however it does lead to significant TR in some cases. The TV is seldom affected by endocarditis.