Severe mitral regurgitation in horses: clinical, echocardiographic and pathological findings

Abstract

Summary Forty‐three horses with mitral regurgitation (MR) and congestive heart failure were examined, using M‐mode, 2‐dimensional real‐time and Doppler echocardiography. There was no breed or sex predisposition when compared to the general hospital population. The mean ± s.d. age of affected horses was 7.6 ±8.1 years. Horses with MR and congestive heart failure had significant increases in mean values for left ventricular chamber size, left atrial size and heart rate and significant decreases in interventricular septal and left ventricular free wall thickness. Significant increases in pulmonary artery diameter were detected compared to aortic diameter. Mean values for fractional shortening were not significantly different from normal. All horses had a Grade 3–6/6 holosystolic or pansystolic murmur with its point of maximal intensity in the mitral to aortic valve area. Atrial fibrillation was found at presentation in 24 horses with MR and congestive heart failure. One horse presented with atrial tachycardia and subsequently developed atrial fibrillation. Seven horses had ventricular premature contractions. Exercise intolerance (n = 34), respiratory signs (n = 31), and fever (n = 21) were the most common presenting signs. Thickening of the left atrioventricular valve leaflets, endocarditis, flail valve leaflets, rupture of a chorda tendineae, and mitral valve prolapse were detected echocardiographically. Doppler echocardiography confirmed the presence of a large systolic regurgitant jet in the left atrium in all horses in which it was used, and in many horses, concurrent tricuspid and pulmonary regurgitation was detected. All horses died or were subjected to euthanasia due to the severity of their MR and/or lack of response to therapy. Post mortem examinations were performed in 35 horses and confirmed the echocardiographic findings. The echocardiographic detection of a flail mitral valve leaflet was significantly associated with the detection of a ruptured chorda tendineae at post mortem examination. There was a significant association between echocardiographic detection of a dilated pulmonary artery and its presence at post mortem examination. M‐mode, 2‐dimensional real‐time, and Doppler echocardiography should be used to accurately characterise the valvular abnormalities and assess the severity of mitral regurgitation. Pulmonary artery dilatation, an echocardiographic indication of severe pulmonary hypertension, should be considered a grave prognostic indicator and may indicate impending pulmonary artery rupture.

Two-dimensional and M-mode echocardiographic measurements of cardiac dimensions in healthy Standardbred trotters

“…Two-dimensional (2D) echocardiography (2DE) was introduced into equine medicine in the mid-1980s (Bonagura et al, 1985;Carlsten, 1987). Echo-cardiographic findings of several cardiac anomalies were reported (Pipers et al, 1985;Reef and Spencer, 1987;Bernard et al, 1990;Taylor et al, 1991;Vörös et al, 1991b;Reef et al, 1998). Papers also dealt with the validation and standardisation of the 2DE examination technique (Carlsten, 1987;Stadler et al, 1988;Vörös et al, 1990aVörös et al, , 1990bVörös et al, , 1991aVörös, 1997).…”

Acute heart insufficiency due to aortic rupture

“…Daraus kann wie im vorliegenden Fall eine erweiterte Pulmonalarterie mit Pulmonalinsuffizienz resultieren (Reef et al 1998) (Abb 2). Die direkte Druckmessung ist dagegen erst mit Hilfe des Rechtsherzkatheters bestimmbar und kann im Lungenkapillarbett, in der Pulmonalarterie und im rechten Ventrikel sowohl bei Linksherzerkrankungen als auch bei pulmonalen Veränderungen sinnvoll sein (Muylle et al 1986, Gehlen et al 2004).…”

Stress echcardiography in warmblood horses: Active stress induction by treadmill and longing exercise

“…In der Humankardiologie zeigten sich ebenfalls signifikante Unterschiede zwischen Ruhe-und Belastungswerten. echokardiographische Messwerte trainierter Menschen waren bereits 2 Minuten nach Ende einer Farradbelastung wieder im Ruhebereich (Corallo et al 1981 (Antoni 2000, Flachskampf 2001, Harmeyer 2000, Silbernagel und Despopoulos 2001 und beim Pferd die meisten Erkrankungen aufweist (Reef et al 1998, Long et al 1992, Gehlen et al 2003b (Reindel 1964), sondern tatsächlich auch in einer erhöhten Vorfüllung, die zu vermehrter Druck-und/oder Volumenarbeit führt, begründet ist (Starling 1918).…”