6.6.1 Clinical signs
Horses with endocarditis are usually systemically ill. The signs can relate to the direct effect on the heart as a result of valvular incompetence. Additional signs are due to the effect of infection or sepsis, or emboli from the infected thrombus, and sometimes associated immune-mediated disease. The horse may be depressed and inappetant. Pyrexia, tachycardia and weight loss are common findings and signs of heart failure may be apparent. The mucous membranes may be injected and the capillary refill time increased or reduced as a result of toxaemia. Auscultation usually reveals the murmur of regurgitation through the affected valve. Uncommonly, in severe cases, the lesion may cause a functional stenosis of the valve. Rarely, endocarditis is present in the absence of a cardiac murmur and the animal may be presented with signs of systemic disease only. The facial pulse quality should be assessed as a guide to severity of aortic regurgitation if this valve is affected. Dysrhythmias, particularly premature ventricular beats, are not uncommon and may be caused by emboli in the coronary vasculature.