In most instances the horse is first and foremost a performance animal and the potential impact of cardiovascular disease on performance and re-sale value is important. Cardiovascular abnormalities of variable clinical significance are frequently encountered in the horse. Evaluation of the cardiovascular system involves, at minimum, acquiring a detailed history and performing a complete physical examination. In a high-level performance animal, even a slight deterioration in performance may precipitate a request for cardiovascular examination. The jugular veins in a horse can be used to assess cardiovascular status. Careful auscultation of the lung fields should be performed as part of the cardiovascular examination because respiratory signs occur in left-sided heart failure and respiratory disease is a differential diagnosis for suboptimal performance. Cardiac catheterisation may provide additional information regarding the direction of flow across a shunt and the cardiovascular effects of an abnormal finding. Ventricular tachycardia is a clinically significant condition that usually involves underlying myocardial or systemic disease.