Systolic dysfunction can be a feature of any myocardial disease in which there is significant ischaemia and replacement fibrosis of the myocardium. This results in reduced stroke volume and increased ventricular filling pressure.
==Clinical Signs==
==Clinical Signs==
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A large proportion of cats with HCM are asymptomatic, and diagnosed as a result of echocardiography for investigation of a murmur or gallop rhythm detected on auscultation. A murmur is present in >50% of cats with HCM, due to dynamic left ventricular outflow tract obstruction and mitral regurgitation caused by SAM of the mitral valve.