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Hypertrophic Cardiomyopathy - Feline Cardiomyopathies (view source)
Revision as of 17:57, 17 October 2013
, 17:57, 17 October 2013no edit summary
The mechanism of SAM is not completely understood. One hypothesis is that deformation of the mitral valve architecture (leaflets, chordae tendinae, papillary muscles) and the hyperdynamic state caused by myocardial hypertrophy cause SAM.
The mechanism of SAM is not completely understood. One hypothesis is that deformation of the mitral valve architecture (leaflets, chordae tendinae, papillary muscles) and the hyperdynamic state caused by myocardial hypertrophy cause SAM.
===Diastolic Dysfunction===
===Diastolic Dysfunction===
Myocardial hypertrophy and interstitial fibrosis leads to reduced LV compliance. Tachycardia can exacerbate diastolic dysfunction by reducing diastolic time, and hence the time allowed for ventricular filling. Since coronary blood flow to supply the myocardium occurs in diastole, tachycardia may accelerate myocardial ischaemia. Diastolic dysfunction causes increased LV filling pressure. Left atrial (LA) enlargement initially compensates for this until maximal compliance of the atrium is reached. Once this point is reached, atrial pressure rises. This will subsequently result in pulmonary venous hypertension and eventually left-sided congestive heart failure. SAM and mitral regurgitation further contribute to ventricular filling pressure.
===Systolic Dysfunction===
===Systolic Dysfunction===
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==
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.
==Diagnosis==
==Diagnosis==
===Genetic Testing===
===Genetic Testing===
==Treatment==
==Treatment==
==Prognosis==
==Prognosis==
[[Category:Cardiology Section]]