Valve Dysfunction Flashcards
what are some causes of valve dysfunction?
infections (including tooth plaque), congenital deformity (2 leaflets instead of 3, can’t fully close), disease (rheumatic fever)
what are the two classifications of valve dysfunction?
functional (stenosis, insufficient) or anatomical deformity (prolapse, congenital)
why is valve dysfunction a problem?
heart works harder, eventually will hypertrophy leading to decreased ventricle space, walls get thicker, decreased CO
what is stenosis in valve dysfunction?
impedence of forward flow due to incomplete or narrowed opening of valves
what is insufficiency in valve dysfunction?
incomplete closing of valve leading to regurgitation/back flow of blood
what are murmers in valve dysfunction
turbulence of flow heard during auscultations cause by stenosis or regurgitation
how is the severity of valve dysfunction scored?
mild, moderate, severe, or critical based on valve diameter, degree of regurgitation, and calculation of blood flow across valve
what aortic valve area is mild?
> 1.5 cm2
what aortic valve area is moderate?
1.0 - 1.5
what aortic valve area is severe?
< 1.0
what aortic valve area is critical?
< 0.6
what is the pathophysiology of aortic stenosis?
narrowing of valve –> increased afterload –> increased LV systolic pressure and LV volume overload –> LV hypertrophy –> decreased stroke volume and decreased compliance –> systolic function maintained for a while especially @ rest –> eventual systolic and diastolic dysfunction
what causes mitral regurgitation?
damage to papillary muscles from MI, heart gailure, congenital, endocarditis, rheumatic fever(most common cause of mitral regurgitation due to untreated strep)
what is the pathophysiology of chronic mitral regurgitation?
incompetent valve –> increased blood volume in left atrium –> blood can backflow through pulm. veins –> left atrium dilates over time –> reduced atrial pressure –> reduced atrial kick –> reduced LV EDV –> reduced cardiac output
what causes mitral stenosis?
progressive calcium deposits, congenital, rheumatic fever