心脏瓣膜病 (65p)课件

Valvular Heart Disease,Reading,Klabunde, Cardiovascular Physiology Concepts CD ROM material on Valve Disease,Overview of Valves,Major Factors That Affect Flow Across Any Valvular Lesion,The valve area The square root of the hydrostatic pressure gradient across the valve The time duration of transvalvular flow (applies to both systole and diastole),Valvular Heart Disease,Increasing any of the major factors that affect flow across the valve increases transvalvular flow. Conversely, decreasing any of these major factors decreases transvalvular flow.,Goals in Management of Various Valvular Lesions,Regurgitant Lesions Reduce or minimize regurgitant flow across the mitral or aortic valve. Stenotic Lesions Maximize and enhance stenotic flow across the mitral or aortic valve,Goals in Management of Various Valvular Lesions,The valve area in regurgitant lesions can respond to changes in loading conditions (preload, afterload) The valve area with stenotic lesions is generally fixed,Adult Valvular Heart Disease,Aortic Stenosis Aortic Regurgitaiton Mitral Stenosis Mitral Regurgitation Hypertrophic Obstructive Cardiomyopathy,Aortic Stenosis,Aortic Stenosis,Normal AVA = 2.6 3.5 cm2 Idiopathic Calcific Degeneration Congenital Bicuspid Endocarditis Other Pagets Disease Systemic Lupus Erythematosus,Aortic Stenosis,Aortic Stenosis: Senile,Natural History of AS,May be a long asymptomatic period Symptomatic Usually have severe AS with AVA of 0.9 cm2 or less Presenting symptoms: Angina Syncope CHF,Natural History of AS,Symptomatic patients without surgery show the following average life spans: Angina = 5 years Syncope = 3 years CHF = 2 years AS is considered an independent risk factor for perioperative morbidity,Survival of Patients with Valvular Heart Disease Treated Medically,Pathophysiology of Aortic Stenosis,Aortic Stenosis,Obstruction to LV Ejection,Chronic LV Pressure Overload,LV Hypertrophy,Pressure Gradient Created Across the Valve,Myocardial Function,Develop left ventricular hypertrophy as an adaptation LVH reduces wall stress T =(Pr)/h LVH causes increased diastolic stiffness,Ischemia in AS,Hypertrophied LV muscle mass Increased systolic pressure Prolongation of ejection Shortened diastolic time Relative decrease in myocardial capillary density High incidence of concomitant coronary artery disease,Aortic Stenosis,Measuring the Valve Gradient in AS,Mean gradient Peak-to-peak gradient Peak instantaneous gradient,Degree of Stenosis,Critical AS Peak systolic pressure gradient 50 mmHg AVA 0.9 cm2 Moderate AS 1.0 1.4 cm2 Mild AS 1.5 2.0 cm2,Aortic Stenosis,AORTIC STENOSIS: HEMODYNAMIC GOALS,Aortic Regurgitation,Aortic Regurgitation (Insufficiency),Rheumatic heart disease Endocarditis Aortic root dissection Trauma Connective tissue disorders Dexfenfluramine (appetite suppressant),Aortic Regurgitation,Natural History,Long asymptomatic period during which the LV undergoes progressive eccentric hypertrophy CHF Angina,Aortic Regurgitation,Pathophysiology of Aortic Regurgitation,Backward flow of blood from aorta into LV (Diastolic),Increased LV volume and pressure,Increased SV (Frank-Starling Mechanism),Peak systolic pressure increased because of increased SV ejected into aorta,Increased diastolic wall-tension produces eccentric hypertrophy,Rapid fall of aortic pressure during diastole,Increased pulse pressure,Increased LA pressure,Increased pulmonary venous pressure,Pulmonary edema,Pathophysiology,LV overloading Increased diastolic wall-tension produces eccentric hypertrophy (increase both in chamber size and wall thickness) Reduced diastolic compliance (Acute AI) Very high diastolic compliance (Chronic AI),Eccentric Hypertrophy,Pathophysiology,Baseline myocardial oxygen demand higher than normal because of increased LV mass Reduced coronary perfusion pressure Lower diastolic pressure Increased LVEDP,Pathophysiology,Myocardial contractility is usually preserved until late in course of the disease Late in disease there is progression to irreversible contractile impairment,Aortic Regurgitation,AORTIC REGURGITATION: HEMODYNAMIC GOALS,Mitral Stenosis,Normal MVA = 4 6 cm2,Mitral Stenosis,Causes: Rheumatic Women 4x Men Congenital Rheumatoid arthritis Systemic Lupus Erythematosus Carcinoid Syndrome Asymptomatic for approximately 20 years Presenting symptoms: CHF (50%) Atrial fibrillation,Mitral Stenosis,Pathophysiology of Mitral Stenosis,Obstruction to LA emptying,Increased LA pressure,Increased LA size,Atrial fibrillation,Increased pulmonary artery pressure,Decreased LV filling,RV overload,Increased pulmonary venous pressure,Pulmonary edema,Mitral Stenosis,Pathophysiology,Chronic obstruction to left atrial emptying during diastole LV chronically volume-underloaded Chronic volume and pressure over-loading of the left atrium and structures behind it,Pressure Gradient across the Mitral Valve,Pressure Gradient CO = Cardiac Output DFP = Diastolic Filling Period,Pathophysiology: LV,LV function is usually normal Decreased LVEF in about 1/3 of MS patients: Rheumatic carditis Chronic volume underloading Concomitant CAD Septal hypertrophy in patients with pulmonary hypertension (PHT),Pathophysiology: RV,RV function is normal in absence of pulmonary hypertension (PHT) Severe pulmonary hypertension will result in RV failure and secondary abnormalities of LV function,Mitral Stenosis,MITRAL STENOSIS: HEMODYNAMIC GOALS,Mitral Regurgitation (Insufficiency),Mitral Regurgitation (Insufficiency),Valve leaflets Chordae tendineae Papillary muscles,Mitral Regurgitation (Insufficiency),Rheumatic disease Endocarditis Mitral valve prolapse Mitral annular enlargement Ischemia Myocardial infarction Trauma Fenfluramine diet suppressants,Prolapsed Mitral Valve Leaflet,Mitral Regurgitation,Pathophysiology of Mitral Regurgitation,Backward flow of blood from LV to LA (Systolic),Increased LA volume and pressure,Increased LV filling (Increased LVEDV),Increased SV,Blood ejected into aorta,Left atrial enlargement,Increased pulmonary venous pressures,Pulmonary edema,Pathophysiology,LV “unloads” itself into left atrium Chronic left atrial overload Chronic overload on left ventricle Volume of regurgitant flow determined by: Ventriculo-atrial gradient Diastolic time Size of the regurgitant orifice Measurements of LV function tend to be slightly elevated Moderately depressed ejection fraction in a patient with MR may be indicative of a severely depressed inotropic state,Natural History,Chronic MR (variable course) Chronic MR may be protected from pulmonary congestion by dilated, highly compliant left atrium Acute MR usually with fulminant pulmonary edema,Mitral Regurgitation,MITRAL REGURGITATION: HEMODYNAMIC GOALS,Hypertrophic Cardiomyopathy,Hypertrophic Cardiomyopathy,Primary disease of cardiac muscle Histologic evidence of myocardial cellular disarray Characteristics LVH (often marked in the septum) Reduced diastolic compliance Subvalvular pressure gradient Ventricular a