Valvular heart disease (aortic + mitral)
Rheumatic Fever and Valvular Heart Disease
Aortic Stenosis
Causesà congenitalà valvularà bicuspid aortic valves (1 -2% of population, undergo accelerated degenerative changes)
à non-valvularà discrete subaortic membrane (formation of fibrous ridge or diaphragm below aortic valve) and supravalvular aortic stenosis (congenital fibrous diaphragm above the aortic valve often associated with mental retardation and hypercalcaemia; William’s Syndrome)
àRheumatic Feverà results in progressive fusion, thickening and calcification of the valve. Second most common valve involved after mitral valve
àCalcific Valvular diseaseà common cause of stenosis in the elderly. Usually due calcification of lipoprotein in the subendotheluim matrix in atherosclerosis. Thus increasing leaflet stiffness and reducing systolic opening.
Pathophysiology--> AS causes fixed outflow obstruction and left ventricular pressure overload. Compensatory left ventricular hypertrophy increases myocardial demand and ischemia can develop even in the absence of CAD. Hypertrophy causes decreased chamber compliance and diastolic left ventricular dysfunction LVF.
Clinical Presentation--> Midsystolic murmur heard loudest in the second right intercostals space and transmitted to the neck. Also when patient is sitting up and in full expirationSmall and slow-rising arterial pulse, systolic thrill in the second right intercostals space or suprasternal notch and sustained apical impulse.Aortic ejection sound is present and second heart sound is normal but sometimes reversed split can occur in severe obstruction.Symptoms= angina pectoris, exertional syncope and LVF. Atrial fibrillation can occur as well.
Aortic Regurgitation
Causesà acuteà Valvular-Infective EndocarditisAortic root- Marfan’s syndrome, dissecting aneurysm of the aortic root
à chronicà Valvular- Rheumatic (infective endocarditis)Congenital- bicuspid valve, ventricular septal defectAortic root dilatation- Marfan’s syndrome, aortitis (seronegative arthropathies, rheumatoid arthritis, tertiary syphilis) and dissecting aneurysm.
Pathophysiologyà Regurgitation causes reflux of blood from aorta through the aortic valve into the left ventricle during diastole. Thus reduces CO. To compensate LV has to pump harder to maintain COLeft ventricular volume overloadà left ventricular dilatation enhances chamber compliance and end-diastolic volumes can be accommodated without a rise in filling pressure.In long termà progressive ventricular dilatation eventually leads to congestive heart failure.In large regurgitant volumes, it can result in rapid increasing diastolic filling pressure, pulmonary oedema and shock.
Clinical Presentationà Patient present with complaint of heart pounding and vigorous pulsation, shortness of breath and angina pectoris.Pulse- characterized as collapsing (a water hammer pulse) and BP with wide pulse pressure.Diastolic thrill can be felt at the left sternal edge when patient sits up and expire.A decrescendo high-pitched mid-diastolic murmur beginning immediately after the 2nd heart sound at left sternal edge.An Austin murmur (mid-systolic) at mitral area, mimicking mitral stenosis.
Mitral Stenosis
Causesà Most common valve to be affected in rheumatic heart disease following an acute rheumatic fever.Congenital parachute valve- all chordae insert into one papillary muscle. (rare)
Pathophysiologyà Commissural fusion and degeneration change in the mitral apparatus obstruct left ventricular inflow. This causes an increase in left atrial pressure to maintain left ventricular filling àleft atrial chamber dilation, pulmonary venous congestion and secondary pulmonary arterial hypertension à right heart failure.
Clinical Presentationà symptoms- dypsnoea, ortopneoa, paroxysmal norturnal dyspnoea, haemoptysis; ascites, oedema.à Atrial fibrillation can occur due to atrial dilation.àPalpable S1- tapping quality of the apex beat, and right ventricular heave.à On auscultation- Loud S1(valve cusps widely apart at the onset of systole. Low pitched mid-diastolic murmur at mitral area (best heard with a bell with patient in the left lateral position)
Mitral Regurgitation
Causesà Rheumatic heart disease (infective endocarditis, myocarditis)Papillary muscle dysfunction secondary to IHDDilated Cardiomyopahy (IHDConnective tissue disease (SLE)Collagen abnormalities (Marfan’s syndrome and Ehlers-danlos syndromeDegeneration of the valve cusps or mitral annular calcification.Drugs- fenfluramine
Pathophysiologyà In acute mitral regurgitation, the normal compliance of the left atrium does not allow much dilation but atrial pressure rises. In chronic regurgitation, atrial and ventrical dilation can occur since a proportion of the stroke volume is regurgitatedà the stroke volume increases to maintain the forward cardiac outputà left ventricular failure.Pulmonary venous hypertension is common either due to increase pressure in atrial chamber or left ventricular failure.
Clinical presentationàSymptoms are related to left heart failure and atrial or ventricular arrhythmiaà Dyspnoea and ortopnoeaà laterally displaced (forceful) diffuse apex beat and systolic thrill at apex areaà Parasternal heave due to left atrium enlargementà Pansystolic murmur maximal in the apex and radiating towards the axilla. Soft or absent S1(atrial and ventricular pressures have equalized and the valve cusps have drifted back together) and left ventricular S3 which is due to rapid left ventricular filling in the early diastole.
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