CAM201 Lecture Notes - Lecture 9: Pulse Pressure, Aortic Valve Replacement, Pressure Overload
The Basics
• Valves are thin, translucent membranes
• Allow blood to flow freely in one direction
• Stenotic
• Incompetent (regurgitation)
• Can be congenital or acquired
• Acute or chronic
• Spectrum changes (as with Rheumatic fever)
Management
Medical
• Prevent endocarditis
• Prevent thromboembolism and arrhythmias
• Reduce preload (diuretics via increasing salt and water excretion)
• Reduce afterload (vasodilators to reduce systemic BP)
Surgical
• Repair
• Replace
• Tissue (Xenograft, Homograft)
• Prosthetic valves
• Bioprosthetic from cadava or animal
Why do Hearts Fail?
• increased afterload and work causes hypertrophy
• Increased volume causing dilation
• Starlings Law dictates that efficiency will decrease overtime after a certain dilation
• Hypertrophy increases ventricular stiffness and increase filling pressure
• Decreased CO causes catecholamine drive (more adrenaline and NA)
• Prolonged catecholamine drive results in catecholamine depletion
• Decreased CO reduces GFR causing fluid retention and aldosterone release
• Chronic volume and pressure overload leads to eventual muscle failure
Manifestations of Heart Failure
• Forward (increased)
• Fatigue
• Dyspnoea
• Syncope
• Angina
• Backwards (decreased)
• Pulmonary oedema
• Right heart strain and failure as pressure rises
• Elevated JVP
• Hepatosplenomegaly
• Ascites
• Peripheral oedema
Approach
• What is the lesion?
• Where?
• Severity?
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• Consequences?
• Aetiology?
• Management?
Mitral Stenosis (MS)
Aetiology
• Rheumatic
• Congenital
• Calcification
Haemodynamics
• Elevated LA pressure, due to narrowed valve
• Elevated Pulmonary arterial pressure
• JVP prominent 'a' wave and gradual 'y' descent
• Normal LV diastolic pressure
Clinical Features
Examination
Inspection
• Malar flush
• Peripheral cyanosis (severe MS)
• Jugular venous distension (RV failure)
Palpation
• Parasternal RV impulse
• Palpable pulmonary arterial impulse
• Palpable S1, S2, and occasionally, the diastolic rumble
Auscultation
• Increased intensity of the first heart sound
• Opening snap
• Low-pitched diastolic rumbling murmur
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• Diastolic murmur in MS
• OS is opening snap and diastolic gurgling of mitral valve
Investigation
• LA/LAA enlargement
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Document Summary
The basics: valves are thin, translucent membranes, allow blood to flow freely in one direction. Incompetent (regurgitation: can be congenital or acquired, acute or chronic. Medical: prevent endocarditis, prevent thromboembolism and arrhythmias, reduce preload (diuretics via increasing salt and water excretion, reduce afterload (vasodilators to reduce systemic bp) Surgical: repair, replace, tissue (xenograft, homograft, prosthetic valves, bioprosthetic from cadava or animal. Why do hearts fail? increased afterload and work causes hypertrophy. Syncope: angina, backwards (decreased, pulmonary oedema, right heart strain and failure as pressure rises, elevated jvp, hepatosplenomegaly, ascites, peripheral oedema. Haemodynamics: elevated la pressure, due to narrowed valve, elevated pulmonary arterial pressure. Jvp prominent "a" wave and gradual "y" descent: normal lv diastolic pressure. Inspection: malar flush, peripheral cyanosis (severe ms) Palpation: parasternal rv impulse, palpable pulmonary arterial impulse, palpable s1, s2, and occasionally, the diastolic rumble. Increased intensity of the first heart sound: opening snap.
