Flashcards in L29. Valve Diseases Deck (26):
What is Stenosis?
A narrowing of the valve leading to a restriction of flow
Causes a pressure gradient across the valve
Increase in the pressure chamber behind it
= PRESSURE OVERLOAD
What is Regurgitation?
A leaky or incompetent valve that doesn't close fully. Blood leaks back into the previous chamber.
The heart is required to pump a higher SV in order to maintain the same overall CO. (Leads to increased ESV) and increased ejection fraction
= VOLUME OVERLOAD
How do we diagnose valve diseases by clinical examinations?
Stenosed and incompetent valves cause TURBULENT blood flow which can be heard as murmurs.
Are all murmurs pathogenic?
NO - some are benign and can occur in high flow/high output states like in children, fever, anaemia and pregnancy
What are the major causes of valvular heart disease?
Rheumatic Fever (decreasing incidence in western countries)
Are all valvular diseases symptomatic?
No: mild and moderate lesions are asymptomatic because cardiac compensation is very effective for many years
What happens when cardiac compensation for valvular disease begins to fail?
Ventricular enlargement and irreversible failure of the heart (loss of contraction)
Symptoms present: Eg. Shortness of breath
Other irreversible changes to the heart occur
What is the Gold Standard Assessment Method for diagnosis of valvular disease?
Echocardiography - gives diagnosis, severity, ventricular size and function, atrial size, pulmonary artery pressure
- can show LV changes before they are irreversible
What are the major interventions for valve diseases?
Heart Valve replacements (metal, plastic, bioprosthesis, stents)
Describe aortic stenosis
Progressive narrowing of the aortic valve that can lead to fibrosis and calcification
Reduced area 2.5)
Leads to an increased pressure in the heart: PRESSURE OVERLOAD and subsequent concentric hypertrophy. The increased LVEDP and atrial kick are important
What kind of murmur is heard in aortic stenosis?
Blood cannot get out of the heart easily and thus turbulent flow during ejection/systole
= SYSTOLIC MURMUR (crescendo, decrescendo harsh and rough sound)
What are the outcomes of aortic stenosis?
Usually calcification and is often well tolerated with no symptoms until severity increases to a point where surgical intervention is required.
Describe aortic Regurgitatoin
When the aortic valve is damaged in a way that means it is unable to close.
Leads to an increase in the volume of the ventricle: VOLUME OVERLOAD and subsequent eccentric hypertrophy. The EDP and the EF increase to compensate and maintain an normal SV
What are some causes of Aortic regurgitation?
Damage of the valve itself (endocarditis, rheumatic fever), aortic root dilation (Marfan's syndrome, aortic dissection, collagen disorders
What kind of murmur is heard in aortic regurgitation?
There are problems in keeping the valve shut when it needs to me (diastole) and hence there is a diastolic murmur heard: "Whoosh" sound heard just after S2
and End Diastolic Murmur
What are the outcomes of aortic regurgitation?
Increased Pulse Pressure: Bounding pulse
Often well tolerated without symptoms until decompensation where LV function decreases due to the overload of volume and inability to increase EDP to maintain CO (cardiac failure)
Describe Mitral Valve Regurgitation
When the mitral valve doesn't close properly (leakage during systole back into the atria) which leads to a VOLUME OVERLOAD and subsequent concentric hypertrophy of the atria (not as much as a ventricular hypertrophy)
This increases the EDV and increases EF to compensate
What are some causes of mitral valve regurgitation?
Myxomatous degeneration is the commonest cause (prolapse of the valves with age)
Ruptured chorda tendinae
Myocardial Infarction: ruptured papillary muscle
Collagen vascular diseases
What are the outcomes of mitral regurgitation?
Generally well tolerated until decompensation occurs leading to increased LV diastolic volume.
Thrombus formation can occur in the LA due to accumulated blood
Pulmonary hypertension due to increased back pressure
What kind of murmur is heard as a result of mitral regurgitation?
The valve is not able to keep closed during systole and turbulent back flow into the atrium occurs and so a systolic murmur is heard.
It is a pansystolic sound (same the whole way through systole)
Describe Mitral Stenosis
A progressive narrowing of the mitral valve meaning problems with filling (diastole) and higher pressures need to be made by the atrium (atrial kick) to fill the ventricle (ventricle systolic function is not affected)
What are the causes of mitral valve stenosis
Most often due to preveious rheumatic fever that causes a fibrotic narrowing of the mitral valve
What is the right atrial response to mitral valve stenosis?
Increase in both the pressure and volume in the right atrium which is a risk of fibrillation and thrombus formation.
Increased pulmonary venous pressure leading to pulmonary congestion, oedema and hypoxia leading to pulmonary hypertension
What are the outcomes of mitral valve stenosis?
Well tolerated if mild or moderate but decompensation leads to pulmonary hypertension and other problems.
For valve problems, what does the onset of symptoms usually coincide with?
A need for surgical intervention