valvular heart disease Flashcards
what is a normal aortic valve area ?
3-4 cm2
when do symptoms occur in aortic stenosis?
when valve area is 1/4th of normal
what are the three types of aortic stenosis?
Supravalvular
Subvalvular
Valvular
describe the pathophysiology of aortic stenosis
-A pressure gradient develops between the left ventricle and the aorta. (increased afterload)
-LV function initially maintained by compensatory pressure hypertrophy
-When compensatory mechanisms exhausted, LV function declines.
describe the presentation of aortic stenosis
-Syncope: (exertional) 15%
-Angina: (increased myocardial oxygen demand; demand/supply mismatch) 35%
-Dyspnoea: on exertion due to heart failure (systolic and diastolic) 50%
-Sudden death <2%
what are the physical signs of valvular heart disease?
- slow rising carotid pulse and decreased pulse amplitude
- heart sounds- soft or absent second sound, s5 gallop due to LVH
- ejection systolic murmur- crescendo- decrescendo character
- loudness does not tell you anything about severity
what does the onset of treatment show?
The onset of symptoms is an indication of poor prognosis if left untreated.
how do you investigate valvular heart disease?
Echocardiography
what are the two measurements obtained from an echocardiogram
Left ventricular size and function: LVH, Dilation, and EF
Doppler derived gradient and valve area (AVA)
describe the AVA of mild aortic stenosis
> 1.5 cm 2
describe the AVA of moderate aortic stenosis
1.0-1.5 cm2
describe the AVA of severe aortic stenosis
< 1.0 cm 2
what is the general management of AS?
Fastidious dental hygiene / care- small risk of infection going into blood stream
Consider IE prophylaxis in dental procedures
what is the medical management of AS?
limited role since AS is a mechanical problem.
Vasodilators are relatively contraindicated in severe AS
what is the aortic valve replacement management of AS?
Surgical
TAVI – Transcatheter Aortic Valve Implantation
what are the indications for intervention before it gets too severe in aortic stenosis?
Any SYMPTOMATIC patient with severe AS (includes symptoms with exercise)
Any patient with decreasing EF
Any patient undergoing CABG with moderate or severe AS
Consider intervention if adverse features on exercise testing in asymptomatic patients with severe AS
define chronic mitral regurgitation
Backflow of blood from the LV to the LA during systole
Mild (physiological) MR is seen in 80% of normal individuals.
what are the aetiologies of chronic mitral regurgitation ( causes)?
Primary causes ( disease of leaflets- not enough tissue)
1. Myxomatous degeneration (MVP)
2. Ischemic MR
3. Rheumatic heart disease
4.Infective Endocarditis
secondary causes ( normal valve architecture but impaired closure due to abnormal LV/LA geometry)
1. dilated cardiomyopathy
describe the pathophysiology of MR
pure volume overload
compensatory mechanisms
describe the pathophysiology of mitral regurgitation compensatory mechanisms
Left atrial enlargement, LVH and increased contractility
Progressive left atrial dilation and right ventricular dysfunction due to pulmonary hypertension.
Progressive left ventricular volume overload leads to dilatation and progressive heart failure.
what are the physical signs and symptoms of mitral regurgitation?
- Auscultation
- exertion dyspnoea ( exercise intolerance)
- heart failure
what are the physical signs and symptoms of mitral regurgitation- describe auscultation?
-pansystolic murmur at the apex radiating to the axilla
-S3 (CHF/LA overload)
-In chronic MR, the intensity of the murmur does correlate with the severity.
-Displaced hyperdynamic apex beat
what investigations take place in MR
ECG:
CXR:
ECHO:
what may an ECG in MR show?
May show, LA enlargement, atrial fibrillation and LV hypertrophy with severe MR
what may an CXR in MR show?
LA enlargement, central pulmonary artery enlargement.
what may an ECHO in MR show?
Estimation of LA, LV size and function. Valve structure assessment
TOE v helpful