2 Types of Valvular Dysfunction
a. 2 types: stenotic vs insufficiency
b. Valve disorders more common in left vs right side of heart
Etiology of Aortic Stenosis
- Congenital – abnormal bicuspid formation vs tri-valve semilunar valve
- Degenerative changes
- Inflammatory - 2° to rheumatic heart disease
a. Rheumatic fever – post-infectious systemic inflammatory disease/response due to streptococci bacteria, effects joints, skin, CNS and heart
b. Rheumatic heart disease – untreated rheumatic fever can scar/deform heart structures (i.e. valves) - Other: CAD risk factors, genetics
Primary Mechanical effects on cardiac pump for Aortic Stenosis
a. Reduced outflow of left ventricle (LV)
b. Incomplete emptying of left ventricle/increased end-systolic LV pressures
Secondary Mechanical Effects on Cardiac pump for Aortic Stenosis
a. Hypertrophy of left ventricle as compensation to increased workload
d. Hypertrophy may cause coronary circulation insufficiency
i. Coronary capillary density insufficient for myocardial hypertrophy
ii. May lead to ischemia and potential dysrhythmias
e. All above may progress to MI/heart failure
Output changes and Cardiac pressure for Aortic Stenosis
b. Output changes:
i. ↓SV/↓CO, ↓systolic BP, ↓pulse pressure
c. Cardiac pressure/congestion changes:
i. ↑ left atrial pressure (↑ PCWP), pulmonary HTN, ↑ pulmonary pressures lead to edema
Clinical for Aortic Stenosis
- Classic: Dyspnea on exertion (DOE), syncope, angina symptoms
a. can progress to heart failure - Heart murmur: systolic
a. Auscultate aortic valve: right parasternal 2nd intercostal space (see anatomy notes)
b. Murmur heard during systolic phase
Mitral Valve Stenosis Etiology
- Rheumatic heart disease
2. female > male
Primary Mechanical effects on cardiac pump for Mitral Valve Stenosis
a. Reduced outflow of left atria
b. Incomplete emptying of left atria/increased LA pressures
Secondary Mechanical effects on Cardiac Pump for Mitral Valve Stenosis
a. Left atria dilation due to incomplete emptying of left atria and hypertrophy as compensation to increased workload
d. Atrial wall changes may lead to ischemia and potential atrial dysrhythmias
i. Blood flow stasis of A-flutter/fib will add risk of thrombi formation
e. All above may progress to right sided heart failure
Output changes and Cardiac pressure for Mitral Valve Stenosis
b. Output changes:
i. Potential exertional insufficiency of ↓SV/↓CO
c. Cardiac pressure/congestion changes:
i. ↑ left atrial pressure (↑ PCWP), pulmonary HTN, ↑ pulmonary pressures lead to edema, right ventricular congestion/failure
Clinical for Mitral Valve Stenosis
- Prominent pulmonary symptoms/complications due to pulmonary HTN/edema
a. DOE, orthopnea (difficult breathing laying down/easier sitting up), nocturnal dyspnea, etc… - Non-angina type chest discomfort (atypical chest pain)
- Heart murmur: diastolic (narrowed AV valve during ventricular filling)
a. Auscultate mitral valve: left 5th intercostal space along mid-clavicular line (i.e apex) - see anatomy notes
b. Murmur heard during diastolic phase
Etiology of Aortic Insufficiency
- Congenital
- Secondary to disease pathology
a. Rheumatic heart disease, bacterial endocarditis, CAD
b. CT disorders and other systemic diseases
Primary Mechanical effects on cardiac pump for Aortic Insufficiency
a. During ventricular relaxation (diastole) blood from aorta “back-flows” into left ventricle
b. Increased end-diastolic filling volumes of left ventricles
Secondary Mechanical effects on cardiac pump for Aortic Insufficiency
a. Dilation and hypertrophy of left ventricle
i. Left ventricular dilation to compensate/maintain SV/CO volumes
ii. Left ventricular hypertrophy to compensate for increased workload with larger SV/CO
c. Potential for dysrhythmias and associated complications due to wall changes
d. Heart failure occurs as compensation mechanisms can’t maintain cardiac output
Cardiac and Output changes in Aortic Insufficiency
b. Cardiac pressure/congestion changes:
i. ↑ pulmonary pressure and edema
c. Output changes:
i. ↑ SV/CO to accommodate for “back-flow loss”
ii. ↑ systolic BP, ↓ diastolic BP, ↑ pulse pressure
Clinical for Aortic Insufficiency
- Angina type discomfort, DOE
- Bounding peripheral pulses (from pulse pressure changes)
- Heart murmur: diastolic
a. Auscultate aortic valve: right parasternal 2nd intercostal space (see anatomy notes)
b. Murmur heard during diastolic phase
Etiology of Mitral Valve Insufficiency
- Rheumatic heart disease
- Mitral valve prolapse
- Other: CAD, congestive cardiomyopathy, systemic CT disorders
Primary Mechanical effects on cardiac pump for Mitral Valve Insufficiency
a. Back flow of blood into left atria during ventricular contraction (systole)
i. Increased left atrial volumes/pressures
ii. Leads to left atrial dilation/hypertrophy
iii. Viscous cycle as atrial dilation may enlarge mitral valve opening more
b. Increased ventricular filling volumes/pressures due to increased filling volumes from atria
i. Hypertrophy and dilation of left ventricle follows
c. Increased atrial pressures also may lead to congestive back-up into pulmonary circulation as previously described
i. Increased PCWP, pulmonary HTN/edema
d. Eventually compensation fails to maintain CO and heart failure occurs
Clinical for Mitral Valve Insufficiency
- Gradual onset that may not manifest until heart failure symptoms develop
- DOE, non-angina like chest discomfort
- Heart murmur: systolic
a. Auscultate mitral valve: left 5th intercostal space along mid-clavicular line (i.e apex) - see anatomy notes
b. Murmur heard during throughout systolic phase
Mitral Valve Prolapse Syndrome
- Most common valve disorder in US
2. Enlarged cusps of mitral valve prolapse back into left atrium during systole
Pathogenesis for mitral valve prolapse Syndrome
a. Abnormal connective tissue accumulation/degeneration in the leaflets cause enlargement
b. The cusps will billow back into the atria
c. Chordae tendineae become stretched/elongated as cusps billow back
d. Eventually cusps may not be able to fully close and mitral valve regurgitation develops
Clinical for Mitral Valve Prolapse Syndrome
a. May, or may not, be symptomatic – large continuum of clinical presentation/prognosis
i. Routine exam reveals: mid-systolic click or systolic murmur
b. Majority of patients have good prognosis without symptoms/complications
c. Some individuals at risk of more severe consequences
i. Rupture of chordae tendineae, emboli formation, ventricular failure, etc..
ii. Infective endocarditis, stroke, death
Etiology for Tricuspid Valve Insufficiency
- Congenital
2. Secondary result of pulmonary HTN pathologies
Mechanical effects on cardiac pump for Tricuspid Valve Insufficiency
- Pulmonary HTN/congenital regurgitation causes back flow into right atria
a. Increased right atrial pressures creates increased venous pressures (increased CVP)
b. Increased atrial volumes/pressures progress to increased right ventricular volumes/pressures (see above)
c. Right ventricular hypertrophy/dilation compensate to maintain cardiac output - Compensation eventually fails and right sided heart failure occurs
