SM 141 Valvular Heart Disease Flashcards
What is the main cause of Mitral Stenosis?
Rheumatic Fever -> Rheumatic Heart Disease
Describe the global burden of Rheumatic Heart Disease?
Rare in developed countries with antibiotics to treat Strep infections, common in developing countries
How does Mitral Stenosis affect the Left Atrium?
Mitral Stenosis increases the contraction pressure of the Left Atrium
What is Mitral Stenosis?
Thickening of the Mitral Valve that leads to LV Hypertrophy, decreased LVEDV and decreased SV
How does the increase in Left Atrial pressure affect the lungs?
Increased Left Atrial pressures leads to fluid backup into the lungs, causing fluid to accumulate in the alveoli
How does Mitral Stenosis affect the right side of circulation?
Increased Left Atrial pressure -> pulmonary congestion -> increase pulmonary pressure -> increase RV/RA Pressure = systemic venous congestion
Does Mitral Stenosis cause systemic congestion or pulmonary congestion?
Both; increasing pulmonary pressure causes congestion that ultimately induces systemic congestion because the 2 circuits of the heart are in series
How does Mitral Stenosis affect cardiac output?
Decreased LVEDV = Decreased CO
How does Mitral Stenosis affect the Left Atrium and what does it predispose?
Increased LA Pressure causes dilation of the LA, which leads to Fibrosis -> Atrial Fibrillation -> Embolism formation
What heart sound indicates LV Hypertrophy?
S4 - always pathologic
What heart sound indicates LV Dilation?
S3 - may be pathologic, can be normal in pregnancy
What does an S4 sound indicate and when does it occur?
S4 indicates loss of compliance of the LV leading to LV Hypertrophy
What does an S3 sound indicate and when does it occur?
S3 indicates the LV is overfilled with blood and leads to LV Dilation
How does Mitral Stenosis affect the Venous return curve?
Increased pressures in the Left Atrium shift the entire curve upward, so that S1 occurs later and Ventricular filling occurs earlier
What murmur presents with an opening snap?
Mitral Stenosis, seen as the presystolic potentiation on the upward shifted venous return curve
What are the physical findings of Mitral Stenosis?
Loud S1, opening snap, diastolic rumble
How does Mitral Stenosis progress with time?
Calcification and thickening of the Mitral Valve continues, leading to increased LA dilation and pressure
What can be used to quantify the extent of Mitral Stenosis?
Ultrasound w/ Doppler, which measures fluid velocity; increased velocity = greater stenosis
How does Atrial Fibrillation affect Mitral Stenosis?
Increased risk of embolism formation
What is a “paroxysmal” rhythm?
One that is entered and exited randomly
How does Mitral Stenosis progress?
Mitral Stenosis progresses over time, varying from mild increases in LA Pressure + RA Pressure + CO only during exercise to increases in LA Pressure + RA Pressure + Decreased CO at rest
When should Mitral Stenosis be treated and why?
Immediately after detected, especially if the patient is symptomatic, because it worsens with time
What is the treatment for Mitral Stenosis?
Mitral Commisurity, which cleaves the calcified commisures to restore valve function, as well as balloon inflation
What causes a bicuspid Aorta?
Normally tricuspid, due to Congenital Aortic stenosis
How can Aortic Stenosis arise?
Congenital AS, Rheumatic AS, and Calcification AS
Why do valve problems occur on the Left side of the heart?
Left side is a high pressure system, Right side is not
Why is a bileaflet Aortic Valve inherently stenotic?
Doesn’t open as much as Trileaflet Aortic Valve
How does Aortic Stenosis affect the Left Ventricle?
Increased LVEDP and decreased SV
Why does Aortic Stenosis cause LV Hypertrophy?
LV needs to hypertrophy to reach higher pressures and overcome increased afterload from Aortic Valve
How does Aortic Stenosis affect LV and Aortic pressures?
LV has to reach higher pressure to eject blood and therefore the Aortic pressure decreases
Why does Aortic Stenosis produce a crescendo-decrescendo murmur?
High increase in pressure to overcome stenotic Aortic valve causes crescendo while drop in pressure causes decrescendo
What are the physical exam findings for Aortic Stenosis?
Delayed Carotid impulse due to higher pressure needed for ejection, systolic thrill, paradoxical S2
What is a thrill?
Feel the murmur from the heart
Explain the mechanism behind paradoxical splitting of S2?
Normal S2 splitting results in Pulmonary Valve closing after Aortic Valve due to increased blood flow and decreased thoracic pressure through the Right Ventricle; Paradoxical splitting in Aortic Stenosis causes the Aortic Valve to close after the Pulmonary valve because it reaches a higher peak pressure to overcome increased afterload
What valvular defect causes paradoxical splitting of S2?
Aortic Stenosis
When is the optimal time to operate in Aortic Stenosis patients and why?
Only operate after symptoms develop, because they decline rapidly and there is no evidence to support early intervention
What are symptoms of Aortic Stenosis?
Dyspnea, Angina, Syncope
What is the treatment for Aortic Stenosis?
Operate and replace Aortic Valve with either a prosthetic valve or a mechanical valve?
How do prosthetic vavles compare to mechanical valves?
Prosthetic valves are made of non-thrombogenic material so clots don’t form and blood thinners aren’t need, but they’re less durable; Mechanical valves are made of metal and form clots, so blood thinners are needed, but they’re more durable
What is the newest treatment for Aortic Stenosis?
TAVR = Transaortic Valve Replacement
