Valvular Heart Disease and Infective Endocarditis

What is valvular heart disease?

Involves stenosis or regurgitation of cardiac valves, leading to pressure or volume overload. Commonly affected valves include the aortic valve and the mitral valve

Stenosis creates ___ overload. Regurgitation creates ___ overload

pressure; volume

What is aortic stenosis?

A fixed, systolic outflow obstruction at the aortic valve. Narrowing of the aortic valve orifice, resulting in increased left ventricular pressure

Narrowing of aortic valve orifice → LV pressure overload → LV hypertrophy

What is the classic traid of symptoms in aortic stenosis?

Angina, syncope, and heart failure

On physical exam of aortic stenosis, what will you hear?

harsh systolic murmur radiating to the carotids - radiation to the neck is a key feature that helps distinguish it from other murmurs

What is the definitive treatment for aortic stenosis?

Valve replacement

What is mitral stenosis?

Obstruction to flow from the left atrium to the left ventricle.

Impaired opening of the mitral valve during diastole → elevated LA pressure → pulmonoary venous congestion and pulmonary edema

• because blood flow is obstructed across the mitral valve, the left atrium dilates and pressure rises → pulmonary congestion and pulmonary HTN → hallmark symptoms of dyspnea, orthopnea, and paroxysmal nocturnal dysnpnea

• Big picture: left atrial enlargement → pulmonary congestion → pulmonary HTN → right sided heart failure

What is mitral stenosis primarily caused by?

rheumatic fever/rheumatic heart disease

In mitral stenosis, the ___ ventricle has to work harder to push blood into the lungs. Over time this can cause what?

right. Can cause tight ventricular hypertrophy and right sided heart failure

What can be heard on physical exam of mitral stenosis?

opening snap followed by low pitched diastolic rumble

What is the definitive treatment for mitral stenosis?

Valve intervention, either repair, replacement, or balloon valvotomy

What characterizes mitral regurgitaion?

Mitral valve fails to close properly during systole. As a result, blood leaks back from the left ventricle into the left atrium while the ventricle is contracting. This increases left atrial volume and pressure

• MR is a volume overload lesion caused by incomplete valve closure. Left atrium dilates, pulm pressure rises, and left ventricular function declines

Clinically, mitral regurgitation produces what sound?

A holosystolic murmur

What is mitral valve prolapse?

Bowing of one or both mitral leaflets into the left atrium during systole. On exam will hear mid-systolic click followed by late systolic murmur

• most cases benign

What is infective endocarditis?

Infection of the endocardial surface of the heart

What is the pathogenesis of infective endocaridits?

1. Endothelial damage to valve surfaces.

2. Formation of a sterile platelet-fibrin thrombus.

3. Bloodborne bacterial colonization of the clot.

4. Formation of an infected vegetation (a meshwork of fibrin, platelets, microbes, and inflammatory cells) that damages valve structure

What organisms commonly are associted with IE?

Staphylococcus; Streptococci; Enterococci

What are the most common and consistent features of IE?

Fever and new murmur. Beyond this there are other signs:

• Petechia

• osler nodes

• Janneway lesions

What are janeway lesions?

Nontender, flat, erythematous lesions on palms or soles caused by septic emboli

What are osler nodes?

Tender and panful nodules on fingers/toes thought to result from immune complex deposition

What are risk factors of IE?

Prosthetic heart valves, pre-existing valvular disease, congenital heart defects, rheumatic heart disease, and IV drug abuse