Heart Valves

the valve opening narrows the valve leaflets may become fused or thickened that the valve cannot open freely obstructs the normal flow of blood

EFFECTS: the chamber behind the stenotic valve is subject to greater stress must generate more pressure or work hard to force blood through the narrowed opening

initially, the compensates for the additional workload by

gradual hypertrophy and dilation of the myocardium heart failure

scarring and retraction of valve leaflets or weakening of supporting structures incomplete closure of the valve result to leakage or backflow of blood from the previous chamber

EFFECTS: causes the to pump the same blood twice (as the blood comes back into the chamber)

the dilates to accommodate more blood (the usual blood it needs to pump + regurgitated blood) ventricular dilation and hypertrophy eventually leads to heart failure

Congenital heart disease Rheumatic heart disease Heart attack – damage to the heart muscle, papillary muscles Weakening of supporting structures of the heart Weakening of the heart muscle Infections – bacterial endocarditis

most common valvular disorder in rheumatic fever may also be caused by bacterial infection, thrombus formation, calcification obstruct blood flow from left atrium to the left ventricle

Narrowing of mitral valve

CO

O2/CO2 exchange(fatigue, dyspnea,

orthopnea)

Left ventricular

atrophy

pulmonary congestion

pulmonary pressure

left atrial pressure

Hypertrophy left atrium

blood flow to left

ventricle

Right-sided failure

Fatigue

exertional dyspnea and fatigue (most common) orthopnea, paroxysmal nocturnal dyspnea, cough, hemoptysis cyanosis Right-sided heart failure – distended neck veins, peripheral edema, hepatomegaly, abdominal discomfort Auscultation: S1 followed by an opening snap--created by

forceful opening of mitral valve- rumbling diastolic murmur (apex)

CXR- left atrial enlargement ECG – atrial fibrillation may develop (50-80% of pts.)

- pulses becomes irregular & faint, BP Echocardiogram (2D Echo) – most sensitive in diagnosis

Na+ restriction, diuretics – to relieve pulmonary congestion bed rest, sitting position Digitalis – improve cardiac contraction, HR, treat atrial fibrillation Anticoagulants (blood thinners) – coumadin, aspirin, ticlopidine (Ticlid), Plavix, dipyridamole Surgical interventions:

Mitral commissurotomy – separation or incision of the stenosed valve leaflets at their borders or commissures

Balloon mitral valvuloplasty Mitral valve replacement – when stenosis is severe

Balloon mitral valvuloplasty

incomplete closure of the mitral valve rheumatic disease is the predominant cause may also be due to congenital anomaly, infective endocarditis, rupture of papillary muscle following MI

a leaking mitral valve - Stroke volume, CO - Left atrial hypertrophy- Pulmonary congestion

Incomplete closure of mitral valve

vol. of blood ejected by left ventricle

Left atrial pressure

Right-sided heart failure

Left atrial hypertrophy CO

Pulmonary pressure

Backflow of blood to the left atrium

Right ventricular pressure

Fatigue & weakness – due to CO – predominant complaint exertional dyspnea & cough – pulmonary congestion palpitations – due to atrial fibrillation (occur in 75% of pts.) Right-sided heart failure – distended neck veins, edema, ascites, hepatomegaly Auscultation: blowing, high-pitched systolic murmur (apex)

- S1 is diminished - S3 –severe regurgitation

restrict physical activity – to prevent fatigue & dyspnea Na+ intake, diuretics – relieve congestion Digitalis, vasodilators – promote adequate ventricular emptying and prevent or decrease regurgitation ACE inhibitors – arterial dilation, afterload Surgery:

- Valvuloplasty (repair or reconstruction)- Valve replacement

Mitral Valve Prolapse

when 1 or both of the valve leaflets bulge into the left atrium during ventricular contraction more common in women Cause: due to an inherited connective tissue disorder enlargement of one or both valve leaflets Elongates/stretches the chordae tendinae & papillary muscles regurgitation may occur usually asymptomatic Extra heart sound (Mitral click) – an early sign that a valve leaflet is ballooning into the left atrium fatigue, shortness of breath arrhythmias may develop – dizziness, chest pain, dyspnea, palpitations, syncope high-pitched late systolic murmur

Interventions: antibiotic prophylaxis to prevent endocarditis If w/ dysrhythmia – avoid caffeine, alcohol, stop smoking anti-arrhythmic drugs for chest pain – nitrates, calcium channel blockers, beta blockers surgery not indicated

may be due to rheumatic heart disease, atherosclerosis, congenital valvular disease or malformations narrowing of the aortic valve

flow of blood from the left ventricle to the aorta

blood volume and pressure in the left ventricle

Left ventricle hypertrophy develops as a

compensatory mechanism to continue pumping blood

through the narrowed opening

Aortic Stenosis

Aortic Stenosis

Stiffening/Narrowing of Aortic Valve

Incomplete emptying of left atrium

Left ventricular hypertrophy

Pulmonary congestionCompression of

coronary arteries

Right-sided heart failure

CO

Myocardial O2 needs

Myocardial ischemia(chest pain)

O2 supply

fatigue & exertional dyspnea – 1st symptoms – due to COand pulmonary congestion

chest pain (angina) – most common symptom- occurs during exercise – due to inability of the heart to

increase coronary blood flow to cardiac muscle

exertional syncope, vertigo, periods of confusion -- CO weakness, orthopnea, PND, pulmonary edema (severe cases) signs of right-sided heart failure –- end-stage symptoms

- if untreated, survival rate: 1.5-3 years Auscultation: harsh, rough, mid-systolic murmur

restrict activity digitalis Na+ restriction, diuretics Nitroglycerin – for chest pain Surgical:

Balloon aortic valvuloplasty Aortic valve replacement – if not done –- poor

prognosis

may be due to rheumatic fever – most common cause other causes: connective tissue disease (Marfan’s syndrome), severe hypertension, congenital anomaly

Incomplete closure of the aortic valve

Backflow of blood to Left ventricle

Left ventricular hypertrophy & dilation

Left atrial pressure

Left-sided heart failure(late stage)

Left atrium hypertrophy

CO Pulmonary pressure

Right-sided heart failure

Right ventricular pressure

pt. may remain asymptomatic for years --- heart compensates by hypertrophy & dilation 1st s/sx- heightened awareness of the heart beat & palpitations esp. when pt. lies on left lateral position tachycardia, PVC assoc. w/ left ventricular dilation bounding pulse, marked carotid artery pulsation, apical pulse force and volume of contraction of the hypertrophied left ventricle Decompensation occurs (cardiac muscle fatigue)

exertional dyspnea chest pain – myocardial ischemia left-heart failure – fatigue, orthopnea, PND right-heart failure – peripheral edema

Auscultation: soft, blowing diastolic murmur

antibiotic prophylaxis before any invasive or dental procedures avoid physical exertion, competitive sports vasodilators, calcium channel blockers, ACE inhibitorsAortic valvuloplasty or valve replacement

usually occurs together w/ aortic or mitral stenosis may be due to rheumatic heart disease blood flow from right atrium to right ventricle

right ventricular output

left ventricular filling CO blood accumulates in systemic circulation systemic pressure S/Sx: symptoms of right-sided heart failure

- hepatomegaly- peripheral edema- neck vein engorgement- CO – fatigue, hypotension

uncommon, may be caused by RF, bacterial endocarditis may also be caused by enlargement of right ventricle an insufficient tricuspid valve allows blood to flow back into the right atrium venous congestion & right ventricular output blood flow towards the lungs

may not produce any symptoms  moderate-to-severe tricuspid regurgitation exist, the ff. may result:

Active pulsing in the neck veins Swelling of the abdomen Swelling of the feet and ankles Fatigue, tiredness Weakness Decreased urine output

on palpation, there may be a lift (beating of enlarged right ventricle) murmur on auscultation

rare, usually congenital in origin flow of blood to the pulmonary artery due to narrowing

blood flows back to right ventricle and right atrium

right ventricle hypertrophy to compensate for blood volume and force blood to the pulmonary arteryS/Sx:

harsh systolic murmur fatigue, dyspnea on exertion, cyanosis poor weight gain or failure to thrive in infants hepatomegaly, ascites, edema

a rare condition caused by infective endocarditis, tumors or RF

blood flows back into Right ventricle Right ventricle and atrium hypertrphy symptoms of Right-sided heart failure

Valvuloplasty is repair of cardiac valve• pt. does not require continuous anti-coagulant medication• usually require cardiopulmonary bypass machine

1.Commissurotomy – to separate the fused leaflets Balloon Valvuloplasty – performed in the cardiac cath.

lab. - balloon inflated for 10-30 secs., w/ multiple

inflations - common used for mitral and aortic stenosis

Closed surgical valvuloplasty – done in the OR under GA

- midsternal incision, a small hole is cut into the heart, the surgeons finger or a dilator is used to open the commissure

Open Commissurotomy – done w/ direct visualization of

the valve, thrombus and calcifications may be identified

and removed

2. Annuloplasty is repair of valve annulus (junction of the valve leaflets and the muscular heart wall)

- narrows the diameter of the valve’s orifice, useful for valvular regurgitation

3. Chordoplasty is repair of chordae tendineae- done for mitral valve regurgitation – caused by stretched, torn or shortened chordae tendineae

Mechanical valves – Ex. Caged ball valve, Tilting-disk valve- more durable, used for younger pts.- risk of thromboembolism – long-term use of anti-

coagulants Tissue or biological valves:

- xenografts – porcine or bovine heterografts (7-10 yrsviability)

- homografts – from cadaver tissue donations (10-15 yrs)- autografts – excising the pts.’s own pulmonic valve and

portion of pulmonary artery for use as the artic valve Long-term anticoagulant therapy Antibiotic prophylaxis