Pulmonary valve

The semilunar valves separate the ventricles from their associated arteries. The pulmonary valve is found between the right ventricle and the pulmonary artery and the aortic valve is found between the left ventricle and the aorta. These valves prevent backward flow of blood from the pulmonary artery or the aorta into their preceding ventricles when the ventricles relax. The semilunar valves also have three cusps. There are no valves between the venae cavae or the pulmonary veins and the atria into which they deliver blood. The closure of the valves causes the "lub-dub" associated with the heart beat. Tire first heart sound, or the "lub," occurs when the ventricles contract and the AV valves close. The second heart sound, or the "dub," occurs when the ventricles relax and the semilunar valves close. 

Heart sounds Sound Si occurs at the beginning of systole as the mitral and tricuspid valves close S2 occurs at the beginning of diastole as the aortic and pulmonary valves close. These points should be in line with the beginning of electrical depolarization (QRS) and the end of repolarization (T), respectively, on the ECG trace. The duration of Si matches the duration of isovolumic contraction (IVC) and that of S2 matches that of isovolumic relaxation (IVR). Mark the vertical lines on the plot to demonstrate this fact. 

Pulmonary atery (PA) As the catheter moves into the PA, the diastolic pressure will increase owing to the presence of the pulmonary valve. Normal PA systolic pressure is the same as the RV systolic pressure but the diastolic pressure rises to 10-15 mmHg. 

Fig. 4. Preparation of the fixed heart for visceral examination. Cut 1 Ventral view Open the right ventricle along the septum in baso-apical direction going trough the aorta and the truncus pulmonalis (cross pulmonary valve) dorsal view open right ventricle near the septum from the heart apex towards the right atrium (through tricuspidal valve). Cut2 Ventral view Open the left ventricle along the septum from the heart apex into the left atrium (through bicuspidal valve) dorsal view cut the wall of left ventricle from the heart apex towards the left atrium.

Wagner et al. (3) prepared elastomeric materials consisting of biodegradable poly(urea-urethanes), (II), containing microintegrated cells that were useful as pulmonary valves, vocal chords, and blood vessels. 

A full-term girl with pulmonary atresia and an intact intraventricular septum had balloon dilatation of the pulmonary valve performed on the third day of life. 

The first report of percutaneous balloon dilation of a pulmonary valve was published in 1982 (14). Today the transcatheter approach has largely replaced surgical valvulotomy for pure stenosis. Surgery is only necessary when balloon dilatation was not successful or other heart abnormalities demand an open heart procedure. 

Currently transcatheter replacement of heart valves is limited to the aortic and pulmonary valves. 

Kan JS, White Rl Jr, Mitchell SE, et al. Percutaneous balloon valvuloplasty a new method for treating congenital pulmonary-valve stenosis. N Engl J Med 1982 307(9) 540-542. 

Bonhoeffer P Boudjemline Y Saliba Z et al. Percutaneous replacement of pulmonary valve in a right-ventricle to pulmonary-artery prosthetic conduit with valve dysfunction. Lancet 2000 356 1403-1405. 

Phenylpropanolamine (norephedrine) is similar but with less CNS effect. Prolonged administration of phenylpropanolamine to women as an anorectic has been associated with pulmonary valve abnormalities and led to its withdrawal in some countries. 

Right Ventricle Pumps blood to the pulmonary artery through the pulmonary valve and pulmonary trunk to the lungs where C02 is exchanged for 02... 

Noonan s syndrome (short stature, pulmonary valve stenosis, hypertelorism, and ptosis)... 

AO Aorta MPA Main pulmonary artery RSCV Right superior vena cava TV Tricuspid valve MV Mitral valve PV Pulmonary valve AV Aortic valve RA Right atrium LAA Left atrial appendage RV Right ventricle LV Left ventricle LV-PM Left ventricle, muscle IVS Interventricular septum CR Crista supraventricularis SN sinus node AVN + B Atrioventricular node LBB Left bundle branch. 

The mitral and aortic valves are affected most commonly in cases involving a single valve. Subacute endocarditis tends to involve the mitral valve, whereas acute disease often involves the aortic valve. Up to 35% of cases involve concomitant infections of both the aortic and the mitral valves. Infection of the tricuspid valve is less common, with a majority of these cases occurring in patients with a history of IVDA. It is rare for the pulmonary valve to be infected. ... 

Lurz P, Coats L, Khambadkone S, et al. Percutaneous pulmonary valve implantation. Impact of evolving technology and learning curve on clinical outcome. Circulation 2008 117 1964-72. 

Right ventricular failure can occur due to chronic lung disease, pulmonary valve disease and congenital defects. The symptoms are systemic oedema, particularly of the legs and ankles. 

FIGURE 10.5 (a) The chambers and valves of the heart. LV, left ventricle RV, right ventricle LA, left atrium RA, right atrium M, mitral valve A, aortic valve T, tricuspid valve P, pulmonary valve, (b) The left ventricular cardiac cycle in the P-V plane. See text. 

The cardiac pump theory advocates that there is (direct) pressure on the ventricles. This is supported by indications that compression depth is related to output, that cardiac (or more specifically ventricular) deformation is related to stroke volume, that the duration of compression has no effect, and that an increased compression rate will increase flow [17]. In the original manuscripts, as well as over time, 1.5 to 2 in. (4 to 5 cm) has been maintained as standard. Forward flow of blood is assumed to be caused by competent atrioventricular valves and sufficient competence of the aortic and pulmonary valves to avoid regurgitation during CPR diastole. Implicitly, ventricular filling is essential and artificial systole must be sufficiently frequent to generate acceptable flow, as stroke volumes may be relatively small compared to the normal 60 to 100 ml per beat at ejection fractions of 40 to 75%. Mitral valve closure during CPR systole is deemed essential for the cardiac pump theory to work. 

FIGURE 55.4 Velocity profiles downstream of the human pulmonary valve obtained with magnetic resonance phase velocity mapping [Sloth, 1994]. Again the timing of the measurements is shown by the market on the flow curve. 

Pulmonary valve Direction of blood flow Right ventricle... 

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