But it should be remembered that right ventricle failure or low output through the pulmonary valve may eventually result in a relatively lower gradient and masquerade a severe PS.
    In the other hand, In case of large cardiac output, the gradient through the same valve area will be higher.
    Due to this lack of accuracy for the evaluation of the degree of stenosis by the valvular gradient, the calculation of the orifice area by the Gorling and Gorling formula is advisable.

CALCULATION OF PULMONARY VALVE AREA (PVA)

Co = Cardiac Output
SEP = Systolic Ejection Fraction or period
HR = Heart Rate
RVsMP = Mean Right Ventricular Systolic Pressure
MPAsMP = Mean Pulmonary Artery Pressure

    In case of intact atrial and ventricular septum, central cyanosis will not be present, but if critical PS is present with right ventricle failure, low output and high tisular oxygen extraction, the patient may present peripheral cyanosis.
    If patent foramen ovale appears late in the course of the disease, a patient until then acyanotic may turn cyanotic in a matter of weeks (ASD is a phase in the evolution of many of these patients).
    There is another group where severe pulmonary or infundibular stenosis is associated with patent foramen ovale or ostium secundum since birth and with cyanosis. These patients are categorized as Trilogy of Fallot.

CLINICAL PICTURE

    The symptomatology will depend upon the severity of PS. The most common symptoms in the mild and moderate PS are:

1. Dyspnea, which is the more common complaint
2. General fatigue
3. Palpitations
4. Mild retrosternal "anginal" pain, in close relation to exertion, can be seen if the gradient is higher than 50 mm Hg

    In case of severe PS (gradient higher than 90 mm Hg) the cardinal symptoms are:

1. Syncope in relation to exertion.
2. Angina pectoris with exertion which may result from right ventricle ischemia.
3. Symptoms and signs of right ventricle failure.
4. Peripheral cyanosis in cases with low cardiac output and right ventricle failure.

    Syncope, angina, andlor signs of right ventricle failure are symptoms of critical importance which in general suggest the need of urgent surgical repair.

PHYSICAL FINDINGS

    Jugular pulse: Giant a wave in the phlebogram can be seen not only in PS but also in pulmonary hypertension and tricuspid stenosis.
    Hepatic pulse can be seen as a counterpart of the giant a waves of the jugular pulse and not only as a manifestation of tricuspid insufficiency.
    Hypertelorism and the so-called "moon facies" are described in about 35% to 40% of these patients.
    Left parasternal pulse as a result of right ventricular hypertrophy and clockwise rotation of the heart over the horizontal plane is common.
    Systolic thrill is the counterpart of the ejection murmur and is better palpated in the second and third parasternal intercostal spaces.
    Grade III to V systolic ejection murmur located in the same area and which can go beyond the second sound in cases of severe stenosis can be auscultated.
    Wide splitting of S₂ due to the prolongation of the systolic ejection time in the right ventricle may be present, with a P₂ of decreased intensity.
    The more severe the stenosis the later the systolic peak of the ejective murmur, the wider S₂ splitting and stronger the left parasternal pulse. The intensity of "a" wave in the jugular pulse also parallels quite well the degree of stenosis.
    In extreme PS, P₂ is soft and many times practically inaudible.
    The Phonocardiogram, as in most of the congenital diseases, has a special value for accurate identification of the auscultatory phenomenons and is enough in most of the cases for the analysis of the hemodynamic status of the patient.
    Usually the analysis of splitting S₂ can help in predicting the pulmonary valve gradient.
    S₂ splitting less than 0.08" = gradient below 80 mm Hg
    S₂ splitting more than 0.08" = gradient more than 80 mm Hg
    S₄ as a manifestation of a strong right atrium contraction indicate severe stenosis.
    An ejection sound is typical in early systole, preceding many times the ejective pulmonic murmur. The more severe the stenosis the softer the systolic ejection sound.

ELECTROCARDIOGRAM

    From the anatomical and hemodynamic viewpoint, pulmonary stenosis can be divided into three different categories: mild, moderate and severe. The electrocardiogram will reflect these three categories due to the more or less significant right ventricular systolic overload noted in each one of them.

1. Right atrium overload is a frequent finding. Tall and narrow P waves will be observed in lead II and at times I and V₁ (P congenitale). The tallest P wave will be observed in the Trilogy of Fallot where the amplitude of the P wave will have an inverse correlation with the arterial oxygen saturation.
2. The ORS complex configuration and main axis over the frontal and horizontal plane will result from the different degrees of right ventricular hypertrophy and systolic overload.
       In the bipolar leads, the most constant finding is a tall and often slightly wider than normal R wave in lead aVR, which occasionally may be taller than 10 mm. In children younger than four years of age, the diagnosis of right ventricular hypertrophy can be difficult and the finding of a tall R wave in lead aVR (taller than 10 mm.) is a good sign of a real and important right ventricular hypertrophy.
3. Right axis deviation over the frontal plane is the rule, with a main axis at times in + 150°, + 160° position. The S wave is often very deep in lead I and may pass at times the 20 mm.
4. The R wave in the right precordial leads is typically very tall, existing a good correlation between the voltage of R wave in lead V₁ and V₂ and the right ventricle' systolic pressure (R wave used to be in lead V₁ between 20 and 30 mm., and at times it may even surpass the 40 mm. barrier).
5. Rs complex or qR in lead V₁ may be observed.
6. The S wave is in general absent or very small in leads V₁ and V₂ increasing progressively its deepness from leads V₃ to V₆. In lead V₆, the R wave and S wave at times have the same voltage.
       These typical QRS changes in the precordial leads result from marked clockwide rotation of the heart in the horizontal plane.

ROENTGENOGRAM

1. There is a normal cardiac size or moderate enlargement in the AP projections due to a predominant concentric hypertrophy. In final stages with CHF, dilatation of the cardiac silhouette can be seen.
2. The enlargement of right ventricle is easy to observe in lateral veiw with a reduction of the normal space which usually exists between the sternum and the heart.
3. Enlargement of the pulmonary artery which is better seen in AP projection. (Enlargement and at times aneurysmatic dilatation of the pulmonary arch.)
4. The pulmonary circulation is classically diminished but it can be practically normal in moderate cases.

ECHOCARDIOGRAM

    The identification of the pulmonary valve is always difficult by echocardiography, hence, the assessment of valve stenosis is still more unreliable. The degree and severity of stenosis is not possible with the current M-Mode and the real time cross-sectional echocardiography will probably not add substantially. The enlargement of the right ventricle can be clearly appreciated in the majority of cases.
    In pulmonary atresia, marked hypoplasia of the right ventricle will be noted. The absence of pulmonary valve echoes does not have much value since even many normal valves are difficult to identify by this technique.

HEMODYNAMICS AND ANGIOGRAPHY

    The passage with the catheter to the pulmonary artery is the most essential part in the hemodynamic study of these patients.
    The study will consist of:

1. Determination of the systolic gradient across the pulmonary valve and possible subvalvular gradient to rule out hypertrophy of the crista supraventricularis at the infundibular level (pull back pressure recording from pulmonary artery to right ventricle).
2. Analysis of the pressure curve in the right ventricle with high systolic pressure (at times as high as 250 mm Hg) and prolonged systolic ejection time.
3. Damped, low amplitude pressures in the pulmonary artery.
4. Increased atrial kick (counterpart of the jugular a wave).
5. In cases of subvalvular, infundibular stenosis a second intermediary gradient will be seen at that level.
6. Blood sampling from peripheral artery, pulmonic artery, right ventricle, right atrium at high, middle and low levels superior and inferior vena cavas (necessary for calculation of cardiac output and to study associated malformations).
7. Calculation of the pulmonary valve area, accomplished by the Gorling and Gorling formula, knowing the valve gradient and cardiac output.

    Angiography, although not essential, can be helpful in the final anatomical analysis of the disease.
    The most useful injection is done positioning the patient in a lateral view and injecting the right ventricle. It is particularly useful for the study of the valvular structures and infundibulum.
    The post stenotic dilatation is also seen in the same projection.
    If the patient has ASD (Trilogy of Fallot) injection in the right atrium is advisable. (For further details regarding hemodynamic and angiographic evaluation of ASD refer to this chapter.)

MEDICAL AND SURGICAL TREATMENT

    Prophylaxis of SBE
    Surgical approach is indicated in case of:

1. Systolic gradient higher than 75 mm Hg
2. Right ventricle failure
3. Central cyanosis
4. Syncopal attacks andlor chest pain

    Mild or moderate stenosis must be closely controlled medically if there are none of the previous situations present.
    The use of cardiopulmonary bypass for this surgery still continues to be debatable. If ASD is present it should be corrected via right atriotomy.

Pulmonary Valvular Stenosis in a 1 1/2 year-old infant.

Diagrammatic portrayal of pulmonary valve stenosis with intact ventricular septum. A right to left shunt at the atrial level may develop as a consequence of elevation of right sided pressures, through a patent foramen ovale.

21 year-old male admitted after a syncopal attack. Pulmonary Stenosis. Right side catheterization demonstrates a 60 mm Hg gradient across the pulmonary valve.

Electrocardiogram of a 6 year-old boy with Valvular Pulmonary Stenosis. The valvular gradient across the pulmonary valve was 80 mm Hg.