An 18- year old girl was taken to a neurologist by her parents. They had come back
from a hill-resort vacation two days back, where she had fainted while playing
badminton. There were no accompanying tonic-clonic movement, tongue-bite or
frothing at the mouth. There was no past history of seizures, syncopal episodes,
anoxic spells or squatting attacks during early childhood. A computed tomography
(CT) scan of the brain and an electroencephalogram (EEG) were taken which were
normal. The girl was referred to a cardiologist for evaluation of a heart murmur,
which was detected by the astute neurologist.
On examination, pulse was of low volume at a rate of 84 beats/min. with a BP of
104/66 mm Hg. Prominent a waves were observed in the venous pulsations at the
neck. The apex beat was normal in location and character. A sustained left parasternal
heave was palpable, with the inner edge of the palm. The S1 was normal and the S2
appeared single; a right-sided S4 was heard in diastole. A long and harsh ejection
systolic murmur was audible over the upper left parasternal area. The murmur was
not preceded by an ejection click or accompanied by a palpable thrill and it did not
radiate towards the carotid arteries.
CLINICAL DISCUSSION
From the history and physical examination, this young girl probably had some
cardiac outflow tract obstruction, which led onto syncope. The most likely
diagnosis in this case is pulmonary valve stenosis (Fig. 20.1). The a waves in the
jugular veins indicate forceful right atrial contraction against a noncompliant right
ventricle. The parasternal heave is indicative of right ventricular hypertrophy.
The S2 appears single because the P2 is muffled. If P2 is audible, the splitting of
S2 is wide due to prolonged right ventricular (RV) ejection time. Other reasons
for wide splitting of S2 are right bundle branch block (delayed RV activation) and
atrial septal defect (increased RV ejection volume).
The long and harsh ejection systolic murmur of pulmonary stenosis indicates
turbulent flow across the narrow valve. Length and loudness of the murmur
correlate with the severity of stenosis but once right ventricular failure sets
in, the murmur becomes short and soft. The systolic murmur of pulmonary
stenosis radiates towards the back and increases in intensity during inspiration.
An ejection click and palpable thrill are less often observed compared to aortic
stenosis. Interestingly, the ejection click of pulmonary stenosis is the only rightsided heart sound that decreases during inspiration.
The ejection click marks the end of isovolumic contraction and heralds the
onset of the ejection period. During inspiration, the increase in right ventricular
end-diastolic pressure (RVEDP) leads to partial opening of the pulmonary valve
and reduces the intensity of the ejection click. The ejection click is a feature
of valvular stenosis and is not heard in infundibular stenosis. It also helps to
differentiate pulmonary stenosis from atrial septal defect which produces a
similar murmur with wide splitting of the second heart sound or S2.
ECG showed tall R waves in right precordial leads with T wave inversion
. There was right axis deviation of the QRS complex and right atrial
enlargement (P. pulmonale). X-ray chest findings were an enlarged right ventricle
to the right of midline, with a dilated pulmonary artery suggestive of post-stenotic
dilatation. The lung fields were oligemic . On ECHO, the left ventricle
was normal in size with a normal ejection fraction and the free wall of the right
ventricle was thickened. The mitral and aortic valves were structurally normal.
The pulmonary valve leaflets were mildly thickened with mild systolic doming
and restricted excursion. On colour flow mapping, a jet was observed in the
proximal pulmonary artery, with increased systolic velocity across the valve on
Doppler The ECG findings of right ventricular hypertophy (RVH) are tall R waves in
lead V1, S-T segment depression and T wave inversion (RV strain) and right axis
deviation of the QRS vector. The voltage criteria of RVH are R in V1> 4 mm, R/S
ratio in V1> 1 and S in V6>7 mm. On chest X-ray, right ventricular enlargement and
pulmonary artery dilatation are also seen in pulmonary hypertension but in that
case there is pulmonary plethora and not oligemia. When pulmonary stenosis
is a component of Fallot’s tetralogy, the pulmonary artery is small (pulmonary
atresia) and not dilated. In pulmonary hypertension, ECHO findings are a
pulmonary regurgitant jet on color flow mapping and increased trans-tricuspid
flow velocity (TR Vmax).Pulmonary stenosis needs to be clinically differentiated from other conditions
that produce a systolic murmur over the upper left parasternal area. These clinical
entities are pulmonary hypertension, aortic stenosis and a high cardiac output
state. Pulmonary hypertension is also associated with clinical, electrographic and
radiological signs of right ventricular hypertrophy but the ejection
murmur is accompanied by a loud P2 sound and sometimes the murmur of
pulmonary regurgitation. Moreover, the lung fields show pulmonary plethora
and not oligemia.
The systolic murmur of aortic stenosis is often accompanied by an ejection
click and a palpable thrill, radiates towards the neck and is better heard during expiration. Moreover, there are clinical, electrographic and radiological signs of
left ventricular hypertrophy. An innocent hemic murmur known as Still’s murmur
is sometimes heard in anemia, pregnancy, thyrotoxicosis and beri-beri disease.
It is associated with a good volume pulse wide pulse-pressure and there is no
ejection click or palpable thrill. On electrographic and radiological investigations,
the cardiac chambers and valves are structurally normal.
Valvular pulmonary stenosis is often congenital in origin, as part of the
Rubella syndrome. Rarely, valvular pulmonary stenosis is due to rheumatic heart
disease (pulmonary valve involvement is least common) or carcinoid syndrome
(tricuspid valve involvement is more common). Subvalvular or infundibular
stenosis is often a part of Fallot’s tetralogy. Supravalvular stenosis due to a
discrete shelf-like band or a tunnel type deformity, is the least common form of
pulmonary stenosis MANAGEMENT ISSUES
There is no medical management of pulmonary stenosis. Surgery is indicated
in the presence of symptoms, right ventricular hypertrophy and a systolic
gradient above 50 mm Hg. The stenotic pulmonary valve has to be replaced
by a surgical procedure, if the valve anatomy is distorted. Artificial pulmonary
valve deployment is also feasible by the percutaneous route and expertise in this
technique is growing. In isolated subvalvular or infundibular pulmonary stenosis,
subvalvular muscle resection with valvotomy is the preferred procedure. When
infundibular stenosis is part of Fallot’s tetralogy, the procedure is combined
with patch closure of the ventricular septal defect. Pulmonary regurgitation is
the leading complication of valvotomy, which leads to dilatation of the tricuspid
valve annulus and enlargement of the right-sided cardiac chambers.
RECENT ADVANCES
As mentioned above, expertise in the technique of percutaneous artificial
pulmonary valve deployment has increased considerably. Also, percutaneous
native valve balloon valvuloplasty has gained popularity in recent years.