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Page 8 of 24 Rao. Vessel Plus 2022;6:22 https://dx.doi.org/10.20517/2574-1209.2021.105

border and/or in the suprasternal notch. Since most PS patients have stenosis at the valve, an ejection click
usually is heard and precedes the ejection murmur [Figure 2]. The ejection click is auscultated at lower left,
mid left, and upper left sternal borders. The click changes with the respiratory cycle (decreases or becomes
absent with inspiration). The location of the click can help differentiate AS from PS. The features of the 2nd
sound vary with the magnitude of obstruction [Figure 2]. The BP and pulses are usually normal.

The relationship of click with the 1st heart sound, the degree of splitting of the 2nd sound, the loudness of
the pulmonary component of the 2nd heart sound, and the length of and timing of peaking of the systolic
murmur are generally indicative of the degree of PS [Figure 2]. In mild PS cases, the ejection click is
evidently distinct from the 1st sound, the 2nd heart sound is normally split with normal to a slightly
increased pulmonary component of the 2nd sound, and an ejection systolic murmur which peaks early in
systole and terminates clearly prior to the aortic closure of the 2nd heart sound (Figure 2; top). The findings
in moderate PS are an ejection systolic click that is closer to 1st heart sound than in mild PS, wide splitting
of the 2nd sound with a reduced (softer) pulmonary component of the 2nd sound, and an ejection systolic
murmur which peaks in mid to late systole and terminates just prior to the aortic component of the 2nd
heart sound (Figure 2; middle). The characteristics of severe valvar PS (Figure 2; bottom) are an ejection
systolic click which is either absent or occurs so close to the 1st sound that it is not separable from it,
noticeably increased split of the 2nd heart sound with either an inaudible or a soft pulmonary component,
and a prolonged ejection systolic murmur which peaks late in systole and extends way beyond the aortic
[15]
closure of the 2nd sound so that the latter cannot be auscultated .

The loudness of the systolic murmur does not point to the severity of PS, but instead, the length of and
timing of peaking of the murmur are determinants of severity of PS. The longer the murmur and the later it
peaks, the more severe is the PS. Likewise, the shorter the interval between the 1st heart sound and the
ejection click, the wider the split of second sound, and softer the pulmonary component, the more severe is
[15]
the degree of PS . Moderate and severe PS cases are associated with a precordial thrill in patients older
than three to four months.

Usually, in PS, the ECG demonstrates right ventricular hypertrophy (RVH). The severity of RVH parallels
the magnitude of PS. In most cases, the chest roentgenogram shows no cardiac enlargement, although a
dilated main pulmonary artery (PA), post-stenotic dilatation, is frequently seen. The degree of PA dilatation
has no relationship with the severity of PS. Echo-Doppler studies demonstrate enlargement of the RV,
thickened and domed pulmonary valve leaflets, and increased Doppler flow velocity across the pulmonary
valve. Doppler flow velocity magnitude across the pulmonary valve indicates the severity of PS. The peak
instantaneous pressure gradient across the pulmonary valve may be calculated utilizing a modified Bernoulli
equation:

ΔP = 4V 2

Where, V is the peak velocity across the pulmonary valve in meters/sec, and ΔP is peak instantaneous
pressure gradient in mmHg.

Other RV outflow tract obstructions
Ejection systolic murmurs auscultated best at LUSB are also present in patients who have infundibular PS,
supravalvar PA stenosis, branch PA stenosis, and idiopathic enlargement of the main PA. Similarly,
functional systolic murmurs of pulmonary ejection type are also heard best at LUSB. These entities should
be differentiated from valvar PS. The characteristic ejection systolic click of valvar PS is not present in all the