Pulmonary Stenosis with Interatrial Communication

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Chapter 16 Pulmonary Stenosis with Interatrial Communication

In 1769, Giovanni Battista Morgagni ¹ described pulmonary stenosis with a patent foramen ovale, and in 1848, Thomas Peacock² published “Contraction of the Orifice of the Pulmonary Artery and Communication Between the Cavities of the Auricles by a Foramen Ovale.”

Pulmonary stenosis with reversed interatrial shunt has been called the triologie de Fallot.³ Right ventricular outflow obstruction resides in a stenotic mobile dome-shaped pulmonary valve (Figure 16-1) and is occasionally represented by stenosis of the pulmonary artery and its branches (Figure 16-2).⁴^–⁷ Infundibular obstruction takes the form of secondary hypertrophic subpulmonary stenosis (Figure 16-3).⁸^–¹¹ The interatrial communication is by a patent foramen ovale or an ostium secundum atrial septal defect,^4,^6,^8,¹²^–¹⁵ less commonly by an ostium primum¹⁶ or sinus venosus atrial defect,¹⁴ or much less commonly by anomalous pulmonary venous connection.¹⁷ This chapter deals with pulmonary valve stenosis and a patent foramen ovale or a nonrestrictive ostium secundum atrial septal defect.⁴

Figure 16-1 Lateral right ventricular angiocardiogram (RV) from a 2-day-old male with pinpoint pulmonary valve stenosis, reversed shunt through a patent foramen ovale, and tricuspid regurgitation. The arrow identifies a tiny jet into a dilated pulmonary trunk (PT).

Figure 16-2 X-rays from a 5-year-old boy with stenosis of the pulmonary arterial branches (gradient, 50 mm Hg) and a 2.2 to 1 left-to-right shunt through an ostium secundum atrial septal defect. A, Posteroanterior projection shows vascular lung fields, moderate dilation of the pulmonary trunk, an inconspicuous ascending aorta, and a prominent right atrial convexity. B, Angiocardiogram with contrast material injected into the pulmonary trunk delineates stenoses of the right and left pulmonary arteries (arrows) with distal dilation.

Figure 16-3 A, Lateral right ventricular angiocardiogram in a 5-year-old girl with severe mobile pulmonary valve stenosis (PV) and secondary dynamic systolic narrowing of the infundibulum (Inf). There was a 1.4 to 1 left-to-right shunt through an atrial septal defect despite suprasystemic right ventricular systolic pressure. The pulmonary trunk (PT) was dilated. B, Infundibular narrowing disappeared during diastole (arrow). (RV = right ventricle.)

Severe pulmonary valve stenosis with a right-to-left shunt through a patent foramen ovale is more common than pulmonary valve stenosis with a nonrestrictive atrial septal defect, irrespective of the direction of the shunt.⁴ A restrictive interatrial communication is almost always a patent foramen ovale, the shunt is right-to-left, and pulmonary stenosis is necessarily severe.^4,¹⁸ A nonrestrictive interatrial communication is almost always an ostium secundum atrial septal defect, the shunt is left-to-right, and pulmonary stenosis is necessarily mild to moderate.^4–6,^8,¹²

The physiologic consequences of pulmonary stenosis with an interatrial communication depend on the degree of obstruction to right ventricular outflow and the size of the interatrial communication.^4,¹⁸ Patients with pulmonary stenosis and a right-to-left interatrial shunt (Figure 16-4) almost always have a severely stenotic pulmonary valve and a patent foramen ovale (see previous).⁴ Patients with pulmonary stenosis and a left-to-right interatrial shunt almost always have a mild to moderate pulmonary valve stenosis and a nonrestrictive ostium secundum atrial septal defect (see previous).⁴

Figure 16-4 Red fingertips without cyanosis or clubbing in a 6-year-old boy with severe mobile pulmonary valve stenosis (gradient, 108 mm Hg), a small intermittent right-to-left shunt across a patent foramen ovale, and normal systemic arterial oxygen saturation.

Severe pulmonary stenosis with right ventricular hypertrophy results in an increase in force of right atrial contraction (Figures 16-5 and 16-6) that generates a presystolic right-to-left interatrial shunt. High right atrial pressure stretches the margins of the foramen ovale and increases its patency. When right atrial blood escapes through the interatrial communication, pulmonary flow tends to fall reciprocally.

Figure 16-5 Tracings from a cyanotic woman who underwent surgical repair at age 58 years for severe mobile pulmonary valve stenosis (gradient, 120 mm Hg) with a reversed shunt through a patent foramen ovale. Large A waves (arrow) appear in the right atrium (RA). The right atrial intracardiac phonocardiogram (RA PHONO) recorded the holosystolic murmur (SM) of tricuspid regurgitation. A soft presystolic murmur is represented by vibrations just before the first heart sound (S₁).

Figure 16-6 Right atrial (RA) and right ventricular (RV) pressure pulses from a 15-month-old cyanotic male with severe mobile pulmonary valve stenosis (gradient, 105 mm Hg) and a right-to-left shunt across a patent foramen ovale. A, Large A waves (arrow) appear in the right atrial pressure pulse. B, The large A wave was transmitted into the right ventricle (RV) as presystolic distention (arrow).

A nonrestrictive atrial septal defect with a large left-to-right shunt and mild to moderate pulmonary valve stenosis clinically resembles an isolated atrial septal defect (see Chapter 15). The small gradients generated by hyperkinetic right ventricular ejection across a normal pulmonary valve can generate a small gradient that should not be mistaken for mild pulmonary stenosis.

history

Familial pulmonary valve stenosis with atrial septal defect has been reported in a mother and her two children.¹⁹ Severe pulmonary stenosis with a right-to-left shunt across a patent foramen ovale is clinically analogous to isolated severe pulmonary valve stenosis, except for cyanosis that can be present at birth^13,¹⁸ or can develop in childhood, puberty, or young adulthood.^6,^8,^13,²⁰ Infants usually come to attention because of a murmur; although in neonates with pinpoint pulmonary valve stenosis (see Figure 16-1), the murmur is disarmingly soft. Symptoms can be appreciable even when cyanosis is mild^13,²¹ because right ventricular pressure can exceed systemic before the right-to-left interatrial shunt is established. However, among the author’s patients are a teenager who became cyanotic only when he engaged in sports,⁸ a woman with severe pulmonary stenosis and reversed interatrial shunt who was in good health until age 40 years,¹⁴ and a woman with a gradient of 120 mm Hg who underwent surgical repair at age 58 years (see Figure 16-5).

Giddiness, light-headedness, and syncope are provoked by exertion. Large jugular venous A waves (see Figure 16-5) are sometimes subjectively sensed, especially after effort or excitement. Chest pain that resembles angina pectoris is attributed to ischemia in the high-pressure hypertrophied right ventricle. Death is usually from right ventricular failure and less commonly from hypoxia, cerebral abscess, or infective endocarditis.^5,⁶

Mild to moderate pulmonary stenosis with a nonrestrictive atrial septal defect clinically resembles an isolated nonrestrictive ostium secundum atrial septal defect (see Chapter 15), except for the conspicuous murmur of pulmonary stenosis.¹⁸ Relatively asymptomatic survival into the sixth and seventh decades is not uncommon. A 59-year-old man had a nonrestrictive sinus venous defect and calcific pulmonary stenosis.¹⁴

Physical appearance

Retarded growth and development are consequences of right ventricular failure that begins in infancy or early childhood. Cyanosis associated with pulmonary stenosis and a patent foramen ovale can be obvious or evident only during exercise.^8,^22,²³ Mild or intermittent right-to-left shunts are sometimes manifested by highly colored cheeks or by distinctive erythema of the fingertips and toes (see Figure 16-4).^8,^20,²¹ The central cyanosis of a right-to-left shunt must be distinguished from the peripheral cyanosis of diminished skin blood flow caused by the low cardiac output of severe pulmonary stenosis. Peripheral cyanosis is accompanied by cold hands and feet and tends to be more pronounced in the lower extremities. When skin blood flow is improved by warmth, peripheral cyanosis diminishes or may vanish, and central cyanosis becomes more evident.

Children with a nonrestrictive atrial septal defect and mild to moderate pulmonary stenosis may have a delicate gracile body habitus, with weight more affected than height (see Figure 15-14). Noonan’s syndrome (see Figure 11-8C) is a distinctive appearance associated with dysplastic pulmonary valve stenosis that may coexist with an atrial septal defect.

arterial pulse

In severe pulmonary stenosis with a right-to-left interatrial shunt, the systemic arterial pulse is small unless the reversed shunt is sufficient to maintain adequate left ventricular stroke volume. With the advent of right ventricular failure, the arterial pulse decreases despite right atrial blood shunted into the left side of the heart.

jugular venous pulse

When pulmonary stenosis coexists with a nonrestrictive atrial septal defect, the hypertrophied right ventricle is less distensible, the right atrium contracts with greater force, and the A wave is prominent. The contour and height of the jugular pulse are determined by the presence and degree of pulmonary stenosis, not by the atrial defect. When pulmonary stenosis is severe enough to reverse the shunt, the jugular venous A wave is large, even giant (see Figures 16-5 and 16-6A). With the advent of right ventricular failure, the mean jugular venous pressure rises, and with it the V wave, especially if tricuspid regurgitation coexists.

Precordial movement and palpation

Pulmonary stenosis with a right-to-left interatrial shunt is associated with precordial palpation similar to severe isolated pulmonary valve stenosis (see Chapter 11). A nonrestrictive atrial septal defect with mild to moderate pulmonary stenosis is associated with precordial signs similar to an isolated atrial septal defect of equivalent size, except for a systolic thrill of coexisting pulmonary valve stenosis.²³

Auscultation

Severe pulmonary valve stenosis with a right-to-left interatrial shunt is accompanied by auscultatory signs analogous to isolated severe pulmonary stenosis (see Chapter 11). The systolic murmur is maximal in the second left intercostal space (Figure 16-7); radiates upward and to the left; extends up to or beyond the aortic component of the second heart sound, which it obscures (Figures 16-7 and 16-8A and D);²⁴ and has a late systolic peak with a kite-shaped configuration.^24,²⁵ In neonates with critical pulmonary valve stenosis and right ventricular failure, the murmur is short and soft (see previous), and the pulmonary component of the second heart sound is delayed, soft, or absent (see Figures 16-7 and 16-8D). The most prominent auscultatory sign is then a holosystolic murmur of tricuspid regurgitation (see Figure 16-5).

Figure 16-7 Phonocardiogram from the second left intercostal space of a 5-month-old cyanotic female with severe mobile pulmonary valve stenosis, a right-to-left shunt across a patent foramen ovale, and suprasystemic right ventricular systolic pressure. The fourth heart sound (S₄) in the first cycle became a short presystolic murmur in the next cycle. A long systolic murmur (SM) goes up to the aortic component of the second heart sound (A₂). The pulmonary component (P₂) is late and diminutive (arrow). Tall peaked right atrial P waves appear in lead 2 of the electrocardiogram.

Figure 16-8 Phonocardiograms from the second left intercostal space of four patients whose malformations include an isolated atrial septal defect (ASD) and atrial septal defects with mild, moderate, or severe pulmonary valve stenosis. A, Isolated atrial septal defect (ASD) with 2.5 to 1 left-to-right shunt. The short soft systolic murmur (SM) ends well before both components of the split second heart sound. B, Atrial septal defect with a 2 to 1 left-to-right shunt and a 25–mm Hg gradient across a stenotic pulmonary valve. The systolic murmur is relatively loud and long and goes up to but does not obscure the aortic component of the second heart sound. The splitting is wider because pulmonary closure is more delayed. C, Atrial septal defect with a 2 to 1 left-to-right shunt and 50–mm Hg gradient across a stenotic pulmonary valve. The loud long systolic murmur extends beyond the aortic component of the second heart sound. The pulmonary component is soft and even later. D, Severe pulmonary valve stenosis (gradient, 110 mm Hg) with a right-to-left shunt through a patent foramen ovale. A kite-shaped systolic murmur envelopes the aortic component of the second sound. The pulmonary component is delayed and diminutive. (A₂ = aortic component; P₂ = pulmonary component).

Presystolic distention of the right ventricle (see Figure 16-6B) is accompanied by a fourth heart sound that is occasionally long enough to qualify as a murmur (see Figures 16-5 and 16-7). A short presystolic murmur is also generated when powerful right atrial contraction forces blood across a restrictive patent foramen ovale. A large right atrial A wave that is transmitted into the right ventricle (see Figure 16-6) can exceed the diastolic pressure in the main pulmonary artery, open the pulmonary valve, and generate presystolic flow and a presystolic murmur.

When a nonrestrictive atrial septal defect is associated with mild to moderate pulmonary stenosis, the auscultatory signs resemble an isolated nonrestrictive ostium secundum atrial septal defect with three exceptions: 1, an ejection sound is generated by the mobile stenotic pulmonary valve; 2, the pulmonary systolic murmur is loud and long (Figures 16-9 and 16-10); and 3, the second heart sound is more widely split because of a greater delay in the pulmonary component (see Figures 16-8B and C, 16-9, and 16-10). The more severe the pulmonary stenosis, the later and softer the pulmonary component of the second heart sound (see Figures 16-7 and 16-8).

Figure 16-9 Phonocardiogram from a 23-year-old man with a 2.4 to 1 left-to-right shunt through an ostium secundum atrial septal defect and a 45–mm Hg gradient across a mobile stenotic pulmonary valve. The first heart sound (S₁) is normal. A prominent crescendo-decrescendo systolic murmur (SM) is maximal in the second left intercostal space (2 LICS) and goes up to but does not envelope the aortic component of the second heart sound (A₂). The pulmonary component (P₂) is delayed and soft. (4 LICS = fourth left intercostal space).

Figure 16-10 Phonocardiograms from a 6-year-old girl with a 2.3 to 1 left-to-right shunt through an ostium secundum atrial septal defect and a 25–mm Hg gradient across a mobile stenotic pulmonary valve. A, The prominent crescendo-decrescendo systolic murmur (SM) in the second left intercostal space (2 LICS) ends before the aortic component of the second heart sound (A₂). The pulmonary component (P₂) is moderately delayed and relatively soft. The systolic murmur is shorter and softer at the lower left sternal edge (LSE) where both components of the split second heart sound are recorded. The jugular venous pulse (JVP) exhibits a small dominant A wave and a blunted X descent (lower tracing). B, Intracardiac phonocardiogram from within the main pulmonary artery (PA) recorded a prominent crescendo-decrescendo systolic murmur (SM) that ends before pulmonary valve closure (P₂). The murmur vanished when the microphone was withdrawn into the right ventricle (RV).

Stenosis of the pulmonary artery and its branches with an ostium secundum atrial septal defect (Figure 16-11) is accompanied by conspicuously wide thoracic distribution of systolic murmurs because the murmurs of pulmonary artery stenosis are reinforced by hyperkinetic pulmonary blood flow of the atrial septal defect. Persistent splitting of the second heart sound is the result of the atrial septal defect (see Figure 16-11).

Figure 16-11 Tracings from a 5-year-old boy with bilateral pulmonary artery stenosis (gradient, 50 mm Hg), an ostium secundum atrial septal defect, and a 2.2 to 1 left-to-right shunt. A, The phonocardiograms show systolic murmurs (SM) of approximately equal intensity in the second left intercostal space (2 LICS) and in the left back. Persistent splitting of the second heart sound (A₂/P₂) was the result of the atrial septal defect. B, Pressure pulse in the main pulmonary artery (PA) shows the characteristic contour of bilateral stenosis of the pulmonary arterial branches, with a steep rise and a rapid fall to a low dicrotic notch (arrow). The right ventricular pulse (RV) is for comparison.

electrocardiogram

In pulmonary valve stenosis with a right-to-left interatrial shunt, the electrocardiogram is similar to that of severe isolated pulmonary stenosis (Figures 16-12 and 16-13; see Chapter 11).²⁶ Peaked right atrial P waves appear in lead 2 and in right precordial leads (see Figures 16-7, 16-12, and 16-13) and occasionally are exceptionally tall (see Figures 16-7 and 16-12).^8,²² P wave duration in lead 2 is prolonged when a large right atrium writes the terminal inscription of the P wave.²⁷ Right axis deviation (see Figure 16-12) can be extreme (see Figure 16-13). The terminal force of the QRS can be prolonged and slurred (see Figure 16-13). Right ventricular hypertrophy caused by suprasystemic right ventricular systolic pressure is manifested by R waves of great amplitude in right and mid precordial leads with upward convexity of ST segments and deeply inverted T waves, together with deep left precordial S waves (see Figures 16-12 and 16-13).²⁶ The striking ST segment and T wave patterns sometimes extend to lead V₄. Small q waves appear in lead V₁ (see Figure 16-13) when the precordial electrode topographically overlies a large right atrium (see Chapter 13).

Figure 16-12 Electrocardiogram from the 5-month-old cyanotic female referred to in Figure 16-7 with severe pulmonary valve stenosis and a right-to-left shunt across a patent foramen ovale. Tall peaked right atrial P waves appropriate for the 20–mm Hg A wave in the right atrium appear in leads 2, 3, aVF, and V_1-4. Right axis deviation and right ventricular hypertrophy are manifested by tall monophasic R waves in leads V_1-4 and a deep S wave in lead V₆, findings appropriate for suprasystemic right ventricular systolic pressure.

Figure 16-13 Electrocardiogram from a 20-year-old man with severe mobile pulmonary valve stenosis (gradient, 110 mm Hg) and a right-to-left shunt through a patent foramen ovale. A tall right atrial P wave appears in lead 2. Small q waves in right precordial leads are evidence of right atrial enlargement. The PR interval is prolonged. Right ventricular hypertrophy is reflected in striking right axis deviation, tall monophasic R wave, and deeply inverted T wave in V₁ and deep S waves in mid to left precordial leads.

In a nonrestrictive atrial septal defect with a left-to-right shunt and mild to moderate pulmonary stenosis, the electrocardiogram is a combination of isolated ostium secundum atrial septal defect (see Chapter 15) and the right ventricular hypertrophy of pulmonary stenosis (Figures 16-14 and 16-15). P waves can be peaked and moderately tall (see Figure 16-14). The QRS axis is vertical or rightward (see Figures 16-14 and 16-15). Terminal force prolongation widens the R wave in lead aVR and widens the S waves in leads 1, aVL, and V₆ (see Figures 16-14 and 16-15). The rsR prime in lead V₁ is characterized by a relatively small s wave and a relatively tall R prime compared with an atrial septal defect without pulmonary stenosis (see Figures 16-14 and 16-15).

Figure 16-14 Electrocardiogram from an 18-year-old man with a 2 to 1 left-to-right shunt through an ostium secundum atrial septal defect and a 25–mm Hg gradient across a mobile stenotic pulmonary valve. The P waves in lead 2 and in leads V_2-4 are peaked but not tall. Right ventricular hypertrophy is manifested by right axis deviation, a tall R prime in lead V₁, and deep S waves in leads V_5-6. Prolongation of the terminal portion of the QRS axis in lead aVR is appropriate for the atrial septal defect.

Figure 16-15 Electrocardiogram from the 23-year-old man referred to in Figure 16-9 with a 2.4 to 1 left-to-right shunt through an ostium secundum atrial septal defect and a 45–mm Hg gradient across a mobile stenotic pulmonary valve. The normal P waves, the vertical QRS axis, the rsR prime in lead V₁, and the slight prolongation of the terminal force in leads V₁ and aVR are appropriate for the atrial septal defect.

x-ray

Nonrestrictive atrial septal defects with mild to moderate pulmonary stenosis have x-rays indistinguishable from isolated ostium secundum defects (Figure 16-16).²⁸ Severe pulmonary stenosis with a right-to-left interatrial shunt through a patent foramen ovale is associated with an x-ray that resembles that of isolated severe pulmonary valve stenosis (Figure 16-17; see Chapter 11). Lung fields are oligemic because right atrial blood is shunted away from the lungs across the atrial septum. The reduced right ventricular output and pulmonary blood flow become even more apparent with the advent of right ventricular failure. The pulmonary trunk is dilated (Figures 16-1, 16-3, 16-17, and 16-18) for reasons analogous to dilation in isolated mobile pulmonary valve stenosis (see Chapter 11).^5,⁸ Heart size is increased because of enlargement of the right atrium and right ventricle (see Figures 16-17 and 16-18).^8,¹³ The right ventricular apex is not boot-shaped as in Fallot’s tetralogy because the size of the left ventricle is not reduced (see Figure 16-17; see Chapter 18).

Figure 16-16 X-ray from a 10-year-old girl with a 2.1 to 1 left-to-right shunt through an ostium secundum atrial septal defect and a 25–mm Hg gradient across a mobile stenotic pulmonary valve. The x-ray closely resembles that of an isolated ostium secundum atrial septal defect with increased pulmonary blood flow, a dilated pulmonary trunk (PT), an inconspicuous ascending aorta, a prominent right atrium (RA), and an enlarged right ventricle (RV).

Figure 16-17 X-rays from the 15-month-old cyanotic male referred to in Figure 16-6 with severe mobile pulmonary valve stenosis, suprasystemic right ventricular systolic pressure, and a right-to left shunt through a patent foramen ovale. A, The pulmonary trunk (PT) is dilated. An enlarged right ventricle (RV) occupies the apex. B, The left anterior oblique shows a dilated right ventricle (RV) displacing the left ventricle posteriorly. C, In this lateral projection, the normal location of the inferior vena cava (arrow) at the junction of the left ventricle and diaphragm indicates that the left ventricle in not enlarged.

Figure 16-18 X-ray from a 30-month-old cyanotic male with severe mobile pulmonary valve stenosis, a right ventricular systolic pressure of 130 mm Hg, and a right-to-left shunt through a patent foramen ovale. The pulmonary trunk (PT) is dilated. Appreciable right atrial enlargement (RA) was the result of severe tricuspid regurgitation.

echocardiogram

Mobile pulmonary valve stenosis with a right-to-left shunt through a patent foramen ovale is associated with an echocardiogram similar to isolated severe pulmonary valve stenosis (see Chapter 11). Color flow imaging records a high-velocity jet directed toward the left pulmonary artery (Figure 16-19A and Videos 16-1A through 16-1C), and continuous-wave Doppler scan establishes the peak velocity and the gradient (Figure 16-19B). Two-dimensional imaging identifies the patent foramen ovale with its valve (see Chapter 15), and color flow imaging confirms the right-to-left shunt.