Shone's syndrome

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Shone's syndrome
Other namesShone's complex, Shone's anomaly, or Shone's disease
Specialty Cardiology

Shone's syndrome is a rare congenital heart defect described by Shone in 1963. In the complete form, four left-sided defects are present: [1]

Contents

Of these four defects, supravalvular mitral membrane (SVMM) is the first to occur and triggers the development of the other three defects. Partial complexes, or forme fruste, have also been described. [1] The definition is often expanded to include lesions of the left side of the heart not originally ascribed to Shone's syndrome, including mitral and aortic valvular lesions and supravalvular aortic stenosis. [2]

The term parachute mitral valve stems from the morphological appearance of the valve; that is to say, the mitral valve leaflets appear as the canopy of the parachute, the chordae as the strings and the papillary muscle as the harness.

Presentation

Shone’s syndrome is a rare disorder that is often detected in very young children. The children tend to show symptoms like fatigue, nocturnal cough, and reduced cardiac output by the age of two years. They also develop wheezing due to the exudation of fluid into the lungs. [1]

Mechanism

In the normal human heart, there are two mitral valve leaflets, each with its own set of chordae. However, in the case of the parachute mitral valve, the chordae insert on only one papillary muscle instead of two distinct papillary muscles. Often, the chordae are short and thick, which can cause restricted movement of the mitral valve leaflets and obstruct the blood flow into the left ventricle. [1]

The supramitral ring is a connective tissue ring at the base of the atrial surfaces of the mitral valve leaflets. They may protrude into the orifice of the mitral valve, leading to fixed obstruction of blood flow from the left atria to the left ventricles. [1]

Subaortic stenosis has been observed in both muscular and membranous forms. In either case, a variable degree of obstruction may be observed at the ventricular surface of the aortic valve. [1] This presents an obstruction of flow of blood from the ventricle to the aorta.

Coarctation of the aorta which is, narrowing of a section of the aorta may also be observed. [1] Again this presents an obstruction to blood flow out from the left ventricle. [3]

Since there is obstruction of flow into and out of the left ventricle, the prognosis depends on the degree of obstruction and its effect on blood flow.

Diagnosis

Cardiac magnetic resonance imaging is best suited to evaluate patients with Shone's syndrome. [4] Routine blood tests should be done prior to cardiac catheterization. The surgeons will repair the mitral valve and partially remove the supramitral ring. [5] This surgical method is preferred to a valve replacement procedure.

Classifying cardiac lesions in infants is quite difficult, and accurate diagnosis is essential. The diagnosis of Shone’s syndrome requires an ultrasound of the heart (echocardiogram) and a cardiac catheterization procedure, that is, insertion of a device through blood vessels in the groin to the heart that helps identify heart anatomy. [3]

Treatment

When treated early, that is, before the onset of pulmonary hypertension, a good outcome is possible in patients with Shone’s syndrome. However, other surgical methods can be employed depending upon the patient’s medical background. The single most important determinant of poor outcome during the surgical management of patients with Shone's syndrome is the degree of involvement of the mitral valve and the presence of secondary pulmonary hypertension. [6]

Related Research Articles

<span class="mw-page-title-main">Heart valve</span> A flap of tissue that prevent backflow of blood around the heart

A heart valve is a biological one-way valve that allows blood to flow in one direction through the chambers of the heart. Four valves are usually present in a mammalian heart and together they determine the pathway of blood flow through the heart. A heart valve opens or closes according to differential blood pressure on each side.

<span class="mw-page-title-main">Heart sounds</span> Noise generated by the beating heart

Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut. In cardiac auscultation, an examiner may use a stethoscope to listen for these unique and distinct sounds that provide important auditory data regarding the condition of the heart.

<span class="mw-page-title-main">Aortic valve</span> Valve in the human heart between the left ventricle and the aorta

The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. The aortic valve normally has three cusps or leaflets, although in 1–2% of the population it is found to congenitally have two leaflets. The aortic valve is the last structure in the heart the blood travels through before stopping the flow through the systemic circulation.

<span class="mw-page-title-main">Mitral valve</span> Valve in the heart connecting the left atrium and left ventricle

The mitral valve, also known as the bicuspid valve or left atrioventricular valve, is one of the four heart valves. It has two cusps or flaps and lies between the left atrium and the left ventricle of the heart. The heart valves are all one-way valves allowing blood flow in just one direction. The mitral valve and the tricuspid valve are known as the atrioventricular valves because they lie between the atria and the ventricles.

<span class="mw-page-title-main">Heart murmur</span> Medical condition

Heart murmurs are unique heart sounds produced when blood flows across a heart valve or blood vessel. This occurs when turbulent blood flow creates a sound loud enough to hear with a stethoscope. Turbulent blood flow is not smooth. The sound differs from normal heart sounds by their characteristics. For example, heart murmurs may have a distinct pitch, duration and timing. The major way health care providers examine the heart on physical exam is heart auscultation; another clinical technique is palpation, which can detect by touch when such turbulence causes the vibrations called cardiac thrill. A murmur is a sign found during the cardiac exam. Murmurs are of various types and are important in the detection of cardiac and valvular pathologies.

<span class="mw-page-title-main">Stenosis</span> Abnormal narrowing of a blood vessel or other tubular organ or structure

Stenosis is the abnormal narrowing of a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture.

<span class="mw-page-title-main">Bicuspid aortic valve</span> Medical condition

Bicuspid aortic valve (BAV) is a form of heart disease in which two of the leaflets of the aortic valve fuse during development in the womb resulting in a two-leaflet (bicuspid) valve instead of the normal three-leaflet (tricuspid) valve. BAV is the most common cause of heart disease present at birth and affects approximately 1.3% of adults. Normally, the mitral valve is the only bicuspid valve and this is situated between the heart's left atrium and left ventricle. Heart valves play a crucial role in ensuring the unidirectional flow of blood from the atrium to the ventricles, or from the ventricle to the aorta or pulmonary trunk. BAV is normally inherited.

<span class="mw-page-title-main">Congenital heart defect</span> Defect in the structure of the heart that is present at birth

A congenital heart defect (CHD), also known as a congenital heart anomaly, congenital cardiovascular malformation, and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascular disease. Signs and symptoms depend on the specific type of defect. Symptoms can vary from none to life-threatening. When present, symptoms are variable and may include rapid breathing, bluish skin (cyanosis), poor weight gain, and feeling tired. CHD does not cause chest pain. Most congenital heart defects are not associated with other diseases. A complication of CHD is heart failure.

<span class="mw-page-title-main">Mitral regurgitation</span> Form of valvular heart disease

Mitral regurgitation(MR), also known as mitral insufficiency or mitral incompetence, is a form of valvular heart disease in which the mitral valve is insufficient and does not close properly when the heart pumps out blood. It is the abnormal leaking of blood backwards – regurgitation from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts. Mitral regurgitation is the most common form of valvular heart disease.

<span class="mw-page-title-main">Coarctation of the aorta</span> Medical condition

Coarctation of the aorta, also called aortic narrowing, is a congenital condition whereby the aorta is narrow, usually in the area where the ductus arteriosus inserts. The word coarctation means "pressing or drawing together; narrowing". Coarctations are most common in the aortic arch. The arch may be small in babies with coarctations. Other heart defects may also occur when coarctation is present, typically occurring on the left side of the heart. When a patient has a coarctation, the left ventricle has to work harder. Since the aorta is narrowed, the left ventricle must generate a much higher pressure than normal in order to force enough blood through the aorta to deliver blood to the lower part of the body. If the narrowing is severe enough, the left ventricle may not be strong enough to push blood through the coarctation, thus resulting in a lack of blood to the lower half of the body. Physiologically its complete form is manifested as interrupted aortic arch.

The Rastelli procedure is an open heart surgical procedure developed by Italian physician and cardiac surgery researcher, Giancarlo Rastelli, in 1967 at the Mayo Clinic, and involves using a pulmonary or aortic homograft conduit to relieve pulmonary obstruction in double outlet right ventricle with pulmonary stenosis.

<span class="mw-page-title-main">Chordae tendineae</span> Inelastic cords of fibrous connective tissue connecting papillary muscles to heart valves

The chordae tendineae or tendinous cords, colloquially known as the heart strings, are inelastic cords of fibrous connective tissue that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart.

A transthoracic echocardiogram (TTE) is the most common type of echocardiogram, which is a still or moving image of the internal parts of the heart using ultrasound. In this case, the probe is placed on the chest or abdomen of the subject to get various views of the heart. It is used as a non-invasive assessment of the overall health of the heart, including a patient's heart valves and degree of heart muscle contraction. The images are displayed on a monitor for real-time viewing and then recorded.

<span class="mw-page-title-main">Valvular heart disease</span> Disease in the valves of the heart

Valvular heart disease is any cardiovascular disease process involving one or more of the four valves of the heart. These conditions occur largely as a consequence of aging, but may also be the result of congenital (inborn) abnormalities or specific disease or physiologic processes including rheumatic heart disease and pregnancy.

Pulsus bisferiens, also known as biphasic pulse, is an aortic waveform with two peaks per cardiac cycle, a small one followed by a strong and broad one. It is a sign of problems with the aorta, including aortic stenosis and aortic regurgitation, as well as hypertrophic cardiomyopathy causing subaortic stenosis.

The following outline is provided as an overview of and topical guide to cardiology, the branch of medicine dealing with disorders of the human heart. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease and electrophysiology. Physicians who specialize in cardiology are called cardiologists.

<span class="mw-page-title-main">Ventricular outflow tract obstruction</span> Medical condition

A ventricular outflow tract obstruction is a heart condition in which either the right or left ventricular outflow tract is blocked or obstructed. These obstructions represent a spectrum of disorders. Majority of these cases are congenital, but some are acquired throughout life.

The Yasui procedure is a pediatric heart operation used to bypass the left ventricular outflow tract (LVOT) that combines the aortic repair of the Norwood procedure and a shunt similar to that used in the Rastelli procedure in a single operation. It is used to repair defects that result in the physiology of hypoplastic left heart syndrome even though both ventricles are functioning normally. These defects are common in DiGeorge syndrome and include interrupted aortic arch and LVOT obstruction (IAA/LVOTO); aortic atresia-severe stenosis with ventricular septal defect (AA/VSD); and aortic atresia with interrupted aortic arch and aortopulmonary window. This procedure allows the surgeon to keep the left ventricle connected to the systemic circulation while using the pulmonary valve as its outflow valve, by connecting them through the ventricular septal defect. The Yasui procedure includes a modified Damus–Kaye–Stansel procedure to connect the aortic and pulmonary roots, allowing the coronary arteries to remain perfused. It was first described in 1987.

<span class="mw-page-title-main">Parachute mitral valve</span> A congenital mitral valve disease that needs to be on wikipedia

Parachute mitral valve is a rare congenital heart disease where the mitral valve only has a single papillary muscle from which all chordae tendineae originate. It is caused by an embryologic failure of papillary muscles to divide into two normally distinct columns, giving the mitral valve orifice and chordea an irregular, parachute-like appearance. Due to the abnormal anatomy, there are almost always associated mitral valve disorders, and because of its abnormal embryologic origin, PMV almost always coincides in a complex of other congenital heart defects. PMV is usually identified during infancy or childhood due to its symptomatic nature, and hardly ever diagnosed during adulthood.

References

  1. 1 2 3 4 5 6 7 Shone JD, Sellers RD, Anderson RC, Adams P, Lillehei CW, Edwards, JE (1963). "The Developmental Complex of "Parachute Mitral Valve," Supravalvular Ring of Left Atrium, Subaortic Stenosis and Coarctation of Aorta". Am J Cardiol. 11 (6): 714–25. doi:10.1016/0002-9149(63)90098-5. PMID   13988650.
  2. ↑ Moustafa, S.E.; Lesperance J.; Rouleau J.L.; Gosselin G. (2008). "A forme frust of Shone's anomaly in a 65 year-old patient". McGill Journal of Medicine. 1. 11 (1): 19–21. PMC   2322915 . PMID   18523519.
  3. 1 2 Ma, Xiao-jing; Huang, Guo-ying; Liang, Xue-cun; Liu, Xiao-qin; Jia, Bing (2011-04-01). "Atypical Shone's Complex Diagnosed by Echocardiography". Pediatric Cardiology. 32 (4): 442–448. doi:10.1007/s00246-011-9886-y. ISSN   1432-1971. PMID   21279339. S2CID   10075058.
  4. ↑ Roche, K. J.; Genieser, N. B.; Ambrosino, M. M.; Henry, G. L. (November 1998). "MR findings in Shone's complex of left heart obstructive lesions". Pediatric Radiology. 28 (11): 841–845. doi:10.1007/s002470050478. ISSN   0301-0449. PMID   9799314. S2CID   19190579.
  5. ↑ academic.oup.com https://academic.oup.com/ejcts/article/38/5/556/416731 . Retrieved 2024-01-23.{{cite web}}: Missing or empty |title= (help)
  6. ↑ Brauner, R.A.; Laks H.; Drinkwater D.C.; Scholl F.; McCaffery S. (1997). "Multiple Left Heart Obstructions (Shone's Anomaly) With Mitral Valve Involvement: Long-Term Surgical Outcome". Ann Thorac Surg. 64 (3): 721–9. doi:10.1016/s0003-4975(97)00632-2. PMID   9307464.
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