Shone's syndrome is a rare

congenital heart defect A congenital heart defect (CHD), also known as a congenital heart anomaly 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 ...

described by Shone in 1963. In the complete form, four left-sided defects are present: * Supravalvular mitral membrane (SVMM) * Parachute

mitral valve 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-w ...

* Subaortic

stenosis A stenosis (from Ancient Greek στενός, "narrow") is an abnormal narrowing in a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture (as in urethral stricture). ''Stricture'' ...

(membranous or muscular) * Coarctation of the

aorta The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes ...

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 In medicine, a ''forme fruste'' ( French, "crude, or unfinished, form"; ''pl.'', ''formes frustes'') is an atypical or attenuated manifestation of a disease or syndrome, with the implications of incompleteness, partial presence or aborted state. Th ...

, have also been described. The definition is often expanded to include

lesions A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classifi ...

of the left side of the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...

not originally ascribed to Shone's

syndrome A syndrome is a set of medical signs and symptoms which are correlated with each other and often associated with a particular disease or disorder. The word derives from the Greek σύνδρομον, meaning "concurrence". When a syndrome is paired ...

, including mitral and

aortic The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes ox ...

valvular lesions and supravalvular

aortic stenosis Aortic stenosis (AS or AoS) is the narrowing of the exit of the left ventricle of the heart (where the aorta begins), such that problems result. It may occur at the aortic valve as well as above and below this level. It typically gets worse ove ...

. 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 Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an a ...

of the

parachute A parachute is a device used to slow the motion of an object through an atmosphere by creating drag or, in a ram-air parachute, aerodynamic lift. A major application is to support people, for recreation or as a safety device for aviators, who ...

, the chordae as the strings and the

papillary muscle The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae and contract to prevent inversion or prol ...

as the

harness A harness is a looped restraint or support. Specifically, it may refer to one of the following harness types: * Bondage harness * Child harness * Climbing harness * Dog harness * Pet harness * Five-point harness * Horse harness * Parrot harness * ...

Presentation

Shone’s syndrome is a rare

disorder Disorder may refer to randomness, non-order, or no intelligible pattern. Disorder may also refer to: Healthcare * Disorder (medicine), a functional abnormality or disturbance * Mental disorder or psychological disorder, a psychological pattern a ...

that is often detected in very young children. The children tend to show symptoms like

fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...

nocturnal cough A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three pha ...

, and reduced

cardiac output In cardiac physiology, cardiac output (CO), also known as heart output and often denoted by the symbols Q, \dot Q, or \dot Q_ , edited by Catherine E. Williamson, Phillip Bennett is the volumetric flow rate of the heart's pumping output: t ...

by the age of two years. They also develop

wheezing A wheeze is a continuous, coarse, whistling sound produced in the respiratory airways during breathing. For wheezes to occur, some part of the respiratory tree must be narrowed or obstructed (for example narrowing of the lower respiratory tract ...

due to the

exudation An exudate is a fluid emitted by an organism through pores or a wound, a process known as exuding or exudation. ''Exudate'' is derived from ''exude'' 'to ooze' from Latin ''exsūdāre'' 'to (ooze out) sweat' (''ex-'' 'out' and ''sūdāre'' 'to ...

of fluid into the lungs.

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 The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae and contract to prevent inversion or prol ...

. Often, the chordae are short and thick, which can cause restricted movement of the

leaflets and obstruct the blood flow into the left ventricle. The supramitral ring is a

connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...

ring at the base of the atrial surfaces of the

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. Subaortic stenosis has been observed in both muscular and

membranous A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. ...

forms. In either case, a variable degree of obstruction may be observed at the ventricular surface of the aortic valve. This presents an obstruction of flow of blood from the ventricle to the

. Coarctation of the aorta which is, narrowing of a section of the aorta may also be observed. Again this presents an

obstruction Obstruction may refer to: Places * Obstruction Island, in Washington state * Obstruction Islands, east of New Guinea Medicine * Obstructive jaundice * Obstructive sleep apnea * Airway obstruction, a respiratory problem ** Recurrent airway o ...

to blood flow out from the left ventricle. Since there is obstruction of flow into and out of the left ventricle, the

prognosis Prognosis (Greek: πρόγνωσις "fore-knowing, foreseeing") is a medical term for predicting the likely or expected development of a disease, including whether the signs and symptoms will improve or worsen (and how quickly) or remain stabl ...

depends on the degree of obstruction and its effect on

blood flow Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously m ...

Diagnosis

Cardiac magnetic resonance imaging Cardiac magnetic resonance imaging (cardiac MRI), also known as cardiovascular MRI, is a magnetic resonance imaging (MRI) technology used for non-invasive assessment of the function and structure of the cardiovascular system. Conditions in which it ...

is best suited to evaluate patients with Shone's syndrome. Routine blood tests should be done prior to

cardiac catheterization Cardiac catheterization (heart cath) is the insertion of a catheter into a chamber or vessel of the heart. This is done both for diagnostic and interventional purposes. A common example of cardiac catheterization is coronary catheterization that ...

. The surgeons will repair the mitral valve and partially remove the supramitral ring. 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 Ultrasound is sound waves with frequency, frequencies higher than the upper audible limit of human hearing range, hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hea ...

of the heart (

echocardiogram An echocardiography, echocardiogram, cardiac echo or simply an echo, is an ultrasound of the heart. It is a type of medical imaging of the heart, using standard ultrasound or Doppler ultrasound. Echocardiography has become routinely used in th ...

) and a cardiac catheterization procedure, that is, insertion of a device through

blood vessels The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away f ...

in the groin to the heart that helps identify heart anatomy.

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 Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...

management of patients with Shone's syndrome is the degree of involvement of the

and the presence of secondary pulmonary

hypertension Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high bl ...

References

External links

{{Medicine Heart diseases Syndromes affecting the heart