Contact your doctor if you or your child has any of these signs or symptoms:

• Shortness of breath
• Tiring easily, especially after activity
• Swelling of legs, feet or abdomen
• Heart palpitations or skipped beats

These could be signs or symptoms of heart failure or another complication of congenital heart disease.

Autism spectrum disorder (ASD) is a group of conditions that cause people to have difficulties with social communication, to have narrow interests and repetitive behaviours, or to be over-sensitive or under-sensitive to taste, touch, sight or sounds.
• About autism spectrum disorder
• What causes autism spectrum disorder?
• Autism spectrum disorder: difficulties and abilities
• Different types of autism spectrum disorder
• Autism spectrum disorder diagnosis
• Other autism spectrum disorder facts

About autism spectrum disorder

Autism spectrum disorder (ASD) is a brain-based condition – that is, where the brain hasn’t developed in a typical way. Although no two children with ASD are the same, they all face challenges in interacting and communicating with others. And they also have either a narrow range of interests or engage in repetitive activities.

What causes autism spectrum disorder?

We don’t know exactly what causes autism spectrum disorder (ASD). But the latest research shows that in children with ASD:

• there’s early brain overgrowth, which means the brain grows faster than average
• different parts of the brain don’t communicate with each other in a typical way.

  Autism spectrum disorder: difficulties and abilities

  Children with autism spectrum disorder (ASD) have a wide range of difficulties and abilities. In fact, some have very impressive skills and strengths. One child with ASD might know lots of words and have a very good memory. Other children might respond mostly to things they can see, making them good at completing puzzles and sorting objects by shape and colour.

  By about the age of three, however, all children with ASD will show difficulties in two main areas – social communication, and interests and behaviour.

  Social communication 
  Children with ASD usually take longer than other children to learn language and often find it hard to make sense of language, so understanding simple instructions and social norms can be difficult. Almost all children with ASD learn at least some language but they don’t always communicate for purely social reasons and often appear to be uninterested in social contact with others.

  They:

  • might not respond when people speak or gesture towards them, even when their names are called out
  • often make little eye contact with others and usually won’t copy other people’s actions, like clapping or waving
  • usually don’t share interests with others, rarely pointing at anything or showing interest in giving or sharing
  • aren’t very interested in chatting or playing, especially with other children.

  When children with ASD do have language skills, they:

  • will talk about their own special interests, and rarely use language skills to communicate with others
  • might focus on categorising everything around them, such as labelling all their toy trains
  • might echo what they hear, repeating patterns of words without attaching any meaning to them
  • rarely use nonverbal gestures, like nodding their heads or hand gestures, to communicate.

  Narrow interests and repetitive behaviour
  Even from a young age, children with ASD will often prefer the same routines. They might:

  • need to eat from the same plate and drink from the same cup at every meal
  • take the same route from home to child care each time
  • be upset by changes like moving furniture. 

  Many children with ASD also like to repeat behaviour, sometimes in an obsessive way. They might:

  • like to repeatedly flick switches or open and shut doors
  • like lining their toys up in a particular way over and over again
  • like to collect things like twigs, string or balls
  • tightly clutch their favourite objects and become upset if they’re taken away.

  Older children with ASD might have very narrow and intense interests. For example, they might be interested in trains, always choosing a toy train over other toys, labelling every train in their surroundings, and insisting on repeatedly watching cartoons or videos that feature trains. If they have strong verbal skills, they might talk only about trains.

  Sensory sensitivities 
  Many children with ASD also have sensory issues. They might:

  • be especially sensitive to sound and raise their hands to their ears to block out noise
  • like to watch spinning objects, such as fans and wheels
  • like the feel of objects with a certain texture
  • want to eat only foods with a certain texture – for example, they might be happy to eat soft, smooth food, but will refuse anything lumpy
  • use their peripheral vision a lot, or tilt their heads to look at objects from a particular angle.

    Autism spectrum disorder diagnosis

    Diagnosis of autism spectrum disorder (ASD) is based on a child not reaching certain age-based developmental milestones, because there are no other physical characteristics of the condition.

    Signs of ASD are often present early in infancy, but become more noticeable in the toddler years, as children are expected to start talking and playing with other children. The first sign of ASD that most parents notice is their child’s lack of interest in other people. For example, many babies later diagnosed with ASD don’t look at their parents while being held or during nappy changes.

    Children who are diagnosed with ASD will get a description of how severe their symptoms are and the amount of support they need. This ranges from `requiring support’ to ‘requiring very substantial support’.

    Health professionals will also look at children’s language and cognitive abilities. Some children with ASD have intelligence in the typical range, but others have below-average intelligence.

    Children who show difficulties in social communication only might be diagnosed with social communication disorder, rather than ASD.

    If you’re concerned about your child’s development, talk to your health care provider about a developmental assessment. Finding out for sure is the first step to helping your child and getting services and programs suited to your child’s needs.

    It’s important to get help and support as soon as possible. The sooner children get early intervention services, the more effective these services can be.

    A paediatrician, psychiatrist, psychologist or other professional trained in ASD can diagnose ASD. They’ll use a combination of behaviour tests (watching the child play and interact) and interviews with parents about the child’s development.

  • Other autism spectrum disorder facts

    The prevalence of autism spectrum disorder (ASD) has risen since the 1990s. Research suggests that the apparent increase is at least partly because of:

    • increased awareness about ASD, so more cases are being identified
    • changes in the criteria for diagnosing ASD.

    Some researchers suggest that recent changes in the criteria used when diagnosing ASD will affect the number of people diagnosed with ASD. Some argue that the changes will lead to an increase in the number of people diagnosed with ASD, while others think it will lead to a decrease. This is because of the diagnostic criteria and how researchers measure prevalence.

    In the past, most studies focused on measuring the prevalence of ASD in general, or of autistic disorder. Fewer focused on Asperger’s disorder or PDD–NOS. Now that all these categories have been combined into one, it’s likely to affect the prevalence of ASD.

    Atrial septal defect

    Atrial septal defect

    Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria(upper chambers) of the heart. Normally, the atria are separated by a dividing wall, theinteratrial septum. If this septum is defective or absent, then oxygen-rich blood can flow directly from the left side of the heart to mix with the oxygen-poor blood in the right side of the heart, or vice versa.^[1] This can lead to lower-than-normal oxygen levels in the arterial blood that supplies the brain, organs, and tissues. However, an ASD may not produce noticeable signs or symptoms, especially if the defect is small.^[2]

    A "shunt" is the presence of a net flow of blood through the defect, either from left to right or right to left. The amount of shunting present, if any, determines the hemodynamic significance of the ASD. A "right-to-left-shunt" typically poses the more dangerous scenario.

    During development of the fetus, the interatrial septum develops to separate the left and right atria. However, a hole in the septum called the foramen ovale, allows blood from the right atrium to enter the left atrium during fetal development. This opening allows blood to bypass the nonfunctional fetal lungs while the fetus obtains its oxygen from the placenta. A layer of tissue called the septum primum acts as a valve over the foramen ovale during fetal development. After birth, the pressure in the right side of the heart drops as the lungs open and begin working, causing the foramen ovale to close entirely. In approximately 25% of adults,^[3] the foramen ovale does not entirely seal.^[4] In these cases, any elevation of the pressure in the pulmonary circulatory system (due to pulmonary hypertension, temporarily while coughing, etc.) can cause the foramen ovale to remain open. This is known as a patent foramen ovale (PFO), which is a type of atrial septal defect.

    Cause

    • Down syndrome – patients with Down Syndrome have higher rates of ASDs, especially a particular type that involves the ventricular wall.^[5] As many as one half of Down Syndrome patients have some type of septal defect.^[5]
    • Ebstein's anomaly^[6] - About 50% of individuals with Ebstein anomaly have an associated shunt between the right and left atria, either an atrial septal defect or a patent foramen ovale.^[7]
    • Fetal alcohol syndrome – about one in four patients with fetal alcohol syndrome has either an ASD or a ventricular septal defect.^[8]
    • Holt–Oram syndrome – Both the osteium secundum and osteum primum types of ASD are associated with Holt–Oram syndrome^[9]
    • Lutembacher's syndrome – the presence of a congenital ASD along with acquired mitral stenosis.^[10]

    Types

    
    Schematic drawing showing the location of different types of ASD, the view is into an opened right atrium.
    HV: right ventricle; VCS: superior vena cava; VCI: inferior vena cava
    1: upper sinus venosus defect; 2: lower sinus venosus defect;3: secundum defect; 4: defect involving coronary sinus; 5;primum defect.

    There are many types of atrial septal defects. They are differentiated from each other by whether they involve other structures of the heart and how they are formed during the developmental process during early fetal development.

    Ostium secundum atrial septal defect[edit]

    The ostium secundum atrial septal defect is the most common type of atrial septal defect, and comprises 6–10% of all congenital heart diseases.

    The secundum atrial septal defect usually arises from an enlarged foramen ovale, inadequate growth of the septum secundum, or excessive absorption of the septum primum. Ten to twenty percent of individuals with ostium secundum ASDs also have mitral valve prolapse.^[11]

    If the ostium secundum ASD is accompanied by an acquired mitral valve stenosis, that is called Lutembacher's syndrome.^[10]

    Natural history

    Most individuals with an uncorrected secundum ASD do not have significant symptoms through early adulthood. More than 70 percent develop symptoms by about 40 years of age. Symptoms are typically decreased exercise tolerance, easy fatigueability, palpitations, and syncope.

    Complications of an uncorrected secundum ASD include pulmonary hypertension, right-sided heart failure, atrial fibrillation or flutter, stroke, and Eisenmenger's syndrome.

    While pulmonary hypertension is unusual before 20 years of age, it is seen in 50 percent of individuals above the age of 40. Progression toEisenmenger's syndrome occurs in 5 to 10 percent of individuals late in the disease process.^[10]

    Patent foramen ovale

    A patent foramen ovale (PFO) is a small channel that has some hemodynamic consequence; it is a remnant of the fetal foramen ovale(/f??re?m?n o??væli, -?v??-, -?ve?-/^[12]), which normally closes at birth. In medical use, the term "patent" (/?pe?t?nt/^[13]) means open or unobstructed.^[14] In approximately 25% of people, the foramen ovale fails to close properly, leaving them with a PFO or at least with what some physicians classify as a "pro-PFO", which is a PFO that is normally closed but can open under increased blood pressure. Clinically it is linked to decompression sickness, paradoxical embolism and migraine. On echocardiography, there may not be any shunting of blood noted except when the patient coughs.

    PFO has been linked to strokes and the mechanism by which a PFO may play a role in stroke is called paradoxical embolism. In the case of PFO, a blood clot from the venous circulatory system is able to pass from the right atrium into the left atrium via the PFO, and ultimately into systemic circulation.^[15] PFO is common in patients with atrial septal aneurysms (ASA) which are also linked to cryptogenic (i.e. of unknown cause) strokes.^[16] PFO is more prevalent in patients with cryptogenic stroke than in patients with a stroke of known cause.^[17]

    Treatments for PFO include surgical closure, percutaneous device closure, anticoagulant therapy, and antiplatelet agents.^[16]

    There is debate within the neurology and cardiology communities about the role of a PFO in cryptogenic neurologic events such as strokes and transient ischemia attacks (TIAs) without any other potential cause. Some data suggest that PFOs may be involved in the pathogenesis of some migraine headaches.^[18] Several clinical trials are currently underway to investigate the role of PFO in these clinical situations.^[18]

    Ostium primum atrial septal defect

    A defect in the ostium primum is occasionally classified as an atrial septal defect,^[19] but it is more commonly classified as anatrioventricular septal defect.^[20][21] Ostium primum defects are less common than ostium secundum defects.^[22] This is type of defect is usually associated with Down Syndrome.
    

    Sinus venosus atrial septal defect

    A sinus venosus ASD is a type of atrial septum defect in which the defect in the septum involves the venous inflow of either the superior vena cava or the inferior vena cava.

    A sinus venosus ASD that involves the superior vena cava makes up 2 to 3% of all interatrial communication. It is located at the junction of the superior vena cava and the right atrium. It is frequently associated with anomalous drainage of the right-sided pulmonary veins into the right atrium (instead of the normal drainage of the pulmonary veins into the left atrium).^[23]

    
    Ultrasound picture of the heart, seen in asubcostal view. The apex towards the right, atria to the left. ASD secundum seen as a discontinuation of the white band of the atrial septum. Enlarged right atrium below. Enlarged pulmonary veins seen entering left atrium above.

    Common or single atrium

    Common (or single) atrium is a failure of development of the embryologic components that contribute to the atrial septal complex. It is frequently associated with heterotaxy syndrome.^[24]

    Mixed atrial septal defect

    The inter atrial septum can be divided into 5 septal zones. If the defect involves 2 or more of the 5 septal zones, then the defect is termed a mixed atrial septal defect.^[25]

    Mechanisms

    In unaffected individuals, the chambers of the left side of the heart are under higher pressure than the chambers of the right side of the heart. This is because the left ventricle has to produce enough pressure to pump blood throughout the entire body, while the right ventricleneeds only to produce enough pressure to pump blood to the lungs.

    In the case of a large ASD (>9mm), which may result in a clinically remarkable left-to-right shunt, blood will shunt from the left atrium to theright atrium. This extra blood from the left atrium may cause a volume overload of both the right atrium and the right ventricle. If untreated, this condition can result in enlargement of the right side of the heart and ultimately heart failure.^[25]

    Any process that increases the pressure in the left ventricle can cause worsening of the left-to-right shunt. This includes hypertension, which increases the pressure that the left ventricle has to generate in order to open the aortic valve during ventricular systole, and coronary artery disease which increases the stiffness of the left ventricle, thereby increasing the filling pressure of the left ventricle during ventriculardiastole. The left-to-right shunt increases the filling pressure of the right heart (preload) and forces the right ventricle to pump out more blood than the left ventricle. This constant overloading of the right side of the heart will cause an overload of the entire pulmonary vasculature. Eventually, pulmonary hypertension may develop.

    The pulmonary hypertension will cause the right ventricle to face increased afterload. The right ventricle will be forced to generate higher pressures to try to overcome the pulmonary hypertension. This may lead to right ventricular failure (dilatation and decreased systolicfunction of the right ventricle).

    If the ASD is left uncorrected, the pulmonary hypertension progresses and the pressure in the right side of the heart will become greater than the left side of the heart. This reversal of the pressure gradient across the ASD causes the shunt to reverse; a right-to-left shunt will exist. This phenomenon is known as Eisenmenger's syndrome. Once right-to-left shunting occurs, a portion of the oxygen-poor blood will get shunted to the left side of the heart and ejected to the peripheral vascular system. This will cause signs of cyanosis.

    Pathophysiology -

    blood flow to right atria from superior vena cava & inferior vena cava

    ?

    right atria to right ventrical

    ?

    right ventrical to pulmonary artery

    ?

    pulmonary arteries to lungs

    ?

    lungs to left atria via pulmonary vein

    ?

    left atria to left ventricals and some flow to right atria also

    ?

    causes overload of right heart

    ?

    right side heart failure

    Diagnosis

    
    Abnormal chest X-ray as seen in a patient of atrial septal defect

    Most individuals with a significant ASD are diagnosed in utero or in early childhood with the use ofultrasonography or auscultation of the heart sounds during physical examination.

    Some individuals with an ASD will have undergone surgical correction of their ASD during childhood. The development of signs and symptoms due to an ASD are related to the size of the intracardiac shunt. Individuals with a larger shunt tend to present with symptoms at a younger age.

    Adults with an uncorrected ASD will present with symptoms of dyspnea on exertion (shortness of breath with minimal exercise), congestive heart failure, or cerebrovascular accident (stroke). They may be noted on routine testing to have an abnormal chest x-ray or an abnormal ECG and may haveatrial fibrillation. If the ASD causes a left-to-right shunt, the pulmonary vasculature in both lungs may appear dilated on chest x-ray, due to the increase in pulmonary blood flow.^[26]

    Physical exam

    The physical findings in an adult with an ASD include those related directly to the intracardiac shunt, and those that are secondary to the right heart failure that may be present in these individuals.

    Upon auscultation of the heart sounds, there may be a systolic ejection murmur that is attributed to the pulmonic valve. This is due to the increased flow of blood through the pulmonic valve rather than any structural abnormality of the valve leaflets.

    In unaffected individuals, there are respiratory variations in the splitting of the second heart sound (S₂). During respiratory inspiration, the negative intrathoracic pressure causes increased blood return into the right side of the heart. The increased blood volume in the right ventricle causes the pulmonic valve to stay open longer during ventricular systole. This causes a normal delay in the P₂ component of S₂. During expiration, the positive intrathoracic pressure causes decreased blood return to the right side of the heart. The reduced volume in the right ventricle allows the pulmonic valve to close earlier at the end of ventricular systole, causing P₂ to occur earlier.

    In individuals with an ASD, there is a fixed splitting of S₂. The reason that there is a fixed splitting of the second heart sound is that the extra blood return during inspiration gets equalized between the left and right atrium due to the communication that exists between the atria in individuals with ASD.

    The right ventricle can be thought of as continuously overloaded because of the left to right shunt, producing a widely split S2. Because the atria are linked via the atrial septal defect, inspiration produces no net pressure change between them, and has no effect on the splitting of S2. Thus, S2 is split to the same degree during inspiration as expiration, and is said to be “fixed.”

    Echocardiography

    In transthoracic echocardiography, an atrial septal defect may be seen on color flow imaging as a jet of blood from the left atrium to the right atrium.

    If agitated saline is injected into a peripheral vein during echocardiography, small air bubbles can be seen on echocardiographic imaging. It may be possible to see bubbles travel across an ASD either at rest or during a cough. (Bubbles will only flow from right atrium to left atrium if the RA pressure is greater than LA).

    Because better visualization of the atria is achieved with transesophageal echocardiography, this test may be performed in individuals with a suspected ASD which is not visualized on transthoracic imaging.

    Newer techniques to visualize these defects involve intracardiac imaging with special catheters that are typically placed in the venous system and advanced to the level of the heart. This type of imaging is becoming more common and involves only mild sedation for the patient typically.

    If the individual has adequate echocardiographic windows, it is possible to use the echocardiogram to measure the cardiac output of the left ventricle and the right ventricle independently. In this way, it is possible to estimate the shunt fraction using echocardiography.

    Transcranial doppler bubble study

    A less invasive method for detecting a PFO or other ASDs than transesophagal ultrasound is Transcranial Doppler with bubble contrast.^[27]This method reveals the cerebral impact of the ASD or PFO.

    Electrocardiogram

    The ECG findings in atrial septal defect vary with the type of defect the individual has. Individuals with atrial septal defects may have a prolonged PR interval (a first degree heart block). The prolongation of the PR interval is probably due to the enlargement of the atria that is common in ASDs and the increased distance due to the defect itself. Both of these can cause an increased distance of internodal conduction from the SA node to the AV node.^[28]

    In addition to the PR prolongation, individuals with a primum ASD have a left axis deviation of the QRS complex while those with a secundum ASD have a right axis deviation of the QRS complex. Individuals with a sinus venosus ASD exhibit a left axis deviation of the P wave (not the QRS complex).

    A common finding in the ECG is the presence of incomplete right bundle branch block. The presence of a right bundle branch block is so characteristic that if it is absent, the diagnosis of ASD should be reconsidered.