Ventricular septal defect VSD

is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart.

The ventricular septum consists of an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes.

The membranous portion, which is close to the atrioventricular node, is most commonly affected in adults and older children in the United States. It is also the type that will most commonly require surgical intervention, comprising over 80% of cases.

Membranous ventricular septal defects are more common than muscular ventricular septal defects, and are the most common congenital cardiac anomaly.

Diagnosis

A VSD can be detected by cardiac auscultation. Classically, a VSD causes a pathognomonic holo- or pansystolic murmur. Auscultation is generally considered sufficient for detecting a significant VSD. The murmur depends on the abnormal flow of blood from the left ventricle, through the VSD, to the right ventricle. If there is not much difference in pressure between the left and right ventricles, then the flow of blood through the VSD will not be very great and the VSD may be silent. This situation occurs a) in the fetus (when the right and left ventricular pressures are essentially equal), b) for a short time after birth (before the right ventricular pressure has decreased), and c) as a late complication of unrepaired VSD. Confirmation of cardiac auscultation can be obtained by non-invasive echocardiography. To more accurately measure ventricular pressures, cardiac catheterization, can be performed.

Signs and symptoms

Ventricular septal defect is usually symptomless at birth. It usually manifests a few weeks after birth.

Symptoms

VSD is an acyanotic congenital heart defect, aka a Left-to-right shunt, so there are no signs of cyanosis.

Signs

Pansystolic (Holosystolic) murmur (depending upon the size of the defect) +/- palpable thrill (palpable turbulence of blood flow). Heart sounds are normal. Larger VSDs may cause a parasternal heave, a displaced apex beat (the palpable heartbeat moves laterally over time, as the heart enlarges). An infant with a large VSD will fail to thrive and become sweaty and tachypnoeic (breathe faster) with feeds.

CAUSES: The cause of VSD ( ventricular septal defect) includes the incomplete looping of the heart during days 24-28 of development. Faults with NKX2.5 gene can cause this.

Complications

• Aortic insufficiency (leaking of the valve that separates the left ventricle from the aorta)
• Damage to the electrical conduction system of the heart during surgery (causing an irregular heart rhythm)
• (failure to thrive in infancy)
• Heart failure
• Infective endocarditis
• Pulmonary hypertension
  
  

Treatment 

Most cases do not need treatment and heal at the first years of life. Treatment is either conservative or surgical. Smaller congenital VSDs often close on their own, as the heart grows, and in such cases may be treated conservatively. Some cases may necessitate surgical intervention, i.e. with the following indications:

1. Failure of congestive cardiac failure to respond to medications

2. VSD with pulmonic stenosis

3. Large VSD with pulmonary hypertension

4. VSD with aortic regurgitation

For the surgical procedure, a heart-lung machine is required and a median sternotomy is performed. Percutaneous endovascular procedures are less invasive and can be done on a beating heart, but are only suitable for certain patients. Repair of most VSDs is complicated by the fact that the conducting system of the heart is in the immediate vicinity.

Ventricular septum defect in infants is initially treated medically with cardiac glycosides (e.g., digoxin 10-20mcg/kg per day), loop diuretics (e.g., furosemide 1–3 mg/kg per day) and ACE inhibitors (e.g., captopril 0.5–2 mg/kg per day).

References  

1. Cameron P. et al: Textbook of Paediatric Emergency Medicine. p116-117 [Elsevier, 2006]

Atrial septal defect (ASD)

Atrial septal defect (ASD) is a congenital heart defect in which the wall that separates the upper heart chambers (atria) does not close completely. Congenital means the defect is present at birth.

Causes, incidence, and risk factors

In fetal circulation, there is normally an opening between the two atria (the upper chambers of the heart) to allow blood to bypass the lungs. This opening usually closes around the time the baby is born.

If the ASD is persistent, blood continues to flow from the left to the right atria. This is called a shunt. If too much blood moves to the right side of the heart, pressures in the lungs build up. The shunt can be reversed so that blood flows from right to left. Small atrial septal defects often cause very few problems and may be found much later in life. Many problems can occur if the shunt is large, however. In advanced and severe cases with large shunts the increased pressure on the right side of the heart would result in reversal of blood flow (now from right to left). This usually results in significant shortness of breath.

ASD is not very common. When the person has no other congenital defect, symptoms may be absent, particularly in children. Symptoms may begin any time after birth through childhood. Individuals with ASD are at an increased risk for developing a number of complications including:

• Atrial fibrillation (in adults)
• Heart failure
• Pulmonary overcirculation
• Pulmonary hypertension
• Stroke

Symptoms

Small to moderate sized defects may produce no symptoms, or not until middle age or later. Symptoms that may occur can include:

• dyspnea
• Frequent respiratory infections in children
• palpitations in adults
• Shortness of breath with activity

Signs and tests

The doctor may hear abnormal heart sounds when listening to the chest with a stethoscope. A murmur may be heard only in certain body positions, and sometimes a murmur may not be heard at all. The physical exam may also reveal signs of heart failure in some adults.

If the shunt is large, increased blood flow across the tricuspid valve may create an additional murmur when the heart relaxes between beats.

Tests that may done include:

• Cardiac catheterization
• Chest x-ray
• Coronary angiography (for patients over 35 years old)
• Doppler study of the heart
• ECG
• Echocardiography
• Heart MRI
• Transesophageal echocardiography (TEE)

Treatment

ASD may not require treatment if there are few or no symptoms, or if the defect is small. Surgical closure of the defect is recommended if the defect is large, the heart is swollen, or symptoms occur.

A procedure has been developed to close the defect without surgery. The procedure involves placing an ASD closure device into the heart through tubes called catheters. The health care provider makes a tiny surgical cut in the groin, then inserts the catheters into a blood vessel and up into the heart. The closure device is then placed across the ASD and the defect is closed.

Not all patients with atrial septal defects can have this procedure.

Prophylactic (preventive) antibiotics should be given prior to dental procedures to reduce the risk of developing infective endocarditis immediately after surgery for the ASD, but they are not required later on.

Expectations (prognosis)

With a small to moderate atrial septal defect, a person may live a normal life span without symptoms. Larger defects may cause disability by middle age because of increased blood flow and shunting of blood back into the pulmonary circulation.

Some patients with ASD may have other congenital heart conditions, such as a leaky valve.

Complications

• Arrhythmias, particularly atrial fibrillation
• Heart failure
• Pulmonary hypertension
• Stroke

References

1. Webb GD, Smallhorn JF, Therrien J, et al. Congenital heart disease. Zipes DP, Libby P, Bonow RO, Braunwald E, eds.Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. St. Louis, Mo: WB Saunders; 2007:chap 61.

Ebstein's anomaly

Ebstein anomaly is a congenital heart defect in which the opening of the tricuspid valve is displaced towards the apex of the right ventricle of the heart.

Causes 

Ebstein's anomaly occurs as a baby develops in the womb. The exact cause is unknown, although the use of certain drugs (such as lithium or benzodiazepines) during pregnancy may play a role. The condition is rare. It is more common in white people.

Symptoms

Symptoms range from mild to very severe. Often, symptoms develop soon after birth and include bluish-colored lips and nails due to low blood oxygen levels. In severe cases, the baby appears very sick and has trouble breathing.

Symptoms in older children may include:

• Cough
• Failure to grow
• Fatigue
• Rapid breathing
• Shortness of breath

Very fast heartbeat

The annulus of the valve is still in the normal position. The valve leaflets, however, are to a varying degree, attached to the walls and septum of the right ventricle. There is subsequent 'atrialization' of a portion of the morphologic right ventricle (which is then contiguous with the right atrium). This causes the right atrium to be large and the anatomic right ventricle to be small in size.

• S3 heart sound
• S4 heart sound
• Systolic murmur of tricuspid regurgitation
• Mid-diastolic murmur along the lower left sternal border
• Right atrial hypertrophy
• Right ventricular conduction defects
• Wolff-Parkinson-White syndrome often accompanies

Signs and tests

Newborns who have a severe leakage across the tricuspid valve will have very low levels of oxygen in their blood and significant heart swelling. The doctor may hear abnormal heart sounds, such as murmur, when listening to the chest with a stethoscope.

Tests that can help diagnose this condition include:

• Chest x-ray 
• Magnetic resonance imaging (MRI) of the heart
• Measurement of the electrical activity of the heart (EKG)
• Ultrasound of the heart (echocardiogram)

Treatment

Treatment depends on the severity of the defect and the specific symptoms. Medical care may include:

• Medications to help with heart failure
• Oxygen and other breathing support
• Surgery to correct the valve may be needed for children who continue to worsen or who have more serious complications
  
  
  

  The Canadian Cardiovascular Society (CCS) recommends surgical intervention for the following indications:

  • Limited exercise capacity (NYHA III-IV).
  • Increasing heart size (cardiothoracic ratio greater than 65%).
  • Important cyanosis (resting oxygen saturation of less than 90%). (Level B)
  • Severe tricuspid regurgitation with symptoms.
  • Transient ischemic attack or stroke

  The CCS further recommends patients who require operation for Ebstein anomaly should be operated on by congenital heart surgeons who have substantial specific experience and success with this operation. Every effort should be made to preserve the native tricuspid valve.

  
  

  Prognosis

In general, the earlier symptoms develop, the more severe the disease.

Some patients may have either no symptoms or very mild symptoms. Others may worsen over time, developing blue coloring (cyanosis), heart failure, heart block, or dangerous heart rhythms.

Complications

A severe leakage can lead to swelling of the heart and liver, and congestive heart failure.

Other complications may include:

• Abnormal heart rhythms (arrhythmias), including abormally fast rhythms (tachyarrhythmias) and abnormally slow rhythms (bradyarrhythmias and heart block)
• Blood clots from the heart to other parts of the body
• Brain abscess

Prevention

There is no known prevention, other than talking with your doctor before a pregnancy if you are taking medicines that are thought to be related to developing this disease. You may be able to prevent some of the complications of the disease. For example, taking antibiotics before dental surgery may help prevent endocarditis.

References

1. Cyanotic Congenital Heart Defects. In: Park MK, Troxler RG, eds. Pediatric Cardiology for Practioners. 5th ed. St. Louis, Mo: Mosby, Inc; 2008: chap 14.
2. ^ ^a b Silversides, C. K.; Salehian, O.; Oechslin, E.; Schwerzmann, M.; Vonder Muhll, I.; Khairy, P.; Horlick, E.; Landzberg, M. et al. (2010). "Canadian Cardiovascular Society 2009 Consensus Conference on the management of adults with congenital heart disease: Complex congenital cardiac lesions". The Canadian journal of cardiology 26 (3): e98–117.

Congenital heart disease

Causes, incidence, and risk factors

Congenital heart disease (CHD) can describe a number of different problems affecting the heart. It is the most common type of birth defect. Congenital heart disease causes more deaths in the first year of life than any other birth defects.

Congenital heart disease is often divided into two types: cyanotic (blue skin color caused by a lack of oxygen) and non-cyanotic. The following lists cover the most common congenital heart diseases:

Cyanotic:

• Ebstein's anomaly
• Hypoplastic left heart
• Pulmonary atresia
• Tetralogy of Fallot
• Total anomalous pulmonary venous return
• Transposition of the great vessels
• Tricuspid atresia
• Truncus arteriosus  

Non-cyanotic:

• Aortic stenosis
• Atrial septal defect (ASD)
• Atrioventricular canal (endocardial cushion defect)
• Coarctation of the aorta
• Patent ductus arteriosus (PDA)
• Pulmonic stenosis
• Ventricular septal defect (VSD)  

These problems may occur alone or together. Most children with congenital heart disease do not have other types of birth defects. However, heart defects can be part of genetic and chromosomal syndromes. Some of these syndromes may be passed down through families.

Examples include:

• DiGeorge syndrome
• Down syndrome
• Marfan syndrome
• Noonan syndrome
• Trisomy 13
• Turner syndrome

Often, no cause for the heart disease can be found. Congenital heart diseases continue to be investigated and researched. Drugs such as retinoic acid for acne, chemicals, alcohol, and infections (such as rubella) during pregnancy can contribute to some congenital heart problems.

Poorly controlled blood sugar in women who have diabetes during pregnancy has also been linked to a high rate of congenital heart defects.

Symptoms

Symptoms depend on the condition. Although congenital heart disease is present at birth, the symptoms may not appear right away.

Defects such as coarctation of the aorta may not cause problems for many years. Other problems, such as a small ventricular septal defect (VSD), may never cause any problems. Some people with a VSD have a normal activity level and lifespan.

Signs and tests

Most congenital heart defects are found during a pregnancy ultrasound. When a defect is found, a pediatric heart doctor, surgeon, and other specialists can be there when the baby is delivered. Having medical care ready at the delivery can mean the difference between life and death for some babies.

Which tests are done on the baby depend on the defect, and the symptoms.

Treatment

Which treatment is used, and how well the baby responds to it, depends on the condition. Many defects need to be followed carefully. Some will heal over time, while others will need to be treated.

Some congenital heart diseases can be treated with medication alone. Others need to be treated with one or more heart surgeries.

Prevention

Women who are expecting should get good prenatal care:

• Avoid alcohol and illegal drugs during pregnancy.
• Tell your doctor that you are pregnant before taking any new medicines.
• Have a blood test early in your pregnancy to see if you are immune to rubella. If you are not immune, avoid any possible exposure to rubella and get vaccinated right after delivery.
• Pregnant women who have diabetes should try to get better control over their blood sugar levels.

Certain genes may play a role in congenital heart disease. Many family members may be affected. Talk to your health care provider about genetic screening if you have a family history of congenital heart disease.

References

1. Webb GD, Smallhorn JF, Therrien J, Redington AN. Congenital heart disease. In: Bonow RO, Man DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 9th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 65.

Source: 

http://www.ncbi.nlm.nih.gov