Cardiology

The commonest form of this defect (so called Secundum ASD) is a defect in the central part of the "Atrial Septum" (the partition separating the Atriums). This allows red blood to pass through into the right side of the heart, leading to enlargement of the right ventricle and excessive flow in the lung circulation. Most affected children are free of any major symptoms, but the risk of heart failure developing later in life makes closure desirable, unless the defect is very small. These defects may be repaired surgically or by using an expanding plug ("Device"), which can be inserted through a heart catheter without an operation (Device Closure).

Other types of ASD affect different parts of the atrial septum. Defects in the lower part of the septum, close to the Atrioventricular Valves (e.g. Tricuspid valve) are called 'Primum ASD' (or Partial Atrioventricular Septal Defect).

The commonest heart defect ("Hole in the heart"). When small, such defects cause little in the way of problems and often "heal" (close) on their own. Blood flows from left ventricle to right ventricle at high pressure, often producing a loud "murmur" with each heart beat. The effect on heart function depends on the size of the defect, but may be very minor. Surgery may not be required, if the heart shows no evidence of "strain".

Larger VSDs allow more blood to flow from the left ventricle to the right ventricle and lead to increase in pressure and flow in the lung circulation. This places significant strain on the heart and affected babies usually need surgical repair of the defect. An operation may be required in the first three to four months of life, though some defects, which are causing less trouble, may be left for a few years, in the hope that they may get smaller, only needing surgery if they remain large or are associated with other problems.

Failure of the ductus to close in the early weeks of life, as normally occurs, results in a PDA. This allows blood to flow between the aorta and the pulmonary artery, leading to an increase in flow in the lung circulation. If the PDA is large the pressure in the lungs may also be elevated.
Surgery may be needed when the ductus is large, but in many cases the ductus can be closed using a spring coil introduced with a heart catheter.

With some larger PDAs a 'Device' (similar to that used for closure of ASD) may be employed.

This is usually a large defect involving both the atrial (ASD) and the ventricular (VSD) septums, which allows blood to pass freely between the two ventricles and the atriums. The valve apparatus at the junction between atriums and ventricles is "shared" - there being effectively only one valve instead of the normal two. Blood flow and pressure in the lung circulation is substantially increased. Early surgical repair is needed in most cases (in the first four to six months).

Truncus Arteriosus
In this defect, only one artery originates from the heart and forms both the aorta and the pulmonary artery. The truncus arises above a VSD that is almost always associated with this defect.

The truncus receives low oxygen blood from the right ventricle and oxygen rich blood from the left ventricle. This mix of high and low oxygen blood is sent out to the body and to the lungs.

Open heart surgery in infancy is needed to correct this defect. The surgery involves closure of the VSD and removal of the pulmonary arteries from the truncus. The pulmonary arteries are then connected to the right ventricle with a prosthetic tube. This prosthetic tube usually needs to be replaced as the infant grows.

The Pulmonary Veins, which carry blood back to the heart after it has circulated through the lungs, are not connected to the left atrium. Instead they are connected to one of the veins from the main circulation so that the blood returning from the lungs drains back to the right side of the heart. The affected babies may be blue or show signs of heart failure. Most of them require surgical repair in the newborn period.

The Pulmonary Valve is thickened and narrowed leading to the development of abnormally high pressure in the right ventricle. The right ventricular wall becomes thickened ("Hypertrophied"). If the problem is severe it may require treatment which usually involves stretching the valve with a balloon catheter (Balloon Valvuloplasty)

The combination of a VSD with Pulmonary Stenosis, with the Aorta "Overriding" (sitting 'astride') the VSD and with RV Hypertrophy is termed "Tetralogy of Fallot". The obstruction to flow into the lungs leads to blood being diverted through the VSD to the aorta. Flow in the lung circulation is reduced and the child appears 'Blue' (Cyanosed).

This defect is a form of Tetralogy of Fallot in which there is complete obstruction of the Pulmonary Artery resulting in total diversion of blood from the right ventricle into the aorta. Survival depends on the ductus remaining open in the early days of life (in order for blood to reach the lungs), or on the presence of other connecting blood vessels between the Aorta and the Pulmonary Arteries in the lungs (Collaterals). Most babies will need a 'Shunt' operation during infancy, involving insertion of a tiny piece of artificial tube (made from Goretex) between the Aorta, or a branch (usually one of the arm arteries), and one of the branch Pulmonary Arteries. Complete Repair is carried out at two to three years. Complete repair for Pulmonary Atresia is usually carried out after the first year of life, though sometimes it may be performed earlier.

As in Pulmonary Atresia with VSD, this defect is also associated with complete obstruction of the Pulmonary Artery. However, as there is no associated VSD, blood is diverted from the right atrium to the left atrium via the Foramen Ovale. The right ventricle (RV) is usually small (Hypoplastic), though its wall may be thickened (Hypertrophied). Survival depends on the ductus remaining open in the early days of life (in order for blood to reach the lungs), Most babies will need a 'Shunt' operation during infancy, involving insertion of a tiny piece of artificial tube (made from Goretex) between the Aorta, or a branch (usually one of the arm arteries), and one of the branch Pulmonary Arteries.

Absence of any connection between the right atrium and the right ventricle leads to blood being diverted from the right atrium to the left atrium. The right ventricle (RV) is usually small (Hypoplastic) Survival depends on an associated VSD (often quite small), in order for blood to reach the lungs, or on the ductus remaining open in the early days of life. Most babies will need a 'Shunt' operation during infancy, involving insertion of a tiny piece of artificial tube (made from Goretex) between the Aorta, or a branch (usually one of the arm arteries), and one of the branch Pulmonary Arteries.
At a second operation some blood from veins in the upper part of the body may be connected directly to the lung arteries (BCPC)
Definitive surgery is usually delayed until the age of at least two years. It involves the so called Fontan operation. This involves connecting the veins from the main circulation (SVC & IVC) directly to the pulmonary arteries. Blue blood is thus directed into the lungs rather than to the left atrium. A patch is placed to prevent blood passing from the RA to the LA - though sometimes a small hole (a 'Fenestration') is deliberately left

This involves connecting the veins from the main circulation (SVC & IVC) directly to the pulmonary arteries. Blue blood is thus directed into the lungs rather than to the left atrium. A patch is placed to prevent blood passing from the RA to the LA - though sometimes a small hole (a 'Fenestration') is deliberately left.

The Aortic Valve is thickened and narrowed leading to the development of abnormally high pressure in the left ventricle. The left ventricular wall becomes thickened ("Hypertrophied"). If the problem is severe it may require treatment, which usually involves surgery in younger patients, though it may be possible to stretch the valve with a balloon catheter (Balloon Valvuloplasty), in older children. The catheter is passed from an artery in the leg. When the tip is through the valve the balloon is inflated to open the valve. Treatment does not completely cure the problem and the valve sometimes tends to develop further problems with time, sometimes needing reoperation or further balloon stretching.

In this condition the narrowing is below the aortic valve (indicated by arrow). The effect on heart function is similar to aortic valve stenosis. In many cases the obstruction is produced by a 'membrane', but other types of subaortic stenosis also occur - notably a 'muscular' type (also called "Hypertrophic Obstructive Cardiomyopathy" (HOCM) or "Idiopathic Hypertrophic Subaortic Stenosis" (IHSS).

A narrow area (stricture) is present in the aorta and leads to restricted blood flow to the lower part of the circulation. Blood pressure in the arms and head is high, whilst that in the legs is low. Heart failure may develop. In most cases surgical repair is needed, sometimes in the early weeks of life.

Repair may involve surgical removal of a short segment of aorta, including the stricture (with the ends sewn back together) or use of the artery to the left arm to create a flap, which is turned down to enlarge the narrow section.

Alternatively it may, in some cases, be possible to deal with the problem with a balloon catheter.

The left side of the heart is very poorly formed and cannot support the main circulation (round the body). The left ventricle and aorta are abnormally small (hypoplastic). This is amongst the most severe forms of heart defect. Most babies are very ill in the early days of life and need urgent surgery to survive. The first stage of surgery is called a 'Norwood' operation.

The Norwood operation involves connecting the origin of the pulmonary artery to the aorta, to allow the right ventricle to pump blood to the main circulation and a 'Shunt' operation, involving insertion of a tiny piece of artificial tube (made from Goretex) between the right arm artery and the right pulmonary artery, to maintain blood flow to the lungs. Later in childhood it may be possible to carry out a modified Fontan operation.

In this condition the narrowing is below the aortic valve (indicated by arrow). The effect on heart function is similar to aortic valve stenosis. In many cases the obstruction is produced by a 'membrane', but other types of Subaortic stenosis also occur - notably a 'muscular' type (also called "Hypertrophic Obstructive Cardiomyopathy" (HOCM) or "Idiopathic Hypertrophic Subaortic Stenosis" (IHSS).

The Aorta arises from the right ventricle and receives "blue" blood, whilst the Pulmonary Artery arises from the left ventricle. The baby becomes blue immediately after birth and needs urgent treatment. Survival depends on the ductus or the Foramen Ovale remaining open in the early days of life until treatment can be applied. The Foramen Ovale can be enlarged with a catheter procedure, called Balloon Septostomy, which is performed in the first few days of life. This involves a catheter with a balloon at the tip, which is passed from a leg vein until the balloon is in the left atrium (across the Foramen Ovale). The balloon is then inflated and the catheter is pulled back to the right atrium.

Early surgery is essential and involves the
" Arterial Switch Operation", which is carried out in the first week or two of life and corrects the abnormality. The small coronary arteries, which feed the heart muscle with blood, need to be transferred as well as the two Great Arteries (Aorta and Pulmonary Artery).

Until around 1980 this delicate surgery could not be performed safely and an alternative procedure was used, redirecting blood within the atriums. This was called a "Senning" operation. (The "Mustard" operation was very similar.)

Senning Procedure
In this operation the blood from the SVC and IVC was redirected to the left atrium and ventricle, while blood from the pulmonary veins was channelled to the right atrium and ventricle. This relieved Cyanosis but did not correct the original abnormality, leaving the Right Ventricle pumping blood to the Aorta.
Eventually some patients may develop heart failure or other problems after this type of surgery, which is now seldom used.

In this abnormality both atriums are connected to the Left Ventricle. Usually there is a small (hypoplastic) right ventricle (RV), which may be on the opposite side of the heart to the usual (as in "Corrected Transposition"). The arteries usually arise with the aorta from the RV and the pulmonary artery from the LV (Transposition).

Many other defects are often present (e.g. Pulmonary Stenosis or Atresia; Coarctation of the aorta).

Northeast Indiana Pediatric Specialists, PC

Dr. Michael Dick & Dr. Todd Dillon
11123 Parkview Plaza Drive Suite 102
Fort Wayne, IN 46845
(260) 483-0688
http://www.med-web.com/nips/

nips@med-web.com

Pregnancy	Maternal Illness, exposure to drugs, chemicals, teratogens, infections
Family History	Cardiomyopathy, recent viral illness, coronary artery disease, hypertension, sudden death, dysrhythmias, arterial abnormalities Murmurs: too nonspecific
Personal History	Growth delay, edema, exercise intolerance, stridor/hoarseness, diaphoresis, difficulty feeding, palpitations, squatting, cyanotic episodes Less helpful: chest pain, syncope

Color	pallor, cyanosis (O2 sat < 85%) not acrocyanosis
Cap Refill	> 3 seconds
Clubbing	> 1 year
Edema	Ankle/Sacrum rare in infants, periorbital, weight gain
Distal Pulses	radial and femoral should be synchronous, increased (incompetent valve) or decreased (obstructive)
Abdomen	Hepatospleenomegaly
Thorax - inspection	precordial bulge, pectus, stridor
Thorax - Percussion	not useful