Congenital Abnormalities
This category will help you learn how to identify the auscultatory sounds associated with congenital heart diseases. It is also known as a congenital heart anomaly and a congenital heart defect. It is a defect in the structure of the heart or great vessels that are present at the time of birth.
Please use good quality headphones or earphones. Computer or phones speakers often fail to reproduce some heart sounds.
Congenital heart disease can be the result of defects in the formation of the heart, vessels, or can arise because the anatomical changes that occur during the transition between the fetus and the newborn child fail to proceed normally. Congenital heart disease usually presents in childhood but some patients do not have the disease until adult life.
It has been estimated that the incidence of hemodynamically significant congenital cardiac abnormalities is about 0.8% of live births. Defects that are well countenance, such as atrial septal defect, may indicate no sign nor symptoms until adult life or they may be detected incidentally on routine examination or chest X-ray. Congenital heart defects that were previously deadly in childhood can now be corrected, or at least partially so that survival to adult life is the norm. Such patients remain well for many years but subsequently re-present themselves later in life with related problems such as arrhythmia or heart failure.
Incidence and relative frequency of congenital cardiac malformations
Lesion percentages of congenital heart disease:
- Coarctation of the Aorta 7%
- Patent Ductus Arteriosus
- Atrial Septal Defect 10%
- Ventricular Septal Defect 30%
- Tetralogy of Fallot 6%
- Ebstein’s Anomaly
Pathophysiology
Compassionating the fetal circulation helps clarify how some forms of congenital heart disease occur. In the fetus, there is less blood flow through the lungs, which are collapsed because they are not required for gaseous exchange. preferably, oxygenated blood from the placenta passes directly from the right atrium to the left side of the heart through the foramen ovale without having to flow through the lungs, and also from the pulmonary artery into the aorta via the ductus arteriosus.
During early embryonic life, the heart develops as a single tube that folds back on itself and then divides into two separate circulations. Failure of septation can cause some forms of the atrial and ventricular septal defect, whereas failure of alignment of the great vessels with the ventricles contributes to the transposition of the great arteries, tetralogy of Fallot and truncus arteriosus. Atrial septal defects occur because the foramen ovale decline to close at birth, as is normal.
Correspondingly, a persistent ductus arteriosus will remain persistent if it fails to close after birth. The bankruptcy of the aorta to develop at the point of the aortic isthmus and where the ductus arteriosus attaches can lead to coarctation of the aorta. Maternal infection and baring to drugs or toxins are the foremost causes of congenital heart disease.
Maternal rubella infection is correlated with persistent ductus arteriosus, pulmonary valvular and/or artery stenosis, and atrial septal defect. Maternal alcohol abusage is correlated with septal defects and maternal lupus erythematosus with congenital complete heart block. Genetic or chromosomal abnormalities, such as Down’s syndrome, may cause septal defects, and gene defects have also been identified as leading to specific abnormalities, such as Marfan’s syndrome and DiGeorge’s syndrome (deletion in chromosome 22q).
Clinical features
Sign and Symptoms may be absent, or the child may be breathless or fail to attain normal growth and development. Some defects are not compatible with extrauterine life and lead to neonatal death. Clinical signs vary with the anatomical lesion. Murmurs, thrills, or signs of cardiomegaly may be present.
In coarctation of the aorta, the radio-femoral delay may be recorded and some female patients have the features of Turner’s syndrome. The appearance of other congenital conditions, such as Marfan’s syndrome or Down’s syndrome, may also be apparent. Cerebrovascular events and cerebral abscesses may interweave severe cyanotic congenital disease.
Early diagnosis is valuable because many types of congenital heart disease are amenable to surgery, but this opportunity is astray if secondary changes, such as irreversible pulmonary hypertension, occur.
Coarctation of the Aorta
The first echo of the heart is normal. The second tone of the heart is improved.
In the first half of the diastole, there is a diamond-like murmur, which is the bulk of the systole.
In the following figure below, the descending aorta, which produces the systolic murmur, has to be limited.
Regurgitant leakage from the aorta is caused by a diastolic murmur in the left ventricle.
The aortic pressure rise caused by aortic coarctation raises the thickness of the left ventricle wall.
Patent Ductus Arteriosus
Failure of the closure of ductus arteriosus gives rise to a severe medical condition called patent ductus arteriosus. This results in the flowing of the oxygenated blood into the lungs through the aorta to the pulmonary artery. Extra blood is pumped to the patient’s heart and lungs.
A small patent ductus arteriosus is not very problematic and subsides on its own. A larger patent ductus arteriosus causes serious issues as poorly oxygenated blood flows in the wrong direction. This weakens the muscles of the heart, which leads to heart failure and its complications. This can be treated by cardiac catheterization.
On auscultation, a continuous murmur is heard during systole and diastole.
Atrial Septal Defect
An atrial septal defect is a hole between the upper two septa of the heart. An atrial septal defect is a congenital defect. If the hole or defect is small, it may not be problematic ad some congenital atrial septal defects close on their own during infancy or early childhood, but larger defects are complicated.
Atrial septa separate the right and left sides of the heart. When this separation does not happen, space or a hole is formed between the septa.
On auscultation, the atrial septal defect has a sound of mid systolic or ejection systolic murmur with a fixed split of S2, generally on the sternum’s upper left border.
Ventricular Septal Defect
An abnormal opening or hole between the heart’s lower chambers is known as a ventricular septal defect. This opening causes the mixing of oxygen-rich blood with low oxygen blood.
Ventricular septal defects are not life-threatening conditions. These defects can close on their own. Sometimes these defects can cause symptoms of congestive heart failure. This can be treated by surgery. Ventricular septal defects are rare but can be present congenitally like other heart defects.
On auscultation grade 1 to 2/6 short systolic murmurs are heard. Grade 3 to 4/6 holosystolic murmurs are also heard at the lower left border of the sternum.
Tetralogy of Fallot
It is a special kind of disorder in which there is a combination of four different heart defect types. Following are the four congenital defects that contribute to tetralogy of Fallot:
- Ventricular septal defect
- Pulmonary valve stenosis
- A misplaced aorta
- A thickened right ventricular wall
Mostly there is no genetic predisposition related to tetralogy of Fallot. This occurs during the developmental stages of an individual when the heart is growing. Maternal malnutrition increases the risk of tetralogy of Fallot. The treatment options include surgery (intracardiac repair). It can be fatal if left untreated. On auscultation, usually, a loud systolic ejection murmur is observed.
Ebstein’s Anomaly
Ebstein’s anomaly occurs due to the malformations of the right atrium and right ventricle. It disturbs the functions of these valves. This leads to the backflow of blood into the right atrium through the valve.
It is a congenital heart defect. The efficacy of the heart is decreased. Heart enlargement and MI can lead to Ebstein’s anomaly. Its symptoms include difficulty in breathing, tiredness, abnormal heart rhythms, snd cyanosis. Some significant complications like stroke, cardiac arrest, and MI may be encountered.
On auscultation, the first heart sound is widely split with a high-pitched tricuspid component. This occurs due to a delay in the closure of the elongated anterior tricuspid leaflet. The mitral feature may be low or absent in the presence of prolonged PR interval.