TETRALOGY OF FALLOT
BY,
V.MAYURANITHYA
BOT-4TH YEAR
INTRODUCTION
o Tetralogy of fallot is a rare condition caused by a combination of four heart defects
that are present at birth(congenital).
o These defects, which affect the structure of the heart ,cause oxygen poor blood to
flow out of the heart and rest of the body.
o Infants and children with tetralogy of fallot usually have blue-tinged skin because
their blood doesn’t carry enough oxygen.
o Tetralogy of fallot often diagnosed while the baby is an infant or soon after.
sometimes, depending on the severity of the defects and symptoms, tetralogy of
fallot is not detected until adulthood.
o All babies who have tetralogy of fallot need corrective surgery . people with
tetralogy of fallot need regular doctors checkup for the rest of their life and may
have activity restriction.
o FOUR DEFECTS:
1. Narrowing of pulmonary output
2. Ventricular septal defect
3. Aorta connects of both ventricles
4. Hypertrophy of right ventricle
1. NARROWING OF PULMONARY OUTPUT(pulmonary valve
stenosis):
Narrowing of the valve that separates the lower right chamber of the heart
(right ventricle)from the main blood vessel leading to the lungs (pulmonary
artery)reduces blood flow to the lungs.
The narrowing might also affect the muscle beneath the pulmonary valve.
sometimes, the pulmonary valve doesn’t form properly.
2. VENTRICULAR SEPTAL DEFECT( A hole between the bottom
heart chambers)
A ventricular septal defect is a hole in the wall (septum)that separates the
two lower chambers of the heart (left and right ventricles).
The hole cause oxygen-poor blood in the right ventricle to mix oxygen-rich
blood in the left ventricles.
This causes inefficient blood flow and reduces the supply of oxygen-rich
blood to the body. The defect eventually can weaken the heart.
3. AORTA CONNECTS OF BOTH VENTRICLES
Normally the aorta branches off the left ventricle.
In tetralogy of fallot, the aorta is in the wrong position. It’s shifted to the
right and lies directly above the hole in the heart wall(ventricular septal
defect).
As the result, the aorta receives a mix of oxygen-poor blood from both the
right and left ventricles.
4. RIGHT VENTRICULAR HYPERTROPHY(Thickening of the right lower
heart chamber)
When the heart's pumping action is overworked, the muscular wall of the
right ventricle becomes thick.
Over time this might cause the heart to stiffen, become weak and
eventually fail.
Some children or adults who have tetralogy of Fallot may have other heart
defects such as a hole between the heart's upper chambers (atrial septal
defect), a right aortic arch or problems with the coronary arteries.
SYMPTOMS
Tetralogy of fallot symptoms vary, depending on the amount of blood flow that’s
blocked. Signs and symptoms may include,
o A bluish coloration of the skin caused by low blood oxygen levels(cyanosis)
o Shortness of breath and rapid breathing , especially during feeding or exercise
o Poor weight gain
o Tiring easily during play or exercise
o Irritability
o Prolonged crying
o Heart murmur
o Fainting
o An abnormal , rounded shape of the nail bed in the fingers and toes(clubbing)
CAUSES:
Tetralogy of fallot occurs as the baby’s heart is developing during pregnancy.
Usually, the cause is unknown
TET SPELLS
o Sometimes, babies who have tetralogy of Fallot will suddenly
develop deep blue skin, nails and lips after crying or feeding,
or when agitated.
o These episodes are called tet spells. Tet spells are caused by
a rapid drop in the amount of oxygen in the blood. Tet spells
are most common in young infants, around 2 to 4 months old.
RISK FACTORS
While the exact cause of tetralogy of Fallot is unknown, some things might
increase the risk of a baby being born with this condition. Risk factors for
tetralogy of Fallot include:
o A viral illness during pregnancy, such as rubella (German measles)
o Drinking alcohol during pregnancy
o Poor nutrition during pregnancy
o A mother older than age 40
o A parent who has tetralogy of Fallot
o The presence of Down syndrome in the baby
DIAGNOSIS
Usually, tetralogy of Fallot is diagnosed soon after birth. baby's skin may
appear blue. A doctor might hear an abnormal whooshing sound (heart
murmur) when listening to the baby's heart with a stethoscope.
TESTS TO DIAGNOSIS TETRALOGY FALLOT INCLUDE:
PULSE OXIMETRY: A small sensor placed on a finger or toe measures
the amount of oxygen in the blood.
ECHOCARDIOGRAM: An echocardiogram uses sound waves to create pictures of the
heart in motion. An echocardiogram can show the structure, placement and function of
the heart wall, heart chambers, heart and pulmonary valves, and aorta.
ELECTROCARDIOGRAM(ECG or EKG):
An electrocardiogram records the electrical activity in the heart each time
it contracts.
During this procedure, sticky patches with wires (electrodes) are placed
on the chest, wrists and ankles. The wires connect to a computer, which
displays the heart's rhythm. An ECG can help determine if the heart
chambers are enlarged and if there's an abnormal heartbeat (arrhythmia).
CHEST X-RAY:A chest X-ray can show the structure of the heart and
lungs. A common sign of tetralogy of Fallot on an X-ray is a boot-shaped
heart, because the right ventricle is enlarged.
CARDIAC CATHETERIZATION: Doctors may use this test to evaluate
the structure of the heart and plan surgical treatment.
During this procedure, the doctor inserts a thin, flexible tube (catheter)
into a blood vessel, usually in the groin, and guides it to the heart.
TREATMENT
o All babies who have tetralogy of Fallot need corrective surgery
performed by a heart (cardiovascular) surgeon. Without treatment,
baby might not grow and develop properly.
o doctor will determine the most appropriate surgery and the timing of
the surgery based on your child's condition.
o Some children may need medicine while waiting for surgery to
maintain blood flow from the heart to the lungs
o Oxygen administration when there is
cyanosis.
o Small and frequent meals to be given.
o During ‘TET SPELLS’ give a knee chest
position or squatting position to increase
blood flow to the lungs.
o Limit straineous activities , reduce anxiety
and stress to the child.
SURGERY
Surgery for tetralogy of Fallot involves open-heart surgery to correct the
defects (intracardiac repair) or a temporary procedure that uses a shunt.
Most babies and older children have intracardiac repair.
INTRACARDIAC REPAIR This open-heart surgery is usually done
during the first year after birth and involves several repairs. Adults with
tetralogy of Fallot rarely may undergo this procedure if they didn't have
surgical repair as children.
During intracardiac repair, the surgeon will:
o Patch over the ventricular septal defect to close the hole between the
lower chambers of the heart (ventricles).
o Repair or replace the narrowed pulmonary valve to increase blood flow
to the lungs.
o Because the right ventricle won't need to work as hard to pump blood
after this procedure, the right ventricle wall will go back to its normal
thickness. After intracardiac repair, the oxygen level in the blood
increases and symptoms decrease.
TEMPORARY SHUNT SURGERY
o Occasionally babies need to undergo a temporary (palliative) surgery
before having intracardiac repair in order to improve blood flow to the
lungs. This procedure may be done if baby was born prematurely or has
pulmonary arteries that are undeveloped (hypoplastic).
o In this procedure, the surgeon creates a bypass (shunt) between a large
artery that branches off from the aorta and the pulmonary artery.
o When baby is ready for intracardiac repair, the surgeon removes the
shunt during the procedure for intracardiac repair.
REFERENCE
1)Essential of medical physiology-8th edition –k.sembulingam
2)Textbook of medical physiology- Guyton and Hall
3)Slideshare
4)Health line.com
QUESTIONS
1) Define tetralogy of fallot ?
2) What are the four defects ?
3) Any 4 symptoms of tetralogy of fallot ?
4) Define TET SPELLS ?
5) Any 3 risk factors of TOF ?