CYANOTIC

TETRALOGY OF FALLOT

obstruction to right ventricular outflow (pulmonary stenosis)

ventricular septal defect (VSD)

dextroposition of the aorta with override of the ventricular septum

right ventricular hypertrophy

Normal Heart Tetralogy of Fallot

Clinical Manifestations

Cyanosis

Often not present at birth but with increasing hypertrophy of the right ventricular infundibulum and patient growth, cyanosis occurs later in the

1st yr of life

most prominent in the mucous membranes of the lips and mouth and in the fingernails and toenails

Infants and toddlers play actively for a short time and then sit or lie down.

Older children may be able to walk a block or so before stopping to rest.

Children assume a squatting position for the relief of dyspnea caused by physical effort

The child is usually able to resume physical activity within a few minutes

Dyspnea

Common in 1st 2 yrs of life

• hyperpneic and restless

• cyanosis increases

• gasping respirations ensue and syncope may follow

• frequently occur in the morning or after episodes of vigorous crying

• spells may last from a few minutes to a few hours but are rarely fatal

• short episodes are followed by generalized weakness and sleep

• severe spells may progress to unconsciousness and, occasionally, to convulsions or hemiparesis

Paroxysmal Hypercyanotic Atacks ( TET SPELL)

Growth and development delay

Metabolic acidosis (PO2 <40mmHg)

- IV Sodium bicarbonate

Clinical Manifestations

Work Up

Oximetry and ABG

Oximetry is particularly useful in a dark-skinned patient or an anemic patient

whose level of cyanosis is not apparent.

Cyanosis is not evident until 3-5 g/dL of reduced hemoglobin is present.

Prolonged cyanosis causes reactive polycythemia that increases the

oxygen-carrying capacity.

Hyperviscosity and coagulopathy.

Hematology

CHEST X-RAY

Coeur en sabot (boot-shaped

heart) secondary to uplifting of the cardiac apex from RVH and the absence of a normal main pulmonary artery segment

Electrocardiography

Typical preoperative ECG

Right axis deviation (+120° to +150°)

Right or combined ventricular hypertrophy

Right atrial hypertrophy

Partial or complete right bundle branch block

2D ECHO

Reveals a large VSD with an overriding aorta and variable degrees of right ventricular outflow tract (RVOT) obstruction

Treatment

GOALS:

to reduce the ventilatory drive

decrease systemic venous return

increase peripheral venous return.

Place the baby on the mother's shoulder with the knees tucked up underneath → This provides a calming effect, reduces systemic venous return, and increases

SVR.

Oxygen is of limited value since the primary abnormality is reduced

pulmonary blood flow.

Hypercyanosis

Morphine sulfate, 0.1-0.2 mg/kg intramuscularly (IM)/subcutaneously (SC),

may reduce the ventilatory drive and decrease systemic venous return.

Phenylephrine, 0.02 mg/kg IV, is used to increase SVR.

Treating acidosis with sodium bicarbonate may reduce the respiratory center

stimulating effect of acidosis.

General anesthesia is a last resort.

Palliative Surgery

Blalock-Taussig shuntElective primary repair is usually performed after 3 months

and preferably by the age 2 years.

Symptomatic patients require immediate surgical repair irrespective of age → These patients have traditionally been managed with initial palliative surgery followed by future correction repairs at older ages tend to lead to

increased complications and long-term morbidity.

Complications

Erythrocytosis

Brain abscess

Infective endocarditis

Cerebrovascular thrombosis

Delayed puberty

Prognosis

If right ventricular outflow tract obstruction is severe, the mortality rate is high without

palliative or corrective surgery

ACYANOTIC

PATENT DUCTUS ARTERIO

SUS

DEFINITION

*Patent ductus arteriosus (PDA) is the persistence of a normal fetal structure between the left pulmonary artery and the descending aorta.

Persistence of this fetal structure beyond 10 days of life is considered abnormal.

*During fetal life, most of the pulmonary arterial blood is shunted through the ductus arteriosus into the aorta.

*Functional closure of the ductus normally occurs soon after birth, but if the ductus remains patent when pulmonary vascular resistance falls, aortic blood is shunted into the pulmonary artery.

ANATOMY

*The aortic end of the ductus is just distal to the origin of the left subclavian artery, and the ductus enters the pulmonary artery at its bifurcation.

*When a term infant is found to have a PDA, the wall of the ductus is deficient in both the mucoid endothelial layer and the muscular media.

The ductus arteriosus is normally patent during fetal life. This patency is promoted by continual production of prostaglandin E2 (PGE2) by the ductus.

Normally, functional closure of the ductus arteriosus occurs by about 15 hours of life in healthy infants born at term.

-by abrupt contraction of the muscular wall of the ductus arteriosus, which is associated with increases in the partial pressure of oxygen (PO2) coincident with the first breath.

* In a premature infant, the PDA usually has a normal structure; patency is the result of hypoxia and immaturity.

*Thus, a PDA persisting beyond the 1st few weeks of life in a term infant rarely closes spontaneously or with pharmacologic intervention

*if early pharmacologic or surgical intervention is not required in a premature infant, spontaneous closure occurs in most instances.

True anatomic closure, in which the ductus loses the ability to reopen, may take several weeks.

Cassels et al defined true persistence of the ductus arteriosus as a. patent ductus arteriosus present in infants older than 3 months

EPIDEMIOLOGY

Female patients with PDA outnumber males 2:1.

*also associated with maternal rubella infection during early pregnancy.

*a common problem in premature infants, where it can cause severe hemodynamic derangements and several major sequelae.

**seen in 10% of patients with other congenital heart lesions

PATHOPHYSIOLOGY

*A patent ductus arteriosus produces a left-to-right shunt. In other words, it allows blood to go from the systemic circulation to the pulmonary circulation. Therefore, pulmonary blood flow is excessive.

*The magnitude of the excess pulmonary blood flow depends on relatively few factors:

1. The larger the internal diameter of the narrowest portion of the ductus arteriosus, the larger the left-to-right shunt.

2. If the ductus arteriosus is restrictive, then the length of the narrowed area also affects the magnitude of the shunt. A longer ductus is associated with a smaller shunt.

3. Finally, the magnitude of the left-to-right shunt is partially controlled by the relationship of the pulmonary vascular resistance to the systemic vascular resistance.

If the systemic vascular resistance is high and/or the pulmonary vascular resistance is low, the flow through the ductus arteriosus is potentially large.

Course of blood flow in a typical patient with PDA

Pulmonary Capillaries

Pulmonary Arteries

Ductus arteriosus

Pulmonary Veins

Left Atrium

Left Ventricle

Aorta

Therefore, a large left-to-right shunt through a patent ductus arteriosus results in left atrial and left ventricular enlargement.

The pulmonary veins and the ascending aorta can be dilated with a sufficiently large patent ductus arteriosus.

Also, if little or no restriction is present at the level of the patent ductus arteriosus, pulmonary hypertension results.

HISTORY

* typically asymptomatic

*a history of :premature birthperinatal distressperinatal hypoxia

*a history of (during infancy) feeding difficulties poor growth described as failure to thrive

PHYSICAL

small for their age

because of significant pulmonary overcirculation:tachypneatachycardiawidened pulse pressure

findings upon cardiac examination include the following:increased precordial activity (related to the magnitude of

LR shunt (large LR shunt))

laterally displaced apical impulse

thrill in the suprasternal notch or in the left infraclavicular region

normal S1*second heart sound (S2) is often obscured by the murmur

paradoxical splitting of S2 related to premature closure of the pulmonary valve and a prolonged ejection period across the aortic valve.

continuous machinery murmur accentuated in systoleloudest at the left upper chest

apical flow rumble caused by high flow into the left ventricle, is frequently present

seen if the pulmonary-to-systemic blood ratio approaches or exceeds 2:1

aortic ejection murmur may be heard because flow through the left ventricle into the aorta is increased

bounding peripheral pulses because of :

high left ventricular stroke volume causing systolic hypertension

the low diastolic pressure in the systemic circulation as blood runs off from the aorta into the

pulmonary circulation.

DIAGNOSIS

SMALL SHUNT

LARGE SHUNT

ECG Normal (+) left ventricular or biventricular hypertrophy

The diagnosis of an isolated, uncomplicated PDA is untenable when right ventricular hypertrophy is noted.

Radiographic studies

-prominent pulmonary artery with increased intrapulmonary vascular markings- left atrium and ventricle. - aortic knob is normal or prominent

ECHO cardiac chambers is normal

left atrial and left ventricular dimensions are increased

Color and pulsed Doppler

systolic or diastolic (or both) retrograde turbulent flow in the pulmonary artery and aortic retrograde flow in diastole

Cardiac catheterization demonstrates:

Normal or increased pressure in the right ventricle and pulmonary artery, depending

on the size of the ductus

The presence of oxygenated blood shunting into the pulmonary artery confirms a

left-to-right shunt.

The catheter may pass from the pulmonary artery through the ductus into the

descending aorta.

Injection of contrast medium into the ascending aorta shows opacification of the

pulmonary artery from the aorta and identifies the ductus

The clinical pattern is sufficiently distinctive to allow an accurate

diagnosis by noninvasive methods in most patients.

In patients with atypical findings or when associated cardiac lesions

are suspected, cardiac catheterization may be indicated.

Patients with a small PDA may live a normal span with few or no cardiac symptoms, but late manifestations may occur.

Spontaneous closure of the ductus after infancy is extremely rare.

Cardiac failure most often occurs in early infancy in the presence of a large ductus but may occur late in life even with a moderate-sized

communication.

The chronic left ventricular volume load is less well tolerated with aging.

Infective endarteritis may be seen at any age.

PROGNOSIS

COMPLICATIONS

Pulmonary or systemic emboli may occur.

Rare complications include:aneurysmal dilatation of the pulmonary artery or the ductuscalcification of the ductusnoninfective thrombosis of the ductus with embolizationparadoxical emboli.

Pulmonary hypertension (Eisenmenger syndrome) usually develops in patients with a large PDA who do not undergo

surgical treatment.

TREATMENT

Irrespective of age, patients with PDA require surgical or catheter closure.

RATIONALE FOR CLOSURE:In patients with a small PDA - prevention of bacterial endarteritis or other late complications.

In patients with a moderate to large PDA - to treat heart failure or prevent the development of pulmonary vascular disease, or both.

Once the diagnosis of a moderate to large PDA is made, treatment should not be unduly postponed after adequate medical therapy for cardiac failure has been instituted.

Transcatheter PDA closure is routinely performed in the cardiac catheterization laboratory .

Small PDAs - generally closed with intravascular coils.

Moderate to large PDAs - closed with a catheter-introduced sac into which several coils are released or with an umbrella-like device.

Surgical closure of PDA can be accomplished by a standard left thoracotomy or using thoracoscopic techniques.

Case fatality rate with interventional or surgical treatment is less than 1% and the risk without it is greater, closure of the ductus is indicated in

asymptomatic patients, preferably before 1 yr of age.

Pulmonary hypertension is not a contraindication to surgery at any age if it can be demonstrated at cardiac catheterization that the shunt flow is

still predominantly left to right and that severe pulmonary vascular disease is not present.

After closure:symptoms of frank or incipient cardiac failure rapidly disappear.

Infants who had failed to thrive usually have immediate improvement in physical development.

The pulse and blood pressure return to normal

The machinery-like murmur disappears.

A functional systolic murmur over the pulmonary area may persist; it may represent turbulence in a persistently dilated pulmonary artery.

The radiographic signs of cardiac enlargement and pulmonary overcirculation disappear over a period of several months, and the

electrocardiogram becomes normal.

References

Nelson textbook of pediatrics 18th edition

Medscape.com