Atrial Septal Defect (ASD)

Responses to Altered Cardiac and Tissue Perfusion

• Cardiovascular disorders are split into congenital and acquired heart diseases
• Congenital heart disease (CHD) includes birth-present anatomical abnormalities causing abnormal cardiac function
• CHD occurs in approximately 5 to 8 per 1000 live births
• Around 2 to 3 in every 1000 infants show CHD symptoms requiring treatment within their first year
• Most congenital heart defects occur in the first 8 weeks of gestation
• Congenital heart defects result from combined or interactive genetic and environmental factors
• Categorization of congenital heart defects is based on pathophysiology and hemodynamics, not cyanosis presence

Defects With Blood Flow: Atrial Septal Defect (ASD)

• Atrial Septal Defect (ASD) involves atypical opening between the atria, enabling left-to-right blood shunting
• The opening varies from small (foramen ovale fails to close) to large (complete septum absence)
• ASD occurs in 30% to 50% of kids with congenital heart disease in combination with other defects
• ASD occurs as an isolated defect in 5% to 10% of kids
• Small defects can be asymptomatic
• Symptomatic infants show dyspnea, fatigue, poor growth, and a soft systolic heart murmur over the pulmonic area (splitting S2)
• ASD can lead to congestive heart failure

ASD Diagnosis and Management

• Echocardiogram shows dilated right ventricle from blood overload and shunt size
• Chest X-ray and ECG provide minimal information unless the ASD is large
• Large ASDs show excessive shunting, and right ventricular hypertrophy
• Spontaneous closure of small ASDs is possible within the first 4 years of life, and no activity limits are needed
• ASDs are closed using a septal occluder (Amplatzer Septal Occluder) during cardiac catheterization
• 81mg of aspirin daily is prescribed for 6 months after the procedure
• Surgery (Pericardial or Dacron patch) is indicated when increased pulmonary blood flow causes congestive heart failure
• Arrhythmias may develop postoperatively
• Surgical patch closure is for moderate to large defects
• Open repair with cardiopulmonary bypass is performed before school age

Ventricular Septal Defect (VSD)

• Ventricular Septal Defect (VSD) features an atypical opening between the right and left ventricles, leading to increased pulmonary blood flow
• Blood shunts from the left ventricle through the open septum into the pulmonary artery
• Single defect in 15% to 20% of cases, varying in size
• Small VSDs may cause on symptoms

VSD Symptoms and Diagnosis

• Moderate or large VSDs are associated with CHF, stunted growth, decreased exercise tolerance, frequent pulmonary infections, and pulmonary hypertension
• A systolic murmur can be auscultated at the third or fourth left intercostal space at the sternal border, and a thrill may be present
• Chest radiograph and ECG show limited information for small VSDs
• Enlarged heart and pulmonary vascular markings on chest radiograph suggest large VSDs with shunting
• Right and left ventricular hypertrophy may be seen on ECG
• Echocardiogram determines VSD size and location

VSD Treatment

• Most small VSDs close spontaneously within the first 6 months to first year of life; conservative management is used if no CHF or pulmonary artery hypertension signs are observed
• Surgical closure is performed after 1 year of age unless CHF cannot be medically managed
• Surgery is performed before 6 months of life
• Device closure during cardiac catheterization possible for VSDs not close to heart valves
• Pulmonary artery banding (band around the main pulmonary artery to decrease pulmonary blood flow) is done in infants with multiple muscular VSDs or complex anatomy
• Complete repair in infancy is the preferred approach due to surgical advancements
• Small defects are repaired with sutures
• Large defects require a knitted Dacron patch
• Cardiopulmonary Bypass is used for both procedures via right atrium and tricuspid valve approach
• Postoperative complications include residual VSD and conduction disturbances
• Highest risk in first 2 months after surgical repair
• Children experience catch-up growth post-surgery
• Arrhythmias, right bundle branch block, and complete heart block are possible, and some children require a pacemaker

Patent Ductus Arteriosus (PDA)

• Patent Ductus Arteriosus (PDA) occurs when the fetal ductus arteriosus (connecting the aorta and pulmonary artery) fails to close within the first weeks
• This allows blood to flow from the higher-pressure aorta to the lower-pressure pulmonary artery (left-to-right shunt)

PDA Prevalence and Pathophysiology

• PDA is a common congenital defect due to persistent fetal circulation, accounting for 5% to 10% of all infants with congenital heart disease
• Post-birth, pressures in the aorta become greater than in the pulmonary arteries
• Blood shunts from the aorta to the pulmonary arteries, increasing circulation to the pulmonary system
• Common of preterm infants with respiratory distress syndrome or hypoxemia, which work to keep the ductus arteriosus open

PDA Symptoms

• Symptoms include: dyspnea, tachypnea, tachycardia, full and bounding pulses, widened pulse pressure; hypotension when cardiac output is low
• Also includes: May be asymptomatic, CHF, intercostal retractions, hepatomegaly, and poor growth if a large PDA
• A "machinery" murmur is typical during systole and diastole, plus a thrill in the pulmonic area, with a risk for frequent respiratory infections and pneumonia

PDA Diagnosis and Treatment

• Chest radiograph and ECG may reveal left ventricular hypertrophy
• PDA visualized and blood flow measured by echocardiogram
• Transcatheter closure via obstructive device is the standard therapy
• Video-assisted thoracoscopic surgery with clip ligation may be performed
• Intravenous ibuprofen or indomethacin often stimulates ductus arteriosus closure in preterm infants, but is avoided if CHF is present

PDA Treatment Details and Outcomes

• Indomethacin (prostaglandin inhibitor) effectively closes PDA in preterm infants and newborns
• Surgical division or ligation through a left thoracotomy
• Newer technique: video-assisted thoracoscopic surgery to place a clip on the ductus, eliminating thoracotomy need
• Coils to occlude the PDA placed in catheterization
• Preterm infants or those with unusual PDAs may need surgery
• Surgical and non-surgical procedures have mortality rates below 1%
• Higher mortality rate for PDA closure in very preterm infants because of significant medical problems
• No long-term sequelae if treated before pulmonary vascular disease (pulmonary hypertension or pulmonary vascular obstructive disease) develops

Atrioventricular Canal (AV Canal)

• Endocardial cushions develop into the mitral and tricuspid valves and atrioventricular AV septum
• The most complex AV canal defect features one AV valve and large septal defects between both atria and ventricles
• AV canal defect occurs in about 2% of congenital heart defect cases, and 70% of these children have Down syndrome

AV Canal: Symptoms, Diagnosis, and Management

• Infants often develop CHF, tachypnea, tachycardia, feeding issues, recurrent respiratory infections, and respiratory failure
• S1 heart sound is accentuated, and S2 is split
• Holosystolic murmur is loudest at the lower left sternal border, with a possible thrill; may be transmitted to the left axilla if mitral regurgitation is present
• Chest radiograph reveals cardiomegaly and pulmonary vascular markings
• ECG shows prolonged PR interval and enlarged ventricles
• Echocardiogram shows dilation of the ventricles, septal defects, and valve malformation
• Pulmonary artery banding is occasionally performed in small infants with severe symptoms
• Surgical repair involves patch closure of septal defects and reconstruction of AV valve tissue
• Postoperative complications: heart block, HF, mitral regurgitation, dysrhythmias, and pulmonary hypertension
• Surgery is performed between 2 and 4 months to prevent pulmonary vascular disease
• Patches are placed over septal defects, and valve tissue is used to form functioning valves; the mitral valve may be replaced
• Prophylaxis for infective endocarditis is needed for 6 months after corrective surgery
• Arrhythmias and mitral valve regurgitation, residual septal defect, and subaortic stenosis may occur postoperatively
• Short-term survival rates are similar among infants with and without Down syndrome

Obstructive Defects: Aortic Stenosis (AS)

• Aortic Stenosis (AS) involves narrowing or stricture of the aortic valve
• This results in resistance to blood flow in the left ventricle, decreased cardiac output, left ventricular hypertrophy, and pulmonary vascular congestion

AS Pathophysiology

• The main anatomic consequence of AS is hypertrophy of the left ventricular wall
• Ultimately leads to increased end-diastolic pressure
• Subsequently causing pulmonary venous and pulmonary arterial hypertension
• Left ventricular hypertrophy interferes with coronary artery perfusion, which may result in myocardial infarction

AS Types and Severity

• In valvular stenosis , malformed cusps result in a unicuspid or bicuspid rather than tricuspid valve, or fusion of the cusps
• Sub-valvular stenosis is from a fibrous ring below a normal valve
• Supravalvular stenosis is rare
• Valvular AS is serious due to: obstruction is progressive, can result in sudden death in cases of myocardial ischemia, and surgical repair rarely results in a normal valve
• Strenuous physical activity may be curtailed

AS: Physiologic Impact and Symptoms

• A stricture in the aortic outflow tract causes resistance to ejection of blood from the left ventricle
• Increased Hypertrophy occurs because of the extra workload on the left ventricle
• Developement of Left ventricular failure will cause elevated left atrial pressure
• Pulmonary vascular congestion (pulmonary edema) develops due to increased pressure in the pulmonary veins
• Newborns show decreased cardiac output signs: faint pulses, hypotension, tachycardia, and poor feeding
• Children show lack of exercise tolerance, chest pain, and dizziness
• A systolic ejection murmur may or may not be present
• Risk factors include: Bacterial endocarditis, coronary insufficiency, and ventricular dysfunction

AS: Treatment Approaches

• Aortic valvotomy is performed under inflow occlusion.
• Balloon dilation is now the first-line treatment
• Newborns with critical AS and small left-sided structures undergo a stage 1 Norwood procedure
• Aortic valvotomy remains a palliative procedure
• Additional surgery required after a span of 10 years for recurrent stenosis in approximately 25% of patients
• Valve replacement may be required during the second procedure
• Aortic homograft, pulmonary valve moved to the aortic position and replaced with a homograft valve as well
• Narrowed valve dilated using balloon angioplasty in the catheterization lab, aortic insufficiency or valvular regurgitation, loss of pulse

Coarctation of the Aorta (COA)

• Coarctation of the Aorta is a narrowing or constriction in the descending aorta
• COA often near the ductus arteriosus or left subclavian artery, which obstructs the systemic blood outflow
• COA occurs in 8% to 10% of congenital heart defects
• Many children are asymptomatic and grow normally

COA: Blood Pressure Variances and Associated Symptoms

• Reduced blood flow causes lower blood pressure in legs and higher blood pressure in arms, neck, and head
• Brachial and radial pulses are typically bounding, while femoral and leg pulses are weak or absent
• Older children may complain of leg weakness and pain after exercise
• Infants with moderate constriction may appear pale, have poor feeding, and have avoidant/restrictive food intake disorder (failure to thrive) and increased respiratory effort

COA: Complications and Diagnosis

• Development of CHF
• Newborns with severe constriction have cyanosis in the lower extremities, heart failure, and shock as the ductus arteriosus closes
• Development of Renal failure and necrotizing enterocolitis.
• S2 is heard as a loud single sound
• A systolic ejection murmur is heard at the upper right and middle/lower left sternal border and a palpable thrill at the suprasternal notch
• Chest radiograph shows cardiomegaly, pulmonary venous congestion, and descending aorta indentation
• Ascending aorta dilation may be seen
• Rib notching is rarely seen before 5 years old
• MRI is preferred for imaging the aortic arch, constriction site, and collateral circulation
• ECG indicates left ventricular hypertrophy
• Echo determines size of the aorta and functioning of the aortic valve.

COA: Treatment

• In symptomatic newborns, PGE1 reopens the ductus arteriosus to increase blood flow to the kidneys and lower extremities
• Treatment includes inotropic medications, diuretics, and oxygen
• Surgical resection is preferred over balloon dilation to reduce re-coarctation risk
• Balloon dilation with stent placement may be done in newborns needing surgical repair
• Balloon angioplasty may be performed if coarctation recurs
• Surgical repair is preferred for infants younger than 6 months, long-segment stenosis, or complex anatomy
• Repair is by resection of the coarcted portion with end-to-end anastomosis or enlargement of constricted section using a graft or subclavian artery
• Cardiopulmonary bypass isn't required
• A thoracotomy incision is used

COA: Post-operative Management and Recurrence

• Treated with intravenous sodium nitroprusside, esmolol, or milrinone, followed by oral medications (ACE inhibitors or beta blockers)
• Residual hypertension After COA repair is connected to age and repair
• Elective surgery for COA is advised within first 2 years of life due to hypertension at rest and exercise
• 15% to 30% risk of recurrence with surgical repair in infants
• Balloon angioplasty is now an intervention to maintain gradients. Stents will be placed to maintain patency
• Balloon dilation and surgical resection are palliative as coarctation may recur
• Life long follow up and persistent hypertension is necessary

Pulmonic Stenosis (PS)

• PS involves narrowing of the pulmonary artery entrance
• Blood flow resistance results in right ventricular hypertrophy and decreased pulmonary blood flow
• Pulmonary atresia is the extreme form, featuring total fusion of the commissures and no blood flow to the lungs
• The right ventricle may be hypoplastic

Pulmonic Stenosis: Effects and Symptoms

• When PS is present, resistance to blood flow causes right ventricular hypertrophy
• Right atrial pressure elevates due to right ventricular failure
• An outcome of this is that the foramen ovale may reopen
• Shunting of unoxygenated blood into the left atrium can occur and systemic cyanosis
• HF and systemic venous engorgement with severe PS
• An associated defect as PDA will partially compensate for obstruction by shunting blood from the aorta to the pulmonary artery and into the lungs

PS: Disease Progression and Diagnosis

• Patients may have mild cyanosis or HF but may be asymptomatic
• Newborns with severe narrowing are cyanotic
• A loud systolic ejection murmur at the upper left sternal border may be present
• In severely ill patients, the murmur may be softer
• Cardiomegaly is evident on chest radiography and patients are at risk for bacterial endocarditis

PS: Treatment

• Infants use trans ventricular (closed) valvotomy (Brock procedure)
• Children use pulmonary valvotomy with CPB
• Surgical treatment is rare with balloon angioplasty
• A catheter is inserted across the stenotic pulmonic valve into the pulmonary artery, and a balloon at the end of the catheter is inflated
• Low risk for surgical and nonsurgical procedures
• Mortality is lower than 1%
• High cases in neonates
• Both balloon dilation and surgical valvotomy results in pulmonic valve incompetence cause opening the fused valve leaflets
• Asymptomatic and longterm problems are re-stenosis or valve incompetence

Tetralogy of Fallot (TOF)

• In tetralogy of fallot, four defects are involved: pulmonary stenosis, right ventricular hypertrophy, ventricular septal defect (VSD), and overriding of aorta
• The overriding aorta and VSD allow unoxygenated blood to pass into the systemic circulation
• TOF accounts for about 5% to 10% of all cases of congenital heart disease

TOF: Hemodynamics and Symptoms

• Hemodynamics vary depending on the degree of PS and the size of the VSD and the pulmonary and systemic resistance to flow
• Shunt direction depends on pulmonary and systemic vascular resistance
• If pulmonary vascular resistance is higher than systemic resistance, the shunt is from right to left
• Decreased blood flow to the lungs
• Reduced amount of oxygenated blood returns to the left side of the heart
• Mixed Blood from both ventricles may be distributed systemically
• The newborn becomes hypoxic and cyanotic as the ductus arteriosus closes
• Degree of pulmonary stenosis determines severity of symptoms
• Older infants and children have tachypnea and cyanosis

Identifying and Treating Tetralogy of Fallot

• Diagnosing includes: Polycythemia, hypoxic spells, metabolic acidosis, stunted growth, clubbing, and exercise
• Toddlers squat to reduce the return of systemic venous blood to the heart with
• A systolic murmur is heard in the pulmonic area and transmitted to the suprasternal notch
• A thrill may be palpated in the pulmonic area.
• Diagnoses: Boot shaped heart for the large right ventricle chest radiograph, diminished vascular markings, and a prominent aorta
• Complete repair involves resection of the infundibular stenosis, with placement of a pericardial patch, midline sternotomy

Tricuspid Atresia

• The tricuspid valve fails to develop; consequently, there is no communication from the right atrium to the right ventricle
• Blood flows through an ASD or a patent foramen ovale to the left side of the heart and through a VSD to the right ventricle and out to the lungs
• The condition is often associated with PS and TGA
• Complete mixing of unoxygenated and oxygenated blood in the left side of the heart happens which results in systemic desaturation
• varying amounts of pulmonary obstruction occurs
• At birth, open foramen ovale provides flow across to the septum
• PDA allows to push to pulmonary for O2 to the lungs
• VSD give small blood amount of blood ventricle
• diminished pulmonary

Tricuspid Atresia - Symptoms, Diagnosis & Treatment

• severe cases of cyanosis show at birth
• Tachypnea, poor feeding, CHF, pulmonary edema develop with growth
• Continuous murmurs and S2 sounds
• EKG show hypotrophic effects For cases, surgery is critical for life

Transposition of Great Arteries

• The PA leaves out the LV, and The aorta leaves the rv
• This is life threatening because the heart has no communication to other systems
• Associated issues, especially defects are required for any chances
• TGA must be caught to prevent Cyanosis

The Symptoms for TGA

• Cyanosis
• Tachypnea
• poor Feding
• Growth deficiency
• HF
• Heart defects