Congenital Heart Defects


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Congenital Heart Defects

  1. 1. CongenitalHeart DefectsDapinderjit Gill
  2. 2. Overview of CHD
  3. 3. Definition and Etiology defect in structure of heart and great vessels present at birth arise first 10 weeks of embryonic development incidence is 1 out of 120 live births 2 to 3% risk in children with affected 1st degree relative 5% have chromosomal abnormalities other etiology maternal illnesses such as diabetes, SLE, rubella and environmental exposure EtOH
  4. 4. ClassificationAcyanotic Cyanotic  Right-to-left  left-to-right  deoxygenated  oxygenated blood venous blood shunted to right shunted to left heart heart  reducing systemic arterial O2  usually saturation asymptomatic unless a large  if >5g/dL deoxygenated defect Hb, cyanosis results
  5. 5. Acyanotic Left-to-Right shunt  Ventricular Septal Defect  Atrial Septal Defect  Patent Ductus Arteriosus  Atrioventricular Septal Defect Obstructive Lesions  Pulmonary Stenosis  Aortic Stenosis  Aortic Coarctation
  6. 6. Cyanotic Right-to-Left shunt  Tetralogy of Fallot  Transposition of the Great Arteries  Tricuspid Atresia  Pulmonary Atresia  Hypoplastic Left Heart Syndrome  Persistent Truncus Arteriosus  Total Anomalous Pulmonary Venous Return
  7. 7. Signs and SymptomsAcyanotic  High pressure shunts (ventricular or great artery level) become apparent several days to a few weeks after birth  Low pressure shunts (atrial) become apparent much later  Can lead to volume overload  Heart failure  failure to thrive  Large shunts decrease lung compliance  frequent lower respiratory tract infections  Murmurs and location are diagnostic
  8. 8. Signs and SymptomsCyanotic  Cyanosis characterized by bluish discolouration of mucous membranes or nail beds, clubbing of nail beds or pulse oximetry <93 to 95%  Murmur audible but not specificObstructive  Pressure overload proximal to obstruction  ventricular hypertrophy and Heart Failure
  9. 9. Signs and SymptomsHeart Failure  Cardiac output is insufficient to meet metabolic needs or when heart cannot adequately handle venous return  pulmonary congestion  Tachycardia, Tachypnea, Dyspnea with feeding (inadequate intake  poor growth), Diaphoresis, Restlessness, Irritability  Infants may present with periorbital edema instead f distended neck veins and dependent edema
  10. 10. Diagnosis Clinical examination, pulse oximetry, ECG, chest x-ray, 2D echo Differential:  Various respiratory disorders  CNS depression  Hypothermia  Hypoglycemia  Sepsis  Methemoglobinemia
  11. 11. TreatmentFirst: medical stabilization in setting of heartfailure or cyanosis Neonate  Secure vascular access (preferably umbilical venous catheter)  Medical tx. For HF:  Diurectics – furosemide/ethacrynic acid  Bolus 1mg/kg an titrated based on urine output  Inotropic drugs – dopamine/dobutamine  5 to 15ug/kg/min  Decrease afterload – milrinone/nitroprusside
  12. 12. Treatment  Infusion of prostaglandins E1  0.05 to 0.1ug/kg/min  Most cardiac lesions at this age are ductal dependent for systemic blood flow (obstructive) or for pulmonary blood flow (cyanotic) HF in older infants and children  Standard approaches to acute and chronic HF similar to adults  Diurectics – furosemide  0.5 to 1.0mg/kg IV or 1 to 3mg/kg PO  ACE inhibitors, Digoxin, Salt Restriction
  13. 13. Treatment Oral Digoxin Dosage in ChildrenAge Total Digitalizing Dose† (μg/kg) Maintenance Dose‡ (μg/kg bid)Preterm neonates 20 2.5Term neonates 30 51 mo–2 yr 30–50 5–62–5 yr 30–40 4–56–10 yr 20–35 2.5–4> 10 yr§ 10–15 1.25–2.5
  14. 14. TreatmentGuidelines of American Heart Associationfor prevention of endocarditis antibiotic prophylaxis is required for children with congenital heart disease who have the following:  Unrepaired cyanotic CHD  Completely repaired CHD during the first 6 months after surgery if prosthetic material or a device was used  Repaired CHD with residual defects at or adjacent to the site of prosthetic patch or prosthetic device
  15. 15. Individual DefectsAcyanotic
  16. 16. Atrial SeptalDefects
  17. 17. Atrial Septal Defects 6-10% of CHD cases Most cases isolated and sporadic; some with genetic syndrome such as Holt-Oram syndrome opening in the interatrial septum causing left to right shunt and volume overload of right atrium and right ventricle usually asymptomatic but long-term complications after 20 years of age include pulmonary HTN, HF, and atrial arrhythmias.
  18. 18. Atrial Septal Defects adults and rarely, adolescents, may present with exercise intolerance, dyspnea, fatigue -soft midsystolic murmur at upper left sternal border with prominent split of S2 is common (fixed split)
  19. 19. Atrial Septal DefectsClassification: By location Ostium Secundum  defect in fossa ovalis, located in the center part of septum Sinus Venosus  defect in posterior aspect of the septum near superior vena cava or inferior vena cava  frequently associated with anomalous return of the right upper or lower pulmonary veins to the right atrium or vena cava Ostium Primum  defect in the anteroinferior aspect of the septum, a form of endocardial cushion defect
  20. 20. Atrial Septal DefectsSpecific Treatment Small shunt  Observation with periodic echocardiography  most small (<3mm) close spontaneously Mod/Large shunt  3-8mm close spontaneously by 18 months.  Transcatheter closure or surgical repair  if pulmonary flow:systemic flow ratio > 1.5:1 or evidence of right ventricular volume overload  close ASD between ages 2 to 6. Ostium primum and sinus venosus ASDs do not close spontaneously
  21. 21. Ventricular SeptalDefects
  22. 22. Ventricular Septal Defects 20% of all cases, second most common congenital heart anomaly opening in interventricular septum harsh holosystolic murmur at lower left sternal border with normal split and non hyperactive precordium
  23. 23. Ventricular Septal DefectsClassification: By location Perimembranous (70-80%)  defect in membranous septum adjacent to the tricuspid valve and extend into surrounding muscular tissue, commonly occurring immediately below the aortic valve. Trabecular muscular (5-20%)  completely surrounded by muscular tissue and may occur anywhere in the se0ptum Subpulmonary outlet (5-7% in US; 30% in Eastern world)  occur immediately under the pulmonary valve  also referred to as supracristal or doubly committed subarterial defects  frequently associated with aortic leaflet prolapse into the defect; causing aortic regurgitation Inlet (5-8%)  bordered superiorly by the tricuspid annulus and are located posterior to the membranous septum. Also referred to as atrioventricular septal-type defects
  24. 24. Ventricular Septal Defects typically asymptomatic; those with larger defects have HF symptoms appearing at age 4 and 6 weeks when pulmonary vascular resistance falls Larger defect chest x-ray shows cardiomegaly, increased pulmonary vascular markings ECG may also show right ventricular hypertrophy and occasionally left atrial enlargement
  25. 25. Ventricular Septal DefectsSpecific Treatment Small VSDs  Observation  mainly muscular and often close spontaneously during the first few years of life Large VSDs  Medical therapy if sx. of HF  Surgical repair in first few months of life  In asymptomatic patients with large shunt (pulmonary flow:systemic flow ratio > 2:1) that persists after 2 to 4 years require surgical repair
  26. 26. Patent DuctusArteriosus
  27. 27. Patent Ductus Arteriosus 5-10% of CHD cases male:female ratio 1:3 common in premature infants 45% with birth weight <1750g and 80% in birth weight <1200g persistent ductus arteriosus between the aorta and pulmonary artery after birth; normally closes at birth with rise in PaO2 and decline in prostaglandins within 10 to 15 hours of life can cause HF in 15% of premature infants with birth weight <1700g and 40-50% with <1500g generally asymptomatic but with large PDA  HF, distress, apnea, worsening mechanical ventilation
  28. 28. Patent Ductus Arteriosus Children with PDA  normal heart sounds Full term infant with PDA  bounding peripheral pulses with a wide pulse pressure  continuous murmur at upper left sternal border Premature infants with a significant PDA  have bounding pulses with hyperdynamic precordium and a continuous murmur at pulmonic area
  29. 29. Patent Ductus ArteriosusSpecific Treatment Indomethacin with or without fluid restriction may be tried in premature infants Therapy is not effective in term infants or older children and need surgical or catheter-based correction
  30. 30. AtrioventricularSeptal Defect
  31. 31. Atrioventricular Septal Defect 5% of CHD cases Consist of primum type atrial septal defect with AV valve malformation, with or without a ventricular septal defect Maldevelopment of endocardial cushion Asymptomatic if small; large may cause HF and HF sx. Common in heterotaxy syndromes (asplenia or polysplenia)
  32. 32. Atrioventricular Septal DefectTwo types: Complete  30% have Down Syndrome  Large ostium primum ASD (at anteroinferior aspect of septum), an inlet VSD, and AV valve orifice.  Enlargement of all four chambers  Hemodynamics of large VSD Partial  Ostium primum ASD, partitioning of the common AV valve into two separate AV orifices, and a cleft in the mitral valve; VSD is not present or small  Hemodynamics of ostium secundum ASD with variable mitral regurgitation
  33. 33. Atrioventricular Septal DefectSpecific Treatment:  Medical treatment before surgery if HF  Complete AV septal defects  Should be repaired by age 2 to 4 months due to HF and failure to thrive  If infant is growing well without significant sx., repair should be done before 6 months (prevent pulmonary vascular disease, especially in Down syndrome)  Partial AV septal defects  If asx. Elective surgery is done at age 1 to 3 years