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2011-09-19 23:45:41

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  1. Pediatric Cardiology
  2. Fetal Circulation
    parallel circulation system
  3. Parallel Circulation System �
    • utilizing Ductus Venosus, Foramen Ovale and Ductus Arteriosus
    • 1 umbilical vein, 2 arteries
    • Know the arteries when you cut the cord because the arteries don�t give you a clean cut and will be raised as compared to the veins
  4. The System of the fetal organization flow
    • All blood enters through 1 umbilical vein
    • 50% of the blood enters the hepatic system
    • 50% bypasses the liver via the ductus venosus and mixed with partially oxygenated blood at the inferior vena cava
    • The blood from the inferior vena cava enters thr right atrium and is shunted to the left atrium through the foramen ovale (oxygenated)
    • The blood then goes to the left ventricle and is ejected through the ascending aorta
    • The blood that returns via the superior vena cava also enters the right atrium (deoxygenated)
    • This blood enters the right ventricle through the tricuspid valve
    • The blood then is ejected through the pulmonary artery
    • 10% of the blood enters the lungs (just enough to keep perfused)
    • 90% of the blood passes the lungs via the ductus arteriosus and enters the descending aorta
    • The blood either perfuses the lower extremities or returns to the placenta via the 2 umbilical arteries
  5. Transitional Circulation=the transition
    • Mechanical expansion of the lungs and an increase in arterial PO2, result in a decrease in pulmonary vascular resistance
    • Removal of low resistance placental circulation, results in an increase in systemic vascular resistance
    • Right ventricular flow is entirely into the pulmonary circulation
    • Reverse shunting of the ductus arteriosus due to the systemic vascular resistance is greater than the pulmonary vascular resistance
    • Constriction of the ductus arteriosus occurs after several days of high PO2
    • The ductus arteriosus closes and forms the ligamentum arteriosum
    • There is an increase in blood volume entering the left atrium
    • The increase in volume and pressure in the left atrium results in a functional closed foramen ovale
    • The removal of the placental circulation results in the closure of the ductus venosus
  6. Persistence of fetal pathways definition
    ductus arteriosus or formane ovale remain patent (blood is being shunted & not going where it needs to go)
  7. Persistence of fetal pathways
    • life-saving
    • life-stressing/threatening
  8. Life-saving:
    • patent ductus-pulmonary atresia
    • (narrowing-almost closed off)
    • coarctation
    • patent foramen- transposition
  9. Life-stressing/threatening:
    • patent ductus-premature infant (<28 weeks)
    • patent ductus & foramen-pulmonary hypertension
  10. Persistenc of fetal pathways=Medications:
    • Prostaglandin E � keeps lesion open
    • Indomethacin � closes (used in kids born < 28 weeks of life)
  11. Congenital Heart Disease=Incidence:
    • 8/1000 live births
    • >1% of all newborns in North America
    • 50-60% of children with CHD will be diagnosed within the 1st month
  12. CHD=Etiology:
    • Unknown in approximately 80% cases
    • Identifiable single gene defect 3%
    • Septal defects, coarctation, tetrology of fallot
    • Chromosomal abnormality 13%
    • Septal defects, coarctation, tetrology of fallot
    • Environmental/maternal 2-4%
    • Moms that have lupus, rubella or diabetes are at higher risk of having a child with CHD
    • Drugs: lithium, alcohol, warfarin, anticonvulsants
    • Defects: (the smaller the hole, the louder the murmur; smaller hole = louder murmur)
  13. Diastolic murmurs in children are never normal!!!
  14. Atrial Septal Defect (ASD):
    opening between the 2 atria, results in shunting. Often asymptomatic or mild FTT/exercise intolerance. Can present as CHF.
  15. ASD=Findings:
    • r/ventricular lift, S2 widely split, systolic ejection murmur in left mid-upper sternal border, short rumbling mid-diastolic murmur
    • Child may suck & pant when eating do to exercise intolerance
  16. Ventricular Septal Defect (VSD):
    opening between the 2 ventricles, results in shunting. Presentation varies according to size & severity of left to right shunting.
  17. Findings in small VSD:
    • loud, harsh, blowing holosystolic murmur LLSB
    • often a thrill
    • in the neonate � murmur greatest at apex
  18. Clinical Presentation in large VSD:
    • dyspnea
    • diaphoresis
    • feeding difficulties
    • poor growth
    • duskiness,
    • cardiac failure
  19. Findings in large VSD:
    • apical thrust
    • systolic thrill
    • increases S2 (louder than it should be)
    • blowing systolic murmur
    • low-pitched diastolic rumble
    • Most common cardiac malformation � 25% of CHD
  20. VSD Shunting:
    • when blood leaves the left ventricle either through the aorta or VSD, the direction is dependent upon resistance
    • In the first days of life, pulmonary vascular resistance is high and there is little flow across the VSD ? no murmur
    • At 3 days of life, PVR falls and shunting begins ? murmur
  21. Patent Ductus Arteriosus:
    persists in extrauterine life. Often asymptomatic but with large shunting � cardiac failure or growth retardation are possible
  22. PDA=Findings:
    continuous machinery systolic murmur 2nd left intercostal space and or radiate left sterna border or left clavicle
  23. Pulmonary Valve Stenosis:
    • deformed valve cusps which do not fully open which results in right ventricular outflow obstruction
    • Most often asymptomatic but in severe cases right ventricular failure � hepatomegaly, peripheral edema, exercise intolerance
    • In neonate cyanosis is possible if shunting occurs though the foramen ovale. If heart failure occurs it is typically during the 1st month of life
  24. pulmonary valve stenosis=Findings:
    • ejection click after S1
    • split S2
    • systolic ejection murmur pulmonic region radiating to the lungs
  25. Peripheral Pulmonary Stenosis:
    • single or multiple constrictions along the branches of the pulmonary arteries. Often associated with other malformations
    • Presentation varies with severity and other defects. In neonatal period, there is a mild transient form
  26. peripheral pulm stenosis=Findings: vary!
    • Increase in right ventricular pressure and in the pulmonary artery proximal to the obstruction
    • Systolic ejection murmur
  27. Aortic Stenosis:
    • leaflet thickening and commissures are fused to variable degrees which results in left ventricular outflow obstruction and hypertrophy
    • Presentation varies with severity. In severe cases � cardiomegaly, failure, pulmonary edema, decreased pulses and pallor
  28. Aortic Stenosis=Findings:
    • ejection click at apex and left sterna border
    • split S2
    • systolic ejection murmur right upper sterna border radiating to neck and left middle sterna border
    • a soft diastolic murmur may be present
  29. Coarctation of the Aorta:
    • constriction of the aorta, typically at the ductus arteriosus
    • Most are symptomatic, may complain of weakness/pain in legs after exercise. Can go onto cardiac failure but rare. Often diagnosed when found to be hypertension on routine PE
  30. Coarctation of the aorta=Findings:
    pulse disparity (pulses unequal), short systolic murmur and left sternal 3rd-4th intercostals space
  31. Tetralogy of Fallot (TOF):
    • right ventricular outflow obstruction (pulmonary stenosis/atresia), VSD (right to left shunting), overriding aorta (or rather hypoplasia of pulmonary trunk) and right ventricular hypertrophy
    • Most common type of cyanotic heart disease & 10-15% of all CHD
    • Presentation varies depending on degree of obstruction. Acyanotic � CHF. Cyanosis is typically present by 4 months and progressive
    • It is a major concern in neonates if dependent on a patent ductus arteriosus
    • Other � growth retardation, fatigue, exertion, dyspnea, clubbing. Hypoxemic or cyanotic spells can occur, especially under 2 years
  32. TOF=Findings: 50% will have a systolic thrill at the left sternal border, single S2, loud harsh systolic murmur left sternal border and may radiate
    CXR: boot-shaped heart
  33. Transposition of the Great Arteries:
    • the aorta arises from the right ventricle and the pulmonary artery from the left ventricle
    • Common cyanotic heart lesion. Often associated with other cardiac defect
  34. TOF=Presentation:
    cyanosis, respiratory distress (dependent on associated lesions)
  35. TOF=Other:
    growth retardation and cardiac failure
  36. TOF=Findings: single, loud S2, a soft systolic murmur left middle sternal border may be heard
    • Tetrology is more common so if you hear this kind of murmur suspect tetrology first
    • In the neonate, the defect can be fatal. If suspected, begin prostaglandin E
    • ?
    • Total Anomalous Pulmonary Venous Return:
    • No direct pulmonary venous connection into the left atrium.
    • Pulmonary veins may drain into the r/atrium coronary sinus, superior vena cava or the inferior vena cava via descending vein.
    • Blood then goes into the right ventricle or left atrium via ASD or foramen ovale.
    • Further complicated if there is an obstruction of the pulmonary venous return ?pulmonary congestion and pulmonary hypertension ?surgical emergency.
    • Prostaglandin E may not be helpful and can stress baby more
  37. Total Anomalous pulmonary venous return Presentation
    varies with severity. Cyanosis, tachypnea
  38. total anomalous pulmonary venous return Findings:
    varies with severity, systolic murmur left sternal border, gallop rhythm (having an S3 or S4)
  39. Hypoplastic Left Heart Syndrome:
    • a group of anomalies � underdeveloped left side of heart (aortic atresia, mitral stenosis) and hypoplasia of the ascending aorta
    • Dependent on a patent ductus arteriorsus
    • May be associated with other anomalies � kidney/CNS
  40. hypoplastic LHS=Presentation:
    • cyanosis, cardiomegaly, CHF, dyspnea, hepatomegaly, low cardiac output, weak or absent pulses, systolic murmur
    • Majority of cases, it is fatal
    • Surgical intervention has a variable prognosis � norwood operation
  41. Truncus Arteriosus:
    • only one great vessel arises from heart and supplies both the systemic, pulmonary and coronary arteries
    • VSD always present
    • Relative rare cyanotic lesion
  42. Congenital heart disease
    • cyanosis
    • CHF
    • abnormal heart sounds
  43. Presentation of Congenital Heart Disease=cyanosis
    • distinguish between general (all) or circumoral cyanosis (around mouth) and acryocyanosis (hands and feet)
    • Lasts greater than 3 hours in the newborn
    • Warning sign: if pulmonary etiology is absent, think cardiac!
    • About half will need cardiac surgery
  44. CHD=Diff Dx:
    • Decreased pulmonary blood flow: TOF, pulmonary stenosis, pulmonary atresia, tricuspid atresia
    • Increased pulmonary blood flow: transposition, hypoplastic left heart, single ventrile, truncus arteriosus, total anomalous pulmonary venous return
  45. Congestive Heart Failure: presents with tachypnea, tachycardia, dyspnea with feeds, poor weight gain, hepatosplenomegaly
  46. CHF=Diff Dx: ASD, VSD, PDA, coarctation, aortic stenosis, hypoplastic heart, myocarditis
  47. Abnormal Heart Sounds
    Diastolic murmurs are NEVER normal
  48. Evaluation of Suspected Congenital Heart Disease
    • History and physical (prenatal history (high parity with high spontaneous abortions)and family history)
    • 4 extremity blood pressures � pulse disparity ? coarctation
    • Look at normal blood pressures
    • Pulse ox
    • Hyperoxic test � giving O2 and watching symptoms; if not helping, probably not a respiratory issue ? rather a cardiac issue
    • EKG may be normal, axis deviation or hypertrophy
    • Chest x-ray � shape of heart, rule out pulmonary reasons
  49. Innocent Heart Murmurs
    Found in more than 30% of children and increases in the presence of fever, infection, and anxiety (due to increased demand on the heart)
  50. Innocent heart murmurs=Types
    • Vibratory or �Musical� � aka �Still�s murmur;� short systolic murmur at left mid-lower sternal border that changes with respiration or position. Usually does not radiate.
    • Typically seen in 3-7 year olds
  51. Innocent Pulmonic Murmurs �
    higher pitched, blowing, early systolic murmur at 2nd left parasystolic space. Easier to hear when patient is supine
  52. Venous Hum � innocent murmurs
    soft humming sound during systole and diastole in neck and upper anterior chest (turbulence in the jugular venous system). Can vary by changing position or light compression of jugular vein
  53. Chest Pain
    • oIt is a very unusual manifestation of cardiac disease!
    • Increase in teens having MIs - hypertension, hypercholesterolemia, obesity, cocaine
    • History & Physical are key!
  54. Chest pain=Differential Diagnosis:
    • Musculoskeletal � trauma, exercise, costochondritis (inflammation of the costal cartilage along sternal border)
    • Pulmonary � asthma/rad, pneumonia, chronic cough, foreign body
    • Idiopathic � anxiety, panic disorder
    • GI � espohagitis, esophageal spasm, foreign body, reflux
    • Cardiac � pericarditis, mitral valve prolapse, arrhythmias, MI***
  55. Preventative Cardiology
    • Coronary Artery Disease may begin at childhood
    • Family History and Social History are critical
    • Routine blood pressure screening begins at 3yo CHS
    • Hypercholesterolemia & Hyperlipidemia Screening
    • Children & Teens with:
    • A parent or grandparent with documented CAD before 55 yo
    • Parents with elevated cholesterol > 240 mg/dL
    • If family history is unobtainable, especially if there are risk factors (smoking, obesity, decreased physical activity, diet high in saturated fats and cholesterol, fasting glucose > 100, diabetic, hypertension)
    • Diet: fat restrictions do not begin before 1 year of life
    • Consider Statins if lifestyle changes are not enough in children > 8 yo with persistent high LDL