1. Alterations of Cardiovascular Function in Children Chapter 31 Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.

2. 2 Developmental Anatomy of the Cardiovascular System  Embryology  Cardiogenesis begins at approximately 3 weeks’ gestation  The heart arises from the mesenchyme Develops as an enlarged blood vessel with a large lumen and muscular wall Develops as an enlarged blood vessel with a large lumen and muscular wall Midsection grows faster than the ends Midsection grows faster than the ends  The heart tube elongates and rotates to the right, creating a bulboventricular loop  Fetal heart contractions begin by approximately the 28th day

3. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 3 Developmental Anatomy of the Cardiovascular System  Cardiac septation  Endocardial cushions  Septum primum and the septum secundum  Ostium primum  Ostium secundum  Foramen ovale  Ductus arteriosus

4. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 4 Developmental Anatomy of the Cardiovascular System

5. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 5 Transitional Circulation  Circulatory changes take place that affect blood flow, vascular resistance, and oxygen tension  Shift of gas exchange from placenta to lungs  Closure of fetal shunts  Ductus venosus Round ligament of the liver Round ligament of the liver  Foramen ovale Pressure gradient change Pressure gradient change  Ductus arteriosus Ligamentum arteriosum Ligamentum arteriosum

6. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 6 Postnatal Development  Changes in the position of the heart  Changes in the size of the right ventricle  Hemodynamics  Decreased pulmonary vascular resistance  Increased systemic vascular resistance  Heart rate ranges from 100 to 180 beats per minute Newborns have a high oxygen demand Newborns have a high oxygen demand

7. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 7 Congenital Heart Defects  Leading cause of death (except for prematurity) in first year of life  Cause known in only 10% of defects  Prenatal, environmental, and genetic risk factors  Maternal rubella, insulin-dependent diabetes, alcoholism, PKU, and hypercalcemia  Drugs  Chromosomal aberrations

8. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 8 Complications of Congenital Heart Defects  Congestive heart failure (acquired)  Insufficient cardiac output relative to demand  Cardiomyopathy most common cause  Hypoxemia  Cyanosis  Eisenmenger syndrome

9. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 9 Complications of Congenital Heart Defects  Clinical signs of congestive heart failure (acquired)  Poor feeding and sucking; leads to failure to thrive  Dyspnea, tachypnea, diaphoresis, retractions, grunting, nasal flaring  Wheezing, coughing, rales are rare (even with significant heart failure)  Skin changes, such as pallor or mottling  Hepatomegaly

10. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 10 Defects Increasing Pulmonary Blood Flow  Patent ductus arteriosus (PDA)  Failure of the ductus arteriosus to close Normally closes within 15 hours to 2 weeks of age Normally closes within 15 hours to 2 weeks of age  PDA allows blood to shunt from the pulmonary artery to the aorta  Prevalence 5%-10% full-term infants 5%-10% full-term infants Up to 45% premature infants Up to 45% premature infants

11. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 11 Patent Ductus Arteriosus (PDA)

12. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 12 Defects Increasing Pulmonary Blood Flow  Atrial septal defect  Abnormal communication between the atria Allows blood to be shunted from left to right due to higher pressure of the left atrial chamber and lower pulmonary vascular resistance as compared to systemic vascular resistance Allows blood to be shunted from left to right due to higher pressure of the left atrial chamber and lower pulmonary vascular resistance as compared to systemic vascular resistance Right atrial enlargement Right atrial enlargement  Often asymptomatic, diagnosed by murmur  Three major types Ostium primum defect Ostium primum defect Ostium secundum defect Ostium secundum defect Sinus venosus defect Sinus venosus defect

13. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 13 Atrial Septal Defect

14. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 14 Defects Increasing Pulmonary Blood Flow  Ventricular septal defect (VSD)  Abnormal communication between ventricles  Common congenital heart lesion (25%-33%)  Pulmonary overcirculation accounts for symptoms associated with a large VSD  Types Perimembranous VSD Perimembranous VSD Muscular VSD Muscular VSD Supracristal VSD Supracristal VSD Atrioventricular (AV) canal VSD Atrioventricular (AV) canal VSD

15. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 15 Ventricular Septal Defect (VSD)

16. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 16 Defects Increasing Pulmonary Blood Flow  Atrioventricular canal defect (AVC)  Results from nonfusion of the endocardial cushions  Demonstrates abnormalities in the atrial and ventricular septa and AV valves  Complete, partial, and transitional AVCs

17. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 17 Atrioventricular Canal Defect

18. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 18 Defects Decreasing Pulmonary Blood Flow  Tetralogy of Fallot  Syndrome represented by four defects Ventricular septal defect (VSD) Ventricular septal defect (VSD) Overriding aorta straddles the VSD Overriding aorta straddles the VSD Pulmonary valve stenosis Pulmonary valve stenosis Right ventricle hypertrophy Right ventricle hypertrophy  Most cases corrected surgically in early infancy

19. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 19 Tetralogy of Fallot

20. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 20 Defects Decreasing Pulmonary Blood Flow  Tricuspid atresia  Imperforate tricuspid valve  No communication between right atrium and right ventricle  Central cyanosis Exertional dyspnea, tachypnea, hypoxemia Exertional dyspnea, tachypnea, hypoxemia Polycythemia, clubbing Polycythemia, clubbing  Additional defects Septal defect Septal defect Hypoplastic or absent right ventricle Hypoplastic or absent right ventricle Enlarged mitral valve and left ventricle Enlarged mitral valve and left ventricle Pulmonic stenosis Pulmonic stenosis

21. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 21 Tricuspid Atresia

22. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 22 Obstructive Defects  Coarctation of the aorta  Narrowing of the lumen of the aorta that impedes blood flow (8%-10% of defects)  Coarctation of the aorta is almost always in a juxtaductal position, but it can occur anywhere between the origin of the aortic arch and the bifurcation of the aorta in the lower abdomen

23. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 23 Obstructive Defects  Coarctation of the aorta  Newborns usually present with congestive heart failure Once the ductus closes, rapid deterioration hypotension, acidosis, and shock Once the ductus closes, rapid deterioration hypotension, acidosis, and shock  Older children Hypertension in upper extremities Hypertension in upper extremities Decreased or absent pulses in lower extremities Decreased or absent pulses in lower extremities Cool mottled skin Cool mottled skin Leg cramps during exercise Leg cramps during exercise

24. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 24 Coarctation of the Aorta

25. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 25 Obstructive Defects  Aortic stenosis  Narrowing of the aortic outflow tract (5% of defects)  Caused by malformation or fusion of the cusps  Causes an increased workload on the left ventricle  Symptoms Often asymptomatic Often asymptomatic Signs of exercise intolerance in preadolescence Signs of exercise intolerance in preadolescence Syncopal episodes, epigastric pain, and exertional chest pain in more severe forms Syncopal episodes, epigastric pain, and exertional chest pain in more severe forms

26. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 26 Aortic Stenosis

27. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 27 Obstructive Defects  Pulmonary stenosis  Narrowing of the pulmonary outflow tract  Abnormal thickening of the valve leaflets  Narrowing of the valve  Pulmonary semilunar valve atresia  Symptoms Often asymptomatic Often asymptomatic  Exertional dyspnea, fatigue

28. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 28 Pulmonary Stenosis

29. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 29 Obstructive Defects  Hypoplastic left heart syndrome  Abnormal development of the left-sided cardiac structures Obstruction to blood flow from the left ventricular outflow tract Obstruction to blood flow from the left ventricular outflow tract  Underdevelopment of the left ventricle, aorta and aortic arch, and mitral atresia or stenosis

30. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 30 Hypoplastic Left Heart Syndrome

31. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 31 Mixed Defects  Transposition of the great arteries  Aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle  Results in two separate, parallel circuits Unoxygenated blood circulates continuously through the systemic circulation Unoxygenated blood circulates continuously through the systemic circulation Oxygenated blood circulates continuously through the pulmonary circulation Oxygenated blood circulates continuously through the pulmonary circulation  Extrauterine survival requires communication between the two circuits

32. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 32 Mixed Defects  Total anomalous pulmonary venous connection (TAPVC)  Pulmonary veins connect to the right side of the heart, directly or indirectly through one or more systemic veins that drain into the right atrium

33. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 33 Total Anomalous Pulmonary Venous Connection (TAPVC)

34. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 34 Mixed Defects  Truncus arteriosus  Failure of the embryonic artery and the truncus arteriosus to divide into the pulmonary artery and the aorta  The trunk straddles an always present VSD

35. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 35 Truncus Arteriosus

36. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 36 Acquired Cardiovascular Disorders  Kawasaki disease  Also known as mucocutaneous lymph node syndrome  Acute, self-limiting systemic vasculitis that may result in cardiac sequelae  80% of cases occur in children under age 5  Cause Unknown Unknown Theories: an immunologic response to an infectious, toxic, or antigenic substance (including superantigen) Theories: an immunologic response to an infectious, toxic, or antigenic substance (including superantigen)

37. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 37 Kawasaki Disease  Stages  One (0-12 days): capillaries, venules, arterioles, and the heart become inflamed  Two (12-35 days): inflammation of larger vessels; coronary aneurysms appear  Three (26-40 days): medium-sized arteries begin granulation process; small vessel inflammation decreases  Four (day 40 and beyond): scarring of vessels, thickening of tunica intima, calcification, coronary artery stenosis

38. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 38 Kawasaki Disease  Diagnosis (5 of 6 major findings)  Fever for 5 or more days (unresponsive to antibiotics)  Bilateral conjunctivitis without exudation  Erythema of oral mucosa (strawberry tongue)  Changes in the extremities, such as peripheral edema and erythema with desquamation of palms and soles  Polymorphous rash  Cervical lymphadenopathy

39. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 39 Acquired Cardiovascular Disorders  Systemic hypertension  Hypertension in children differs from adult hypertension Often have an underlying disease Often have an underlying disease  Renal disease or coarctation of the aorta Cause of hypertension in children is almost always found Cause of hypertension in children is almost always found Children with hypertension are commonly asymptomatic Children with hypertension are commonly asymptomatic

40. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 40 Acquired Cardiovascular Disorders  Childhood obesity  Multivariable and multidimensional  Risk factors Race, socioeconomic status, and lack of health insurance Race, socioeconomic status, and lack of health insurance Childhood nutrition, level of physical activity, and engagemnt in sedentary activities (TV, computer use, etc.) Childhood nutrition, level of physical activity, and engagemnt in sedentary activities (TV, computer use, etc.)  Association with parental obesity  Places child at risk for asthma, sleep apnea, hypertension, type 2 diabetes, dyslipidemia, cardiovascular disease  Social and economic consequences