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

Alterations of Cardiovascular Alterations of Cardiovascular Function in ChildrenFunction in Children

Chapter 31Chapter 31

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

22Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.

Developmental Anatomy of the Developmental Anatomy of the Cardiovascular SystemCardiovascular System

EmbryologyEmbryology Cardiogenesis begins at approximately 3 weeks’ Cardiogenesis begins at approximately 3 weeks’

gestationgestation The heart arises from the mesenchymeThe heart arises from the mesenchyme

• Develops as an enlarged blood vessel with a large lumen Develops as an enlarged blood vessel with a large lumen and muscular walland muscular wall

• Midsection grows faster than the endsMidsection grows faster than the ends

The heart tube elongates and rotates to the right, The heart tube elongates and rotates to the right, creating a bulboventricular loopcreating a bulboventricular loop

Fetal heart contractions begin by approximately Fetal heart contractions begin by approximately the 28th daythe 28th day



Cardiac septationCardiac septation Endocardial cushionsEndocardial cushions Septum primum and the septum secundumSeptum primum and the septum secundum Ostium primumOstium primum Ostium secundumOstium secundum Foramen ovaleForamen ovale Ductus arteriosusDuctus arteriosus




Transitional CirculationTransitional Circulation

Circulatory changes take place that affect blood Circulatory changes take place that affect blood flow, vascular resistance, and oxygen tensionflow, vascular resistance, and oxygen tension

Shift of gas exchange from placenta to lungsShift of gas exchange from placenta to lungs Closure of fetal shuntsClosure of fetal shunts

Ductus venosusDuctus venosus• Round ligament of the liverRound ligament of the liver

Foramen ovale Foramen ovale • Pressure gradient changePressure gradient change

Ductus arteriosusDuctus arteriosus• Ligamentum arteriosumLigamentum arteriosum


Postnatal DevelopmentPostnatal Development Changes in the position of the heartChanges in the position of the heart Changes in the size of the right ventricleChanges in the size of the right ventricle HemodynamicsHemodynamics

Decreased pulmonary vascular resistanceDecreased pulmonary vascular resistance Increased systemic vascular resistanceIncreased systemic vascular resistance Heart rate ranges from 100 to 180 beats per Heart rate ranges from 100 to 180 beats per

minuteminute• Newborns have a high oxygen demandNewborns have a high oxygen demand


Congenital Heart DefectsCongenital Heart Defects Leading cause of death (except for prematurity) Leading cause of death (except for prematurity)

in first year of lifein first year of life Cause known in only 10% of defectsCause known in only 10% of defects Prenatal, environmental, and genetic risk factorsPrenatal, environmental, and genetic risk factors

Maternal rubella, insulin-dependent diabetes, Maternal rubella, insulin-dependent diabetes, alcoholism, PKU, and hypercalcemiaalcoholism, PKU, and hypercalcemia

DrugsDrugs Chromosomal aberrationsChromosomal aberrations


Complications of Complications of Congenital Heart DefectsCongenital Heart Defects

Congestive heart failure (acquired)Congestive heart failure (acquired) Insufficient cardiac output relative to demandInsufficient cardiac output relative to demand Cardiomyopathy most common causeCardiomyopathy most common cause HypoxemiaHypoxemia

CyanosisCyanosis Eisenmenger syndromeEisenmenger syndrome


Complications of Complications of Congenital Heart DefectsCongenital Heart Defects

Clinical signs of congestive heart failure Clinical signs of congestive heart failure (acquired)(acquired) Poor feeding and sucking; leads to failure to thrivePoor feeding and sucking; leads to failure to thrive Dyspnea, tachypnea, diaphoresis, retractions, Dyspnea, tachypnea, diaphoresis, retractions,

grunting, nasal flaringgrunting, nasal flaring Wheezing, coughing, rales are rare (even with Wheezing, coughing, rales are rare (even with

significant heart failure)significant heart failure) Skin changes, such as pallor or mottlingSkin changes, such as pallor or mottling Hepatomegaly Hepatomegaly


Defects Increasing Defects Increasing Pulmonary Blood FlowPulmonary Blood Flow

Patent ductus arteriosus (PDA)Patent ductus arteriosus (PDA) Failure of the ductus arteriosus to closeFailure of the ductus arteriosus to close

• Normally closes within 15 hours to 2 weeks of ageNormally closes within 15 hours to 2 weeks of age PDA allows blood to shunt from the pulmonary artery PDA allows blood to shunt from the pulmonary artery

to the aortato the aorta PrevalencePrevalence

• 5%-10% full-term infants5%-10% full-term infants• Up to 45% premature infantsUp to 45% premature infants


Patent Ductus Arteriosus (PDA)Patent Ductus Arteriosus (PDA)



Atrial septal defectAtrial septal defect Abnormal communication between the atriaAbnormal communication between the atria

• Allows blood to be shunted from left to right due to higher Allows blood to be shunted from left to right due to higher pressure of the left atrial chamber and lower pulmonary pressure of the left atrial chamber and lower pulmonary vascular resistance as compared to systemic vascular vascular resistance as compared to systemic vascular resistanceresistance

• Right atrial enlargementRight atrial enlargement

Often asymptomatic, diagnosed by murmurOften asymptomatic, diagnosed by murmur Three major typesThree major types

• Ostium primum defectOstium primum defect

• Ostium secundum defectOstium secundum defect

• Sinus venosus defectSinus venosus defect


Atrial Septal DefectAtrial Septal Defect



Ventricular septal defect (VSD)Ventricular septal defect (VSD) Abnormal communication between ventriclesAbnormal communication between ventricles Common congenital heart lesion (25%-33%)Common congenital heart lesion (25%-33%) Pulmonary overcirculation accounts for symptoms Pulmonary overcirculation accounts for symptoms

associated with a large VSD associated with a large VSD TypesTypes

• Perimembranous VSDPerimembranous VSD

• Muscular VSDMuscular VSD

• Supracristal VSDSupracristal VSD

• Atrioventricular (AV) canal VSDAtrioventricular (AV) canal VSD


Ventricular Septal Defect (VSD)Ventricular Septal Defect (VSD)



Atrioventricular canal defect (AVC)Atrioventricular canal defect (AVC) Results from nonfusion of the endocardial Results from nonfusion of the endocardial

cushionscushions Demonstrates abnormalities in the atrial and Demonstrates abnormalities in the atrial and

ventricular septa and AV valvesventricular septa and AV valves Complete, partial, and transitional AVCsComplete, partial, and transitional AVCs


Atrioventricular Canal Defect Atrioventricular Canal Defect


Defects Decreasing Defects Decreasing Pulmonary Blood Flow Pulmonary Blood Flow

Tetralogy of FallotTetralogy of Fallot Syndrome represented by four defectsSyndrome represented by four defects

• Ventricular septal defect (VSD)Ventricular septal defect (VSD)

• Overriding aorta straddles the VSDOverriding aorta straddles the VSD

• Pulmonary valve stenosisPulmonary valve stenosis

• Right ventricle hypertrophyRight ventricle hypertrophy

Most cases corrected surgically in early infancyMost cases corrected surgically in early infancy


Tetralogy of FallotTetralogy of Fallot


Defects Decreasing Defects Decreasing Pulmonary Blood FlowPulmonary Blood Flow

Tricuspid atresiaTricuspid atresia Imperforate tricuspid valveImperforate tricuspid valve No communication between right atrium and right No communication between right atrium and right

ventricle ventricle Central cyanosisCentral cyanosis

• Exertional dyspnea, tachypnea, hypoxemia Exertional dyspnea, tachypnea, hypoxemia • Polycythemia, clubbingPolycythemia, clubbing

Additional defectsAdditional defects• Septal defectSeptal defect• Hypoplastic or absent right ventricleHypoplastic or absent right ventricle• Enlarged mitral valve and left ventricleEnlarged mitral valve and left ventricle• Pulmonic stenosisPulmonic stenosis


Tricuspid AtresiaTricuspid Atresia


Obstructive DefectsObstructive Defects Coarctation of the aortaCoarctation of the aorta

Narrowing of the lumen of the aorta that impedes Narrowing of the lumen of the aorta that impedes blood flow (8%-10% of defects)blood flow (8%-10% of defects)

Coarctation of the aorta is almost always in a Coarctation of the aorta is almost always in a juxtaductal position, but it can occur anywhere juxtaductal position, but it can occur anywhere between the origin of the aortic arch and the between the origin of the aortic arch and the bifurcation of the aorta in the lower abdomenbifurcation of the aorta in the lower abdomen


Obstructive DefectsObstructive Defects Coarctation of the aortaCoarctation of the aorta

Newborns usually present with congestive heart Newborns usually present with congestive heart failure failure • Once the ductus closes, rapid deterioration hypotension, Once the ductus closes, rapid deterioration hypotension,

acidosis, and shockacidosis, and shock

Older children Older children • Hypertension in upper extremitiesHypertension in upper extremities

• Decreased or absent pulses in lower extremities Decreased or absent pulses in lower extremities

• Cool mottled skinCool mottled skin

• Leg cramps during exercise Leg cramps during exercise


Coarctation of the AortaCoarctation of the Aorta


Obstructive DefectsObstructive Defects

Aortic stenosisAortic stenosis Narrowing of the aortic outflow tract (5% of defects)Narrowing of the aortic outflow tract (5% of defects) Caused by malformation or fusion of the cuspsCaused by malformation or fusion of the cusps Causes an increased workload on the left ventricleCauses an increased workload on the left ventricle SymptomsSymptoms

• Often asymptomaticOften asymptomatic

• Signs of exercise intolerance in preadolescenceSigns of exercise intolerance in preadolescence

• Syncopal episodes, epigastric pain, and exertional chest pain Syncopal episodes, epigastric pain, and exertional chest pain in more severe forms in more severe forms


Aortic StenosisAortic Stenosis


Obstructive DefectsObstructive Defects Pulmonary stenosisPulmonary stenosis

Narrowing of the pulmonary outflow tractNarrowing of the pulmonary outflow tract Abnormal thickening of the valve leafletsAbnormal thickening of the valve leaflets Narrowing of the valveNarrowing of the valve Pulmonary semilunar valve atresiaPulmonary semilunar valve atresia SymptomsSymptoms

• Often asymptomaticOften asymptomatic Exertional dyspnea, fatigueExertional dyspnea, fatigue


Pulmonary StenosisPulmonary Stenosis


Obstructive DefectsObstructive Defects Hypoplastic left heart syndromeHypoplastic left heart syndrome

Abnormal development of the left-sided cardiac Abnormal development of the left-sided cardiac structuresstructures• Obstruction to blood flow from the left ventricular outflow Obstruction to blood flow from the left ventricular outflow

tracttract

Underdevelopment of the left ventricle, aorta and Underdevelopment of the left ventricle, aorta and aortic arch, and mitral atresia or stenosisaortic arch, and mitral atresia or stenosis


Hypoplastic Left Heart SyndromeHypoplastic Left Heart Syndrome


Mixed DefectsMixed Defects Transposition of the great arteriesTransposition of the great arteries

Aorta arises from the right ventricle and the Aorta arises from the right ventricle and the pulmonary artery arises from the left ventriclepulmonary artery arises from the left ventricle

Results in two separate, parallel circuitsResults in two separate, parallel circuits• Unoxygenated blood circulates continuously through the Unoxygenated blood circulates continuously through the

systemic circulationsystemic circulation• Oxygenated blood circulates continuously through the Oxygenated blood circulates continuously through the

pulmonary circulationpulmonary circulation Extrauterine survival requires communication Extrauterine survival requires communication

between the two circuits between the two circuits


Mixed DefectsMixed Defects Total anomalous pulmonary venous Total anomalous pulmonary venous

connection (TAPVC)connection (TAPVC) Pulmonary veins connect to the right side of the Pulmonary veins connect to the right side of the

heart, directly or indirectly through one or more heart, directly or indirectly through one or more systemic veins that drain into the right atriumsystemic veins that drain into the right atrium


Total Anomalous Pulmonary Total Anomalous Pulmonary Venous Connection (TAPVC)Venous Connection (TAPVC)


Mixed DefectsMixed Defects Truncus arteriosusTruncus arteriosus

Failure of the embryonic artery and the truncus Failure of the embryonic artery and the truncus arteriosus to divide into the pulmonary artery and arteriosus to divide into the pulmonary artery and the aortathe aorta

The trunk straddles an always present VSDThe trunk straddles an always present VSD


Truncus ArteriosusTruncus Arteriosus


Acquired Cardiovascular Acquired Cardiovascular DisordersDisorders

Kawasaki diseaseKawasaki disease Also known as mucocutaneous lymph node syndromeAlso known as mucocutaneous lymph node syndrome Acute, self-limiting systemic vasculitis that may result Acute, self-limiting systemic vasculitis that may result

in cardiac sequelaein cardiac sequelae 80% of cases occur in children under age 580% of cases occur in children under age 5 CauseCause

• UnknownUnknown• Theories: an immunologic response to an infectious, toxic, or Theories: an immunologic response to an infectious, toxic, or

antigenic substance (including superantigen) antigenic substance (including superantigen)


Kawasaki DiseaseKawasaki Disease StagesStages

One (0-12 days): capillaries, venules, arterioles, One (0-12 days): capillaries, venules, arterioles, and the heart become inflamedand the heart become inflamed

Two (12-35 days): inflammation of larger vessels; Two (12-35 days): inflammation of larger vessels; coronary aneurysms appearcoronary aneurysms appear

Three (26-40 days): medium-sized arteries begin Three (26-40 days): medium-sized arteries begin granulation process; small vessel inflammation granulation process; small vessel inflammation decreasesdecreases

Four (day 40 and beyond): scarring of vessels, Four (day 40 and beyond): scarring of vessels, thickening of tunica intima, calcification, coronary thickening of tunica intima, calcification, coronary artery stenosisartery stenosis


Kawasaki DiseaseKawasaki Disease Diagnosis (5 of 6 major findings)Diagnosis (5 of 6 major findings)

Fever for 5 or more days (unresponsive to Fever for 5 or more days (unresponsive to antibiotics)antibiotics)

Bilateral conjunctivitis without exudationBilateral conjunctivitis without exudation Erythema of oral mucosa (strawberry tongue)Erythema of oral mucosa (strawberry tongue) Changes in the extremities, such as peripheral Changes in the extremities, such as peripheral

edema and erythema with desquamation of palms edema and erythema with desquamation of palms and solesand soles

Polymorphous rashPolymorphous rash Cervical lymphadenopathyCervical lymphadenopathy


Acquired Cardiovascular Acquired Cardiovascular Disorders Disorders

Systemic hypertensionSystemic hypertension Hypertension in children differs from adult Hypertension in children differs from adult

hypertensionhypertension• Often have an underlying diseaseOften have an underlying disease

Renal disease or coarctation of the aortaRenal disease or coarctation of the aorta

• Cause of hypertension in children is almost always foundCause of hypertension in children is almost always found

• Children with hypertension are commonly asymptomaticChildren with hypertension are commonly asymptomatic


Acquired Cardiovascular DisordersAcquired Cardiovascular Disorders

Childhood obesityChildhood obesity Multivariable and multidimensionalMultivariable and multidimensional Risk factorsRisk factors

• Race, socioeconomic status, and lack of health insuranceRace, socioeconomic status, and lack of health insurance

• Childhood nutrition, level of physical activity, and engagemnt in Childhood nutrition, level of physical activity, and engagemnt in sedentary activities (TV, computer use, etc.)sedentary activities (TV, computer use, etc.)

Association with parental obesityAssociation with parental obesity Places child at risk for asthma, sleep apnea, Places child at risk for asthma, sleep apnea,

hypertension, type 2 diabetes, dyslipidemia, hypertension, type 2 diabetes, dyslipidemia, cardiovascular disease cardiovascular disease

Social and economic consequencesSocial and economic consequences

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