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Alterations of Cardiovascular Function in Children. Chapter 31. Developmental Anatomy of the Cardiovascular System. Embryology Cardiogenesis begins at approximately 3 weeks’ gestation The heart arises from the mesenchyme - PowerPoint PPT Presentation
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Alterations of Cardiovascular Function in ChildrenChapter 31
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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
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
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Developmental Anatomy of the Cardiovascular System
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Developmental Anatomy of the Cardiovascular System Cardiac septation
Endocardial cushions Septum primum and the septum secundum Ostium primum Ostium secundum Foramen ovale Ductus arteriosus
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Developmental Anatomy of the Cardiovascular System
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Transitional Circulation Circulatory changes take place that affect
blood flow, vascular resistance, and oxygen tension
Closure of fetal shunts Ductus venosus Foramen ovale Ductus arteriosus
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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
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Congenital Heart Defects Underlying cause is known in only 10% of
defects Prenatal, environmental, and genetic risk
factors Maternal rubella, insulin-dependent diabetes,
alcoholism, PKU, and hypercalcemia Drugs Chromosome aberrations
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Complications of Congenital Heart Defects Congestive heart failure Hypoxemia
Cyanosis Eisenmenger syndrome
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Defects Increasing Pulmonary Blood Flow Patent ductus arteriosus (PDA)
Failure of the ductus arteriosus to close PDA allows blood to shunt from the pulmonary
artery to the aorta
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Patent Ductus Arteriosus (PDA)
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Defects Increasing Pulmonary Blood Flow Atrial septal defect
Abnormal communication between the atria Three major types
Ostium primum defect Ostium secundum defect Sinus venosus defect
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Atrial Septal Defect
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Defects Increasing Pulmonary Blood Flow Ventricular septal defect (VSD)
Abnormal communication between the ventricles Most common type of congenital heart lesion Types
Perimembranous VSD Muscular VSD Supracristal VSD AV canal VSD
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Ventricular Septal Defect (VSD)
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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 atrioventricular valves
Complete, partial, and transitional AVCs
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Atrioventricular Canal Defect
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Defects Decreasing Pulmonary Blood Flow Tetralogy of Fallot
Syndrome represented by four defects Ventricular septal defect (VSD) Overriding aorta straddles the VSD Pulmonary valve stenosis Right ventricle hypertrophy
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Tetralogy of Fallot
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Defects Decreasing Pulmonary Blood Flow Tricuspid atresia
Imperforate tricuspid valve Lack of communication between the right atrium
and right ventricle Additional defects
Septal defect Hypoplastic or absent right ventricle Enlarged mitral valve and left ventricle Pulmonic stenosis
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Tricuspid Atresia
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Obstructive Defects Coarctation of the aorta
Narrowing of the lumen of the aorta that impedes blood flow
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
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Coarctation of the Aorta
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Obstructive Defects Aortic stenosis
Narrowing of the aortic outflow tract Caused by malformation or fusion of the cusps Causes an increased workload on the left
ventricle
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Aortic Stenosis
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Obstructive Defects Pulmonary stenosis
Narrowing of the pulmonary outflow tract Abnormal thickening of the valve leaflets Narrowing of the valve Pulmonary semilunar valve atresia
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Pulmonary Stenosis
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Obstructive Defects Hypoplastic left heart syndrome
Abnormal development of the left-sided cardiac structures Obstruction to blood flow from the left ventricular
outflow tract
Under development of the left ventricle, aorta and aortic arch, and mitral atresia or stenosis
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Hypoplastic Left Heart Syndrome
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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 Oxygenated blood circulates continuously through the
pulmonary circulation Extrauterine survival requires communication
between the two circuits
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Transposition of the Great Arteries
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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
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Total Anomalous Pulmonary Venous Connection (TAPVC)
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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
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Truncus Arteriosus
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Acquired Cardiovascular Disorders Kawasaki disease
Also known as mucocutaneous lymph node syndrome
Acute, self-limiting systemic vasculitis that may result in cardiac sequelae
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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
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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
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Acquired Cardiovascular Disorders Systemic hypertension
Hypertension in children differs from adult hypertension Often have an underlying disease
Renal disease or coarctation of the aorta
A cause of the hypertension in children is almost always found
Children with hypertension are commonly asymptomatic
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Acquired Cardiovascular Disorders Childhood obesity
Multivariable and multidimensional Risk factors
Race, socioeconomic status, and lack of health insurance
Childhood nutrition, level of physical activity, and engagement of sedentary activities (TV, computer use, etc.)
Association with parental obesity