Chapter 26 – Cardiac Flashcards
What do right to left shunts cause?
Cyanosis; this can lead to polycythemia, strokes, brain abscess, endocarditis, hypertrophic osteoarthropathy
How do children compensate for right to left shunt?
Squat to increase SVR and decrease right to left shunting
What is Eisenmenger’s syndrome?
Shift from left to right to right to left shunt; sign of increasing pulmonary vascular resistance and pulmonary hypertension, generally irreversible
What do left to right shunts cause?
CHF; can manifest as failure to thrive, tachycardia, tachypnea, hepatomegaly
What is the first sign of left to right shunting in children?
Hepatomegaly
What causes a left to right shunt?
VSD, ASD, PDA
What causes a right to left shunt?
Tetralogy of Fallot, transposition of the great vessels, truncus arteriosus
What is ductus arteriosus?
Connection between descending aorta and left pulmonary artery, blood shunted away from lungs in utero
What is ductus venosum?
Connection between portal vein and IVC, blood shunted away from liver
How many umbilical arteries and veins are there?
Two umbilical arteries, one umbilical vein
What is the most common congenital heart defect?
Ventricular septal defect
VSD causes what type of shunt?
Left to right
What is the pathological timeline of VSDs?
Most close spontaneously by six months.
Large VSD’s cause symptoms after 4 to 6 weeks as pulmonary vascular resistance decreases and shunt increases to the right. Patients get CHF, failure to thrive, tachypnea, and tachycardia (all left to right shunts share these symptoms).
Most common congenital shunt.
Medical treatment for VSD’s?
Diuretics and digoxin
What is the timing of repair of the VSDs?
With CHF: most common reason for repair; before school-age if does not close spontaneously; PVR greater than 4-6 Woods units; PVR greater than 10-12 to Woods units contraindication for repair
What type of shunt does ASD cause?
Left to right
What is ostium secundum?
Most common, centrally located, PFO; can have anomalous pulmonary venous return, IVC can connect the left atrium
What is ostium primum?
Also known as atrioventricular septal defects or endocardial cushion defects; defect more inferior, can get mitral valve and coronary sinus defects, caused by a deficiency in remnants of left horn of sinus venosum?
What are possible complications as an adult with ASD?
Can get paradoxical emboli and arrhythmias
What is the medical treatment of ASD?
Diuretics and digoxin
Timing of repair of ASD?
Volume overload, before school-age if does not close spontaneously, PVR greater than 10 to 12 woods units contraindication for repair; all need repair
What is the Tetralogy of Fallot?
VSD, pulmonic stenosis, overriding aorta, right ventricular hypertrophy
What type of shunt does T of F cause?
Right to left
What is the most common congenital heart defect that results in cyanosis?
T of F
What is the medical treatment for T of F?
Beta blocker
What is the timing of operation for T of F?
Increasing cyanosis; Blalock-Taussig shunt can be used for palliation to delay repair
What is definitive repair for T of F?
RV outflow tract obstruction division, patch enlargement of outflow tract, VSD repair
What is the most common cyanotic disorder presenting in the first week of life?
Transposition of the great vessels
What type of shunt does transposition of the great vessels cause?
Right to left
Where does the mixing usually happen with transposition of the great vessels?
Most often through ASD; VSD or PDA can serve as additional mixing conduit
Medical treatment for transposition of the great vessels?
Atria septostomy, PGE1
When is the optimal time and method of repair for transposition of the great vessels?
Early switch with coronary reimplantation posteriorly in the first 2 to 3 weeks of life while LV is still getting high resistance
What type of shunt does truncus arteriosus cause?
Right to left