"Congenital Heart Disease - Download as DOC"
Congenital Heart Disease L. Jones Chronic Exam One: 4 questions Wong: pgs. 936-65 1 Congenital Heart Disease Incidence and Etiology Occurs in approximately 8 out of 1000 live births Rate is higher in preterm infants-PDA most common in preterm Most common defect is VSD Most cases the cause is unknown Incidence: Factors Associated with Higher Incidence Inheritance Genetic predisposition Viruses Alcohol Drugs Poor maternal nutrition Chromosomal aberration-e.g Trisomy XXI, XIII, XVIII, Turner’s Syndrome Pediatric Differences Heart and great vessels develop during the first weeks of gestation-14th-55th day Heart sounds of the young infant have a higher pitch and are of greater intensity than in the adult Pulse rate is higher in the infant Chest wall of the infant and young child is relatively thin Innocuous murmurs can be auscultated in structurally normally hearts-e.g. innocent murmurs Diagnostic Tests History taking Physical examination including cardiac auscultation and blood pressure of all 4 extremities-In infants: Check bp in upper arms and lower legs (calves—not thighs)! ECG CXR Echocardiography MRI-can visualize tumors, shunts, etc. Cardiac catheterization-invasive—used under fluoroscopy. Can check oxygenation, use dye or contrast media, often use right-sided cath and go through foramen ovale to check the left side of the heart. Fetal Circulation-In Utero Pressure increased on right side of heart-b/c no need to exchange gasses Pressure decreased on left side of heart Pulmonary is high pressure system Open foramen ovale and patent ductus arteriosus (PDA)-PDA is between the pulmonary artery and the aorta. Congenital Heart Disease L. Jones Chronic Exam One: 4 questions Wong: pgs. 936-65 2 Pressure Changes after Birth Pulmonary becomes low pressure system Pressure decreases on right side of heart Pressure increases on left side of heart PDA closes due to oxygen constricting the ductus Foramen ovale (opening between the atria) closes due to pressure changes in the heart Heart Pressures: Newborn Right atrium 2-4 mmHg Right ventricle 20-35 mmHg Left atrium 8-14 mmHg Left ventricle 60-90 mmHg Newborn pressures in Heart Chambers Atria Rt. At. 2-4 mm Hg Lft. At. 8-14 mm Hg. Ventricles Rt. Vent. 20-35 mm Hg Lft Vent. 60-90 mm Hg (whatever systolic bp is) Changes in Vessels in Lungs With each defect, need to determine if blood flow is going to the lungs Under increased pressure With increased flow If hypoxia exist All three cause pulmonary vasoconstriction Changes in Vessels in Lungs If only increased flow, it takes a longer time to get irreversible pulmonary hypertension (15 to 30 years)—e.g. as with an atrial/septal defect If increased flow and increased pressure, irreversible damage can result after only one to two years Check pics on handout that accompanied this lecture! Acyanotic Heart Defects Patent Ductus Arteriosus (PDA) Atrial Septal Defect (ASD) Ventricular Septal Defect (VSD) Coarctation of the Aorta (COA) Congenital Heart Disease L. Jones Chronic Exam One: 4 questions Wong: pgs. 936-65 3 1. PDA: Patent Ductus Arteriosus Connection between pulmonary artery and aorta Normal pathway in fetal circulation Functional closure occurs within a few hours after birth Permanent closure occurs in the first few weeks of life Failure of ductus arteriosus to close results in a left to right shunt Lungs are receiving increased blood flow under increased pressure If not corrected, irreversible pulmonary vascular disease can result Common in premature infants o Symptoms Murmur - machinery-like Widened pulse pressure Bounding peripheral pulses-btw. 20-50 mm Hg Frequent respiratory infections FTT-failure to thrive S/S of CHF –b/c of increased flow to lungs and pulmonary edema o Older Child If found in 12-year-old who is asymptomatic would still fix b/c of possible bacterial endocarditis development. Avoid Subacute Bacterial Endocarditis/Infective Endocarditis o Management Some PDA’s may close spontaneously May use indomethacin-a non-steroidal anti-inflammatory that inhibits prostaglandin synthesis and causes ductus to close. Most successful when given in 1st 7-10 days of life Surgical closure-ligation of defect Newer technique called visual assisted thorascopic surgery (VATS)-clip to be placed on ductus using 3 small thorascopic slits on chest 2. ASD Atrial-Septal Defect 12 to 15% of all congenital cardiac defects Opening between the right and left atrium May be patent foramen ovale May involve valve leaflets Can vary in size, location in septum o Characteristics Left to right shunt-acyanotic Increased flow to lungs without increased pressure Grace II/VI ejection systolic murmur; second left intercostal space. Usually asymptomatic Congenital Heart Disease L. Jones Chronic Exam One: 4 questions Wong: pgs. 936-65 4 More common in females than males Murmurs graded I- IV: Grade I, II may not hear. Grade III, IV, will hear. o Symptoms Growth retardation Diaphoresis Poor feeding Mild fatigue (older child) Dyspnea (older child) Many patients are asymptomatic o Management Surgical closure/open heart-to close defect with dacron or silastic or pericardium patch Interventional cardiac catheterization/transcatheter closure Without surgery child is at risk for infectious endocarditis Surgical closure before school age plus antibiotic prophylaxis before surgery 3. VSD: Ventricular Septal defect The most common defect Abnormal opening between left and right ventricles Can very in size, location in the septum and number Often associated with other more complex defects o Characteristics Left to right shunt Increased blood flow going to the lungs under increased pressure- b/c of left ventricular pressure Approximately 60% will close spontaneously Murmur - grade IV/VI loud, harsh, pansystolic murmur; 4th interspace; left of sternum May wait to close these if patient is asymptomatic o Symptoms Growth retardation Failure to thrive Diaphoresis Poor feeding Tachypnea Frequent respiratory infections S/S of CHF o Management May close spontaneously Pulmonary artery banding - not used that often-to make it harder for the blood to flow through Congenital Heart Disease L. Jones Chronic Exam One: 4 questions Wong: pgs. 936-65 5 Open heart surgery Device closure-e.g. pursestring suture if very small defect. May have some leakage and/or conduction disturbances initially after closure o Prognosis Risks depends on the location of the defect, number of defects and other associated cardiac defects Single membraneous defects - <5% risk of death Multiple muscular defects - 20% risk of death Eismenger’s Complex Can occur with any left to right shunt When child develops sufficient pulmonary vascular disease and pulmonary hypertension to cause the shunt to become right to left Shunt reversal Pressure on the right side has had to increase in order to pump blood to lungs and shunt reverses to Right-left shunt which is a cyanotic condition. Fatal outcome or heart and lung transplant is needed. Coarctation of the Aorta Narrowing of the aorta Usually located near the insertion of the ductus arteriosus Can vary from mild constriction to total occlusion The degree of narrowing determines the severity of the symptoms Pressure builds proximal to the defect and decreases distal to the defect SYMPTOMS o Upper extremity hypertension o Bounding pulses in arms o Weak or absent femoral pulses o Cool lower extremities o May be asymptomatic o Murmur may be present Symptoms in Older Child o Dizziness o Headache o Fainting o Epistaxis-nose bleeds o Risk for hypertension, ruptured aorta, aortic aneurysm, stroke Surgical Treatment o Resection of the coarcted portion with an end-to-end anastomosis of the aorta (for children 6+ yrs old) o Enlargement of the constricted section using a graft of prosthetic material or a portion of the subclavian artery o 2 ½ yrs can do subclavian flap repair—take subclavian and use it is a Congenital Heart Disease L. Jones Chronic Exam One: 4 questions Wong: pgs. 936-65 6 patch over the aorta. Postoperative Complications o Hypertensive response after surgery –vessel has high pressure when opened up and may spasm o Post coartectomy syndrome-when GI tract gets a lot of blood and its not used to it, SPO 2 days to avoid this complication NonSurgical Treatment o Balloon angioplasty o Is now being performed as a primary intervention for coarctation in some centers - limited use at present b/c of aneurism formation and b/c of weakened vessel Prognosis o Surgical mortality is < 5% in patients with isolated coarctation, but increases in infants with associated defects o Some children may have continued hypertension after the repair and need antihypertensive medications Cyanotic Heart Defects Problems o Decreased oxygen circulating causes increase in RBCs (polycythemia) o Helps for a while until hematocrit 60 to 70 o Blood becomes too thick and can get emboli and infarcts o Clubbing-broad fingers and decrease in angle of the nail Tetralogy of Fallot Classic form includes 4 defects o Ventricular septal defect o Pulmonary stenosis o Overriding aorta-aorta placed on the right—sits on top of VSD (Ventricular septal defect) o Right ventricular hypertrophy o Pattern of blood flow is determined by the degree of pulmonary stenosis o Severe pulmonary stenosis will cause right-to-left shunt producing cyanosis o Mild pulmonary stenosis will cause left-to-right shunt (pink tetralogy of fallot) o With classic TOF, the pulmonary stenosis will become more severe with time and the child will become more cyanotic as blood flow to the lungs is decreased o Clinical Manifestations Infants Cyanosis Murmur Congenital Heart Disease L. Jones Chronic Exam One: 4 questions Wong: pgs. 936-65 7 Hypoxic or “tet” spells –transient ischemic spells; become limp and unconscious. Put babies in Knee/chest position!!! o Clinical Manifestations Children Clubbing Squatting-b/c it increases blood flow and increases cardiac output Poor growth o Management Palliative Shunt Called the Ballock-Taussig—temporary shunt Corrective Surgery - usually performed in the first year of life Open pulmonary stenosis Patch Ventricular Septal Defect (VSD)-around the aorta b/c the aorta is displaced. o Prognosis The operative mortality for total correction of TOF is less than 5%. With improved surgical techniques there is a lower incidence of dysrhythmias and sudden death Transposition of the Great Arteries Aorta arises from the right ventricle instead of the left ventricle Pulmonary artery arises from the left ventricle instead of the right ventricle Altered hemodynamics yields 2 parallel pathways o Clinical Manifestations Depend on the type and size of associated defects Cyanosis from birth, hypoxia Various murmurs or no murmur Symptoms of CHF o Therapeutic Management Need to provide intracardiac mixing Mixing of the 2 separate circulations must occur If PDA present, medications (Prostaglandin E ) are given to keep it open o Palliative Procedure Rashkind procedure/atrial balloon septostomy - done to increase mixing and maintain cardiac output Performed during cardiac catheterization Enlarge the interatrial communication o Surgical Correction Arterial Switch Procedure Procedure of choice performed in first few weeks of life Establishes normal circulation Congenital Heart Disease L. Jones Chronic Exam One: 4 questions Wong: pgs. 936-65 8 Major vessels are actually switched in position Mustard/Senning:Don’t see this much anymore Atrial switch Creates an intra-atrial baffle to direct venous blood to the mitral valve and pulmonary venous blood to the tricuspid valve Prognosis Postoperative mortality of arterial switch is 8% Some patients will have sudden cardiac death Death will occur if condition is not promptly diagnosed and treated