Congenital Heart Defects At A Glance

Congenital heart disease (CHD) are the most common congenital anomalies that occur in nearly 1% of all live births. Among the birth defects CHD is the leading cause of child mortality.

(Overview of the heart valve diseases.) Congenital heart defects (CHD) are the most common congenital anomalies that occur in nearly 1% of all live births. Among the birth defects CHD is the leading cause of child mortality. Etiology environmental and genetic factors contribute to the development of CHD. Some common environmental factors include maternal disease (eg., Diabetes, rubella, systemic lupus erythematosus) or the maternal intake of teratogenic agents (eg., Lithium, isotretinoin, anticonvulsants). The paternal age may also be a risk factor. Specific numerical chromosomal abnormalities such as trisomy 21, trisomy 18, trisomy 13 and monosomy X (Turner syndrome) are strongly associated with CHD. However, these abnormalities are responsible for only about 5% of patients with CHD. Many other cases include microscopic deletions on chromosomes (microdeletion syndrome gene), or mutations of individual genes. Often the microscopic deletions and mutations causing congenital syndromes that affect several organs besides the heart. Examples include DiGeorge syndrome (microdeletion on 22q11.2) and Williams Syndrome (microdeletion on 7p11.23). Defects of single genes that cause syndromes associated with coronary heart disease include mutations in the fibrillin-1 (Marfan syndrome), TXB5 (Holt-Oram syndrome) and possibly PTPN11 (Noonan syndrome). Defects of individual genes can cause congenital heart defects also includes isolated (i. E. Non-syndromic). The recurrence risk of CHD in a family depends on the cause. The risk is negligible in de novo mutations, 2 to 5% with non-syndromic multifactorial CHD and 50% if an autosomal dominant mutation is the cause. It is important to identify the genetic factors, because more patients survive with CHD into adulthood may start families. Pathophysiology Congenital heart defects are classified (see Table: Classification of congenital heart defects *) in cyanotic Azyanotische (left-right shunt or obstructive lesions) The physiological consequences of congenital heart disease are very different, ranging from an asymptomatic heart murmur or abnormal impulses to severe cyanosis , congestive heart failure or zirkulatorischem collapse. Classification of congenital heart defects * Classification Examples cyanotic – Tetralogy of Fallot Transposition of the great vessels Tricuspid atresia pulmonary atresia truncus arteriosus Persistent Full anomaly of Pulmonalvenenrückflusses acyanotic left-right shunt ventricular septal defect atrial septal defect Patent ductus arteriosus Atrioventri kulärer channel Obstructive pulmonary valve stenosis Aortic coarctation Hypoplastic left heart syndrome (often manifested with cyanosis, which may be mild) * In order of decreasing frequency. Left-right shunts Oxygenated blood passes from the left heart (left atrium or ventricle) or in the right heart from the aorta (right atrium or ventricle); or the blood flows from the pulmonary artery through an opening or communication between the two sides. Immediately after birth, the pulmonary vascular resistance is high and the flow through this communication can be minimal or bidirectional. Within the first 24 to 48 hours of life, however, the pulmonary vascular resistance decreases progressively; At this time, blood flows increased from left to right. The additional blood volume on the right side increases blood flow and pressure in the pulmonary artery to a different degree. The larger the volume, the more pronounced the symptoms are. A small left-right shunt usually causes no symptoms or signs. High pressure shunts (on Ventrikelhöhe or at the level of the great vessels) until a few weeks after birth, apparently a few days; low-pressure shunt (atrial septal defects) can be symptomatic much later. An untreated increased pulmonary blood flow and pressure in the pulmonary artery may lead to pulmonary vascular disease and finally to a Eisenmenger syndrome (Eisenmenger’s syndrome). Large left-right shunt (z. B. large ventricular septal defect [VSD], patent ductus arteriosus [PDA]) cause an excessive pulmonary blood flow and volume overload that during childhood can often lead to failure to thrive for signs of heart failure and. A large left-right shunt also reduces the lung compliance and often leads to infections of the lower Atemwege.Obstruktive heart failure The blood flow is obstructed and causing a pressure gradient along the obstruction. The increased pressure proximal to the obstruction caused ventricular hypertrophy and heart failure. The most obvious manifestation is a heart sound coming from the turbulence in the narrowed point. such. B. shunted to the left heart in congenital aortic stenosis, the 3-6%, or in congenital pulmonary stenosis, which accounts for 8-12% of congenital heart defects (overview of the heart valve diseases) .Zyanotische heart defect Various amounts of non-oxygenated blood to reduce and systemic O2 saturation. If> 5 g / dl deoxygenated Hb is present, the result is cyanosis. In dark-skinned children cyanosis can be overlooked. The consequences of a permanent cyanosis may be thromboembolism, bleeding disorders, clubbing and hyperuricemia. In children with unrepaired tetralogy of Fallot cyanotic and seizures may occur (tetralogy of Fallot). Depending on heart failure can be normal or decreased pulmonary blood flow increases (often ending in addition to the cyanosis in heart failure), which has a cyanosis of varying severity result. The heart sounds are different and not spezifisch.Herzinsuffizienz Some congenital heart defects (eg. As bicuspid aortic valve, mild aortic stenosis) does not lead to a significant change in hemodynamics. Other anomalies cause a failure by a high pressure gradient or volume overload. Heart failure occurs when the metabolic demands of the body can not be met by the cardiac output or when the heart can not distribute the venous return and this results in a left heart failure to a pulmonary congestion. Edematous congestion can then be seen first in the depending portions and right heart failure at the entrails (heart failure). The heart failure in infants and children has many non-cardiac causes (see Table: Common causes of heart failure in children). Common causes of heart failure in children age of onset causes in utero Chronic anemia with subsequent high-output heart failure Large systemic arteriovenous fistulas (z. B. cerebral vein of Galen shunts) Myocardial dysfunction as a result of myocarditis Persistent intrauterine tachycardia first days of life all up findings called critical aortic stenosis or critical coarctation Ebstein’s anomaly with severe tricuspid and / or pulmonary insufficiency Hypoplastic left heart syndrome Intrauterine or neonatal paroxysmal supraventricular tachycardia metabolic disorders (eg. B. hypoglycemia, hypothermia, severe metabolic acidosis) Perinatal asphyxia with myocardial damage severity intrauterine anemia (fetal hydrops) anomalous pulmonary venous drainage (with severe obstruction infrakardialer usually type) Up to 1 month All of the above findings anomalous pulmonary venous drainage (with less severe obstruction) coarctation with or without associated anomalies Complete heart block with structural heart defects large left-right shunt in preterm infants (z. B. ductus arteriosus) transposition of the great vessels with a large ventricular septal defect infancy venous (especially in an age of 6-8 weeks) abnormalities in pulmonary reflux (ohn e obstruction) Broncho-pulmonary dysplasia (failure of the right ventricle) Complete defect in the atrioventricular canal Patent ductus arteriosus Persistent Truncus arteriosus Rare metabolic diseases (eg. As glycogen storage disease) Single ventricle supraventricular tachycardia ventricular Childhood Acute pulmonary heart disease (caused by obstruction of the upper airways such. As large tonsils) Acute rheumatic fever with carditis Acute severe hypertension (Bacterial acute glomerulonephritis) endocarditis Chronic (severe) anemia dilated congestive cardiomyopathy iron overload due to changed iron metabolism (juvenile hemochromatosis) or by frequent transfusions (z. B. for thalassemia major) malnutrition heart valve disease due to a congenital or acquired heart disease such. As rheumatic fever viral myocarditis volume overload with cardiac disease symptoms and complaints The manifestations of coronary heart disease vary, but often include heart murmurs cyanosis heart failure Other anomalies in the physical examination may include circulatory shock, poor circulation, abnormal second heart sound (S2 individually or split), systolic click, gallop or irregular rhythm include. Murmurs Most left-right shunts and stenoses cause a systolic murmur. Systolic noise and buzz are best heard at the points on the body surface that are the source of the noise at the next and can help in the diagnosis. The increased blood flow along the pulmonary or aortic valve causes a mittsystolisches crescendo Decrescendo- (Ejektions-) noise. Regurgitantflüsse to the AV valves or flow of blood through a VSD lead to a pansystolischen noise which can often complicate the differentiation of the heart sounds with increasing intensity. Patent ductus arteriosus causes a continuous noise that is not interrupted by S2, since the blood flow during systole and diastole through the ductus. This noise is 2-voice with another sound during systole (the higher pressure) than during the Diastole.Zyanose The central cyanosis is characterized by a bluish discoloration of the lips and tongue and / or the nail beds; it implies a low O2 levels (usually O2 saturation <90%). Perioral cyanosis and acrocyanosis (cyanosis of the hands and feet) without cyanosis of the lips or nail beds is caused by peripheral vasoconstriction instead of hypoxemia and is a common, normal finding in newborns. Older children with long-standing cyanosis often develop Verknüppelung the Nagelbetten.Herzinsuffizienz In infants are symptoms or signs of heart failure tachycardia tachypnea dyspnea with feeding diaphoresis, especially with feeding restlessness, irritability hepatomegaly The respiratory distress during feeding leads to insufficient food intake to reduced growth and to pulmonary infections. It can be worsened by increasing metabolic requirements. In contrast to adults and older children, most infants have no edema in the depending lots and jammed neck veins, although they sometimes have periorbital edema. The clinical findings of heart failure in older children are the same as in adults (congestive heart failure: symptoms and complaints). .Other manifestations A heart and circulatory failure may in newborns the first sign of heart failure be (eg hypoplasia of the left ventricle, severe aortic stenosis, interrupted aortic arch, Aortenverengung). Newborns appear seriously ill, have cold extremities, decreased pulse, low blood pressure and hardly react to stimuli. Chest pain in children are non-cardiac generally. In infants to chest pain by untreated ausprägte irritability can manifest, especially during or after feeding, and they can be caused from the pulmonary artery by an anomalous origin of the left coronary artery. In older children and adolescents chest pain due to a cardiac etiology usually associated with exertion and can be caused by a coronary anomaly, myocardial or severe aortic stenosis. Syncope, usually without warning and often in conjunction with effort, can occur with certain abnormalities, including cardiomyopathy, anomalous origin of a coronary artery or inherited arrhythmia syndromes (z. B. QT syndrome, Brugada syndrome). Athletes in school age are most commonly affected. Diagnostic screening by pulse oximetry ECG and chest X-ray echocardiography Sometimes cardiac MRI or CT angiography, cardiac catheterization with Angiokardiographie When present, interpret heart sounds, cyanosis, abnormal pulses or manifestations of HF attention to CHD. In such a neonatal echocardiography is performed to confirm the diagnosis of CHD. If the only anomaly is cyanosis, methemoglobinemia and should be excluded. However, the manifestations of coronary heart disease can be subtle or absent in newborns and failure or delays in the detection of coronary artery disease, particularly in the 10 to 15% of newborns who require surgery or inpatient medical treatment during the first month (as of critical congenital heart defects [CCHD ] called), can lead to neonatal mortality or significant morbidity. To follow all the asymptomatic newborns be screened with pulse oximetry on CCHD before they are discharged from hospital. The screening is performed when the infants ? 24 hours old, and is considered positive if ? 1 of the following signs is present: Any O2 saturation measurement is <90%. O2 saturation measurements in both the right hand and right foot are <95% in 3 separate measurements taken at 1 h. There are> 3% absolute difference between the O2 saturation in the right hand (präduktal) and foot (postduktal) in 3 separate measurements taken at 1 h. All newborns with a positive screening should have a comprehensive assessment of CHD and other causes of hypoxemia have (z. B. various respiratory diseases, CNS depression, sepsis), which is usually a chest x-ray, ECG, echocardiography and often blood tests include. The sensitivity of pulse oximetry screening is easy to> 75%; CHD lesions that are most often overlooked, are obstructive left heart lesions (z. B. coarctation). A cardiac MRI or CT angiography cleared it important anatomical details. A cardiac catheterization and angiography may need to be performed to determine the extent of the defect. These investigations shall be carried out more frequently for therapeutic reasons. Treatment Drug stabilization of heart failure (eg. As with O2, diuretics, ACE inhibitors, digoxin and salt reduction) Surgical correction or transcatheter intervention After medical stabilization of the acute symptoms of heart failure or cyanosis, most children need a surgery or interventional procedures. Exceptions are certain ventricular septal defects (VSD), which are likely to be smaller with time or disappear, or a light valve dysfunction. Among the transcatheter procedure atrial Ballonseptostomie include (Rashkind method) for the alleviation of difficult cyanotic neonates with transposition of the great arteries, balloon dilation of severe aortic or pulmonary valve stenosis and interventional closure of cardiac shunts – usually atrial septal defect and patent ductus arteriosus ( ductus arteriosus). Heart failure in newborns Acute severe heart failure or cyanosis in the first week of life is a medical emergency. A safe vascular access should be established, preferably via a umbilical catheter. If a critical coronary artery disease is suspected or confirmed, an intravenous infusion of prostaglandin E1, with an initial dose of 0.01 mcg / kg / min should be started. Some infants require higher doses, such as about 0.05 to 0.1 mcg / kg / min to restore the patency of the ductus arteriosus or receive. to keep the ductus open is important because most heart defects associated at this age with the duct, either in terms of the systemic blood flow (eg. as hypoplastic left heart syndrome, critical aortic stenosis, coarctation) or pulmonary blood flow (cyanotic lesions such as pulmonary atresia or severe tetralogy of Fallot). Critically ill babies often require mechanical ventilation. Additional O2 should be carefully added or even denied because O2 can reduce pulmonary vascular resistance, which for infants with certain deficits (z. B. hypoplastic left heart syndrome) is harmful. Other treatments for neonatal heart failure include diuretics, inotropic drugs and medications to reduce the afterload. Diuretic furosemide is as an initial dose of 1 mg / kg i.v. added and titrated by evaluation of the urinary excretion. Infusions of dopamine or dobutamine inotropem can support the blood pressure, but have to increase the heart rate and afterload the disadvantage, whereby the myocardial O2 consumption is increased. Milrinone, which is often used in postoperative patients with coronary heart disease, is both a positive inotrope and a vasodilator. Dopamine, dobutamine and milrinone all have the potential to increase the risk of cardiac arrhythmias. Nitroprusside, a pure vasodilator, is often used for postoperative hypertension. Its administration can be started at a dose of 0.3-0.5 ug / kg / min and titrated to achieve the desired effect. The usual maintenance dose is about 3 ug / kg / min.Herzinsuffizienz in older infants and children often therapies include the administration of a diuretic (e.g., furosemide example 0.5-1.0 mg / kg iv or 1-3 mg / kg po all of 8-24 h, depending on the need for top) and an ACE inhibitor titrated (eg., captopril 0.1-0.3 mg / kg po tid). A potassium diuretic (z. B. spironolactone 1 mg / kg po once or 2 times daily, as needed titrated up to 2 mg / kg / dose) can be especially useful when a high dose of furosemide is required , ?-blockers (eg. B. carvedilol, metoprolol) are often added in children with chronic congestive heart failure. Digoxin is used less frequently than in the past, but can still play a role in some infants with heart defects, the big left-right shunts have varied the dose in postoperative patients with coronary heart disease and some infants (with supraventricular tachycardia with age, see table: Oral digoxin dosage in children *). Oral digoxin dosage in children * Age digitized overall dose † (ug / kg) maintenance dose ‡ (mcg / kg 2 times a day) preterm newborns 20 2.5 Maturity 30 5 1 month – 2 years 30-50 5-6 2- 5 years 30-40 4-5 6-10 20-35 years 2.5-4> 10 Jahre§ 10-15 1.25-2.5 * All doses are based on the ideal body weight for children with normal renal function. I.v. Dose is 75% of the oral dose. † The digitaliserte dose is usually necessary only in the treatment of cardiac arrhythmia or acute heart failure. The entire digitization dose is usually given over 24 hours at half the initial dose, followed by 2-times 1/4 of the dose at intervals of 8-12 h; ECG monitoring is required. ‡ The maintenance dose is 25% of the digitization dose, administered in two separate doses. § Do not exceed the digitization / preservation adult dose of 1-1.5 mg / 0.125 to 0.250 mg / day. However, one such dose a day is acceptable after the age of 10 years. Additional O2 can reduce hypoxemia and relieve shortness of breath; If possible, fractionally inspired O2 (FiO2) should be maintained at <40%, to minimize the risk of Lungenepithelzellenschaden. In general, a healthy diet, including dietary salt restriction, recommended, although dietary modifications depending on the specific disease and the specific manifestations may be required. A heart failure increases the metabolic requirements and shortness of breath associated makes feeding difficult. In infants with CCHD, especially those with obstructive left heart lesions, feedings may be withheld in order to minimize the risk of necrotizing enterocolitis. In infants with heart failure due to a left-right shunt lesion increased caloric content of food is recommended; characterized the intake of calories without an increased risk of volume overload is improved. To ensure a sufficient size growth, some children require nutrition through a tube. If these measures to gain weight are insufficient surgical therapy must be initiated werden.Endokarditis prophylaxis The current American Heart Association for the prevention of endocarditis guidelines: include that antibiotic prophylaxis in children is required with congenital heart disease (Infectious endocarditis prevention) if the following is given: a non-operated cyanotic congenital heart disease (including palliative shunts and conduits) a completely abolished congenital heart disease during the first 6 months after the operation, when a prosthetic material or a prosthesis has been used a treated congenital heart disease with residual defects at or near the operated site with prosthetic patch or prosthetic

Health Life Media Team

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