The Child with a Cardiovascular Disorder

Cardiovascular Disorders in Children

• Cardiovascular System Differences: The infant's cardiovascular system differs anatomically and physiologically from an adult's. Pulse, respiration, blood pressure, and hematological values vary until the child ages. Chest walls are thinner due to less subcutaneous tissue. Newborn circulation differs from fetal, and capillary function is immature. Heart rate is higher, and stroke volume response to decreased cardiac output is limited. Heart abnormalities are often due to embryonic defects.

• Signs of Cardiac Pathology: Failure to thrive, cyanosis/pallor, neck vein pulsations, tachypnea/dyspnea, irregular pulse, clubbing of fingers, fatigue during feeding/activity, excessive perspiration are common signs of congenital heart problems. Bradycardia can indicate impending arrest due to hypoxia.

• Congenital Heart Defects (CHD): CHD occurs in approximately 8 out of 1000 births and is often apparent before the first year. Some, like mitral valve prolapse, may manifest later. They can be caused by genetic, maternal (e.g., drug intake, rubella), or environmental factors. Fetal echocardiography can detect CHD in high-risk pregnancies. CHD are categorized as cyanotic or acyanotic based on the presence of cyanosis; more accurately, based on effects on blood circulation (increasing/restricting/decreasing pulmonary flow, and mixed oxygenated and non-oxygenated blood).

CHD Classifications & Descriptions

• Atrial Septal Defect (ASD): An abnormal opening between the right and left atria. Blood flows from the left to the right atrium, often without symptoms; recognized by a murmur. Diagnosed by cardiac catheterization, ECG, and echocardiography. Sometimes closes spontaneously. Repair is done with a Dacron patch. Low-dose aspirin therapy is common post-repair.

• Ventricular Septal Defect (VSD): Most common CHD, involving an opening between the right and left ventricles. Increased pressure in the left ventricle forces blood to the right ventricle. Characterized by a loud, harsh murmur. Often closes spontaneously during the first year; minor defects might be corrected later. Surgery uses hypothermia and cardio-pulmonary bypass during open heart surgery to close the hole with sutures or a synthetic patch.

• Patent Ductus Arteriosus (PDA): Failure of the ductus arteriosus to close after birth. Blood flows from the aorta (higher pressure) to the pulmonary artery, increasing pulmonary flow potentially leading to dyspnea, wide pulse pressure, and a machinery-type murmur. More frequent in girls. Treatment varies by severity. Indomethacin/Ibuprofen can cause closure for premature infants. Coils can be inserted via cardiac catheterization. Surgery is possible.

• Coarctation of the Aorta: Narrowing of the aorta, causing increased pressure proximal to the defect and reduced pressure distally. Characterized by different blood pressures and pulses in upper and lower extremities. X-rays may show rib notching. Treatment may include surgery (anastomosis) or percutaneous balloon angioplasty with stent insertion in older children.

• Tetralogy of Fallot: Four heart defects: pulmonary artery stenosis, right ventricular hypertrophy, dextroposition of the aorta, and VSD. Causes unoxygenated blood to flow into the general circulation, leading to cyanosis. Characteristic is a squatting position for easier breathing. Tet spells (hypercyanotic episodes) are possible. Diagnosis is aided by chest X-ray (boot-shaped heart), ECG, 3D echocardiography, cardiac catheterization. Treatment includes temporary shunts or complete open heart surgery.

• Hypoplastic Left Heart Syndrome: Underdevelopment of the left side of the heart, often requiring a three-stage surgical procedure or a transplant.

Acquired Heart Disease

• Congestive Heart Failure (CHF): Occurs due to inadequate cardiac output. Manifestations differ based on the affected side of the heart (right or left) with systemic symptoms like cyanosis, pallor, tachypnea, tachycardia, feeding difficulties, weight gain, edema, and frequent respiratory infections. Care emphasizes reducing heart workload, improving respiration, maintaining nutrition, preventing infection, reducing anxiety, and supporting parents.

• Treatment and Nursing Care: Medications like digitalis (e.g., digoxin) or ACE inhibitors are administered to manage CHF. Diuretics (e.g., furosemide) help reduce edema. Fluid and nutrition management, along with careful monitoring of vital signs, are necessary to prevent complications.

Rheumatic Fever (RF)

• Pathophysiology: An autoimmune disease due to untreated group A beta-hemolytic streptococcal infection of the throat. It affects joints, heart, CNS, skin, etc., causing connective tissue damage, particularly affecting the heart valves causing, mitral valve scarring.

• Manifestations: Symptoms can vary from mild to severe, appearing 1-6 weeks after a strep infection. Classic signs include migratory polyarthritis, skin lesions (erythema marginatum), chorea, and carditis. Other signs include abdominal pain, fever, pallor, fatigue, and unexplained nosebleeds. Elevated ASO titer supports diagnosis.

• Treatment and Prevention: Antibiotic therapy (e.g., penicillin or erythromycin) is a first step to eliminate strep infection and long-term antibiotic prophylaxis to prevent recurrence. Rest, pain relief, and management of cardiac failure (if present) are also crucial. Prompt and adequate treatment of strep throat is vital for prevention.

Systemic Hypertension

• Pathophysiology: High blood pressure in children, often linked to increased cardiac output or peripheral resistance. Diagnosis requires confirmed blood pressure readings across multiple occasions.

• Normal vs. Elevated: Normal blood pressure is below the 90th percentile for age, height, and sex; elevated blood pressure falls between 90th and 95th percentile.

Explore the anatomical and physiological differences in the cardiovascular system of infants compared to adults. Learn about the signs of cardiac pathology and the prevalence of congenital heart defects (CHD) in children. This quiz will enhance your understanding of how these conditions manifest in early development.