Congenital Heart Disease

Congenital heart disease (CHD) in Pediatric Patients

Congenital heart disease (CHD) denotes one or more structural abnormalities that develop before birth, although the clinical symptoms may not be present in the newborn period.

Classifications

CHD classifications are subdivided into groups that are defined by blood flow patterns. Cardiovascular alterations in children are either 1.) Congenital Many congenital lesions cause shunting of the blood. This causes oxygenation alterations and blood flow disturbances. 2.) Acquired  

Physiological Consequences

There are two primary physiologic consequences of CHD in children: 1.) Heart failure 2.) Cyanosis.  

Shunting - A Condition

Shunting - A condition in which blood, by going through an abnormal pathway or bypass, does not travel its normal route. A shunt occurs when: There is an abnormal opening or connection between the cardiac chambers or great arteries There is a pressure change The oxygen saturation is increased or decreased in the normally desaturated or fully saturated blood

Left-To-Right Shunting

Volume overload in the right side of the heart increases pulmonary blood flow. One of the major consequences of left-to-right shunting lesions is heart failure (HF) [atrial septal defect (ASD), ventricular septal defect (VSD), patent ductus arteriosus (PDA), and atrioventricular septal defects (AVSD, also known as endocardial cushion defect).] Symptoms “Tet spells” that include episodes of increased cyanosis with crying, deep respirations, and other abnormal breathing patterns, and increased pulmonary venous return. These symptoms require surgery! One finding that parent’s often note in an undetected left to right shunt is that their infant develops cyanosis when feeding.

Down Syndrome Patient

Down syndrome might have a marked increase in pulmonary blood flow. AVSD (atrioventricular septal defect) is often associated with genetic syndromes such as Down syndrome. In AVSD there is abnormal development of both septa and AV valves. 

Cyanotic Lesions

Cyanotic lesions result in hypoplasia, malalignment, or obstruction on the right side of the heart, resulting in decreased blood volume to the lungs. 

Cyanosis

ADULTS - Cyanosis becomes visible when the measured oxygen saturation drops below 85%.   In anemic infants or children with polycythemia (high red blood cell production) , desaturation will be higher before cyanosis is apparent. 

IV Lines

If air is introduced to an IV line, the venous blood obtaining this air can enter the arterial system and send an air embolus to the brain causing a cerebrovascular accident. This child will require immediate attention since changes in neurologic status can be evidence of a stroke.  

Pulmonary Stenosis

Stenosis -  the narrowing or constriction of an opening. Pulmonary artery stenosis causes an increase in right ventricular pressure, which increases cardiac workload. If the foramen oval remains in a patient with pulmonary stenosis decreased oxygenation of blood will enter the systemic circulation  

Stenotic Lesion

Proximal [Toward the middle] to the lesion, pressure will be high Distal [Away from the middle] to the lesion, pressure will be decreased or absent.

Aortic Stenosis

A child with aortic stenosis may experience symptoms of myocardial infarction (MI)

Patent Ductus Arteriosus (PDA)

What it is A congenital disorder (Type of heart failure) related to PREMATURE infants The ductus arteriosus fails to close after birth.   Issues Creates a left-to-right shunt [Increased workload on the left side of the heart/ Volume overload on the right side]   Signs & Symptoms The blood that flows through this duct has a "machine like quality murmur" heard in 2nd and 3rd intercostal spaces Bounding pulses Cardiac enlargement Cyanosis Finger clubbing   Treatment Medications such as Indomethacin and Ibuprofen to close PDA. Cardiac catheterization

Atrial Septal Defect (ASD)

What it is Abnormal OPENING between the atria Congenital Defect   Issues Creates a left-to-right shunt   Signs & Symptoms More often seen In girls. Murmurs Arrhythmias   Treatment Mitral Valve Replacement Surgery Placement of occluder devices, sutures, or prosthetic patch Small defects can close on their own. encourage range of motion

Ventricular Septal Defect (VSD)

What it is Abnormal opening between the left and right ventricles   Issues Creates a left-to-right shunt   Signs & Symptoms Congestive Heart Failure Signs Increased pulmonary blood flow and increased pulmonary resistance.   Treatment 30-40% of cases close by themselves Medications to increase heart’s contractions such as digoxin Insertion of an occluder device or suture/patch closure

Atrioventricular Septal Defect (ADS)

What it is Abnormal development of the heart affecting both septa and AV valves.   Issues Effects children with Down syndrome Creates left to right shunting Rarely closes on its own   Signs & Symptoms Can be diagnosed in utero with echocardiogram Failure to Thrive / Weight Loss intermittent cyanosis Murmur Decreased energy  

Obstructive Lesions

Stenosis occurs - Constricting or obstructing an opening. Types include: 1.) Pulmonary Stenosis    2.) Aortic Stenosis     3.) Coarctation of the Aorta      

Pulmonary Artery Stenosis

Causes Narrow entrance to the pulmonary artery prevent the closure of the foramen ovale Pulmonary stenosis affects females slightly more than males.   Symptoms Newborns with critical pulmonary stenosis therefore will have cyanosis (blue discoloration of the lips and nail beds) due to lower oxygen levels in their blood.  Regurgitation Peripheral edema Cyanosis intensifies with crying in children with this defect. It is not alleviated by the administration of 100% oxygen. Right-sided Heart Failure Exercise intolerance and fatigue Heart murmur   Labs/Testing The echocardiogram is the most important non-invasive test to detect and evaluate pulmonary valve stenosis.  Cardiac catheterization is an invasive technique that enables physicians to accurately measure the degree of pulmonary stenosis that is present.    Treatment Low sodium diet if heart failure is present Diuretics, such as furosemide, to address heart failure Angiotensin-converting enzyme (ACE) inhibitors For these conditions surgical pulmonary valvotomy (opening of the valve), partial valvectomy (removal of a portion of the leaflet), and possibly a transannular patch (patch from the right ventricle to pulmonary artery) may be required during the open-heart surgery repair. Oxygen Cardiac observation and antibiotic prophylaxis for children who are asymptomatic Interventional catheterization or surgical management for severe stenosis; PGE1 infusion keeps ductus arteriosus open Valvuloplasty with dilation of valve to decrease pressure

Aortic Stenosis

Causes Narrow entrance to aorta Blood flow impaired through aortic valve   Symptoms ECG abnormalities with exercise Cardiomegaly Systolic ejection murmur with thrill or click Sudden death with strenuous exercise is possibility Severe heart failure Treatment Regular follow-up, especially for athletes Interventional aortic valvuloplasty decreases stenosis and improves CO Surgical aortic valve replacement for recurrent stenosis

Coarctation of Aorta

Causes Aorta is constricted/narrowed  near ductus arteriosus insertion   Symptoms Left-sided HF with low CO Hypertension Poor lower extremity peripheral perfusion = decreased blood pressure/pulses Metabolic acidosis, shock If PDA present, right-to-left shunting with differential cyanosis (color and oxygenation differential between upper and lower extremities) Asymptomatic children may show pulse and BP differences between upper and lower extremities weakness, tingling, cramps in lower extremities Systolic murmur with ejection or thrill Infants can have kidney malfunction   Treatment Diuretics and digoxin to improve CO PGE1 infusion to open ductus arteriosus and improve perfusion to lower body Balloon dilation with placement of stent for recurrences. Surgery performed shortly after diagnosis