Cardiac Conditions and Assessment Quiz

Pediatric Cardiology

• Pediatric cardiology focuses on the heart and circulatory system in children.

Fetal Circulation

• In fetal circulation, pressure is higher on the right side because pulmonary circulation resistance is higher (lungs are collapsed).
• After birth, this reverses, and the left side has higher pressure (lungs are open).
• Key structures involved in fetal circulation include the foramen ovale, ductus arteriosus, and ductus venosus.

Neonates & Infants

• Heart and great vessels develop in the first 3-8 weeks of gestation.
• Neonates and infants have higher-pitched heart sounds of greater intensity than adults.
• They rely on adequate heart rate and rhythm to maintain cardiac output because they cannot increase stroke volume easily.
• Myocardial muscle in neonates and infants is less efficient and has fewer organized myocardial fibers.
• Consequently, they depend greatly on calcium, glucose, and blood volume for adequate cardiac output.

Conduction System

• Surgeries can affect AV nodes and lead to heart blocks or arrhythmias.
• Most surgical procedures target the AV node.
• The Sinoatrial node (pacemaker) initiates the heartbeat.
• The system includes the atrioventricular node, bundle of His, right and left bundle branches, and Purkinje fibers.

Physiology

• Cardiac output is the volume of blood expelled by the heart in one minute.
• Preload is the volume of blood returning to the heart.
• Afterload is the resistance against which the ventricles pump when ejecting blood.
• Contractility is the ability of the cardiac muscle to function as an efficient pump.

Adequate Systemic Profusion

• Appropriate heart rate is essential.
• Adequate blood volume is crucial.
• Low pulmonary vascular resistance is important.
• Capillary permeability and tissue utilization of oxygen (O2) are vital.

Assessment of Cardiac Function

• History: Important aspects to consider include the mother's health (diabetes, lupus, PKU), pregnancy (assisted reproduction), and birth history (Apgar score, birth weight, complications, full-term). Family history of congenital heart disease increases risk.
• Infections (rubella, Coxsackie) and exposure to certain medications during pregnancy can increase the risk of congenital heart defects.
• Birth and family history are important details to note for assessing risk factors.

Health History of Infant

• Feeding patterns, weight gain, and development are evaluated.
• Respiratory infections and breathing problems are considered.
• Color changes, exercise intolerance (in older children), edema, chest pain, palpations, and neurological problems are assessed.
• Recent infections and exposures to toxins are also documented.
• Other health issues and medications are noted.

Physical Exam

• Vital signs, including blood pressure in all four extremities and oxygen saturation, are essential.
• General inspection of skin color, comfort level, and nutritional status are assessed.
• Heart sounds, including point of maximum intensity, apical impulse, and presence of thrill, are evaluated.

Physical Assessment Continued

• The quality and symmetry of pulses, the warmth of extremities, and capillary refill time are checked.
• Edema, and enlarged liver and/or spleen are examined.
• Auscultation of heart and lung sounds (quality, intensity, rhythm, and additional sounds) is performed.

Heart Murmurs

• Murmurs are swishing sounds detected in addition to normal heart sounds.
• Key details: location (where best heard), time (during S1 or S2 cycle), intensity (relation to child's position), and loudness are recorded.

Grading of Murmurs

• Murmur grades range from I (very faint) to VI (loud, audible without stethoscope contact).

Hemodynamics

• Blood flow originates from higher pressure areas, seeking paths of lowest resistance.
• Right-sided pressure is generally less than left-sided pressure.
• Pulmonary artery resistance is typically lower than systemic circulation resistance.
• Pulmonary artery pressure is lower than aortic pressure

Saturations

• Blood returning from the body (SVC and IVC) has lower oxygen saturation.
• Blood returning from the lungs has high oxygen saturation.
• The aorta distributes oxygenated blood to the body's organs.

Hemodynamic Classifications

• Increased pulmonary blood flow
• Decreased pulmonary blood flow
• Obstruction to blood flow out of the heart
• Mixed blood flow

Classification of Congenital Heart Disease

• Acyanotic defects (increased pulmonary blood flow)
• Cyanotic defects (decreased pulmonary blood flow, mixed blood flow, obstruction of blood flow).
• Specific defects: atrial septal defect (ASD), ventricular septal defect (VSD), patent ductus arteriosus (PDA), coarctation of the aorta, aortic stenosis, pulmonic stenosis, tetralogy of Fallot, AV canal defect, tricuspid atresia, transposition of the great arteries, total anomalous pulmonary venous connection, truncus arteriosus, hypoplastic left heart syndrome

Incidence

• Congenital heart defects (CHD) occur in approximately 5 – 8 per 1000 births.
• CHD is a significant cause of death in the first year of life.

Defects with Increased Pulmonary Blood Flow

• Atrial Septal Defect (ASD).
• Ventricular Septal Defect (VSD),
• Patent Ductus Arteriosus (PDA),
• Atrioventricular Canal Defect (AV canal).

Ventricular Septal Defect (VSD)

• Opening between right and left ventricles.
• Defects can be membranous or muscular.
• Often associated with additional defects.
• Many spontaneously close within the first year of life.

AV Canal

• Incomplete closure of endocardial cushions.
• Often accompanies a high VSD.
• Defects in mitral and tricuspid valves.
• Blood flow between all four chambers of the heart.

Patent Ductus Arteriosus (PDA)

• Failure of the ductus arteriosus to close after birth.
• Results in increased pulmonary blood flow.
• Right ventricular hypertrophy can develop.
• Symptoms: signs of heart failure (CHF), murmur.
• Treatment, medical and/or surgical.

Obstructive Defects

• Coarctation of the Aorta.
• Aortic stenosis.
• Pulmonic stenosis.

Aortic Stenosis

• Narrowing or stricture of the aortic valve.
• Results in decreased cardiac output and left ventricular hypertrophy.
• Increased pulmonary vascular congestion.
• Three main types are valvular stenosis, subvalvular stenosis, and supravalvular stenosis.

Pulmonic Stenosis

• Narrowing of entrance to pulmonary artery.
• Results in right ventricular hypertrophy and decreased pulmonary blood flow.
• Symptoms: may be asymptomatic, possible cyanosis or CHF (if severe), murmur in newborns, etc

Defects with Decreased Pulmonary Blood Flow

• Tetralogy of Fallot (TOF).
• Tricuspid atresia.

Tricuspid Atresia

• No communication between the right atrium and right ventricle.
• ASD or patent foramen ovale (PFO) are typically present.
• Complete mixing of oxygenated and deoxygenated blood.
• Patent ductus arteriosus (PDA) facilitates blood flow for oxygenation.
• VSD allows oxygenated blood to pass to the right ventricle.
• Decreased pulmonary blood flow results

Transposition of the Great Arteries (TGV)

• The pulmonary artery and aorta swap positions.
• Systemic circulation defects need to be present to allow for oxygenated blood mixing.
• Characterized by cyanosis and cardiomegaly.
• Treatment is usually an arterial switch operation to re-implant the coronary arteries.

Hypoplastic Left Heart Syndrome (HLHS)

• Underdevelopment of the left side of the heart,
• Aortic atresia.
• Requires a PFO or ASD, and systemic circulation from a PDA.
• Mild cyanosis with CHF.
• Progressive deterioration after PDA closure.
• Treatment includes Norwood procedure, bidirectional Glenn, and modified Fontan operations.

Truncus Arteriosus

• Main artery that fails to bifurcate.

Total Anomalous Pulmonary Venous Connection (TAPVC)

• Pulmonary veins emptying into the wrong circulatory system (usually the right atrium).

Congestive Heart Failure (CHF)

• Volume overload (left-to-right shunts)
• Pressure overload (obstructive defects)
• Poor contractility (cardiomyopathy)
• High cardiac output demands

Types of CHF

• Right-sided: edema, hepatomegaly
• Left-sided: respiratory distress, congestion

Clinical Manifestations

• Symptoms include tachycardia, diaphoresis, easily fatigued, tachypnea, dyspnea, mild cyanosis, retractions, grunting, wheezing, cough, poor profusion, hepatomegaly, edema, weight gain, developmental delays, and variations due to myocardiac contraction, afterload, and preload in the heart to compensate for function.

Management

• Digoxin: Increases cardiac output, reduces heart size, lowers venous pressure, and relieves edema.
• Ace inhibitors (Captopril, Enalapril): May improve heart function and reduce pressure.
• Diuretics (lasix, aldactone): Remove excess fluid and sodium.
• Nutritional support for BMR increase, caloric intake, and well-rested feeding.

Other important concepts

• Central cyanosis
• Clubbing
• Hypercyanotic spells ("tet" spells)
• Knee-chest position

Web Sites

• Websites providing information about pediatric cardiac defects.

Online Resources for Pediatric Cardiac Auscultation

• Links to websites with sounds and information for auscultation.