Ch 33 Heart Failure in children

Heart Failure (HF)

• Sometimes referred to as Congestive Heart Failure (CHF)
• Heart can't pump enough blood to meet the body's metabolic demands
• Cardiomyopathy or poor ventricular functioning are common causes in infancy and childhood
• Overcirculation is a predominant cause with congenital defects

Causes

• HF in infants is shown through:

• Poor feeding and sucking

• Failure To Thrive (FTT)

• Dyspnea

• Tachypnea

• Diaphoresis

• Retractions, grunting, nasal flaring, wheezing, coughing, rales

• Skin changes (pallor or mottling)

• Hepatomegaly

• Peripheral edema and weight gain aren't usually found in infants like adults

• Myocardial hypertrophy results from compensatory measures

• Infants' symptoms can include failure to thrive (FTT), tachypnea, tachycardia, and respiratory tract infections

Evaluation & Treatment

• Evaluation: ECG, growth plotting, and chest x-ray
• Treatment Goal: Lessen cardiac workload and improve heart functioning
• First-line treatment: Diuretics
• Measures can include ACE inhibitors and beta blockers
• Important to supplement caloric intake, if needed

Patent Ductus Arteriosus (PDA)

• Blood vessel connecting the main and left pulmonary arteries and descending aorta
• Usually closes after birth at 15 hours to 2 weeks
• Occurs in 5-10% of all congenital cardiac defects
• Incomplete closure lets blood shunt left to right, from aorta to the PA

Causes

• Increased pulmonary blood flow increases pulmonary venous return to the left atrium and left ventricle, increasing the heart's workload

Clinical Manifestations

• Continuous machinery-type murmur best heard at the left upper sternal border during systole and diastole
• Significant PDA can lead to bounding pulses, active precordium, possible thrill upon palpation, and other signs of pulmonary congestion

Atrial Septal Defect (ASD)

• Opening between atria
• Shunting of blood from left to right causes enlargement of the right atria and ventricle
• Occurs in 5-10% of all congenital cardiac defects, and is the 4th most common
• Children are usually asymptomatic

Types

• Ostium primum defect: Opening found low in the septum
• Ostium secundum: Opening in center of the septum that is the most common
• Sinus venosus defect: Higher in the atrial septum near the superior vena cava, associated with partial anomalous pulmonary venous connection

Clinical Manifestations

• Auscultation reveals a crescendo-decrescendo systolic ejection through the pulmonary valve
• Murmur between the second and third intercostal spaces along the left sternal border
• A wide fixed splitting of the second heart sound is also common in ASD
• Can moderately cause pulmonary hypertension

Ventricular Septal Defect (VSD)

• Open abnormal opening between the ventricles
• Most common type of congenital heart lesion, counts for 25-33% of all congenital heart defects

Types

• Perimembrenous type: LV below aortic valve which is the most common
• Muscular VSD: Low or anterior ventricular septum; most likely to close spontaneously
• Supracristal VSD: Below pulmonary valve
• AV canal or inlet VSD: Posterior or inferior to the membranous system below septal cusp

Pathophysiology

• Newborns with small VSDs are asymptomatic
• Shunting is from the high-pressure left side to the lower-pressure right side
• After 1-2 weeks, when pulmonary vascular resistance has decreased, moderate to large VSDs allow a large amount of shunting from left to right
• Eisenmenger syndrome: Deoxygenated blood now flows into systemic circulation and cyanosis occurs

Clinical Manifestations

• Initially there is no murmur due to high pulmonary vascular resistance
• Once pulmonary vascular resistance has dropped, left-to-right shunting occurs, creating a murmur
• Larger VSDs have CHF symptoms and poor weight gain
• Auscultation of the left lower sternal border reveals a loud, harsh, holosystolic murmur and systolic thrill
• An apical diastolic rumble may be present
• Many VSDs spontaneously close during the first year of life

Atrioventricular Canal Defect (AVC)

• Results from nonfusion of endocardial cushions during fetal life, yielding abnormalities in the atrial and ventricular septa, and the AV valves
• Occurs in 30% of children with Down's syndrome

Types

• Complete AVC (CAVC) defects: consist of an inlet VSD, a primum type of ASD, and defects in both mitral and tricuspid valves

• Partial AVC (PAVC) defects: consist of a primum type of ASD and a cleft in the septal or anterior leaflet of the mitral valve

• Transitional AVC (TAVC) defects: involve partial fusion of the endocardial cushions.

• Shunting is minimal at first, eventually leading to CHF; children with PAVC are usually asymptomatic

• Heart auscultation is similar to those with secundum ASD, with a holosystolic, regurgitant murmur of mitral regurgitation at the apex Children at 4 to 12 weeks of age with CAVC start to show signs of CHF

• Auscultation is similar to those with VSD with a holosystolic murmur radiating to the back and apex

Pathophysiology

• Shunting is minimal during the neonatal period due to high pulmonary vascular resistance
• Once pulmonary vascular resistance drops, a left to right shunting occurs through septal defects, resulting in increased pulmonary blood flow and HF

Clinical Manifestations

• Are similar to ASD with the addition of a holosystolic, regurgitant murmur
• At 4-12 weeks pulmonary vascular resistance drops and symptoms start to show
• Holosystolic murmur radiating to the back and apex, showing mitral regurgitation
• mid-diastolic rumble at the left lower sternal border or apex reflects stenosis of the mitral and tricuspid valve from increased flow
• Infants with CAVC may have signs of HF and respiratory tract infections

Tetralogy of Fallot (TOF)

• A cyanotic congenital heart defect
• Accounts for 5-10% of all defects

It includes the four defects

• A large VSD high in the septum
• Pulmonary stenosis (PD)
• RV (right ventricle) hypertrophy
• Overriding aorta that straddles the VSD
• Ventricular septal defect

Pathophysiology

• Pulmonary stenosis causes low oxygen saturation (hypoxemia)
• Body attempts to compensate from chronic hypoxemia by producing more red blood cells (polycythemia) and by increasing blood flow to lungs through collateral bronchial vessels

Clinical Manifestations

• Occurs when the ductus closes from chronic hypoxemia
• Includes clubbing of toes and fingers
• A rare symptom of TOF that is known as hypercyanotic or tet spell
• Sudden dyspnea, cyanosis, and restlessness with crying and exertion - if these spells occur often or do not stop spontaneously, they are considered a medical-surgical emergency
• Difficulty feeding and slow growth, failure to thrive
• Squatting is a spontaneous compensatory mechanism used by older children with unrepaired Tetralogy of Fallot to alleviate hypoxic spells
• Pulmonary systolic ejection murmur caused by obstruction in outflow tract, which creates turbulence during systole
• Murmurs can disappear during a hypoxic spell
• Enlarged RV may cause left side of chest to be more prominent
• Repair before one year of age

Tricuspid Atresia

• Lacking a normal opening tricuspid valve, resulting in no communication between the RA and RV
• Third most common cyanotic heart defect

Pathophysiology

• Imperforate tricuspid valve
• Septal defect
• Hypoplastic or absent RV
• Enlarged mitral valve and LV, pulmonic stenosis
• Venous blood flow returns through ASD into the left atria, mixing with blood returning from the pulmonary circulation
• PDA is necessary to ensure that some blood flows into the pulmonary circulation

Clinical Manifestations

• Some degree of central cyanosis, and growth failure, exertional dyspnea, tachypnea, and hypoxemia
• Hypercyanotic spells, polycythemia, clubbing
• Murmur noted includes several components – results in a systolic regurgitant murmur, which grows softer and shorter as the VSD enlarges
• Narrowly split-second heart sound from decreased pulmonary blood flow
• Second heart sound may be single if pulmonary atresia is present

Coarctation of the Aorta (COA)

• Narrowing of the lumen of the aorta that impedes blood flow
• About 50% of patients with COA have a bicuspid aortic valve
• COA may develop because of abnormal contractile ductal tissue that constricts at the time of ductal closure

Pathophysiology

• Systolic pressure increases in the ascending aorta and LV and decreases in the descending aorta
• LV hypertrophy develops over time

Clinical Manifestations

• CHF symptoms may occur if the coarctation is severe enough
• In infants, their condition may deteriorate quickly from hypotension, acidosis, and shock when the ductus closes
• Older children may not be diagnosed until hypertension occurs
• High blood-pressure noted in the upper extremities with decreased or absent pulses in the lower extremities
• Cool mottled skin and leg cramps during exercise
• A systolic ejection murmur is best heard at the left interscapular area caused by rapid blood flow through narrowed area
• Rib notching between 4th and 5th ribs may be seen in children over 5 resulting from enlarged collateral vessels from the ascending aorta

Aortic Stenosis (AS)

• Narrowing of aortic outflow tract
• Valvular stenosis comes from malformation or fusion of the cusps
• Most common type of AS that is rare, can lead to death by low cardiac output or myocardial ischemia
• Moderate Aortic Stenosis = Exercise limitations
• Severe Aortic Stenosis = Limited exercise until repaired
• Increased workload on the LV, leading to LVH

Clinical Manifestations

• Usually children with mild to moderate AS are asymptomatic
• More severe cases have syncopal fainting, epigastric pain, and exertional chest pain
• A systolic ejection murmur is noted at the right upper sternal border that transmits to the neck and left lower sternal border that transmits to the neck and left lower sternal border
• Ejection click can be noted with valvular AS

Pulmonary Stenosis (PS)

• Narrowing of the pulmonary outflow tract
• Abnormal thickening of the valve leaflets or narrowing of the arterial side of the valve

Pathophysiology

• Pulmonary atresia (most severe form)
• Complete fusion of the commissures
• No blood flow out of the RV to the PA
• PS produces increased resistance (afterload) to ejection
• Lead to Myocardium hypertrophies

Clinical Manifestations

• Vary based on the severity of the defect A systolic ejection murmur at the left upper sternal border
• Variable systolic ejection click is present with valvular stenosis at the upper left sternal border
• A thrill may also be palpated at the upper left sternal border
• Children may have exertional dyspnea and fatigability
• Severe cases produce cyanosis and HF

Hypoplastic Left Heart Syndrome (HLHS)

• Abnormal development of the left sided cardiac structures, resulting in obstruction to blood flow from the LV outflow tract

Pathophysiology

• Underdevelopment of the LV, aorta, and aortic arch, mitral atresia or stenosis
• Infants need a well-functioning RV and presence of a PDA and atrial septal communication for survival
• Newborns appear normal, but once the ductus closes, perfusion is decreased, causing hypoxemia, acidosis, and shock

Clinical Manifestations

• Generally, no murmur is detected
• The second heart sound is loud and single due to aortic atresia
• Treatment: Prostaglandin infusion, Norwood-Glenn-Fontan procedures or Cardiac transplant

Transposition of the Great Arteries

• The most common cyanotic congenital heart defect
• Represents 10% of all congenital heart defects
• The aorta arises from the RV and the PA from the LV

Pathophysiology

• This results in two separate, parallel circuits in which unoxygenated blood circulates continuously through the systemic circulation and oxygenated blood circulates continuously through the pulmonary circulation
• The patient would not survive outside the uterus unless a mixing of the two occurred by way of a PDA, ASD, or VSD

Clinical Manifestations

• Cyanosis after birth worsens when the ductus arteriosus closes
• Hypoxemia causes metabolic acidosis, tachycardia, and tachypnea
• The first heart sound is normal, and the second sound may be heard as a single sound, even though both aortic and pulmonic valves are working
• The loud single S2 may occur because transposition places the aortic valve closer to the chest wall
• No murmur is noted with transverse great arteries with an intact ventricular septum

Treatment

• Needs two factors as time for repair and survival
  • Blood mix through ductus arteriosus if pulmonary vascular resistance remains high
• Some mixing occurs through the foramen ovale
• Mixing also occurs through the VSD if the child has one

Total Anomalous Pulmonary Venous Connection (TAPVC)

• Pulmonary veins abnormally connect to the right side of the heart either directly or through one or more systemic veins that drain into the RA
• ASD also associated

Clinical Manifestations

• Main clinical manifestation is cyanosis
• Growth retardation, pulmonary infections, and pulmonary overcirculation
• Auscultation reveals a systolic murmur at the left upper sternal border and a mid-diastolic murmur at the left lower sternal border
• Murmur may not occur if TAPVC is obstructed
• A quadruple rhythm where the S1, widely split S2, and S3 or S4, or gallop rhythm is also present

Truncus Arteriosus

Etiology

• A Large embryonic artery fails to divide into the PA and Aorta
• Leads in vessel providing one blood vessel from both ventricles, giving rise to pulmonary and systemic circulation
• Common Trunk straddles the VSD and has valve with 3 or 4 leaflets

Clinical Manifestations

• A systolic regurgitate murmur is audible specifically in the left sternal border given result of the VSD
• System click on the apex and left sternal border may be present
• In apical rumble with an absent or presented gallop rhythm
• Murmur could be present with truncal valve insufficiency

Compensation

• Any condition that increases right-sided pressures or dilation of RA can reopen the foramen ovale
• That could induce a patent foramen ovale in: Pulmonary hypertension, RV failure Tricuspid atresia Conditions that involve low arterial oxygen saturations may delay or prevent ductal closure: Cyanotic heart disease, Decreased medial muscle layer within the ductus, Increased levels of circulating vasodilating substances in the blood
• Providing alternative way to shunt blood for oxygenation, or provide a mixing of oxygenated/deoxygenated blood in order to oxygenate tissues
• Squatting is a spontaneous compensatory mechanism used by older children with unrepaired TOF that alleviate hypoxic spells Squatting and its variants will increases systemic resistance while decreasing venous return to the heart from the inferior vena cava