HEART FAILURE

HEART FAILURE IN NEONATE AND INFANT

Congestive heart failure (CHF) refers to a clinical state of systemic and pulmonary congestion resulting from inability of the heart to pump as much blood as required for the adequate metabolism of the body.

Clinical picture of CHF results from a combination of “relatively low output” and compensatory responses to increase it

PATHOPHYSIOLOGY

Unmet tissue demands for cardiac output result in activation of

Renin-aldosterone angiotensin system

Sympathetic nervous system

Cytokine-induced inflammation

“signaling” cascades that trigger cachexia.

Longstanding increases in myocardial work and myocardial

oxygen consumption (MVO2) ultimately worsen HF
symptoms and lead to a chronic phase that involves cardiac remodeling


CARDIAC REMODELING?

Maladaptive cardiac hypertrophy

Expansion of the myofibrillar components of individual myocytes (new cells rarely form)
An increase in the myocyte/capillary ratio
Activation and proliferation of abundant nonmyocyte cardiac cells, some of which produce cardiac scarring
Produce a poorly contractile and less compliant heart

Endogenous mechanisms defend progressive HF

Stimulation of insulin like growth factor and GH
ANP and BNP are hormones secreted by the heart in response to volume and pressure overload that increase vasodilation and diuresis acutely and chronically prevent inflammation, cardiac fibrosis and hypertrophy.

Variety of age dependent clinical presentations

In neonates, the earliest clinical manifestations may be subtle
CLINICAL MANIFESTATIONS IN INFANTS WITH HF

CLINICAL MANIFESTATIONS IN INFANTS WITH HF

Feeding difficulties
Rapid respirations
Tachycardia
Cardiac enlargement
Gallop rhythm (S3)
Hepatomegaly

Pulmonary rales
Peripheral edema
Easy fatigability.
Sweating
Irritability
failure to thrive.


Feeding difficulties & increased fatigability

Important clue in detecting CHF in infants

Often it is noticed by mother
Interrupted feeding (suck- rest -suck cycles)
Infant pauses frequently to rest during feedings
Inability to finish the feed, taking longer to finish each feed (> 30 minutes)
Forehead sweating during feeds –due to activation of sympathetic nervous system –a very useful sign
Increasing symptoms during and after feedings

Rapid respirations

Tachypnea
> 60/min in 0-2mth
>50/mt in 2mth to 1yr
>40/mt 1-5 yr in calm child
Happy tachypnea- tachypnea with out much retractions
Grunting (a form of positive end-expiratory pressure)
In cyanotic heart disease rapid respirations may be due to associated brain anoxia and not CHF -treatment for these two conditions is entirely different
Fever especially with a pulmonary infection may produce rapid respirations.

Tachycardia

Rate is difficult to evaluate in a crying or moving child
Tachycardia in the absence of fever or crying when accompanied by rapid respirations and hepatomegaly is indicative of HF
Persistently raised heart rate > 160 bpm in infants
> 100 bpm in older children.
Consider SVT if heart rate > 220 bpm in infants and > 180 bpm in older children.

Cardiomegaly

Consistent sign of impaired cardiac function, secondary to ventricular dilatation and/or hypertrophy.
May be absent in early stages, especially with myocarditis, arrhythmias, restrictive disorders and pulmonary venous obstruction(obstructed TAPVC)
Apex 4th space 1cm outside MCL in newborn

Hepatomegaly

Lower edge of the liver is palpable 1 to 2 cms below right costal margin normally in infancy
In the presence of respiratory infection increased expansion of the lungs displace liver caudally
Usually in such circumstances the spleen is palpable
Hepatomegaly is a sign of CHF
Decrease in size is an excellent criterion of response to therapy

Pulmonary rales

Of not much use in detecting CHF in infants
Rales may be heard at both lung bases
When present are difficult to differentiate from those due to the pulmonary infection which frequently accompanies failure

Peripheral edema

Edema is a very late sign of failure in infants and children
Presacral and posterior chest wall edema in young infants
It indicates a very severe degree of failure.
Daily wt monitoring is useful in neonates -- rapid increase in wt > 30 gm /day may be a clue to CCF and is useful in monitoring response to treatment.

Cold extremity, low blood pressure, skin mottling are signs of impending shock

Pulsus alternans (alternate strong and weak contractions of a failing myocardium),or pulsus paradoxus (decrease in pulse volume and blood pressure with inspiration) are frequently observed in infants with severe CHF

MODIFIED ROSS HEART FAILURE CLASSIFICATION FOR CHILDREN

Class I
Asymptomatic
Class II
Mild tachypnea or diaphoresis with feeding in infants
Dyspnea on exertion in older children
Class III
Marked tachypnea or diaphoresis with feeding in infants
Marked dyspnea on exertion
Prolonged feeding times with growth failure
Class IV
Symptoms such as tachypnea, retractions, grunting, or diaphoresis at rest


The time of onset of CHF holds the key to the etiological diagnosis in this age group

Pulmonary vascular resistance falls 4to 6weeks

Congestive heart failure due to L-R shunt
Large VSD
PDA
ALCAPA

CHF in the fetus

Disorders that are fatal in the immediate neonatal period are often well tolerated in the fetus due to the pattern of fetal blood flow (e.g. TGA)
Causes of CHF in the fetus
SVT
Severe bradycardia due to CHB
Anemia
Severe TR due to Ebstein’s anomaly or MR from AV canal defect
Myocarditis

Most of these are recognized by fetal echo

Severe CHF in the fetus produces hydrops fetalis with ascites, pleural and pericardial effusions and anasarca.
Digoxin or sympathomimetics to the mother may be helpful in cases of fetal tachyarrhythmia or CHB respectively.


Premature neonates

PDA
poor myocardial reserve
Fluid overload

CHF on first day of life

Myocardial dysfunction secondary to asphyxia, hypoglycemia, hypocalcaemia or sepsis are usually responsible for CHF on first day
Few structural heart defects cause CHF within hours of birth
HLHS, severe TR or PR, Large AV fistula
TR secondary to hypoxia induced papillary muscle dysfunction or Ebstein’s anomaly of the valve
Improves as the pulmonary artery pressure falls over the next few days

CHF in first week of life

Serious cardiac disorders which are potentially curable but carry a high mortality if untreated often present with CHF in the first week of life
A sense of urgency should always accompany evaluation of the patient with CHF in the first week
Closure of the ductus arteriosus is often the precipitating event
Prostaglandins E1 should be utilised

Peripheral pulses and oxygen saturation (pulse oximeter) should be checked in both the upper and lower extremities
A lower saturation in the lower limbs means right to left ductal shunting due to PAH or AAI
ASD or VSD does not lead to CHF in the first two weeks of life, an additional cause must be sought (eg.COA or TAPVC).


Adrenal insufficiency due to enzyme deficiencies or neonatal thyrotoxicosis could present with CHF in the first few days of life

CHF beyond second week of life

Most common cause of CHF in infants is VSD
Presents around 6-8 weeks of age.
Left to right shunt increases as the PVR falls
Murmur of VSD is apparent by one week
Full blown picture of CHF occurs around 6-8 weeks.
Other left to right shunts like PDA present similarly

CAUSES OF HF IN CHILDREN

CARDIAC
Congenital structural malformations
● Excessive Preload
● Excessive Afterload
● Complex congenital heart disease
No structural anomalies
● Cardiomyopathy
● Myocarditis
● Myocardial infarction
● Acquired valve disorders
● Hypertension
● Kawasaki syndrome
● Arrhythmia
(bradycardia or tachycardia)
NONCARDIAC
● Anemia
● Sepsis
● Hypoglycemia
● Diabetic ketoacidosis
● Hypothyroidism
● Other endocrinopathies
● Arteriovenous fistula
● Renal failure
● Muscular dystrophies


CONGENITAL STRUCTURAL MALFORMATIONS

VOLUME OVERLOAD (EXCESSIVE PRELOAD)

Left-to-right shunting
VSD
PDA
AP window
AVSD
ASD(rare)
Total/Partial Anomalous Pulmonary Venous Connection
AV or semilunar valve insufficiency
AR in bicommissural aortic valve/after valvotomy
MR after repair of AVSD
PR after repair of TOF
Severe TR in Ebstein anomaly

ABNORMAL RV

In pediatric heart disease much of the pathology is due to an abnormal RV
RV myocytes appear to be structurally identical to LV myocytes
Differences in contraction compared to the LV are due to the shape of the RV and myocardial organization


Gene expression patterns are different in the RV and the LV, which may affect function.
Genes that affect angiotensin and adrenergic receptor signaling showed lower expression in the RV than the LV
Genes that contribute to maladaptive signaling showed higher expression in the RV

CHF WITH NO CARDIAC MALFORMATIONS

PRIMARY CARDIAC
Cardiomyopathy
Myocarditis
Cardiac ischemia
Acquired valve disorders
Hypertension
Kawasaki syndrome
Arrhythmia
(bradycardia or tachycardia)
NONCARDIAC
Anemia
Sepsis
Hypoglycemia
Diabetic ketoacidosis
Hypothyroidism
Other endocrinopathies
Arteriovenous fistula
Renal failure
Muscular dystrophies


ARRHYTHMIAS

Arrhythmias cause HF when the heart rate is too fast or too slow to meet tissue metabolic demands

TACHYCARDIA

Diastolic filling time shortens to and cardiac output is decreased.
Most common childhood tachyarrhythmia is SVT
Often presents in the first few months of life
Rarely cause heart failure
Occasionally PJRT ,ectopic atrial tachycardia and VT

CHRONIC BRADYCARDIAS

LV enlarges to accommodate larger stroke volumes
Chamber dilation reaches a limit that cannot be compensated without increase in heart rate
Febrile states are particularly stressful
Congenital CHB may be well-tolerated in utero
Dysfunction cause hydrops and intrauterine demise
After birth, progression to HF depends on the ventricular rate and the speed of diagnosis and intervention
Children with congenital CHB who are pacemaker dependent are at risk of subsequent pacemaker-mediated cardiomyopathy


CARDIAC ISCHEMIA

Relatively rare in children

ALCAPA
Palliative surgery that requires reconstruction of or near the coronary arteries
e.g. Ross procedure, arterial switch operation

HIGH OUTPUT HF +EXCESSIVE PRELOAD

Septic shock causes
Volume load on both sides of the heart
Increased SV associated with hyperdynamic systolic function
Elaboration of vasoactive molecules such as endotoxin and cytokines such as TNF-alpha leads to decreased SVR
Cardiac output is increased
Precapillary shunting
Decreased tissue perfusion and lactic acid production
Increased vascular permeability -increased total body fluid volume
Toxin or direct microbial actions -negative inotropic effects
Stresses produce demands for cardiac output and MVO2

LABORATORY STUDIES

PULSE OXIMETRY
ECG
ABG



CXR
Size of the heart is difficult to determine radiologically, particularly if there is a superimposed thymic shadow.
Enlarged cardiac shadow unassociated with signs of CHF- suspect that shadow noncardiac
Absence of cardiomegaly in a good inspiratory film (with diaphragm near the 10th rib posteriorly) practically excludes CHF except due to a cause like obstructed total anomalous pulmonary venous connection (TAPVC)

CT Ratio method, > 60%

Massive cardiomegaly
RA dilation
Pulm plethora
LV Dialatation

ECHOCARDIOGRAPHY

Not useful for the evaluation of HF, which is a clinical diagnosis
Essential for identifying
Causes of HF such as structural heart disease
Ventricular dysfunction (both systolic and diastolic)
Chamber dimensions
Effusions (both pericardial and pleural)


Assessment of right and single ventricular function is more complicated because of altered geometry
RV tissue Doppler imaging correlates with measurements of RVEDP obtained during cardiac catheterization
Doppler myocardial performance index has been used to assess function in children with SVs and abnormal RVs
Single (left) ventricle physiology-remodeling to a spherical shape associated with deterioration

HF BIOMARKERS

Released primarily in response to atrial stretching
Sensitive marker of cardiac filling pressure and diastolic dysfunction
BNP levels can distinguish between cardiac and pulmonary causes of respiratory distress in neonates and children

MEDICAL THERAPY

Medical management aims to maximize cardiac output and tissue perfusion while minimizing stresses that increase MVO2
Goals are accomplished by reducing afterload stress and preload
Treatments that “rest” the heart such as vasodilators are preferred to inotropic agents that increase MVO2

Few drugs have evidence based efficacy compared to adults

Pediatric dosing is necessary
Scaling adult doses for pediatric use solely based on weight can result in either inadequate or excessive drug levels


GENERAL MEASURES
Bed rest and limit activities
Nurse propped up or in sitting position
Control fever
Expressed breast milk for small infants
Fluid restriction in volume overloaded
Optimal sedation
Correction of anemia ,acidosis, hypoglycemia and hypocalcaemia if present
Oxygen –caution in LT-RT shunt as pulmonary vasodilation my increase shunt
CPAP or mechanical ventilation as necessary

DIGITALIS

Digitalis considered as essential component
Evidence for efficacy is less in volume-overload lesions with normal function where the mild inotropic effect of digitalis is unnecessary
Sympatholytic properties may modulate pathological neurohormonal activation

LOOP DIURETICS

Furosemide improved clinical symptoms on a background of digitalis administration
Decrease pulmonary congestion and thus decrease the work of breathing
It is one of the least toxic diuretics in pediatrics
Associated with sensorineural hearing loss after long-term administration in neonatal respiratory distress
Deafness related to speed of infusion
Torasemide is also safe and effective in this group


ACE INHIBITION

Improved growth was seen in some children with CHF

Captopril and enalapril
Concerning incidence of renal failure particularly in premature and very young infants.
No efficacy data on ARBs in children with heart failure

B BLOCKER

Propranolol to the combination of digoxin and diuretics shown to improve HF symptoms and improve growth

SPIRONOLACTONE

Literature supporting the role in paediatric HF is limited

61. Hobbins SM, Fowler RS, Rowe RD, Korey AG. Spironolactone therapy in infants with congestive heart failure secondary to congenital heart disease. Arch Dis Child. 1981 Dec;56(12):934‐8.
62. Buck ML. Clinical experience with spironolactone in pediatrics. Ann Pharmacother. 2005 May;39(5):823‐8.

INTRACARDIAC REPAIR

Early transcatheter or surgical intervention, often before age 6 months is possible
Minimizes time of significant symptoms or medication
Minimizes the risk of pulmonary vascular disease.
Contemporary data indicate that early repair of a VSD, even in the first month of life and at weights 4 kg, does not confer increased risk compared with older, larger infants.


TRANSCATHETER DEVICE CLOSURE

Transcatheter device closure of muscular VSD

Weight atleast 5.2 kg.

COMPLEX CONDITIONS

RV failure in children
There is no systematic clinical evidence for anticongestive therapy
Furosemide- relieve the clinical symptoms
RV dysfunction - betablocker therapy did not improve ventricular function
Suggest a different pathophysiological process in RV failure and thus a requirement for novel treatment strategies

Single ventricle

No compelling data to guide medical treatment
ISHLT guidelines recommend diuretics, digitalis, and ACE inhibition but not beta blockade, based on expert consensus.

CARDIOMYOPATHIES

Primary or acquired DCM


ISHLT Guidelines reflect only data from studies in adults in recommending both digitalis and diuretics only for symptomatic LV dysfunction in children
Torasemide, a newer loop diuretic with potassium-sparing properties, significantly improved New York University Pediatric Heart Failure Index, decreased BNP levels, and improved fractional shortening

Senzaki etal Efficacy and safety of Torasemide in children with heart failure. Arch Dis Child. 2008 Mar 12

Systemic exposure to carvedilol amongst paediatric heart failure patients and has indicated that higher doses relative to body weight are required to provide exposure comparable to adults
Paediatric carvedilol doses
1mg/kg/day for adolescents
2mg/kg/day for children aged 2 to 11 years
3mg/kg/day for infants (aged 28 days to 23 months)
Carvedilol used in many of the studies have been lower than these recommendations

NUTRITION AND EXERCISE IN PEDIATRIC HEART FAILURE

Important as medical therapy, particularly in infants
Increase the caloric density of feeds as soon as a diagnosis
Sodium restriction is not recommended in infants and young children.
Sodium restriction can result in impaired body and brain growth

THANK U