HEART FAILURE. Congestive heart failure (CHF) is the clinical state of systemic and pulmonary congestion resulting from inability of the heart to pump.

HEART FAILURE

Congestive heart failure (CHF) is the 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 “low output” and compensatory responses to increase it

PATHOPHYSIOLOGY

Tissue demands for cardiac output activates:

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

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 CHF

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 Grunting (a form of positive end-

expiratory pressure) 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 weight monitoring is useful in neonates --

rapid increase > 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

CLASSIFICATION

NYHA Heart Failure Classification is not applicable

Ross Heart Failure Classification was developed for global assessment of heart failure severity in infants

Modified to apply to all pediatric ages Modified Ross Classification incorporates

Feeding difficulties

Growth problems

Symptoms of exercise intolerance

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

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

AVSD (Atrioventricular septal defect)

ASD(rare)

Total/Partial Anomalous Pulmonary Venous Connection AV or semilunar valve insufficiency

MR (Mitral regurgitation) after repair of AVSD

PR after repair of TOF( Tetralogy of Fallot)

Severe TR in Ebstein anomaly

PRESSURE OVERLOAD (EXCESSIVE AFTERLOAD)

Left sided obstruction

Congenital AS

Aortic coarctation

Lethal arrhythmias - severe afterload stress

Right-sided obstruction

Severe PS

CHF (congestive heart failure) WITHOUT 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

DISORDERS OF CONTRACTILITY

Cardiomyopathy is a genetically triggered or acquired disease

Occurs in approximately 1.13 in 100,000 children Characterized by enlarged ventricular chambers and

impaired systolic and diastolic function Usually idiopathic

Infection (myocarditis viral-enterovirus)

Operative injury

Consequence of degenerative or metabolic diseases

Muscular dystrophies

Mitochondriopathy,

Hyperthyroidism

carnitine deficiency

Restrictive cardiomyopathy

Idiopathic

Infiltrative or storage diseases

hemochromatosis

Pompe disease

Hypertrophic cardiomyopathy Idiopathic hypertrophic subaortic stenosis,

rarely associated with pediatric HF.

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 Persistent Junctional

Reciprocating Tachycardia (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 Children with congenital CHB who are

pacemaker dependent are at risk of subsequent pacemaker-mediated cardiomyopathy

CARDIAC ISCHEMIA

Relatively rare in children ALCAPA (Anomalous Left Coronary

Artery from the Pulmonary Artery Palliative surgery that requires

reconstruction of or near the coronary arteries

LABORATORY STUDIES

PULSE OXIMETRY ECG ABG (Arterial Blood Gas)

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 plethoraLV Dialatation

ECHOCARDIOGRAPHY

Doppler myocardial performance index Causes of HF such as structural heart

disease Ventricular dysfunction (both systolic

and diastolic) Chamber dimensions Effusions (both pericardial and pleural)

PRINCIPLES OF MANAGINGHEART FAILURE

Recognition and treatment of underlying systemic disease

Timely Surgical Repair of Structural Anomalies

Afterload Reduction ACE ( Angiotensin converting enzyme ) inhibitors ARB (angiotensin receptor blockers Milrinone Type 4 phosphodiesterase inhibitors Nitrates Recombinant BNP = brain natriuretic peptide

Preload Reduction Diuretics BNP

Sympathetic Inhibition Beta blockers Recombinant BNP Digoxin

Cardiac Remodeling Prevention Mineralocorticoid inhibitors

Inotropy Digoxin

MEDICAL THERAPY

Medical management aims to maximize cardiac output and tissue perfusion

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

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 (Continuous positive airway pressure) or

mechanical ventilation as necessary

CONGENITAL HEART DISEASE: VOLUME OVERLOAD

General therapeutic approach is to minimize symptoms and optimize growth until a definitive procedure can be performed.

Mainstays of medical therapy are digitalis and diuretics.

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 (angiotensin-converting-enzyme inhibitors )

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 ARB s in children with heart failure

CARDIOMYOPATHIES

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

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

Treatment of primary diastolic heart failure in children with hypertrophic or restrictive cardiomyopathy are limited to the judicious use of diuretics to decrease the degree of pulmonary congestion.

Inotropes in acute cardiac failure

Routine use of in children cannot be recommended

Used in treatment of exacerbating conditions and as a bridging therapy pending transplantation

Dopamine as it possesses both the cardiac and renal effects is more useful

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

Pacemaker and implantable defibrillator therapy

Biventricular pacing Ventricular assist devices Heart transplantation