Chronic Heart Failure

In many ways, heart failure in children varies from heart failure in adults. Children of various age groups, as well as children and adults, may have distinct causes and clinical manifestations. The beginning of HF is important in determining the etiological diagnosis. In younger children, the clinical presentation of HF might be vague, necessitating a high level of suspicion. Children have a better overall result with HF than adults because HF in children is more usually caused by structural heart disease and reversible diseases that can be treated. Treatment of the cause, elimination of any precipitating event, and treatment of systemic or pulmonary congestion are among the management principles. Even though HF in adults has been the focus of substantial research and the development of evidence-based guidelines, pediatric HF faces a lack of information.

What is Chronic Heart Failure?

Heart failure (HF) is defined as a defect in cardiac structure or function that causes the heart to fail to provide oxygen at a rate that is proportional to the needs of the metabolizing tissues, despite normal filling pressures (or only at the expense of high filling pressures).

HF in adults has been the topic of substantial research and the development of evidence-based guidelines; but, due to several challenges, it has received far less attention in children. Children's causes of heart failure differ greatly from those that cause the condition in adults, such as coronary artery disease and hypertension. Congenital heart disease (CHD) and cardiomyopathy are the most common causes of cardiac failure in children. Hsu and Pearson have given a good working definition of HF in children as a progressive clinical and pathophysiological syndrome caused by cardiovascular and non-cardiovascular abnormalities that result in characteristic signs and symptoms including edema, respiratory distress, growth failure, and exercise intolerance, and are accompanied by circulatory, neurohormonal, and molecular derangements.

There is a lot of research published on the management of HF in adults, whereas there’s minimal research on pediatric HF and those which do present are often small, retrospective studies. As a consequence, the management of cardiac failure in children has largely evolved based on clinical experience and therefore the extrapolation of adult data, supported by the more limited pediatric literature. This may not be desirable, given the major differences in HF causation between adult and pediatric groups.

Chronic Heart Failure Epidemiology

The causes of HF in children differ greatly from those in adults, and many cases are due to congenital abnormalities that result in high output heart failure. Low output heart failure, such as cardiomyopathy, affects some children. CHD affects about 8 out of every 1000 live births. HF coupled with CHD affects roughly 25% of all patients.

Many children with CHD receive early surgical treatment, and the annual incidence of HF due to congenital anomalies is estimated to be between 1 and 2 per 1000 live births. Following the emergence of early surgical procedures, the outcome of HF linked to CHD has changed substantially. The incidence of symptomatic HF has also declined in the early surgical era. Massin et al. reported that only 10% of their patients in a tertiary care pediatric cardiology care setting developed symptomatic HF.

Cardiomyopathy also contributes significantly to the percentage of pediatric patients who present with the symptoms of cardiac failure. Rossano et al. from the United States report that 10,000-14,000 children are hospitalized annually with HF as a diagnosis of their problems and of those approximately 27% (approximately 3000) have abnormalities of the heart muscle as an underlying cause. The incidence of cardiomyopathies in developed countries is about 0.8-1.3 cases per 100,000 children within the 0–18 years age group but is ten times higher within the 0- to 1-year old age group. Dilated cardiomyopathies account for 92 percent of all cases of cardiomyopathies in children.

Unlike HF caused by CHD, children with cardiomyopathy have a poor prognosis, with a 5-year risk of death or heart transplantation of roughly 55% for children with dilated cardiomyopathy (DCM).

Rheumatic fever and rheumatic heart disease are two more important causes of HF in children in undeveloped countries. While the prevalence and incidence of rheumatic fever and chronic rheumatic heart disease are well known, there is little information on how this group presents with HF. A considerable number of patients with acute rheumatic carditis and established juvenile mitral stenosis have HF symptoms.

Chronic Heart Failure Causes

Children with HF can be categorized into two categories. Pump failure and over-circulation failure. Conditions that lead to volume overload of heart chambers are referred to as over-circulation. In them, either the left ventricular (LV) function is normal or the LV is hypercontractile. Pulmonary venous or arterial hypertension can manifest itself in a variety of ways. Pump failure can be caused by both congenital and acquired diseases. The LV or systemic ventricle function is abnormal, and the majority of individuals in this group have pulmonary venous hypertension.

Over Circulation Chronic Heart Failure

Approximately 2% of all newborn babies will have a structural heart problem. There are gaps between the right and left chambers of the heart in some of these abnormalities. The oxygen-poor and oxygen-rich bloods mix inside the heart as a result of these gaps. Outside the heart, an AV malformation (defect in blood vessels in the brain or other regions of the body) can create comparable mixing of oxygen-poor and oxygen-rich blood.

Heart failure can also be caused by abnormal heart valves. Blood leaks backward due to an improperly developed valve that does not close completely. A strep throat infection can occasionally cause damage to previously healthy heart valves, causing them to leak.

Finally, anemia (low blood) can lead to heart failure. Over-circulation failure is caused by these problems. An overloaded blood flow pattern occurs in one or more of the heart's regions in each case. The heart becomes an unproductive pump as the normal forward blood flow is disrupted.

Pump Failure

A child's heart, like an adult's, can develop pump failure. A viral infection can cause this, which destroys normally healthy heart muscle. Pump failure can also be caused by issues with the coronary arteries, which impede enough blood flow to reach the heart muscle. Coronary artery disease can develop as a result of infection or as a result of birth.

Certain medications, some of which are required to treat other medical conditions (such as cancer or leukemia), can harm the heart muscle. The electrical system of the heart can also be defective from birth or destroyed by infection, causing it to beat too slowly or too quickly. When one of the heart valves fails to open properly, pressure builds up inside the chambers of the heart.

Severe chest trauma can cause cardiac damage in rare cases. Children with muscular dystrophy may suffer from heart muscle problems in the future. The heart muscle fails to operate normally in each condition, and the heart becomes an ineffective pump.

Chronic Heart Failure Symptoms

The causative etiology is determined by the timing of the onset of CHF. Supraventricular tachycardia, serious bradycardia due to complete heart block, significant tricuspid regurgitation due to Epstein’s anomaly of the tricuspid valve, mitral regurgitation due to atrioventricular canal defect, systemic arteriovenous fistula, myocarditis, and other conditions can all cause HF in the fetus. Metabolic disorders such as hypoglycemia, hypocalcemia, hypoxia, or sepsis are typical causes of HF on the first day of life.

The symptoms of structural disorders that cause fetal heart failure can appear as early as the first day. Severe obstructive diseases such as severe aortic stenosis, coarctation of the aorta (COA), obstructed total anomalous pulmonary venous connection (TAPVC), the great arteries (TGA) with the intact ventricular septum (IVS), and others manifest in the first week of birth.

Although a wide ventricular septal defect (VSD), patent ductus arteriosus (PDA), atrio-VSD, and aortopulmonary window can produce HF in the second week of birth, HF owing to left-to-right shunts usually develops with a decline in pulmonary vascular resistance at 4-6 weeks. Other disorders that appear in the second week of life include truncus arteriosus and unobstructed total anomalous pulmonary venous connection (TAPVC). PDA may cause HF in premature newborns in the first week because they have low myocardial reserves and their pulmonary vascular resistance falls quickly.

In newborns, DCM is also a frequent cause of HF. Idiopathic, inborn errors of metabolism, and malformation syndromes are all possible causes of dilated cardiomyopathy in children. Acute rheumatic fever, decompensated rheumatic heart disease, myocarditis, cardiomyopathy, rhythm irregularities, and palliated CHD are all common causes of HF in older children (typically older than 2 years).

Tachypnea, feeding problems, diaphoresis, and other symptoms are suggestive of HF in newborns. Feeding problems can range from long feeding times (>20 minutes) and low volume intake to obvious intolerance and post-feed vomiting. Feeding irritation, sweating, and even feeding rejection are all common.

Established HF is characterized by inadequate weight gain and, in the long run, linear growth failure. In newborns and young children, edema of the face and limbs is quite rare. The clinical signs and symptoms of HF in a newborn are often ambiguous, thus a high index of suspicion is essential. Infants with HF have a tachycardia of more than 150 beats per minute, a respiratory rate of more than 50 per minute, a gallop rhythm, and hepatomegaly. If your heart rate is more than 220 beats per minute, you may have a primary cardiac arrhythmia. The Duct-dependent pulmonary circulation has severe cyanosis and acidosis, whereas the duct-dependent systemic circulation has HF and shock.

Tiredness, effort intolerance, breathlessness, orthopnea, abdominal discomfort, dependent edema, ascites, and other symptoms of HF in older children and adolescents are common.

In any child with unexplained HF, check for unequal upper and lower limb pulses, peripheral bruits, or asymmetric blood pressure, all of which indicate aortic constriction. In the context of PDA, COA in newborns can show normal femoral pulsations. After 1 year old, when adequate collaterals have formed, COA usually does not cause heart failure. In a baby, central cyanosis, even if modest, with HF and soft or no murmurs indicates TGA with preserved IVS, obstructed TAPVC, and so on.

Because an atrial septal defect (ASD) does not induce CHF in the first two weeks of infancy, a secondary etiology such as TAPVC or COA should be checked out. Complications like anemia, infective endocarditis, aortic insufficiency, or over-shunting from aortopulmonary shunts can cause HF in older children with tetralogy of Fallot pathophysiology.

The well-known New York Heart Association (NYHA) HF categorization does not apply to the majority of children. The Ross HF classification was originally designed to determine severity in infants, but it has since been expanded to include children of all ages. For children, the modified Ross classification yields a numerical score comparable to the NYHA classification for adults.

Modified Ross Heart Failure Classification

The Ross Heart Failure Classification was created to give a global assessment of heart failure symptoms in infants, but it has since been expanded to include children of all ages. The modified Ross Classification combines feeding issues, growth problems, and exercise intolerance symptoms into a numerical score that is equivalent to the NYHA classification for adults.

• Class I. There are no limitations or complaints.
• Class II. Mild tachypnea or excessive sweating with breastfeeding in infants; mild to moderate breathlessness with activity in older children
• Class III. Growth retardation and significant tachypnea or excessive sweating with feeding in infants; breathlessness with significant effort in older children.
• Class IV. Symptoms such as tachypnea, retractions, grunting, or excessive sweating may occur at rest.

Chronic Heart Failure Diagnosis

All patients with suspected HF should undergo basic examinations such as chest radiography, electrocardiography (ECG), and echocardiography.

Chest Radiography (CXR)

Cardiomegaly is indicated by a cardiothoracic ratio of >60% in neonates and >55% in older children on CXR. Cardiomegaly has a high specificity and negative predictive value for ventricular dilatation on echocardiography, but low sensitivity and positive predictive value. In children with DCM, cardiomegaly on CXR suggests a bad prognosis. On chest radiographs of infants and neonates, a large thymus can simulate cardiomegaly. Cardiomegaly, dilated main and branch pulmonary arteries, and pulmonary plethora are common findings of left to right shunts. CXR can help with cyanotic CHD that has characteristic radiographic features such as an egg-on-string appearance in the transposition of great arteries, a snowman appearance in obstructed TAPVC, and a figure of eight appearance in unobstructed TAPVC.

Electrocardiography (ECG)

Sinus tachycardia, LV hypertrophy, ST-T alterations, myocardial infarction patterns, and conduction blocks are the most prevalent ECG abnormalities in children with HF. ECG findings of left bundle branch block and left atrial hypertrophy were linked to death in patients with idiopathic DCM. An abnormal left coronary artery from the pulmonary artery is indicated by a myocardial infarction pattern with inferolateral Q waves. The ECG is very helpful in identifying tachycardiomyopathy and other cardiac arrhythmic causes of HF, such as an atrioventricular block. 24-hours holter monitoring can help with tachycardiomyopathy diagnosis and risk stratification for sudden death in HF patients with primary cardiomyopathy.

Echocardiography

In pediatric HF cases, transthoracic echocardiography is recommended to rule out any structural problems. For future comparisons, baseline echocardiography will be necessary. In children, LV systolic dysfunction is generally characterized by an ejection fraction (EF) of less than 55%. Patients with anthracycline chemotherapy, patients with storage disorders, patients with neuromuscular diseases, and others can benefit from echocardiography. In first-degree relatives of patients with various hereditary types of cardiomyopathy, periodic echocardiographic examination is essential. In HF patients, periodic echocardiography follow-up is beneficial for monitoring disease progression and assessing treatment response.

Biomarkers

In acute situations, natriuretic peptides (brain natriuretic peptide [BNP] or amino-terminal [NT]-proBNP) might help distinguish HF from pulmonary causes of respiratory distress. Increased natriuretic peptide levels may be linked to a worse prognosis in HF patients. In children with a variety of CHD, plasma BNP rise is a good diagnostic for detecting ventricular dysfunction. Higher NT-proBNP levels are linked to higher doxorubicin treatment dosages and abnormal echocardiographic characteristics, including ventricular dysfunction, in chemotherapy patients. Serial BNP or NT-proBNP studies in children with HF show promise for guiding therapeutic intervention or monitoring HF status.

All children with HF should have their blood sugar level and serum electrolytes, such as calcium and phosphorus, checked since imbalances can cause reversible ventricular dysfunction. In newborns with HF, testing for hypoxia and sepsis is recommended.

In patients of HF with probable acute rheumatic fever or recurrence of chronic rheumatic heart disease, antistreptolysin O and C-reactive protein should be measured. In primary cardiomyopathy, metabolic and genetic tests may be conducted, as new findings imply that more than half of DCM patients have a hereditary etiology.

Special Testing

When a specific diagnosis is expected that would influence treatment, an endomyocardial biopsy (EMB) may be performed for the diagnosis of myocarditis in selected individuals presenting with HF. In all children with new-onset HF without a history of diminished functional status, acute myocarditis should be considered, especially if ventricular dilation is less than predicted for the degree of systolic dysfunction. Pediatric myocarditis has a far better prognosis than DCM, with a larger chance of recovery in children. However, RV EMB for suspected myocarditis has low diagnostic accuracy, and there is little evidence supporting the use of immunosuppressive or immune-modulating medication in children.

Typical viral pathogen screening by polymerase chain reaction (PCR) may be considered for patients with a clinical diagnosis of myocarditis. In myocarditis, cardiac magnetic resonance imaging (CMRI) provides a less invasive substitute to EMB for detecting inflammation by demonstrating myocardial edema. Although the predictive value of CMRI in children is unknown, it may provide extra information on cardiomyopathy through tissue and scar characterization.

Chronic Heart Failure Treatment

Over-circulation caused by a congenital cardiac abnormality can lead to heart failure, which generally necessitates surgery to correct. Medications are frequently used to treat your child, which may necessitate hospitalization in some cases. Diuretics (water pills) and afterload reducers are examples of drugs. They can aid in the unloading of extra volume, lowering blood pressure resistance, and improving the heart's pumping function.

Because excessive circulation promotes poor growth, your doctor may recommend nutritional supplements to ensure that your child gets enough calories to meet his or her increasing energy needs. Other dietary modifications, such as a low-salt or low-fat diet, may be considered. Your child's health and symptoms may improve with proper therapy. Compensated heart failure is the term for this condition.

The fundamental reason, though, may persist. If heart surgery is necessary, you will be allowed to discuss the various types of surgery and other possible treatments.

The same drugs indicated may be utilized if the heart failure is characterized by pump failure. Other blood pressure drugs can sometimes help the heart pump more effectively. It's possible that you'll need to stay in the hospital to boost your heart function even further. Surgery, such as the replacement of a defective heart valve, may be required at times.

Pump failure caused by a slow heartbeat frequently warrants the use of a pacemaker. Pacemakers serve as a reminder to the heart to keep a regular heart rate. The battery-operated devices, which look like small computers, are implanted under your child's skin and linked to the heart by a short wire. This will require a surgical intervention.

If your child's pump failure is caused by a fast heartbeat, he or she may need medication to slow down the heartbeat. In some cases, radiofrequency ablation, a specific heart catheterization procedure, may be indicated to fix the irregular heart rhythm. Short bursts of radio waves are applied to the portion of the heart muscle that causes the rapid rhythm in this treatment.

If pump failure is induced by irreversible muscle injury, heart function may not improve and may even worsen with medication. To boost heart pump function temporarily, a specific pacemaker, mechanical pump (LVAD), or extracorporeal membrane oxygenator (ECMO) may be required. If your heart muscle function continues to decline despite treatment, your doctor may recommend heart transplantation.

Chronic Heart Failure Prognosis

Heart failure in children has different outcomes depending on the underlying reason. Morbidity and mortality related to structural heart disease have decreased dramatically as a result of breakthroughs in surgical and other interventional treatments. However, there has been little progress in reducing the high mortality and morbidity rates related to symptomatic heart failure in children with cardiomyopathy. However, further research is needed to identify people who are at risk of a poor outcome and those who have a good chance of recovering completely. Although the death rate among children on the waitlist for a heart transplant has decreased, it is stubbornly high at 16%.

Conclusion

The causes and clinical manifestations of heart failure in children differ from those in adults. The general outcome of HF in children is better than in adults. The evidence base for the treatment of HF in adults has significantly improved. While the main concepts of management are similar to those in adults, more and higher-quality research on the treatment of heart failure in children is needed to offer a more robust evidence basis.