Definition

A heart attack, or myocardial infarction, is a condition where heart tissue is damaged due to a sudden decrease or disruption in blood flow through the coronary arteries, which supply oxygen to the heart. Coronary arteries are small arteries surrounding the heart that deliver oxygen to the heart muscle, enabling it to contract normally. When these arteries become blocked for any reason, the heart does not receive sufficient oxygen.

Myocardial infarction is relatively common in adults but very rare in children and adolescents. In adults, it often develops due to a buildup of fat and plaque in the coronary arteries, which can obstruct blood flow to the heart. However, myocardial infarction in children is usually associated with congenital heart disease or abnormalities in the structure and location of the coronary arteries.

Causes

The onset of myocardial infarction is essentially caused by a sudden reduction in oxygen supply to the heart due to a problem with the coronary arteries. The state where heart cells experience a reduced oxygen supply is called ischemia. If this condition persists, it can trigger various inflammatory responses, eventually leading to cell death (infarction).

In children, reduced oxygen supply and blood flow to the coronary arteries can be caused by several conditions, such as:

• Congenital heart disease
• Abnormal location and structure of the coronary arteries, like ALPACA (Abnormal Left Coronary Artery Originating from the Pulmonary Artery)
• Congenital prothrombotic disorders (blood clotting disorders present from birth)
• Vasculitis (inflammation of blood vessels), such as Kawasaki disease, polyarteritis nodosa, SLE, Takayasu arteritis
• Previous heart surgery
• Perinatal asphyxia (breathing difficulties immediately after birth)
• Sepsis (widespread infection throughout the body)
• Genetic disorders, such as Alkaptonuria, Fabry's disease, familial hypercholesterolemia, homocystinuria, Hurler's Syndrome, Pompe's disease
• Cardiac muscle abnormalities
• Certain medications, such as epinephrine, amphetamines, benzodiazepines
• Drug use, including cocaine and marijuana

Risk Factor

Myocardial infarction in children is very rare. The risk increases if the child has abnormal coronary artery structure and location or congenital heart disease, such as:

• Hypertrophic cardiomyopathy, a disorder of the heart muscle that makes it abnormally thick. This thickened heart muscle may require more oxygen than the coronary arteries can supply. This not only damages the heart muscle but can also lead to life-threatening irregular heart rhythms over time.
• Abnormal coronary artery structure and location, where about 1 in 100 babies is born with coronary arteries that originate in unusual locations. In rare cases, this condition can lead to life-threatening symptoms.
• History of certain diseases, such as congenital heart defects, Kawasaki disease, and genetic conditions that lead to high cholesterol levels, which increase the risk of heart attacks due to coronary artery blockages.
• Myocarditis, inflammation of the heart muscle, which occurs when the immune system damages the heart muscle, often during a viral infection. Myocarditis can be life-threatening and lead to poor heart function and irregular heart rhythms, although it is rare in children, occurring in about 1 in 100,000 children per year.

Symptoms

The main symptom of myocardial infarction is usually left chest pain. However, in children, it is often challenging to determine whether chest pain is due to a heart problem or another condition. Most children may not describe the chest pain they feel clearly.

In infants, symptoms of myocardial infarction may include:

• Feeding difficulties
• Lack of responsiveness to the environment
• Irritability
• Diarrhea
• Excessive sweating
• Vomiting
• Paleness
• Rapid breathing
• Shortness of breath

In older children, myocardial infarction may cause symptoms such as:

• Fatigue
• Loss of appetite
• Paleness
• Shortness of breath
• Rapid breathing
• Fast heart rate
• Low blood pressure (hypotension)
• Weak pulse
• Irregular heart rhythms
• Cold hands and feet
• Fainting

Diagnosis

The main symptom of myocardial infarction is usually left chest pain. However, in children, it is often challenging to determine whether chest pain is due to a heart problem or another condition. Most children may not describe the chest pain they feel clearly.

In infants, symptoms of myocardial infarction may include:

• Feeding difficulties
• Lack of responsiveness to the environment
• Irritability
• Diarrhea
• Excessive sweating
• Vomiting
• Paleness
• Rapid breathing
• Shortness of breath

In older children, myocardial infarction may cause symptoms such as:

• Fatigue
• Loss of appetite
• Paleness
• Shortness of breath
• Rapid breathing
• Fast heart rate
• Low blood pressure (hypotension)
• Weak pulse
• Irregular heart rhythms
• Cold hands and feet
• Fainting

Management

Myocardial infarction is a medical emergency requiring immediate treatment. Initial management focuses on stabilizing the patient with oxygen, intravenous fluids, and specific medications. The goal is to reduce the heart’s oxygen demand and provide supplemental oxygen. Once the patient's condition stabilizes, surgical intervention may be considered to improve blood flow to the coronary arteries. Percutaneous Coronary Intervention (PCI) is a common surgical option, involving the insertion of a small flexible tube into the blood vessel to remove the obstruction in the coronary artery. It is also crucial to treat the underlying heart condition causing the myocardial infarction in the child.

Complications

If left untreated, myocardial infarction in children can lead to complications such as irregular heart rhythms and even death.

Prevention

The risk of myocardial infarction in children can be reduced by managing and treating underlying conditions, such as congenital heart disease or coronary artery abnormalities.

When to See a Doctor?

Take your child to the Emergency Department if they experience left chest pain radiating to the arm and lower jaw. Since myocardial infarction symptoms in children can be hard to recognize, consult a doctor if your child shows any unexplained symptoms.

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