**7. Congenital coronary artery abnormalities**

 Arterial switch operation Post-transplantation Post-coronary surgery

Drugs

 Epinephrine Amphetamine Benzodiazepines Hyperlipidemia Blunt Chest trauma Nephrotic syndrome

110 Myocardial Infarction

Vasculitis

Polyarteritis nodosa

 Behcet's disease Takayasu arteritis

 Genetic diseases ALKaptonuria Fabry's disease

 Homocysteinuria Hurler's syndrome

Pompe's Disease

 Occult Malignancy Myocardial bridging

Progeria

Sepsis

Mucopolysaccharidoses

Pseudoxanthoma elasticum

Pulmonary atresia with intact ventricular septum

**Table 4.** Causes of Paediatric myocardial infarction.

Systemic lupus erythematosus

 Atherosclerotic coronary artery disease Disseminated intravascular coagulation

Familial hypercholesterolemia (homozygotes or heterozygotes)]

Hyperbetalipoproteinemia, familial combined hyperlipidaemia, and hypoalphalipoproteinemia

Coronary artery abnormalities generally do not cause clinical findings or the findings are subclinical. However, some coronary artery abnormalities cause serious haemodynamic outcomes [16]. The left coronary artery emerging from the right coronary sinus and the right coronary artery emerging from the left coronary sinus can cause coronary artery circulation problems. The section of the coronary artery that passes between the aorta and the pulmonary artery exposed to pressure at a critical level causes clinical findings [28].

Congenital cardiac abnormalities are a significant cause of MI-related sudden death, most often in the neonatal period (**Table 5**) [28]. Sudden death is often related to exercise especially in patients where the coronary arteries originate from the pulmonary artery and pass between the aorta and the pulmonary artery [28]. Although some cases may show clinical findings with MI in the neonatal period, some cases can remain asymptomatic [29]. In infancy, there may be noticeable findings of heart failure, such as rapid fatigue, sweating, tachypnea and retarded growth and development [2].

Exercise-related death is most often encountered when the left coronary artery emerges from the right coronary sinus, in ALCAPA, and when the right coronary artery emerges from the left coronary sinus [28]. In patients with coronary artery abnormality, the symptoms include chest pain, syncope and findings of heart failure. In infants with ALCAPA, Q-wave seen at DI, AVL or V5–6 on ECG is a good marker for diagnosis [7].

In a Paediatric autopsy study, cardiomegaly was seen in all the cases of children with coronary artery abnormality [30]. The cause of MI seen during exercise in children with coronary artery abnormality has been suggested to originate from an increase in acute angulation of the coronary artery during exercise [29].

Sudden death in the asymptomatic period is a frightening complication of the disease in a significant proportion of cases with coronary artery abnormality [28].

	- **a.** LMCA or LAD from pulmonary trunk
	- **a.** LMCA and RCA from right Aortic Sinus
	- **b.** RCA and LMCA from left Aortic Sinus
	- **c.** LCx and RCA from right Aortic Sinus
	- **d.** RCA and/or LMCA from posterior Aortic Sinus
	- **e.** RCA and LAD from right Aortic Sinus

LCx: left circumflex, CA: Coronary artery, CAs: Coronary arteryies, LMCA: left main coronary artery, left anterior descending, RCA: right coronary artery.

**10. Myocarditis**

**Anamnesis**

Sudden onset

Myocardial infarction

Myocarditis First there may be findings of viral infection

**Physical examination**

Gallop rhythm, ventricular arrhythmia may be seen

The sound of pericardial friction, Gallop rhythm, and arrhythmias may be seen

As myocarditis is generally seen together with pericarditis, it is known as myopericarditis. Myopericarditis may show differences according to whether the effects of the clinical findings are focal or generalised [19]. Typically, diagnosis is made from the determination of chest pain, the sound of pericardial friction, ST elevation on ECG, high levels of troponin I, cardio-

Pericardial effusion is observed in 60% of pericarditis patients. Wall movement abnormalities on echo or systolic dysfunction are a warning sign of myocarditis and/or MI. As the ECG findings in myopericarditis are focal in 50% of cases, differential diagnosis from AMI can be difficult. The presence of PR segment depression on II is a valuable finding of myopericarditis [19]. It has been suggested that coronary thrombus, coronary spasm, coronary artery embolism, large vessel and microvascular vasculitis could be reasons for MI seen in myopericarditis [33, 34]. In follow-up,

> **Cardiac angiography**

Coronary artery thrombosis

**Magnetic resonance**

Increased focal involvement

Normal Increased signal in the myocardium and increased contrast involvement in the myocardium and myocardial thickening

**Telecardiography**

Cardiomegaly Necrosis and inflammatory cells in the involved area

Elevation of troponin, and CKMB levels

Normal Necrosis in the involved area

**Biopsy Labo-**

Myocardial Infarction in Children

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http://dx.doi.org/10.5772/intechopen.74793

**ratory**

Elevated levels of Troponin, CKMB

megaly on telecardiography and pericardial effusion on echo (**Table 6**).

**ECG Echocar-**

ST elevation T-wave changes, pathological Q wave, Ventricular arrhythmia, extended QT distance

Sinus tachycardia, low voltage, PR segment depression, ST elevation, T-wave changes

**Table 6.** Differential diagnosis of myocardial infarction and myocarditis.

**diography**

Segmentary wall movement abnormalities, reduction in EF, papillary muscle rupture, left ventricle free wall rupture

Pericardial effusion, reduction in EF, segmentary wall movement abnormalities

**Table 5.** Taylor classification of congenital coronary artery abnormalities.

#### **8. Kawasaki disease**

Kawasaki disease is a self-limiting acute vasculitis. Children aged between 5 months and 5 years are especially sensitive to Kawasaki disease. It is one of the most common causes of vasculitis and MI in children [41, 42]. Destruction in the coronary arteries, ectasia and coronary artery aneurisms are frightening complications of the disease [43]. Diagnosis is made from the presence of four of the five diagnostic criteria together with unexplained fever ongoing for at least 5 days. The diagnostic criteria are bilateral non-purulent conjunctivitis, oropharynx changes, cervical lymphadenopathy, persistent oedema in the hands and feet and erythematous rash.

#### **9. Takotsuba cardiomyopathy**

Takotsuba cardiomyopathy is a benign clinical condition characterised by chest pain, elevated ST segment on ECG and elevated cardiac enzymes [31]. It is thought to be stress-related. It develops more often with emotional stress and sometimes related to physical stress. Due to chest pain and shortness of breath, it mimics acute myocardial infarction. There is ballooning and/or systolic dysfunction on echo or left ventriculography [32]. Coronary angiography is normal and there is no coronary artery disease. Cardiac enzymes are normal or may be slightly elevated.
