**1. Myocardial infarction in children**

Myocardial infarction (MI) is a clinical condition that develops in association with a sudden reduction or interruption of the blood flow in coronary vessels supplying the heart for various reasons. Coronary artery spasm and myocardial ischaemia are seen in the early stage of occlusion. If the relevant coronary artery is not rapidly re-channelled or cannot be re-vascularised, then MI develops [1]. Myocardial infarction is a common event in adults, but is not common among children. Furthermore, although the electrocardiographic, echocardiographic and

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

enzymatic diagnostic criteria of MI have been well defined in adults, in children there are some difficulties [2, 3]. As the cardiac structure changes with age, there are sometimes difficulties in the electrocardiographic diagnostic criteria of ischaemia.

complaints such as shortness of breath, sweating, palpitations or nausea [10, 11]. It must also be determined whether the child or any family member has any CHD and whether or not any

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Chest pain, which is one of the most significant symptoms for adults presenting to the Emergency Dept, is generally has a benign character in children. However, it is extremely important to decide whether or not the pain frequently seen in children is of cardiac origin [15]. Chest pain with cardiac origin in childhood can be classified in 3 groups; as structural heart diseases, inflammatory causes and dysrhythmias [10]. Structural heart diseases can lead complaints associated with an increased need for oxygen or a reduction in coronary blood circulation. These include events such as hypertrophic obstructive cardiomyopathy or aortic stenosis because of an obstruction in the left ventricle outlet tractus. Coronary artery abnormalities may also cause coronary ischaemia.

Chest pain with cardiac origin generally presents in situations where an increase in cardiac output is required. It is typically in the precordial or substernal region, in a constricting form and radiates to the left arm, neck and jaw. In some cases, there may also be shortness of breath, sweating, nausea, vomiting or syncope. In infants, the findings may be seen as feeding

After the anamnesis and physical examination, ECG examination must be made in all patients and X-ray imaging should be applied in order to exclude any respiratory causes [15]. In cases where the pain is thought to be of cardiac origin, troponin and creatine kinase myocardial band (CK-MB) levels must be examined and if necessary echocardiographic evaluation

family member has recently experienced any chest pain, or MI.

difficulties, crying and screaming (**Table 1**), [2, 6, 15, 16].

**Neonates Older children** Feeding problems Fatigue

Lack of interest in surroundings Lack of appetite Irritability Paleness Diarrhoea Dyspnoea Sweating Tachypnea Vomiting Tachycardia Pallor Hypotension Tachypnea Weak pulse

Dyspnea Rhythm irregularity Sudden paroxysmal abdominal pain Gallop rhythm

**Table 1.** Symptoms and physical examination findings in Paediatric myocardial infarction.

Cold extremities

Ventricular arrhythmia

Shock

Heart block

should be made [15, 17, 18].

Although MI is seen more often in the presence of congenital heart disease (CHD), it may also be seen in patients without CHD. Unlike atherosclerotic coronary artery disease in adult patients, ischaemia and infarct in children are often associated with coronary artery abnormalities and CHD [4]. In addition, congenital prothrombotic diseases, vasculitis, surgical or interventional procedures may also cause ischaemia and infarction [5]. Subendocardial ischaemia, especially aortic stenosis characterised by hypertrophy in the left ventricle is often seen in hypertrophic cardiomyopathy or hypertensive patients [2].

The most important risk factors in neonates and infants are the presence of CHD, coronary artery abnormalities and perinatal asfixia [5, 6]. The most frequently seen causes of Paediatric myocardial infarction (PMI) are abnormal left coronary artery originating from the pulmonary artery (ALCAPA) and Kawasaki disease [7, 8]. Patients undergoing arterial switch operations are also at increased risk for PMI [9].
