Physiological characteristics and heart rate characteristics of preschool children

The heart rate characteristics of different groups of people are different. For example, the heart rate of preschool children is faster than that of adults. And the younger the child, the faster the heart rate. If you want to determine whether your child has an irregular heart rate, you need to have a certain understanding of the normal heart rate values ​​for children at different stages. Below, we will introduce you to the relevant knowledge about children's heart rate in detail.

1. Characteristics of children's heart rate

The sympathetic nerves are dominant in the heart nerves of children, the vagus nerve has low excitability, and the cardiac output is limited. In order to meet the growth and development and vigorous metabolism, the heart rate can only be increased to increase the output. Therefore, children have a fast heart rate, and the heart rate gradually slows down with age. Newborns breathe 120 to 140 times per minute, children under 1 year old breathe 110 to 130 times per minute, children aged 2 to 3 years old breathe 100 to 120 times per minute, children aged 4 to 7 years old breathe 80 to 100 times per minute, and children aged 8 to 14 years old breathe 70 to 90 times per minute.

2. What are the characteristics of arrhythmia in children?

1. Sinus arrhythmia is the most common

It is the most common type of arrhythmia in children, followed by ectopic rhythm and conduction block. Among sinus arrhythmias, sinus tachycardia accounts for the majority. Sinus arrhythmia is also very common. Patients experience an increased heart rate during inhalation, which is more obvious during deep inhalation, and a slower heart rate at the end of inspiration. It often occurs during intense exercise, fever, crying, irritability, and emotional instability. The arrhythmia can disappear after the use of atropine.

2. Symptoms of neonatal arrhythmia

About 60% of children develop paroxysmal supraventricular tachycardia, and about 5%-10% of patients have pre-excitation syndrome, which is more common in children under 1 year old. As they grow older and their development gradually improves, the symptoms may be alleviated or disappear. The sinus rhythm of neonatal children is very unstable, and sinus tachycardia is prone to occur in infancy, which is common when they are nervous, crying, exercising or have a high body temperature.

3. Congenital atrioventricular block

Most of the arrhythmias in children are congenital. If the atrioventricular node and atrioventricular bundle are not connected to each other during embryonic development, congenital atrioventricular block may occur after birth. Grade I is generally asymptomatic, and the electrocardiogram only shows a prolonged PR interval; Grade II patients may experience symptoms of missed heart beats; Grade III patients may develop acute cardiogenic cerebral hypoxia syndrome due to their slow heart rate, which can be life-threatening.

4. Symptoms of arrhythmia during school age

Sinus bradycardia, wandering arrhythmias and incomplete bundle branch block are common in school-age children.

3. Which arrhythmias require treatment?

1. Sinus tachycardia. Sinus tachycardia is usually physiological and does not require treatment, but it should be excluded as a symptom of certain diseases, such as hyperthyroidism, myocarditis, etc.

2. Paroxysmal supraventricular tachycardia. Including preexcitation syndrome, atrioventricular nodal reentrant tachycardia, atrial tachycardia, atrial flutter, and atrial fibrillation, which is rare in children. In most cases, doctors can make the diagnosis by doing an electrocardiogram (ECG).

3. Atrial tachycardia (AT) accounts for about 6% to 10% of supraventricular tachycardia. In mild cases, atrial tachycardia occurs in short bursts, while in severe cases, the attacks may continue for several years without interruption, causing cardiac enlargement and heart failure. Some children can recover through antiarrhythmic drug treatment, but about 40% of children with atrial tachycardia are difficult to treat and various antiarrhythmic drugs are ineffective. Radiofrequency ablation can be considered.

4. Ventricular premature beats. Most patients have a good prognosis. Children with occasional premature beats often have no obvious symptoms and are often discovered during physical examinations or electrocardiograms. Long-term and frequent premature beats may lead to left ventricular enlargement and heart failure, and can be treated with antiarrhythmic drugs or radiofrequency ablation.