Whether a child’s arrhythmia is going to matter or not is determined by the type of arrhythmia. In the vast majority of cases, sinus arrhythmias and atrial arrhythmias are not life-threatening, such as sinus tachycardia, or sinus bradycardia, which is usually not life-threatening, and atrial tachycardia, which is not life-threatening either. However, ventricular tachycardia or junctional tachycardia requires treatment, such as paroxysmal supraventricular tachycardia or ventricular tachycardia that is difficult to correct, and can easily become life-threatening and require emergency treatment. Bradycardia conditions such as third-degree atrioventricular block are also life-threatening and require urgent treatment, and if it develops into ventricular fibrillation it requires immediate treatment and immediate resuscitation.