What is the most common arrhythmia found in children?

Sinus tachycardia is the most common arrhythmia found in children, primarily because it often serves as a physiological response to various stimuli, such as exercise, fever, anxiety, or pain. In children, the heart rate has a naturally higher baseline due to their smaller size and higher metabolic needs, making sinus tachycardia a frequent finding in both healthy and ill children.

Unlike more serious arrhythmias, such as ventricular fibrillation or atrial fibrillation, which can be life-threatening and are much less common in the pediatric population, sinus tachycardia is usually benign when related to physiological factors. Bradycardia, which represents a slower than normal heart rate, can occur but is less common and often indicative of underlying conditions requiring intervention.

In summary, sinus tachycardia arises as a normal adaptation and is therefore more frequently observed in children compared to the more severe or less common arrhythmias.