Sinus rhythm? The importance of systematic electrocardiogram readings

The electrocardiogram (ECG) is a fundamental diagnostic tool in pediatrics for detecting arrhythmias. Its simplicity, low cost, and speed make it an accessible test for primary care pediatricians, especially when supported by a detailed medical history and physical examination.

We present the case of a 10-year-old boy with no relevant medical history and clinically asymptomatic who, during a scheduled check-up, was found to have a slightly elevated heart rate and irregular rhythm on auscultation. At first glance, the ECG appeared normal, but after systematic review, ectopic atrial tachycardia (EAT) was detected, which was subsequently visualized on a 24-hour Holter monitor, where persistent ectopic activity was observed in more than 50% of the recording. The patient was referred to cardiology, where initial treatment with bisoprolol was started, followed by radiofrequency ablation with complete resolution of the arrhythmia.

Although uncommon in children, AET can be silent and constitute a potential cause of tachycardia-induced cardiomyopathy. This case highlights the importance of systematic ECG interpretation in primary care, as well as the value of careful history taking and physical examination, even in the face of seemingly trivial findings. Early diagnosis and a coordinated approach with cardiology can prevent complications and improve prognosis.