Sinus rhythm? The importance of systematic electrocardiogram readings

The electrocardiogram (ECG) is a fundamental diagnostic tool in pediatric care 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 boy aged 10 years with no relevant history and currently asymptomatic who, during a routine check-up, had a slightly elevated heart rate and irregular rhythm on auscultation. At first glance, the ECG appeared normal, but a subsequent systematic interpretation led to detection of ectopic atrial tachycardia (EAT) that was later visualized on a 24-hour Holter monitor, with persistent ectopic activity observed in more than 50% of the recording. The patient was referred to cardiology, where first-line treatment with bisoprolol was initiated, followed by radiofrequency ablation, which achieved complete resolution of the arrhythmia.

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