Abstract
Objective: Report a patient case with false negative heart test result. Case Details: At birth, patient presented good general health according to mandatory hospital screening, in which he has hospital discharged. At 14 days of age, he presented central cyanosis, 70% saturation and pulmonary hiperflow, being diagnosed with transposition of large arteries. At 30 days of life, corrective surgery was performed, opting for Mustard/Senning technique. In 2018, it was identified atrial fibrillation in consultation with a pediatric cardiologist, with a probable consequence of medication-controlled right atrial dilation associated with systolic/diastolic murmur. In 2020, patient is in good general condition and is fit for recreational physical activities and physical education. Final Considerations: Actualmente el paciente está sano, aunque es más probable que comience con insuficiencia cardíaca debido a un déficit inotrópico debido a la técnica quirúrgica adoptada, que fue consecuencia del resultado erróneo de la pequeña prueba cardíaca.