Abstract
Tachycardia is one of the most common presentations in medical practice. In most cases, it could be attributed to emotional problems, anemia, or thyroid disorders. A 16-year-old female visited primary care clinics with the complaints of palpitation for years and initially diagnosed as a case of anxiety or stress. Her condition worsened and became more symptomatic over the last few months for which investigations were done. A provisional diagnosis of pre-excitation syndrome, Lown-Ganong-Syndrome, was made. This was based on short PR interval in ECG and an attack of supraventricular tachycardia and another attack of brief atrial fibrillation in addition to the family history of her mother of having pre-excitation abnormality. She was sent to electrophysiological study where no concealed accessory pathway was confirmed, and the diagnosis of inappropriate sinus tachycardia was the final diagnosis and medical treatment was initiated.