Dengue virus can affect the heart, with complications as bradycardia, arrhythmias, and death. We present a case of a 15-year-old patient, diagnosed 4 years before with severe idiopathic pulmonary hypertension, confirmed by catheterism, with continuous follow up. At that time, she was living in Bogotá (2640 m above sea level). Sildenafil and Macitentan were started. She was recommended to live at low altitude and she moved. The patient was transferred back to Bogota, from that place, due to flu-like symptoms and fever. Immunoglobulin M for dengue was confirmed and second-degree atrioventricular block Mobitz I with bradycardia (40 beats/minute) was documented throughout the clinical course. She recovered.