A 75-Year-Old Natural Survivor with Uncorrected Tetralogy of Fallot Presenting with Hypoxic Spell

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease [1], with only a few patients reaching adulthood without surgical correction; ten percent may survive to their 30s but only 3% reach their 40s or older [2] and survival beyond the seventh decade of life is even rarer [3]. TOF comprises obstruction to right ventricular outflow tract (RVOT; pulmonary stenosis [PS]), ventricular septal defect (VSD), overriding of the aorta, and right ventricular hypertrophy. Systemic hypoxemia correlates with the degree of RVOT obstruction. TOF with hypoxic spells present as periods of profound cyanosis that occur because of almost total RVOT obstruction. The patients with severe RVOT obstruction have more frequent early hypoxic spell events. Unrepaired TOF patients with mild to moderate RVOT obstruction may be clinically silent until adulthood. So, hypoxic spell typically occurs in a crying infant but is rare in an adult [4]. We reported the case of a 75-year-old natural survivor with uncorrected TOF presenting with hypoxic spell. To our best knowledge, this is the oldest case of natural survivor with uncorrected TOF in Korea and the oldest patient presenting hypoxic spell worldwide.