A 4-month-old infant with Tetralogy of Fallot presents with fever and loose stools. Which of the following is compatible with the diagnosis of Tetralogy spells?

Paroxysmal hypercyanotic attacks (hypoxic, "blue," or "tet" spells) are a paicular problem during the first 2 years of life. The infant becomes hyperpneic and restless, cyanosis increases, gasping respiration ensue, and syncope may follow. The spells occur most frequently in the morning on initially awakening or after episodes of vigorous crying. Temporary disappearance or a decrease in intensity of the systolic murmur is usual as flow across the right ventricular outflow tract diminishes.