A 3-month-old girl is brought to the physician because of poor feeding, sweating during feeding, and bluish discoloration of the lips when crying. She is below the 5th percentile for both height and weight. There is moderate cyanosis of the tongue and lips and clubbing of all fingers and toes. A right parasternal heave is felt. Heart sounds are normal. A grade 3/6 systolic ejection murmur is heard over the left second intercostal space. A grade 2/6 holosystolic murmur is heard over the left sternal border. Which of the following is the most likely diagnosis?