A 31-year-old woman presents to the emergency department (ED) 20 minutes after the sudden onset of chest pain; palpitations; shortness of breath; and numbness of her mouth, fingers, and toes. She tells you that it feels like she has a lump in her throat. Her medical history includes multiple visits to the ED over a period of 6 months with a similar presentation. Her only medication is an oral contraceptive. She occasionally drinks a glass of wine after a busy day of work when she feels stressed. She tells you that her mom takes medication for anxiety. Her blood pressure (BP) is 125/75 mm Hg, heart rate (HR) 88 beats per minute, and oxygen saturation 99% on room air. An electrocardiogram (ECG) shows a sinus rhythm. Her symptoms resolve while in the ED. Which of the following is the most likely diagnosis?

a. Paroxysmal atrial tachycardia

b. Hyperthyroidism

c. Major depressive disorder

d. Panic disorder

e. Posttraumatic stress disorder