A 30-year-old primiparous female was admitted to the labor and delivery suite with a 39-week intrauterine pregnancy. She had experienced a spontaneous rupture of membranes in early labor, with a cervical dilation of 4 cm and the attending OB/GYN physician requested that the epidural be placed. With the patient in the left lateral decubitus position a #18 Tuohy-Schliff needle was used with the "loss of resistance" technique. The epidural catheter easily threaded to 3 cm and was negative on aspiration for blood or cerebrospinal fluid. A test dose solution of 3 mL of 1.5% lidocaine with epinephrine 1:200,000 was slowly injected. After 2 minutes, the patient stated that she felt palpitations beginning. The heart rate increased from 88 to144 beats per minute. The blood pressure remained at 110/70, and the oxygen saturation was 96% on room air. The patient was experiencing only slight lightheadedness during this entire time and it was decided to administer adenosine. Adenosine is most effective for treatment of which of the following conditions?
Select one of the following: