56-Year-Old Female With Palpitations, Lightheadedness, and Chest Discomfort
56-year-old healthy female presents to the emergency department with palpitations associated with lightheadedness and chest discomfort. She has a 20-year history of Wolf-Parkinson White syndrome (WPW) and intermittent palpitations associated with lightheadedness, typically lasting 3-4 minutes. However, she sought medical attention because this particular episode persisted for over an hour. She has never had syncope. She also recently underwent exercise stress testing with nuclear imaging revealing no evidence of ischemia.
Physical examination notable for blood pressure of 151/73 and pulse rate of ~200bpm.
WBC 8.3 K/ul, Hct 43.8 %, platelets 327,000 K/ul
Glucose 136 mg/dl
BUN 14 mg/ul
Creatinine 1.0 mg/dl,
Na+ 139 mmol/L
K+ 3.4 mmol/L
CK/CK-MB/troponin T all within normal range.
Her presenting electrocardiogram is shown.
Based on the history and electrocardiogram, the most appropriate initial treatment would be: