A 40-year-old man is evaluated in the emergency department for syncope. He was attending a baseball game when he experienced a witnessed, abrupt episode of syncope while seated. He did not experience any prodromal symptoms. He sustained some facial trauma when he struck the railing in front of him. He has experienced near-syncope on several occasions in the past. His father died suddenly at age 50 years. The patient takes no medications and has no drug allergies.

On physical examination, the patient is afebrile, blood pressure is 125/64 mm Hg, pulse rate is 64/min, and respiration rate is 16/min. BMI is 26. Estimated central venous pressure is normal. Cardiac examination shows a regular rate with normal heart sounds and no murmurs. He has no peripheral edema.

Pertinent laboratory findings include a negative troponin test, a normal metabolic profile, and normal kidney function studies.

Electrocardiogram is shown. Echocardiogram demonstrates no structural heart disease and shows normal left ventricular function.

Which of the following is the most appropriate management?