A 19-year-old long-distance runner, who finished in the top 10 of the local marathon last year, presents for cardiac evaluation after his primary care physician ordered a Holter monitor for screening purposes. On his Holter report, several episodes of second-degree, Mobitz I (Wenckebach) AV block were noted, all occurring during sleep. The patient reports no symptoms but thinks he may have a grandfather who had a pacemaker implanted at an advanced age. What is the most appropriate next step?