Your hear rate, take by me to be as low as 40, is quite low and is likely the basis of the comment about a
pacemaker. Most people require 60 bpm and higher at rest to maintain good oxygen delivery. Some marathon athletes have rest HRs in the 40s and 50s, but the rest of us mortals don't have the powerful cardiovascular systems of these athletes.
Medications to slow the HR, e.g., Beta Blockers and others, are common, but I don't know of any heart meds to raise the HR.