Beeping Funny

Since we started the Digoxin Macsen has been complaining his heart is "beeping funny." He means "beating" but it's adorable the way he says it. His hospital grade pulse oximeter died last month - of course it did- and the company wants $250 just to look at it :( We have a small drug store pulse ox but its pretty crappy. His fingers are so tiny it doesn't pick up very well either. I've contacted both of cards about his complaint. His local card said we can  try an event monitor but she has to order it - who knows how long this will take :(