OK Guys I need your help. I am a nursing Student. We have a patient with A. Fib, CVA w/left sided weakness, COPD. Currently on beta blocker and anticoagulation therapy. We ambulated the patient with pulse ox to check exercise tolerance. She started at 95 O2 sat and pulse of 82. We walked 32 feet and suddenly the monitor is beeping and showing O2 sat of 93 but a pulse of 37. We put the patient back in her wheelchair. She was completely asymptomatic aside from the pulse dropping. She recovered to her usual 65 bpm in less than a minute.
Can anyone tell me why this patient's pulse would drop on excertion?