Hello I Am 27 Years Old Normally Pretty Healthy. I

Hello I am 27 years old normally pretty healthy. I have been running but all the sudden I get so short of breath. I hooked myself up to the EKG monitor it said my pulse 52 and SV bradycardia. I know what bradycardia is but unsure about SV. I am a nurse but don’t deal with ekg or heart monitors very often as I work in mental health