First degree (prolonged PR) :
Mobitz I (prolonged PR, longer PR, even longer PR then dropped beat, cycle repeats. could be 2:1,3:1, etc.):
Treat underlying cause
Mobitz II (Just dropped beats. Constant PR intervals,no prolongation of PR with subsequent beats as in in type I):
3rd degree (No relationship between P and QRS waves and the P rate is faster than QRS rate):
Atropine is used in first degree and Mobitz I if the bradycardia is severe or symptomatic.
IV Atropine is first line in any severe symptomatic bradycardia.