Second-Degree AV Block, Type I
This ECG is from an 80-year-old woman who had an acute inferior wall M.I. with a second-degree AV block.
Some people incorrectly call ALL second-degree AV blocks that are conducting 2:1 "Type II". This is incorrect, as Mobitz Type I can also conduct with a 2:1 ratio. The progressive prolongation of the PR interval will not be seen with a 2:1 conduction ratio, because there are not two PR intervals in a row.
