This is a long MCL1, or V1, rhythm strip, in a patient with anterior-septal wall M.I. It is often seen conducting as a 2:1 block, but when consecutive p waves are conducted, the PR intervals remain constant. It is interesting that, when a p wave is not conducted, there sometimes occurs an escape beat with a right bundle branch block pattern: rsR' in V1. The pathologic Q waves are probably significant for necrosis, and Type II blocks are usually fascicular blocks with a tendency to be permanent and progressive. No 12 Lead ECG is available to enhance this rhythm strip.