Normal sinus rhythm with Mobitz I second-degree AV block

Normal sinus rhythm with Mobitz I second-degree AV block. Lead V1 and lead II rhythm strips show a regularly irregular rhythm with group beat. There are distinct P waves before each QRS as well as during the relative pauses. The P-P interval is constant, consistent with a sinus rhythm at a rate of 80 bpm. There is progressive prolongation of the PR interval followed by a dropped beat (nonconducted sinus P wave), reflective of Mobitz I second-degree AV block.