<prompt> All of the following are features of Mobiz type I block except-Constant PR intervalNormal QRS morphologyRegular atrial rhythmAtrial rate more than ventricular rate  <response>: Type 1 Second-degree AV block, also known as Mobitz I or Wenckebach periodicity, is almost always a disease of the AV node. ... Today, Mobitz I hea block is characterized by progressive prolongation of the PR interval on consecutive beats followed by a blocked P wave i.e., a dropped QRS complex Ref Harrison 20th edition pg 1443 