This arrhythmia is characterized by a progressive delay of the conduction at the AV node, until the conduction is completely blocked. The next P wave occurs and the cycle begins again. Possible causes are acute inferior wall myocardial infraction, digitalis, beta blockers, calcium channel blockers, rheumatic fever, myocarditis, or excessive vagal tone. Rate is ususaly 60-100 beats per minute. Atrial rhythm is regular.
Ventricular rhythm is irregular.
P Wave configuration is normal. PR interval gets longer with each beat until QRS complex is dropped. QRS complex is normal, but is dropped periodically. ST Segment and T Wave are normal in configuration. It is usually associated with acute anterior or anteroseptal myocardial infarction.