Woldemar Mobitz and his 1924 classification of second-degree atrioventricular block

Woldemar Mobitz, an early 20th century German internist, analyzed arrhythmias by graphing the relationship of changing atrial rates and premature beats to AV conduction. Through an astute mathematical approach, he was able to classify second-degree atrioventricular block into 2 types, subsequently referred to as Mobitz type I (Wenckebach) and Mobitz type II (Hay). Type I AV block was most often due to digitalis and was reversible. There were no associated pathological findings. Type II AV block frequently progressed to complete AV block and was associated with seizures, death, and pathological findings.