The Wenckebach phenomenon: a salute and comment on the centennial of its original description.

In 1899, Karel F. Wenckebach unraveled the complicated arrhythmia that bears his name--one of the most famous eponyms in medicine. He reported his findings before the benefit of clinical electrocardiography or the discovery of the sinoatrial and atrioventricular nodes. Born and educated in The Netherlands, Wenckebach first worked in Utrecht in the physiology laboratory of T.W. Engelmann, his respected mentor, where he became familiar with kymographic recordings and rhythm disturbances in frog experiments. He then entered country practice in 1891, where he gained great respect for practicing physicians as well as the importance of clinical experience. In 1896, he returned to Utrecht to work again in the laboratory with Engelmann. In 1898, a woman consulted Wenckebach about her irregular pulse. His investigation of her irregular heart action by using radial arterial pulse tracings and experimental atrial and ventricular pulse tracings from the heart of a frog enabled him to discover the mechanism of partial heart block. In later years, he continued to be a leader in academic medicine, chairing the departments of medicine in Groningen, Strasbourg, and Vienna. He achieved fame for investigating cardiac arrhythmias and other contributions and is considered to be one of the founders of modern cardiology. He is remembered for his insight into atrioventricular conduction, which is as valid today as it was a century ago.