The outlook with bundle-branch block.

A series of papers on patients with various degrees of heart block (Campbell, 1942, 1943a, b, 1944) was meant to be completed with one on bundle-branch block. But when the war ended, my Lumleian lectures on the paroxysmal tachycardias (Camp- bell, 1947) occupied all my time until I became deeply involved in problems of malformations of the heart and their surgical treatment. Recently, when clearing out some filing cabinets I found these data on 50 patients with bundle-branch block. As most of them had been followed till they died, it seemed possible that they might still be of interest, especially as one with left bundle-branch block when 32 is still leading an active life after another 32 years.