Complete heart block with narrow QRS

Complete heart block with narrow QRS subsidiary rhythm. Narrow QRS subsidiary rhythm occurs when the block is above the His bundle. In addition there are deep S waves in V3 and tall R waves in V5, with ST segment depression and T wave inversion in inferior and lateral leads, probably indicating left ventricular hypertrophy.

Leads I, II and III gives a superficial impression of 2:1 AV block, which is proved wrong by the subsequent leads. Such simulation of 2:1 AV block in short strips of a complete heart block is called “Accrochage”.