This case report is kindly provided by Michael Rosengarten from McGill and is part of the McGill Cases. These cases come from the McGill EKG World Encyclopedia.
The rhythm is sinus, and the QRS is wide (>120ms.) There is a dominant R in I and V6 with the loss of septal q waves in I and the lateral precordial leads. There is a q in lead aVL but over all the recording suggests a left bundle branch block.
