McGill Case 263

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. Previous Case: McGill Case 262 | Next Case: McGill Case 264

This is an important EKG. It shows the pacer working well, sensing the atrium and pacing the ventricle. Unfortunately the QRS morphology is very abnormal as it shows a RBBB with an extreme right axis deviation. This suggests that the lead is not in the right ventricle. In this case it was felt that the lead was stimulating the left ventricle through a sinus-venosis atrial septal defect.