McGill Case 333

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 332 | Next Case: McGill Case 334

This is an electrocardiogram from an elderly man with a history of syncope. This electrocardiogram shows sinus rhythm at 74 per minute. The PR interval is grossly prolonged at 288 milliseconds, there's an R S R complex in V1 compatible with a right bundle branch block and a QRS axis of minus 83 degrees compatible with a left anterior hemi-block. Taking all three abnormalities together the tracing suggests a trifasicular block. This patient also had a Holter monitor that showed second-degree heart block and as a result a pacemaker was implanted because of his history of syncope.