McGill Case 61

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 60 | Next Case: McGill Case 62

The rhythm is atrial flutter with flutter waves seen best in the inferior leads and in leads V1 to V3. The atrial rate is about 250/min. The QRS is wide (>120ms) an there is a tall R' wave in V1 and a shallow S in V6. The axis of the QRS seems normal. The EKG shows a right bundle branch block.

This second EKG is interesting as again it shows a supraventricular tachycardia with group ventricular beating with clusters of regular rhythm at about 215/min. The regularity and group beating suggest that this is an organized rhythm and not atrial fibrillation. Look carefully at the interval between the 6th and 7th beats in lead II. Clearly atrial activity is seen at about 215/min. This is an interesting case where the diltiazem has slowed down the SVT which has allowed faster conduction down the A/V node and hence an increase in the ventricular rate.