Heart Lung Circ 2021 Mar 6;30(3):350-361. Epub 2020 Nov 6.
Department of Cardiology, The Royal Melbourne Hospital and the Department of Medicine, University of Melbourne, Melbourne, Vic, Australia; Cardioscan Pty Ltd, Melbourne, Vic, Australia. Electronic address:
The 12-lead resting electrocardiograph (ECG) of a patient with an implanted cardiac pacemaker is a snapshot of cardiac electrical activity at the time of recording and may provide valuable information on both pacemaker function and malfunction, as well as identifying the position of pacing leads in the heart. The traditional site for atrial pacing is within or adjacent to the right atrial appendage and paced P waves on the ECG have a normal frontal plane axis, whereas the traditional site for ventricular pacing is at the right ventricular apex with the ECG demonstrating a left bundle branch block configuration and a left axis. More recently, ventricular leads and to a lesser extent, atrial leads have been positioned in alternate non-traditional sites resulting in 12-lead ECG appearances which have characteristic features, that are generally poorly recognised. Read More