This ECG shows ventricular pacing. Note the pacer spike prior to each QRS complex, most apparent in leads V5 and V6. The P waves appear sinus in origin and have no association with the QRS ...

Also note the pacing spikes on this ECG are quite large. Older devices that were unipolar appeared like this, however most current pacemakers have quite small pacemaker spikes on the ECG which can ...