Below is a rhythm strip from a 60 year old woman who was treated with an atrial pacemaker for sinus node arrest with a nodal rhythm at 40/min. The pacemaker rate was set to 70/min. and no pacemaker activity was seen. The pacemaker rate was increased to 100/min. and still no pacemaker spikes were seen. Pacemaker spikes could only be seen by applying a magnet over the pacemaker.