Swelling and inflammation in the left arm with a pacemaker?

Get it checked: If the pacemaker was recently put in, this could be from a partially obstructed vein which is preventing good blood flow. Also an infection could cause this. Also, if there was some difficulty accessing the vein to put the wires in, this could be what we call a hematoma which is pooling of blood under the skin which has leaked from a vessel. Have it checked.