Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. I would like to tell you that pacemaker doesn t work in high pacing threshold setting which is very uncommon. Pacing threshold can increase on its own if there is an electrolyte imbalance, hypoglycemia, hypothyroidism or acid-base disorder has developed in the body. To avoid these complications your father needs to be very regular with meals, diet, medicines, blood test and personal physician consultations. He will also require pacemaker calibrations on very six months or as per his physician decides. Hopefully this information will answer your query.