Pacemakers are an effective clinical treatment for both slow and rapid arrhythmias. With the development of medical bioengineering and the broadening of indications, the use of pacemakers is becoming more widespread and the number of pacemaker placements is rapidly increasing. Since pacemakers have a useful life span, timely and accurate identification of pacemaker battery depletion is essential for pacemaker carriers and especially for pacemaker-dependent patients. Clinical signs of pacemaker battery depletion can be characterized by a decrease in pacing frequency, irregular pacing frequency, sudden or gradual decrease in magnetic frequency, change in pacing mode (e.g., DDD now becomes VVI, DOO becomes VOO), poor pacing or perception, increase in internal battery impedance, decrease in battery voltage, increase in pulse width, and a battery depletion curve suggesting gradual depletion of battery energy. We have found that the majority of pacemaker battery depletion is manifested by a decrease in pacing frequency and magnet frequency, an increase in pulse width, an increase in internal battery impedance, a decrease in battery voltage, and pacing or perceptual dysfunction, respectively, in more than 1000 pacemaker patients followed up over the years. For the sake of patient safety, the pacemaker was replaced in a timely manner, and the original pacing electrode was tested intraoperatively without any threshold increase or impedance change. The intraoperative test confirmed that the original pacemaker battery was depleted, which is rare. Through the treatment of these two patients, we learned that (1) electrophysiologists need to fully understand the knowledge about pacemakers, grasp the various manifestations of pacemaker battery depletion, and pay attention to follow-up, especially for patients with pacemakers that have been in place for a long time; treat the problems found during follow-up seriously and deal with them in a timely manner; test the parameters of the original pacing electrodes carefully during the replacement of pacemakers, check the pacing electrodes repeatedly under fluoroscopy, and connect the new pacemaker and electrodes intraoperatively. The pacing parameters should be tested before suturing the skin after connecting the new pacemaker and electrodes to avoid any missed diagnosis or misdiagnosis. (2) Patiently educate pacemaker patients about pacemakers and make them receive pacemaker follow-up visits on time (routinely 1, 3 and 6 months after surgery, and every 6 months or a year thereafter, and once every 3 months for late pacemaker placement or close to the guarantee period. If there is any discomfort, it is necessary to consult the doctor at any time). Regular follow-ups can detect pacing system malfunctions including increased pacing thresholds in time to ensure patients’ life safety and prevent problems before they occur.