There is no rigid cut-off for heart rate or age that would indicated a pacemaker for your mother. Permanent pacemakers are typically implanted for a slow heart rate that is causing symptoms such as fainting spells, lightheadedness, shortness of breath, or fatigue. The goal of implanting a pacemaker is to improve quality of life. Before deciding to implant a pacemaker, it would be important to determine that the slow heart rate at night is actually causing symptoms. It would be also important to consider your mother’s other health issues, as well as her own personal wishes about the goals of care at her age.