Objective: To investigate the effect of 12-lead electrocardiogram and 24-hour dynamic electrocardiogram in detecting pacemaker dysfunction and changes in cardiac function indexes in patients with pacemaker implantation. Methods: A total of 136 patients with pacemaker implantation in the First Clinical Medical College of Three Gorges University, Institute of Cardiovascular Disease of Three Gorges University and Yicang Central People’s Hospital from January 2023 to December 2024 were selected as the research objects. All patients received 12-lead electrocardiogram and 24-hour holter 3–14 days after implantation. Results: The overall detection rate of various types of pacemaker dysfunction by Holter was significantly higher than that by conventional ECG (27.21% vs. 5.15%, χ²=24.402, P < 0.001). The overall arrhythmia detection rate of Holter was significantly higher than that of conventional electrocardiogram (57.35% vs. 10.29%, χ²=67.277, P < 0.001). The time domain indexes of heart rate variability obtained by 24-hour continuous monitoring of Holter were significantly improved compared with those of conventional electrocardiogram (P < 0.05). Conclusions: Compared with 12-lead electrocardiogram, 24-hour holter monitoring can more accurately detect pacemaker dysfunction and arrhythmia in patients with pacemaker implantation, and provide more comprehensive data of heart rate variability, which is helpful for clinicians to better evaluate the cardiac function of patients and adjust treatment plans.