(1) Introduction: In the last two decades, telemedicine has been increasingly applied to telemonitoring (TM) of patients with pacemakers; however, presently, its growth has significantly accelerated because of the COVID-19 pandemic, which has pushed patients and healthcare workers alike to seek new ways to stay healthy with minimal physical contact. Therefore, the main objective of this study was to update the current knowledge on the differences in the medium-and long-term effectiveness of TM and conventional monitoring (CM) in relation to costs and health outcomes. (2) Methods: Three databases and one scientific registry were searched (PubMed, EMBASE, Scopus, and Google Scholar), with no restrictions on language or year of publication. Studies published until July 2021 were included. The inclusion criteria were: (a) experimental or observational design, (b) complete economic evaluation, (c) patients with implanted pacemakers, and (d) comparison of TM with CM. Measurements of study characteristics (author, study duration, sample size, age, sex, major indication for implantation, and pacemaker used), analysis, significant results of the variables (analysis performed, primary endpoints, secondary endpoints, health outcomes, and cost outcomes), and further miscellaneous measurements (methodological quality, variables coded, instrument development, coder training, and intercoder reliability, etc.) were included. (3) Results: 11 studies met the inclusion criteria, consisting of 3372 enrolled patients; 1773 (52.58%) of them were part of randomized clinical trials. The mean age was 72 years, and the atrioventricular block was established as the main indication for device implantation. TM was significantly effective in detecting the presence or absence of pacemaker problems, leading to a reduction in the number of unscheduled hospital visits (8.34–55.55%). The cost of TM was up to 87% lower than that of CM. There were no significant differences in health-related quality of life (HRQoL) and the number of cardiovascular events. (4) Conclusions: Most of the studies included in this systematic review confirm that in the TM group of patients with pacemakers, cardiovascular events are detected and treated earlier, and the number of unscheduled visits to the hospital is significantly reduced, without affecting the HRQoL of patients. In addition, with TM modality, both formal and informal costs are significantly reduced in the medium and long term.