The increasing human lifespan and development of technology over the last number of decades has seen an increase in the number of pacemaker and implantable cardioverter defibrillator (ICD) implantations worldwide. Given the number of risk factors common to both heart disease and cancer, it is not uncommon for several of these patients to present for radiation therapy treatment each year. A systematic review was conducted using online databases Medline and Scopus. Results were grouped into in vitro and in vivo studies. In 1994, the American Association of Physicists in Medicine (AAPM) defined guidelines for the management of these patients, which have since been adopted by many radiation oncology departments internationally. More recently, a number of studies have reported an increase in radiation sensitivity of these devices (encompassing the coiled metal leads and generator unit) due to the incorporation of complementary metal oxide semiconductor circuitry. Further avenues of device failure, such as the effect of dose rate and scatter radiation, have only more recently been investigated. There are also the unexplored avenues of electromagnetic interference on devices when incorporating newer treatment technologies such as respiratory gating and intensity modulated radiation therapy. It is suggested that each radiation oncology department employ a policy for the management of patients with ICDs and pacemakers, potentially based upon an updated national or international standard similar to that released by the AAPM in 1994.