We report 67-year-old woman with a sinus node dysfunction and diffuse conduction system disease, with a history of recurrent paroxysmal atrial fibrillation. She was admitted to the Hospital due to palpitations, dizziness, and vertigo, attributing the symptoms to the rhythm disorder described, for which the implantation of a pacemaker was indicated. With a history of tracheal cancer treated with radio and chemotherapy, and chronic steroid therapy for rheumatoid arthritis, she had an important limitation in vascular access for a conventional pacemaker, so, added to a high risk of infection, a decision was made to implant a leadless pacemaker. We discuss the electrocardiographic and clinical manifestations of sinus node disease, its relationship with oncological treatment and the indication for a permanent pacemaker, highlighting the characteristics of this new modality of artificial cardiac stimulation, for a special type of patients.