The rapid development of modern medicine causes the implementation of more efficient, but also more complicated forms of treatment. An important role is played by electrophysiological techniques, among which the most common are heart pacemakers or systems stimulating the heart. The number of the heart pacemakers implantation is still increasing, and the population of patient with such devices is still growing. In Poland, 16 000 such devices are implanted every year, and 60‑70% of cases are the first implantations. Indications for this form of therapy are determined by the societies of cardiology and continuously modified due to the reliable results of randomized clinical trials. The heart pacemakers are used first of all in the treatment of patients with severe, symptomatic disorders of electrical conduction system of the heart. With the more widespread access to this form of therapy, it seems to be very important to know its possible failures, such as early and late surgical complications and non‑surgical problems. This paper describes the case of a female patient who experienced bradycardia with Morgagni‑Adams‑Stokes syndrome i.e. short, frequently recurring episodes of fainting or loss of consciousness due to hypoxia of central nervous system, caused by extreme slowing or stopping the heart rhythm. These symptoms occurred in the course of stimulation disorders caused by mechanical damage of atrial electrode. Rapid and accurate diagnosis allowed to implement proper treatment. Patient underwent the damaged lead extraction and the replacement of the heart pacemaker to new dual chamber device. This form of therapy was effective, the patient was released from symptoms. Such treatment significantly improved patients prognosis.