Prevention of Pacemaker Malfunctions in Patients With Bradyarrhythmia: Results of a Single-Center Follow-up

Abstract

Objective: To evaluate results of surgical treatment in patients with bradyarrhythmia and risk factors for pacemaker (PM) malfunctions using improved preventive measures.Materials and methods: Our study consisted of two stages. At stage I, we retrospectively analyzed histories and outpatient medical records of 948 patients with various forms of bradiarrhythmias who underwent surgery in the clinic between 2006 and 2021 to identify PM malfunctions that occurred both in the early and late postoperative  periods. Based on the data on the most common types of PM malfunctions and possible risk factors for their development, preventive measures were improved in this cohort of patients and were further used at stage II (pilot) to select patients for surgery.During stage II (pilot), 188 patients were operated on between 2019 and 2021: risk factors for malfunctions were identified in 72 (38.3%) cases at the preoperative stage. All the patients underwent surgery with the proposed and improved preventive measures. Follow­up was during the hospital stay and in 6 and 12 months.Results: At stage I (retrospective analysis), 78 (8.23%) patients had signs of PM malfunction. The most common malfunctions were endocardial electrode displacement (30.8%), increased stimulation threshold (25.6%), a change in the endocardial electrode impedance (17.9%), and impaired sensitivity (10.3%). In addition, premature battery depletion and PM syndrome were present in 9% and 6.4% of the patients, respectively.The correlation analysis revealed that the most common findings associated with malfunctions were enlarged right chambers of the heart due to valvular defects and dilated cardiomyopathy, myocardial remodeling caused by chemotherapy and radiation therapy, postinfarction cardiosclerosis in the electrode implantation area, untimely and inadequate PM programming, as well as increased levels of blood uric acid, urea, and creatinine, and prolonged and uncontrolled use of steroid drugs and bronchodilators.At stage II, there were no PM malfunctions requiring changes in the pacing parameters during the hospitalization period. Six months postsurgery, 1 (1.4%) patient had an increase in impedance (to 2843 ohms) caused by the uncontrolled intake of high doses of corticosteroids due to decompensation of chronic obstructive pulmonary disease. After correction of the corticosteroids dose, the ventricular electrode impedance returned to the normal level. Twelve months postsurgery, 2 (2.8%) patients had a decrease in impedance to 215 and 143 ohms, respectively, caused by the ventricular electrode displacement. After correcting the electrode position, normal pacing parameters were restored. No cardiac complications due to malfunctions were observed. Morphofunctional parameters of the heart did not significantly differ when compared with preoperative ones.Conclusions: Surgical treatment of patients with bradyarrhythmia and risk factors for PM malfunctions who underwent surgery with the proposed preventive measures demonstrated high efficiency in reducing the number of malfunctions and cardiac complications associated with inadequate stimulation in the long­term follow­up.