Prognostic importance of indication for pacemaker therapy on five-year survival after device implantation

Abstract Funding Acknowledgements Type of funding sources: None. Background Today's pacemaker patients are of increasing age, with more comorbidities, and with an increased mortality risk, especially from non-cardiac causes. On the other hand, the prognosis of patients after cardiac resynchronization therapy (CRT) is improving, due to advances in both the pharmacological treatment of heart failure and the development of pacemaker technology. Purpose Our goal was to examine the prognostic significance of the indication for pacemaker therapy on long-term survival after device implantation. Also, we aimed to compare the survival rate of these patients and those with structural heart disease (SHD) and implanted CRT-P. Methods This retrospective five-year survival analysis was conducted on all patients who had undergone permanent pacemaker implantation in a tertiary center during three years. The study group was divided into 4 subgroups depending on the indication for pacemaker implantation – patients with atrioventricular (AV) block, with sinus node dysfunction (SND), with permanent atrial fibrillation (AF), and with SHD and an indication for CRT-P implantation. We used patients' medical records to define indications for pacemaker implantation, and to collect data on patients' baseline characteristics. The patients’ survival status was determined on the basis of the recent pacemaker control, or examination at another department of our hospital, covered by a unique information system. For the remaining patients telephone follow-up was performed. To test the significance of the within-group and between-group differences we used t-test, chi square test and Kruskal-Wallis test with Dunn-Bonferroni post hoc analysis. Results We analysed 2029 patients who underwent pacemaker primo implantation from October 2014 to October 2017 and met the inclusion criteria: 799 with AV block (61.6% male, mean age 77.2 ± 10.9 years); 446 with SND (58.5% male, mean age 74.9 ± 11.2 years) , 437 with AF (62.6% male, mean age 76.6 ± 9.2 years ), 347 with SHD (76.1% male, mean age 65.4 ± 9.4 years). Patients with SHD were statistically significantly younger than patients from the other groups (p < 0.01). The mean time to fatal outcome was 3.7 ± 1.2 years, and was not significantly different between groups. Five-year survival in total study population was 40.1%, and it was statistically significant different among 4 groups of patients with different indications for pacemaker implantation (p < 0.01). The survival rate was highest in patients with SND, followed by SHD, and by far the lowest in patients with AF. Conclusion The indication for implantation of a permanent pacemaker significantly determines the five-year survival of patients with bradycardia, and it is the highest in patients with SND. Patients with SHD and implanted CRT are significantly younger and they have a statistically significantly higher five-year survival rate than both patients with AV block and AF with symptomatic bradycardia.