Implantation of Pacemakers in Patients with Chagas disease: A Case-Control Study of Associated Contextual Factors and Prognosis.

BACKGROUND

Chronic Chagas cardiomyopathy (CCC) is the most severe manifestation of Chagas disease and may present with bradyarrhythmias requiring pacemaker (PM) implantation.

OBJECTIVE

1. To identify contextual factors associated with PM implantation among individuals with CCC. 2. To assess the prognosis (death) in these groups over a 4-year follow-up period.

METHOD: 1. Nested case-control study within the SaMi-Trop cohort. We matched cases (patients with CCC who had a PM implanted between waves 1 and 2 of the study) with controls at a 1:3 ratio, considering equivalence in baseline cardiac severity. Independent variables related to the municipal context were considered. Binary logistic regression was conducted. 2. Survival analysis to evaluate the prognosis of these groups, adjusted for clinical variables (Cox regression), considering death as the outcome. Conclusions were based on a significance level of 5%.

RESULTS

The study included 46 cases and 138 controls. The odds of PM implantation were higher among individuals residing in municipalities with: larger population (odds ratio [OR]: 3.6; 95% confidence interval [CI]: 1.3 to 9.6), higher coverage of the Family Health Strategy (OR: 5.3; 95% CI: 1.8 to 15.8), and with a lower number of electrocardiographs per thousand inhabitants (OR: 2.6; 95% CI: 1.0 to 6.6). Considering 4 years of follow-up, death was observed in 32.6% of cases and 21.2% of controls. Only ejection fraction affected survival (relative risk: 7.2; 95% CI: 3.6 to 14.2).

CONCLUSION

Contextual factors interfered with PM implantation. However, PM implantation did not influence death over 4 years of follow-up, which was associated only with ejection fraction.