Prognostic Factors in Patients with an Implanted Pacemaker after 80 Years of Age in a 4-Year Follow-Up

Abstract

Background: The controversy over electrotherapy for patients aged >80 years occurs already at the stage of qualification for this treatment type and concerns optimal device selection, the implantation strategy, and the overall benefit from pacemaker therapy. The group also has a considerable number of cardiovascular risk factors, and the data from the literature on the impact of the pacing mode on the remote prognosis of this group are ambiguous. Objective: Assessment of the risk factors for death among patients with implanted pacemakers >80 years of age in a 4-year follow-up. Methods: The study group consisted of 140 consecutive patients (79 women) aged 84.48 ± 3.65 years with single- or dual-chamber pacemakers implanted >80 years of age because of symptomatic bradycardia. In univariate and multivariate Cox regression analyses, demographic, echocardiographic, and laboratory parameters, pharmacotherapy, and factors related to the implanted device - i.e., indications, pacemaker type, and the implantation position of the tip of the right ventricular lead - were included. The endpoint was death for any reason in a 4-year follow-up. Results: During follow-up, 68 patients (48.6%) died. Although atrial fibrillation with a slow ventricular response constituted 20% of the indications for implantation, 60.8% of the patients received a single-chamber system (VVI/VVIR). In the whole group, the multivariate Cox regression analysis showed both a favourable prognostic significance of DDD pacing system implantation (HR = 0.507; 95% CI: 0.294-0.876) and coexisting hypertension (HR = 0.520; 95% CI: 0.299-0.902). The risk factors were fasting glycaemia (HR = 1.180; 95% CI: 1.038-1.342) and, potentially, female sex (HR = 1.672; 95% CI: 0.988-2.830; p = 0.056). In the female subgroup a more favourable prognosis was related to the use of angiotensin-converting enzyme inhibitors (HR = 0.435; 95% CI: 0.202-0.933) and DDD pacemaker implantation (HR = 0.381; 95% CI: 0.180-0.806). In the male subgroup a more favourable prognosis was related to concerned patients with coexisting hypertension (HR = 0.349; 95% CI: 0.079-0.689). Conclusions: DDD mode pacing seems to serve as a factor which decreases mortality among patients aged >80 years in long-term follow-up. The potentially poorer prognosis for the female patients in this group may result from a combination of the dominant VVI pacing mode, potential propagation of atrial fibrillation, a low proportion of antithrombotic therapy, and sex-related predispositions to thromboembolic complications.