Article type
Year
Abstract
Objective: Pacemaker therapy is widely recognized as effective treatment of symptomatic bradycardia. Older pacing technology enabled pacing of right ventricle only. Recent dual-chamber pacemakers can sense the activity of, and pace, both the atrium and the ventricle and thus are more physiologic than older ventricular pacemakers. Retrospective studies reported that physiologic pacing compared to ventricular pacing reduces development chronic atrial fibrillation, stroke and cardiovascular mortality in patients with sinus node disease or complete heart block. Randomised prospective studies (including large trials) testing hypothesis on benefits of physiologic pacing on mortality did not yield conclusive results. Meta-analyses are now widely used to provide evidence to support clinical decision making or to show the need for further research. The aim of this study was to assess the influence of pacing mode on survival and risk of atrial fibrillation in patients with atrioventricular block or sinus node disease.
Methods: Studies were selected using MEDLINE database and expert's consultations. Results of five randomized, controlled trials that were published (the New England Journal of Medicine, the Lancet, the Circulation) or announced (NASPE conference) were included into analysis. Data were extracted from published materials and odds ratio for death from all causes and for incidence of atrial fibrillation were calculated. A random-effects model was used to quantify the average effects of physiologic pacing (defined as atrial or dual-chamber pacing) on survival and on risk of atrial fibrillation.
Results: There was a highly significant heterogeneity between studies' results (p<0.0001). In five trials (5408 patients) the effect of physiologic pacing was associated with odds ratio 0.73 (95 % confidence interval, 0.64 to 0.83) for death from all causes. Analysis of patients with sinus node disease revealed more benefits of physiologic pacing compared to ventricular pacing: odds ratio 0.62 (95 % confidence interval, 0.5 to 0.79). Odds ratio related to physiologic pacing calculated only for patients with atriovevtricular block (data from two studies) was not significantly associated with better prognosis: odds ratio 0.85 (95 % confidence interval, 0.61 to 1.19). Assessing the risk for atrial fibrillation for all patients physiologic pacing was also associated with better outcome (odds ratio 0.8 (95 % confidence interval, 0.74 to 0.87).
Conclusion: These results support a general recommendation to use physiologic pacing in the treatment of symptomatic sinus node disease. However, results from this meta-analysis are not in accordance with the results of the largest trials CTOPP (The Canadian Trial of Physiologic Pacing, 2568 patients) and MOST (Mode Selection Trial in Sinus Node Dysfunction, 2010 patients) that showed small or even no benefit on survival. Further long-term studies of the effects of physiologic pacing on mortality and morbidity may clarify the disagreements as to the role of more advanced pacing technology in the treatment of complete heart block and sinus node disease.
Methods: Studies were selected using MEDLINE database and expert's consultations. Results of five randomized, controlled trials that were published (the New England Journal of Medicine, the Lancet, the Circulation) or announced (NASPE conference) were included into analysis. Data were extracted from published materials and odds ratio for death from all causes and for incidence of atrial fibrillation were calculated. A random-effects model was used to quantify the average effects of physiologic pacing (defined as atrial or dual-chamber pacing) on survival and on risk of atrial fibrillation.
Results: There was a highly significant heterogeneity between studies' results (p<0.0001). In five trials (5408 patients) the effect of physiologic pacing was associated with odds ratio 0.73 (95 % confidence interval, 0.64 to 0.83) for death from all causes. Analysis of patients with sinus node disease revealed more benefits of physiologic pacing compared to ventricular pacing: odds ratio 0.62 (95 % confidence interval, 0.5 to 0.79). Odds ratio related to physiologic pacing calculated only for patients with atriovevtricular block (data from two studies) was not significantly associated with better prognosis: odds ratio 0.85 (95 % confidence interval, 0.61 to 1.19). Assessing the risk for atrial fibrillation for all patients physiologic pacing was also associated with better outcome (odds ratio 0.8 (95 % confidence interval, 0.74 to 0.87).
Conclusion: These results support a general recommendation to use physiologic pacing in the treatment of symptomatic sinus node disease. However, results from this meta-analysis are not in accordance with the results of the largest trials CTOPP (The Canadian Trial of Physiologic Pacing, 2568 patients) and MOST (Mode Selection Trial in Sinus Node Dysfunction, 2010 patients) that showed small or even no benefit on survival. Further long-term studies of the effects of physiologic pacing on mortality and morbidity may clarify the disagreements as to the role of more advanced pacing technology in the treatment of complete heart block and sinus node disease.