Objective

The objective of the assessment was to estimate the effectiveness and cost-effectiveness of dual-chamber pacemakers versus single-chamber atrial or single-chamber ventricular pacemakers in the treatment of bradycardia due to sick sinus syndrome (SSS) or atrioventricular block (AVB).

Description

A pacemaker consists of a small, battery-powered generator and one or more leads. In a single-chamber system, one lead is used, most commonly pacing the right ventricle. Dual-chamber pacemakers have two leads, placed in the right atrium and right ventricle. They act synchronously when a slow natural heart rate is detected to mimic the sequential physiological contraction of the atria and ventricles.

Single-chamber pacemakers may be atrial or ventricular. Atrial pacemakers are used where slow heart rate is due only to sinoatrial disease, i.e. where conduction between the atria and ventricles is intact. Single-chamber ventricular pacemakers, which are much more commonly used in practice, are appropriate where conduction between the atria and ventricles is impaired.

Epidemiology and background

Bradycardia is abnormally slow heart rate. SSS is present when the heart's natural pacemaker, the sinoatrial node, fails to initiate cardiac contraction. It is mainly the result of chronic fibrodegenerative processes or local calcification in the atrial wall. Prevalence is around 0.03% and rises with age. AVB denotes defective conduction of the atrioventricular conduction system. It may be progressive, with higher grades carrying worse prognosis. Prevalence is around 0.04% and is higher in the elderly and in men.

Methods

A systematic review was carried out of randomised controlled trials (RCTs) of the effectiveness of dual-chamber pacemakers in the relevant populations compared with either ventricular or atrial devices. Studies were identified by searching electronic databases and relevant Internet sites, contact with device manufacturers and experts in the field, and searching bibliographies of studies retrieved. Inclusion criteria were applied by two researchers and related to the populations of interest, study types (systematic reviews or RCTs), language (English only), interventions (minimum 48 hours) and outcomes (restricted to patient-based measures). Data were extracted by one researcher and checked by another. Tabulation and narrative synthesis were carried out. Quality was appraised using standard frameworks, but not summary scores. Meta-analyses, using random effects models, were carried out where appropriate. Limited exploration of heterogeneity through stratification was possible.

A literature search was carried out for published economic evaluations or systematic reviews of such studies. Economic evaluations submitted to the NHS National Institute for Health and Clinical Excellence were obtained. Critical appraisal was carried out using two frameworks, for generic and decision-analytic economic evaluations.

A decision-analytic model was developed in a spreadsheet program, using a Markov approach, to estimate the cost-effectiveness of dual-chamber versus ventricular or atrial pacing over 5 and 10 years from the perspective of the UK NHS as cost per quality-adjusted life-year (QALY). Uncertainty was explored using one-way and probabilistic sensitivity analyses.

Results

Conclusions

Dual-chamber pacing results in small but potentially important benefits in populations with SSS and/or AVB compared with ventricular pacemakers. There is no evidence of superiority in terms of mortality in the medium term (up to 5 years), which increases the importance of intermediate outcomes such as AF and of impacts on quality of life through, for example, pacemaker syndrome.

As well as the potential avoidance of a small number of important cardiovascular disease consequences, pacemaker syndrome is a crucial factor in determining cost-effectiveness. However, difficulties in standardising diagnosis and measurement of severity make it difficult to quantify precisely its impact.

At 5 years, dual-chamber pacing in SSS and AVB is likely to yield additional QALYs at a cost of less than £10,000, although there is some uncertainty around this estimate, particularly with regard to pacemaker syndrome. More conservative assumptions suggest that the cost-effectiveness ratio may be around £30,000 per QALY.

The evidence base comparing dual-chamber with single atrial pacing is much smaller and less robust. A single, small, parallel pilot RCT is available and informs the cost-effectiveness analysis. This suggests that atrial pacing is likely to be cost-effective compared with dual-chamber pacing.

Dual-chamber pacing is in common usage in the UK. Recipients are more likely to be younger. Insufficient evidence is currently available to inform policy on specific groups who may benefit most from pacing with dual-chamber devices, although overall the assessment is that the technology is likely to yield benefits at a level that is generally considered acceptable value for money compared with ventricular devices.

Need for further research

The following areas are recommended for further research.

• An individual patient data meta-analysis of existing trials is required and underway.
• Further trials of dual versus atrial pacing are required and one is underway (DANPACE).
• Publication of the economic evaluation of UKPACE and reporting of utility by health state is needed urgently.
• Further research into the classification, diagnosis and utility associated with pacemaker syndrome is needed.
• There is currently no evidence for the effectiveness of pacemakers in children.

Publication

• Castelnuovo E, Stein K, Pitt M, Garside R, Payne E. The effectiveness and cost-effectiveness of dual-chamber pacemakers compared with single-chamber pacemakers for bradycardia due to atrioventricular block or sick sinus syndrome: systematic review and economic evaluation. Health Technol Assess 2005;9(43). [PubMed: 16266560]

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The research reported in this monograph was commissioned and funded by the HTA Programme on behalf of NICE as project number 03/25/01. The protocol was agreed in December 2003. The assessment report began editorial review in September 2004 and was accepted for publication in October 2004. The authors have been wholly responsible for all data collection, analysis and interpretation, and for writing up their work. The HTA editors and publisher have tried to ensure the accuracy of the authors' report and would like to thank the referees for their constructive comments on the draft document. However, they do not accept liability for damages or losses arising from material published in this report.

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