NICOR: National Institute for Cardiovascular Outcomes Research

The National Audit of Cardiac Rhythm Management (CRM device) audit details clinical activity in the fields of:

• pacemakers (for the treatment of blackouts and other symptoms);
• implantable defibrillators (for the prevention of sudden cardiac death);
• cardiac resynchronisation therapy (for the treatment of heart failure); and
• catheter ablation (for the treatment of simple, complex atrial, and ventricular arrhythmias)

These current data provide a comparative measure of clinical procedure volumes within the populations of health geographies for Integrated Care Boards (ICB) in England and Local Health Boards (LHB) in Wales, as well as showing change of activity over time. Although the age of the patient is included with device implant data, more than 17% of cases in the audit data have no age at procedure recorded, so age-adjustment has not been undertaken in the calculation of rates presented here. For this reason, device implant rates should be treated with caution when comparing between areas. Rates for ablation are also unadjusted for age, as the indications for ablation are not as clearly related to age. Data are shown as maps and the user can click on each geography to show rates and confidence intervals.

Crude rate (per million population) of of device implants in ICB and LHB areas in England and Wales. Rates are available for:

• New implants of pacemakers
• New implants of ICDs
• Total implants of CRTs
• Total implants of CRT-D and CRT-P
• Total implants of high energy devices (ICDs and CRT-D devices)

• Simple ablation
• Complex atrial ablation
• Ventricular ablation

Devices and ablation data: CRM audit, held by the National Institute for Cardiovascular Outcomes Research (NICOR)
Denominators for total crude rates: Office for National Statistics (ONS), mid year population estimates. Denominators for 2021 are 2020 populations due to no official 2021 ICB populations estimates available at the time of publication.

In order to compare device implants accross geographical areas, the numbers of procedures were aggregated by either ICBs in England or LHBs in Wales, based on the residence of the patient. Procedures were aggregated by year and geography for defined device and ablation types.
Rates for devices and ablations are not age-adjusted. Rates include 95% confidence intervals to help with comparability.
Confidence intervals are calculated using Byar's method¹ and this method gives very accurate approximate confidence intervals for counts based on the assumption of a Poisson distribution. This method was used to provide confidence around the rates.

¹ Breslow NE, Day NE. Statistical methods in cancer research, volume II: The design and analysis of cohort studies. Lyon: International Agency for Research on Cancer, World Health Organization; 1987:69

Estimates for geographical areas are based on the patient's postcode of residence. Postcode assignment to a valid health area was over 97% complete for patient details treated at England or Wales hospitals in the CRM audit, so there are a small number of records that have not been mapped to a geographic location. Due to the processing of the audit data in 2023 there may be a very small number of Northern Ireland patients included in the England and Wales data, due an incorrect mapping of their place of residence.
Where the numbers of procedures each year within geographies are less than 6, no rate has been calculated.