Avenues for data sourcing in sudden cardiac death registries
| Benefits | Limitations | UCDP Registry implementation | |
| Ambulance-based out-of-hospital cardiac arrest (OHCA) registries | Many countries have well-established OHCA registries (figure 2) and use comparable Utstein variables. | Rates of first-responder reported OHCA have been shown to have significant mismatch when correlated with autopsy (ie, drugs may be responsible for cardiac arrest).25 Over-reporting of true rates will occur if limited to ambulance-reported OHCA only. | Ambulance data will be a key component of the UCDP Registry and a vital source of case detection. Data will be cross-referenced from other sources to enhance internal case verification and data quality. |
| In-hospital cardiac arrest registers | Most hospitals maintain a ‘Code Blue’ or cardiac arrest registry that can be accessed. | There are over 1300 public and private hospitals in Australia.42 Contacting each hospital and arranging ethical approval for release on in-hospital audits will be prohibitive. | The registry will be an OHCA registry only. The impact of this is discussed further in the article. |
| Forensic institutes: autopsy data | Autopsy is the gold standard investigation in verifying that a sudden death is cardiac in aetiology. | Rates of autopsy are falling.37 Autopsy-focused registries will capture only a subset of total sudden cardiac deaths. | Will be used to verify rates of sudden cardiac death and cross-reference with ambulance data. |
| Death certificate tracking | Should represent the broadest way of capturing the denominator as the endpoint. | Reported rates of death due to ‘sudden cardiac death’, ‘cardiac arrest’ and ‘heart failure’ are notoriously high: the positive predictive value of a death certificate stating ‘sudden cardiac death’ is only 19%.26 | Needs to be correlated against autopsy data as part of a multiple source surveillance protocol to reduce over-reporting. |
| Genetic heart disease registries or disease-specific registries (ie, Brugada syndrome) | There will be overlap between patients with genetic heart conditions (and their families) and sudden cardiac death. | Patients already known to have genetic heart disease and enrolled with disease-specific registries will receive appropriate therapy/devices and be anticipated to have a low rate of sudden cardiac death. | Primary utility may be in data linkage or dual referral to both UCDP Registry and disease-specific registry when a death occurs and culprit is identified. |
UCDP, Unexplained Cardiac Death Project.