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Original research
Diagnostic accuracy of the magnetocardiograph for patients with suspected acute coronary syndrome
  1. Steve Goodacre1,
  2. Stephen J Walters1,
  3. Hasan Qayyum2,
  4. Frank Coffey3,
  5. Edward Carlton4,
  6. Timothy Coats5,
  7. William Glazebrook6,
  8. Lynda Unitt7
  1. 1 School of Health and Related Research (ScHARR), The University of Sheffield, Sheffield, UK
  2. 2 Emergency Department, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
  3. 3 Department of Research and Education in Emergency Medicine, Nottingham University Hospitals NHS Trust, Nottingham, UK
  4. 4 Emergency Department, Southmead Hospital, North Bristol NHS Trust, Bristol, UK
  5. 5 Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
  6. 6 St George's Emergency Department Clinical Research Unit, St George's University Hospitals NHS Foundation Trust, London, UK
  7. 7 Clinical Affairs Department, Creavo Medical Technologies, Coventry, UK
  1. Correspondence to Professor Steve Goodacre, School of Health and Related Research (ScHARR), The University of Sheffield, Sheffield S1 4DA, UK; s.goodacre{at}sheffield.ac.uk

Abstract

Background We aimed to estimate the diagnostic accuracy of the VitalScan magnetocardiograph (MCG) for suspected acute coronary syndrome (ACS).

Methods We undertook a prospective cohort study evaluating the diagnostic accuracy of the MCG in adults with suspected ACS. The reference standard of ACS was determined by an independent adjudication committee based on 30-day investigations and events. The cohort was split into a training sample, to derive the MCG algorithm and an algorithm combining MCG with a modified Manchester Acute Coronary Syndrome (MACS) clinical probability score, and a validation sample, to estimate diagnostic accuracy.

Results We recruited 756 participants and analysed data from 680 (293 training, 387 validation), of whom 96 (14%) had ACS. In the training sample, the respective area under the receiver operating characteristic (AUROC) curves were the following: MCG 0.66 (95% CI 0.58 to 0.74), MACS 0.64 (95% CI 0.54 to 0.73) and MCG+MACS 0.70 (95% CI 0.63 to 0.77). MCG specificity was 0.16 (95% CI 0.12 to 0.21) at the threshold achieving acceptable sensitivity for rule-out (>0.98). In the validation sample (n=387), the respective AUROCs were the following: MCG 0.56 (95% CI 0.48 to 0.64), MACS 0.69 (95% CI 0.61 to 0.77) and MCG+MACS 0.64 (95% CI 0.56 to 0.72). MCG sensitivity was 0.89 (95% CI 0.77 to 0.95) and specificity 0.15 (95% CI 0.12 to 0.20) at the rule-out threshold. MCG+MACS sensitivity was 0.85 (95% CI 0.73 to 0.92) and specificity 0.30 (95% CI 0.25 to 0.35).

Conclusion The VitalScan MCG is currently unable to accurately rule out ACS and is not yet ready for use in clinical practice. Further developmental research is required.

  • cardiac care
  • diagnosis
  • acute coronary syndrome

https://doi.org/10.1136/emermed-2020-210396

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    Footnotes

    • Handling editor Katie Walker

    • Contributors LU conceived the study. SG and SJW designed the study. HQ, FC, EC, TC, WG and LU collected the data. SJW analysed the data. All authors contributed to interpretation of the data and drafting the paper, and all authors approved the final draft.

    • Funding The study was funded by Creavo Medical Technologies. LU is an employee of Creavo Medical Technologies and a coauthor.

    • Disclaimer The authors had full access to the data. The authors were not involved in derivation of the MCG algorithm, which was undertaken by analysts from Creavo Medical Technologies. The statistical analysis presented in this paper was undertaken by SJW, with no involvement from the company other than provision of the algorithm.

    • Competing interests The University of Sheffield received funding from Creavo Medical Technologies for the time committed to the study by its employees (SG, SJW).

    • Patient and public involvement Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the Methods section for further details.

    • Patient consent for publication Not required.

    • Ethics approval The protocol was approved by the Sheffield Research Ethics Committee (reference 16/YH/0454).

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Data availability statement Data are available on reasonable request. Deidentified participant data are available on request from the authors.