How are you taking part in this consultation?

You will not be able to change how you comment later.

You must be signed in to answer questions

    The content on this page is not current guidance and is only for the purposes of the consultation process.

    Zio XT for detecting cardiac arrhythmias

    Closed for comments This consultation ended on at   Request commenting lead permission

    4 Committee discussion

    Clinical-effectiveness overview

    Zio XT is an innovative technology which shows promise for ambulatory monitoring

    4.1 The clinical experts who had experience of using Zio XT explained that it offers continuous monitoring over 14 days and is well accepted by patients. Experts commented on how easy it is to fit and the improved patient acceptability, adding that people are more likely to wear Zio XT for longer. The committee agreed that Zio XT is an innovative design and there is a plausible clinical benefit.

    The evidence shows that Zio XT can improve diagnostic yield and patient acceptability

    4.2 Evidence shows that Zio XT can increase patient wear time. Three of the 4 comparative studies showed improved diagnostic yield over total wear time compared with 24‑hour Holter monitoring. Eysenck et al. (2019) reported a longer wear time for Zio XT compared with the R-test (a cardiac event recorder). The clinical experts agreed that it was plausible that monitoring with Zio XT could increase diagnostic yield, primarily because Zio XT is worn for 14 days, which is much longer than the Holter monitor. The clinical experts also advised that Zio XT has usability advantages for patients: it is more convenient and discreet to use than a Holter monitor and the Zio biosensor stays on better. The committee concluded that Zio XT increases diagnostic yield for detection of cardiac arrythmias compared with 24‑hour Holter monitoring.

    The committee considers Zio XT to be a diagnostic service for detecting cardiac arrhythmia

    4.3 The committee questioned whether Zio XT is a diagnostic service. The company said that the Zio XT algorithm highlights areas of concern on the ECG trace, then a company-based cardiac physiologist reviews and confirms the arrhythmia type. A report including a sample of the ECG trace is generated for the referring healthcare professional. The company said that the technology is a decision support tool that provides a report allowing the referring healthcare professional to make a diagnosis. The company also said that full disclosure of ECG traces is available on request. The committee considered that, although the referring healthcare professional may override the arrythmia event summary in the Zio XT report, the initial diagnosis is made by the company's cardiac physiologist on the basis of events detected by the algorithm in Zio XT. The committee therefore concluded Zio XT to be a diagnostic service and so information on diagnostic accuracy is needed to fully assess the clinical benefit of Zio XT.

    Outcome measures

    Diagnostic accuracy is an important outcome that is not directly assessed against standard care

    4.4 The available evidence does not provide reliable estimates of diagnostic sensitivity or specificity. Although Hannun et al. (2019) showed that Zio XT's ZEUS algorithm was able to classify a broad range of distinct arrhythmias and performed with a similar accuracy to cardiologists, the study was not carried out in a clinical setting. Also, Zio XT's ECG recordings are captured using a single-lead biosensor while Holter monitors use 3 leads. Experts said that although 3‑lead ECG recordings may be better at detecting certain types of arrythmia, most clinical decisions can be made from 1 lead. The committee concluded that further research would be needed to confirm Zio XT's diagnostic accuracy in detecting cardiac arrhythmia compared with Holter monitoring.

    Other patient benefits or issues

    Shaving of bodily hair is common to both Zio XT and Holter monitoring and is unlikely to restrict access for patients

    4.5 Applying the Zio XT biosensor may require body hair to be shaved. Some religions forbid cutting or shaving body hair. The clinical experts advised that shaving is needed for both Zio XT and Holter monitoring. They believed this would not restrict access for particular groups of people and said that, in their experience, most people agree to shave when using the Zio XT biosensor.

    NHS considerations overview

    Information on whether Zio XT meets necessary technical standards is not available

    4.6 The algorithm used to analyse the data in Zio XT is based on a deep neural network (a computational model made up of multiple processing layers). The committee was not presented with information on whether Zio XT meets the Department of Health and Social Care's code of conduct for data-driven health and care technology in the NHS. NHSX has published a proposed NHS digital health technologies standard for digital technologies in the NHS, which is currently in consultation. NICE is commissioning some work to assess Zio XT's compliance with digital standards and to explore the use of artificial intelligence in the technology.

    Zio XT is scalable but there are concerns about the impact on NHS resource

    4.7 Clinical experts highlighted that there is currently a shortage of cardiac physiologists in the NHS, and that more widespread adoption of Zio XT in the NHS may further affect the recruitment of cardiac physiologists if they leave the NHS to work for the service. But they also said that reducing the burden on cardiac physiologists in the NHS of analysing ECG reports should be considered a benefit of Zio XT. The company said that it has the capability to scale up its service to the UK, and that it would adapt a successful model used in the USA. The company confirmed that the turnaround time for reports (4 days maximum but usually 24 hours) would not change. The committee was reassured that Zio XT is potentially scalable across the NHS but it was less certain about the impact on the NHS cardiac physiologist workforce.

    Cost modelling overview

    The EAC's updated model is acceptable but uncertainties remain

    4.8 The committee accepted the EAC's model but considered that, because of the uncertainties about the diagnostic accuracy of Zio XT, it was difficult to draw firm conclusions about any cost benefits. The committee concluded that further evidence on its diagnostic accuracy is needed to show if Zio XT is cost saving compared with standard care.

    Further information about resource use would be valuable

    4.9 In its base-case analysis, the external assessment centre (EAC) assumed that all monitoring tests would be followed up with an outpatient visit. Clinical advice was that outpatient visits are not usually needed after a negative result from Zio XT, and that practice varies. In scenarios in which follow-up outpatient appointments were included for standard care but not for Zio XT, Zio XT was cost saving across all 3 of the EAC's revised models. The committee also noted that the number of repeat tests and assumptions associated with them affect the cost modelling results. The committee concluded that further information about the resource implications of using Zio XT would be valuable to inform the cost modelling.

    Further research

    Further research is needed to address uncertainties about the diagnostic accuracy and resource use associated with Zio XT

    4.10 The committee concluded that further research is needed to address uncertainties about the diagnostic accuracy and resource use associated with Zio XT, compared with standard care using Holter monitoring or cardiac event recorder monitoring. This research should assess the diagnostic accuracy of Zio XT in detecting different types of arrhythmia compared with standard care over the same time period. Information on how Zio XT influences clinical decision making and the impact it has on resource use, in particular on the number of repeat tests and outpatient follow-up appointments, would be valuable to help inform cost modelling.