Advice

Clinical and technical evidence

Clinical and technical evidence

A literature search was carried out for this briefing in accordance with the interim process and methods statement. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology. Further information about how the evidence for this briefing was selected is available on request by contacting mibs@nice.org.uk.

Published evidence

Five prospective studies are summarised in this briefing. In total, there were 189 people included in these studies.

The clinical evidence and its strengths and limitations is summarised in the overall assessment of the evidence.

Overall assessment of the evidence

One of the studies has an appropriate sample size and relevant long-term outcome measures. It was also done partly in the UK, so it's relevant to the NHS. The other 4 studies are limited by their purpose: testing a new algorithm in a small group of people, comparing the accuracy of non-contact with contact mapping technologies without ablation, and assessing the characteristics of persistent atrial fibrillation. Although these studies are useful to the evidence base, they do not provide evidence on long-term treatment outcomes. Further data are needed to directly compare this new technology with standard care.

Willems et al. (2019)

Intervention and comparator(s)

The intervention was the AcQMap System. There was no comparator.

Key outcomes

Acute procedural efficacy was shown in 125 adults (98%). At 12 months, single-procedure freedom from atrial fibrillation on or off anti-arrhythmic drugs was 72.5% (95% confidence interval [CI] 63.9% to 80.3%). After 1 or 2 procedures, freedom from atrial fibrillation was 93.2% (95% CI 87.1% to 97.0%). However, 6 major adverse events were reported including 1 stroke, 2 cardiac tamponades, 1 air embolism causing ventricular fibrillation, 1 femoral arteriovenous fistula and 1 lymphocele.

Strengths and limitations

This study was not randomised and received funding from the company. However, the study included a large group of people and was conducted partly in the UK. The study also followed up procedural effectiveness for 12 months.

Ramak et al. (2020)

Intervention and comparator(s)

The intervention was the AcQMap System. There was no comparator.

Key outcomes

The new algorithm enabled mapping of stable and transient rhythms and identified arrhythmogenic areas in all participants. Acute ablation was successful. The study showed the procedure time was fast with a mean total procedure time of 56.4 minutes (range 12.1) and a mean fluoroscopy time of 13.6 minutes (range 9.49). There were no procedural complications.

Strengths and limitations

This retrospective study had a small cohort size, which limits the conclusions that can be drawn. It showed that the new SuperMap algorithm was safe and effective in the post-atrial fibrillation ablation atrial tachycardia group studied.

Shi et al. (2020a)

Intervention and comparator(s)

The intervention was non-contact (using AcQMap) and contact unipolar electrogram pairs recorded simultaneously from multiple locations. There was no comparator.

Key outcomes

This study aimed to validate the accuracy of non-contact electrograms against contact electrograms in the left atrium during sinus rhythm and atrial fibrillation. Seven hundred and ninety-six electrogram pairs in sinus rhythm and 969 electrogram pairs in atrial fibrillation were compared from 20 adults with persistent atrial fibrillation. The study found that the non-contact dipole density mapping system provided comparable reconstructed atrial electrogram measurements to contact mapping in sinus rhythm or atrial fibrillation in the left atrium when the anatomical site of interest is less than 40 mm from the mapping catheter.

Strengths and limitations

The study compared the accuracy of the electrogram measurements between contact and non-contact mapping methods. However, although the study said that participants had catheter ablation guided by non-contact dipole density mapping after the electrophysiological study, the outcomes of this procedure were not described.

Shi et al. (2020b)

Intervention and comparator(s)

The intervention was non-contact (using AcQMap) and contact unipolar electrogram pairs recorded simultaneously from multiple locations. There was no comparator.

Key outcomes

This study aimed to identify activation patterns in the left atrium during persistent atrial fibrillation using charge density mapping. The study analysed 144 atrial fibrillation segments with 1,068 activation patterns. It found that localised irregular activation was the most common pattern of activation, found in 63% of participants during atrial fibrillation. Ninety-six per cent of participants showed continuous and changing patterns of activation. The authors noted that the clinical implications of individualised ablation strategies need to be determined.

Strengths and limitations

The study showed the variability in activation patterns in people with persistent atrial fibrillation using non-contact mapping methods. However, although the participants identified needed a catheter ablation procedure, there were no clinical outcome data for this.

Chierchia et al. (2021)

Intervention and comparator(s)

The intervention was the AcQMap System. A further procedure using the CARTO 3D mapping system and PentaRay catheter was done in the same study group.

Key outcomes

All included participants had left atria mapping with both technologies. The study found that low voltage areas mapped with bipolar voltage mapping (using CARTO 3D mapping) in sinus rhythm and during coronary sinus pacing only partially overlap in persistent atrial fibrillation. Localised complex conduction cores from global non-contact mapping during persistent atrial fibrillation partially co-localise with low voltage areas. The authors suggested that using bipolar voltage mapping may not be the most appropriate method for identifying ablation areas in people with persistent atrial fibrillation. After an ablation procedure, atrial arrhythmia did not recur in 60% of participants during a 16-month follow-up period.

Strengths and limitations

The study was limited by a small sample size. Although there was procedure follow up, there was no clear evidence on whether atrial fibrillation recurrence was a result of the AcQMap mapping system. The authors said a key limitation of their study was that mapping with the 3D CARTO mapping system was not done in atrial fibrillation.

Sustainability

The AcQMap System, which includes the AcQMap Workstation, console and cabling, are reusable. Other equipment needed, including the AcQMap catheter, sheath, and patient electrode kit, are single use.

Recent and ongoing studies