2017 AF Symposium

Live Case: Ablation Using Non-Contact Ultrasound Basket Catheter Dipole Density Mapping

Acutus Medical Non-Contact Dipole basket catheter with multiple electrodes.

Video streaming of an ablation from Na Homolce Hospital in Prague, the Czech Republic with Drs. Peter Neuzil, Jan Petru, and Jan Skoda.

The doctors used a new high resolution mapping system from Acutus Medical to identify in real time where his A-Fib signals were coming from.

Patient background: A 68-year-old man in paroxysmal A-Fib had a CHA2DS2-VASc score of 4 with hypertension and a pulmonary embolism. He had had a PVI in January 2011 and a repeat PVI to fix gaps in April 2011. His A-Fib recurred in 2014. Electrical cardioversions didn’t work.

Non-Contact Mapping with Ultrasound-Electrode Catheter

The Acutus Medical Non-Contact Dipole Density AcQ Imaging and Mapping catheter uses a basket catheter with multiple electrodes and ultrasound anatomy reconstruction.

‘Non-contact’ means the basket catheter can float freely in the left atrium and doesn’t have to be applied to the surface of the heart to generate A-Fib maps.

The basket catheter has six splines each with eight nodules that contain 48 ultrasound transducers and 48 electrodes. The ultrasound pings the atrium wall and rapidly produces a 3D left atrium anatomy.

Electrical Measurement: Dipole Density vs Voltage

For over one hundred years, voltage has been the major electrical measurement in cardiac medicine. The limitation with using voltage in electrophysiology is that the reading includes both the localized charge (Dipole Density) as well as the sum of the surrounding sources providing a broad, blended view of cardiac activity.

According to Acutus Medical, by eliminating these surrounding sources, and using dipole density (instead of voltage) the field of view becomes sharper and narrower.

This more precise electrical activation is displayed as a Dipole Density map on a 3D ultrasound reconstruction of the heart.

Acutus Medical Illustration: localized charge (Dipole Density) with the sum of the surrounding sources

Live Streaming Video: Ablation from Prague

In the live case, the EPs used the non-contact basket catheter to generate a 3D anatomy of the patient’s left atrium.

They produced propagation maps which looked like rotor action seen in other mapping systems, but sharper and with high resolution.

During the ablation, they used the basket catheter to re-map the left atrium. This showed that there were gaps in the ablation of one of the right vein openings which they corrected. When they made a mitral isthmus line, the patient’s A-Fib terminated which restored him to normal sinus rhythm.

What Patients Need To Know

May Replace Contact Mapping: Non-contact mapping is a significant innovation in catheter ablation and may eventually replace existing contact mapping catheters and make ablations easier. It also seems to require less technical skill than in a traditional contact mapping system.

“Non-contact mapping is a significant innovation and may eventually replace existing contact mapping catheters.”—Steve Ryan

No Radiation & Instantaneous: Using ultrasound to produce a 3D rendering of the heart is innovative and could change the way the anatomy of the heart is generated for an ablation. And unlike a CT scan, it doesn’t use radiation. Also, unlike a CT scan, the ultrasound images of the heart are generated instantaneously in real-time.

Higher Resolution: Dipole Density mapping may prove to be a higher resolution system than current mapping systems.

Not Yet Available in U.S.: But don’t expect the Acutus Medical System to become available in the U.S. any time soon. It isn’t yet FDA approved or available for sale in the U.S.

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If you find any errors on this page, email us. ♥ Last updated: Thursday, March 2, 2017

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