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February 9, 2022

Colour-mapped 3D imaging of fibrotic abnormalities in the heart has presented significant advantages for the diagnosis of cardiac arrhythmias and the planning of ablation procedures. But adoption of a complementary approach that combines this advanced technique with electrocardiogram (EKG), cardiac magnetic resonance imaging (MRI), and cardiac computerized tomography (CT) has been slow.

How can state-of-the-art cardiac fibrosis imaging be embedded into standard practice? That was the question that was posed to two experts - Antonio Berruezo from the Heart Institute at Teknon Medical Center, Barcelona, Spain, and Francis E. Marchlinski from the Perelman Center for Advanced Medicine, Philadelphia, Pennsylvania, USA – in a recent interview with the European Medical Journal.

The barriers to adoption

The latest cardiac fibrosis imaging techniques represent an opportunity to reduce complications, improve patient outcomes and streamline workflows. However, there are several apparent obstacles to adoption viewed by radiologists and electrophysiologists. These include concerns relating to patient safety, insufficient training, and organizational issues.

Before addressing these hurdles, the two cardiac fibrosis imaging pioneers were asked to describe the development of the advanced image processing software that has replaced black and white images with a full-colour, 3D anatomical reconstruction.

Taking cardiac imaging to the next level

Outlining the cardiac imaging advances made with 3D techniques, Marchlinski said: “The next step for us is [the implementation of] very sophisticated techniques where you can use reconstructed 3D images and get well-defined areas of normal and abnormal anatomy and integrate them into our mapping systems. It gives you a roadmap for where the anatomic abnormalities are, and where to focus your electrical recordings. It’s been breathtaking in terms of the information that can now be gleaned.”

Berruezo then outlined how acquired images are processed with Automatic Detection of Arrhythmic Substrate (ADAS 3D) software: “We use them to form the pre-procedure plan, and then start the procedure. The first step is the reconstruction of an anatomic structure, usually the aortic arch, with the mapping catheter for electroanatomic map, and image integration. The next step is navigation, without the need for fluoroscopy, and mapping directed to the scar identified by the images. Different mapping maneuvers can characterize the critical scar components as identified by the images.”

Combining electrical readings and imaging

It was emphasized that advanced cardiac imaging techniques are best used as part of a complementary approach for the diagnosis and treatment of arrhythmias, combining electrical readings and imaging.

Marchlinski stressed: “Electrical recordings are very valuable. We always say electrograms never lie.” He explained that imaging “works hand in glove with the electrical information” and that “it is not that each is perfect. When you use them together, your procedures are faster, and you focus your electrical readings in a more appropriate way. You apply the energy more safely.”

Better outcomes, fewer complications, and less early mortality

Imaging’s potential to decrease the need to induce VT in an ablation procedure means it could make treating hemodynamically unstable patients easier. Berruezo said, “this not only leads to better outcomes and fewer complications during ablation, but also decreases early mortality”.

So how can the obstacles which are slowing the adoption of advanced cardiac fibrosis imaging be overcome?

Addressing challenges

The 2019 Expert Consensus Statement on Catheter Ablation of Ventricular Arrhythmias recommends 3D imaging to guide VT ablation procedures, and the technique compared favorably with conventional mapping in a recent meta-analysis. Yet, there is still the perception of safety issues behind resistance to the introduction of 3D imaging into standard practice.

Marchlinski said: “In some radiology departments, there is still some concern related to the safety of imaging people with implantable electronic devices (IED), worries that it might create heating and damage the technology or the site where the leads contact with the heart.” There is also hesitancy due to the noise artifact that can occur when imaging patients with devices or leads.

He went on to suggest that these concerns could be abated by educating clinicians on data that supports the safety of the technology, contrary to these common perceptions.

Marchlinski explained: “The fear that has been associated with using MRI in people with devices should be forgotten. It should be embraced as a standard because it adds value. It has been tried and tested for years and there are plenty of publications and documents from the evidence-based literature to support this becoming the new standard of care.”

Cross-specialty collaboration

It is not just safety worries around devices and MRI that represent an obstacle. Organizational barriers have blocked the way to introducing advanced cardiac fibrosis imaging into standard practice. Cross-specialty collaboration – specifically between electrophysiology (EP) labs and radiology departments – is seen as the way forward.

“Everybody is using imaging now, so everybody has to stand in line,” Marchlinski said. “If you are going to start using it, you need to have a workflow, both in EP and radiology, that will facilitate that. It is critical these workflow issues are addressed.”

This calls for a synergy between both departments that enables the understanding of advanced imaging’s role, and adherence to standardized protocols. Training in 3D image acquisition and processing was also highlighted as necessary to bring radiologists up to speed with advanced techniques, while the challenge of gaining approval for additional costs should also be considered.

‘The sooner the better’

Berruezo advised clinicians around the globe to adopt advanced 3D imaging sooner, rather than later, as the technology looks set to develop and provide more opportunities further down the line.

Looking to the future, Berruezo projected: “We are at the era of ‘virtual dissection’. 3D anatomy and the possibility to see the structure of the heart and the substrate for VTs in 3D is providing a new way to learn. I’m sure we have only just begun to learn the possibilities of applying this technology to new ways of performing VT ablation.”