Heart trial doesn’t miss a beat

Biomedical engineers in the US have created personalised digital replicas of the upper chambers of the heart and used them to guide the treatment of patients suffering from persistent irregular heartbeats.

The team from Johns Hopkins University says its small proof-of-concept study is a promising step towards simulation-driven treatments and has the potential to eliminate the process of trial-and-error in treating heart rhythm disorders and prevent repeat procedures.

Clinical trials have been approved to begin later this year.

“The personalised digital replicas allowed us to accurately simulate and analyse heart electrical activity in 10 patients and determine where tissue needs to be destroyed,” says Natalia Trayanova, co-author of a paper in the journal Nature Biomedical Engineering. 

“The beauty of working with such replicas is that we could test for and predict where irregular heartbeats persist in ways we never could in the clinic.”

Atrial fibrillation – abnormal electrical signals stemming from the heart’s two upper chambers, the atria – is the most common cause of irregular heartbeats, and if left untreated can cause fatal strokes.

The typical treatment is catheter ablation: a catheter emitting radio frequencies is threaded into the heart to destroy tissue that sends off erratic electrical signals. 

However, some patients with a persistent form of atrial fibrillation and scarring in the atria often have to undergo multiple procedures because abnormal signals keep emerging from new areas of their atria. With each procedure, new scar tissue forms, which changes the atria’s electrical activity and makes targeting of the misfiring areas that much harder.

The new approach used contrast-enhanced MRI scans to create personalised digital replicas of the diseased atria for each patient.

The team ran initial simulations to predict erratic electrical signals and where tissue should be destroyed – and kept performing virtual ablations until no new arrhythmias emerged.

They then took the final “map” of tissue target areas to drive the clinical system for catheter navigation. Physicians steered the catheter towards tissue that was causing errant electrical firing, as well as tissue likely to cause future misfiring, as predicted by the simulations. 

Atrial fibrillation did not recur in any of patients over a more than 300-day observation period.

The entire process, from obtaining an MRI to displaying the final map in the operating room took less than a week. In the future, Trayanova hopes it can be shortened to a day.