Digital heart twin offers potential new tool for treating dangerous heart rhythms

Using computers to make a digital replica of the heart – a digital heart twin – can successfully identify problem areas deep in the heart muscle of people with a serious heart rhythm disorder, a new study finds. The research lays the groundwork for a new way of treating a life-threatening condition often caused by prior heart attacks or genetic heart disorders.

The study, published Monday in the American Heart Association journal Circulation, suggests digital heart twins could offer a non-invasive means of identifying the scarred parts of the heart muscle responsible for abnormal rhythms, allowing cardiologists to treat them faster and more effectively.

"People are now living with the consequences of heart attacks for many years, so the number of people who need procedures to treat these life-threatening abnormal heart rhythms is rising," said lead study author Dr. Michael Waight, a cardiology registrar at St George's University of London. "If digital twins were to become a reality, it could offer a safer and potentially more effective means of treatment."

Scar-dependent ventricular tachycardia, or VT, is a dangerous, sporadic, rapid heart rhythm caused by scar tissue on the heart muscle from a prior heart attack or a genetic condition. It is treated by implanting a defibrillator to shock the heart back into a normal rhythm as needed, or by inserting a catheter to ablate, or burn, scar tissue inside the heart so it can no longer cause abnormal rhythms.

Both treatments have their limitations, Waight said. Defibrillators don't stop abnormal rhythms from recurring, and repeated shocks can cause the patient discomfort and reduce their quality of life. But finding – and reaching – the scarred areas to ablate them can be challenging because scarring can occur at multiple sites and may be hidden deep in the heart where it's difficult to find.

To find scarred sites, surgeons first make a map of the inside of a patient's heart by inserting a catheter to detect electrical pulses that signal problem areas. They may also induce abnormal rhythms to better locate the source. Then they burn part of the scar tissue so it can no longer sustain the abnormal rhythm. Patients often experience surgical complications and high recurrence rates if all the sites are not found.

"It is quite a time-consuming process that isn't without risk," Waight said. "These patients can be quite sick, with poor heart function, and this is a long and arduous procedure. We're looking at ways we can improve that by hopefully trying to shorten the procedure, make it more accurate and more targeted to where the problem is."

Waight and his colleagues investigated whether digital heart twins could be used to predict areas where abnormal rhythms might occur. Using enhanced cardiac imaging and other data, they created computer models that mimicked the structure and function of the hearts of 18 people with scar-dependent VT who were undergoing catheter ablation. Using a catheter, they also mapped the inside of each participant's heart by inducing the abnormal rhythm to identify problem areas.

Researchers tested the digital models for rhythm problems similar to what the participants were experiencing in real life, Waight said. When they looked at abnormal electrical signals in the patients' actual hearts, he said the areas the digital twins predicted would be problematic had a 41% greater frequency of abnormalities than areas the twins had not flagged, suggesting the digital heart models could be used to identify potential treatment areas without the need for catheter mapping.

The digital twins also predicted about 80% of the sites in patients' hearts that had slowing of electrical signals, which occurs near scarring in the heart muscle. "Digital twins can render the heart in 3D and see exactly where the faulty circuit is," Waight said. "That means we can have an idea of the area to target before the patient even comes to the catheter lab facility. We already know where we need to go and don't need to spend hours making a map of the heart."

And, he said, using digital heart twins could potentially reduce the number of abnormal rhythm recurrences and the need for additional treatment. "The nature of the digital twin is that it doesn't just predict VTs the patient is having now, but also all possible VTs that might occur in the future."

Researchers have not yet tested the effectiveness of using digital heart twins to guide catheter ablations, Waight said. "The first step was to prove these places in the heart are important, compared to other places not picked up by the digital heart. The next step would be a clinical trial where we compare the current standard of care of VT ablation to a strategy where we are guided by the digital twin from the outset."

The findings show potential for reducing the time it takes to treat VTs while making those treatments safer and more effective, said Dr. Dhanunjaya Lakkireddy, executive medical director of the Kansas City Heart Rhythm Institute in Overland Park, Kansas.

"If you are able to successfully eliminate these areas that are potentially sites of ventricular tachycardias, you can reduce the time of the procedure and go precisely to the areas that are important with minimal unnecessary ablation," Lakkireddy said. "This could potentially improve overall morbidity and mortality with a higher success rate and result in dramatically improved patient outcomes."

The digital heart twin "gives you a road map of areas to focus on," said Lakkireddy, who was not involved in the research. "It's an incredibly powerful advancement. It's really moving the field forward, making these procedures a lot more effective and more precise."

However, he said, the procedure requires highly sophisticated technology, and access could be limited by cost.

"Whether we can apply this on a large scale is an open question," Lakkireddy said. "Creating a digital twin is a very expensive process at this time."