The use of digital models of organs, or digital twins, for medical science, research and diagnostics has made significant strides in recent years. New research, carried out at St George's University in London, has shown that using a digital twin of the heart, a dangerous cardiac arrhythmia, scar-dependent ventricular tachycardia (VT), can be diagnosed more easily and without risky examination, potentially enabling new treatment options.
“People now live with the effects of heart attacks for many years, so the number of people needing procedures to treat these life-threatening abnormal heart rhythms is increasing,” he said. If digital twins became a reality, this could provide a safer and potentially more effective treatment option,” said Dr. Michael Waight, assistant professor of cardiology at St George's University of London and lead author of the study.
VT diagnosis and treatment
Scar-dependent ventricular tachycardia (VT) is a not common but very serious form of cardiac arrhythmia caused by Scar-dependent ventricular tachycardia. Two treatment options are available for this condition. Implanting a defibrillator is the least invasive, but depending on the nature of the condition, not always the best or desired solution. Ablation, by using a catheter to ablate (burn) the scar tissue in the heart so that it can no longer cause abnormal rhythms, is then the alternative.
However, this treatment also carries risks. To find scarred areas, surgeons first make a map of the inside of the patient's heart by inserting a catheter to detect electrical pulses that signal problem areas. They can also induce abnormal rhythms to better locate the source. Then they burn some of the scar tissue so it can no longer support the abnormal rhythms. Patients often face surgical complications and a high recurrence rate if all spots are not found.
“It is a time-consuming process that is not without risk. 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 shortening the procedure, making it more accurate and more focused on where the problem is,” Waight says.
Digital twin
Waight and his colleagues investigated whether a digital twin of the heart 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 underwent catheter ablation. Using a catheter, they also mapped the inside of each participant's heart by eliciting the abnormal rhythm to identify problem areas.
The researchers tested the digital models for arrhythmias similar to what the participants experienced in real life. Then they looked at abnormal electrical signals in the patients' real hearts and found that areas that the digital twin predicted would be problematic had a 41 percent higher frequency of abnormalities than areas that the twin did not flag. This suggests that 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 percent of places in patients' hearts where electrical signals were delayed. Something that occurs near scarring in the heart muscle. “Digital twins can render the heart in 3D and see exactly where the defective circuit is located. That means we already have an idea of the area to target before the patient comes to the catheter lab. We already know where to go and don't have to spend hours making a map of the heart,” Waight said.
The value of a digital twin in improving care for (cardiac) patients is also being researched in the Netherlands. Last year, researchers Lukas Dekker and Carlijn Buck of the TU/e and the Catharina Hospital mapped out how to use such a digital twin to provide better customized care for heart patients.
