The doctor is performing heart surgery. Photo: Sichuan Scol.

One of the first clinical trials using these personalized models showed that the technology could improve the treatment of ventricular tachycardia, a type of arrhythmia considered difficult to treat and a major cause of sudden cardiac arrest. This condition is thought to be linked to approximately 300,000 deaths annually in the United States.

The research conducted by a team of scientists at Johns Hopkins University is the first step. The U.S. Food and Drug Administration (FDA) has only recently authorized the "digital clone" technology to be used to guide treatment for 10 patients, and much larger studies are needed to verify the results.

However, results recently published in the New England Journal of Medicine reveal a noteworthy approach. Instead of stopping at testing, doctors can "try out" a digital version of the organ itself before intervening in the patient's body.

In medicine, 3D models, including both physical and computer models, have long been used to simulate disease or practice treatment techniques. However, according to biomedical expert Natalia Trayanova of Johns Hopkins University, a true "digital replica" is not just an anatomical simulation, but can also predict how a real organ will respond to different treatments.

In other words, this isn't just a "model to look at," but a "model to experiment with." Using advanced magnetic resonance imaging (MRI) and other data from each patient, Trayanova's lab builds interactive, multicolored models that recreate how the heart works.

According to her, the research team will conduct treatments on "twin bodies" before treating real patients, to see if the method is effective and whether any new problems arise that need to be addressed.

Based on the computer screen, colors like blue, green, yellow, and orange represent how electrical waves travel through healthy heart tissue before becoming trapped in damaged tissue. The electrical impulses can be held in a circular motion, like the swirling vortex of a storm. It is this swirling motion that causes arrhythmias.

The key to the technology is that it helps identify the dysfunctional area, where the electrical waves continuously collide and bounce back. When the research team tested cardiac ablation—a method of treating heart disorders by using hot or cold energy to create tiny scars in heart tissue, targeting areas of the heart causing arrhythmias—on the digital model, they could observe whether the problem had been resolved or whether a different type of arrhythmia had emerged, requiring further treatment.

If the disorder persists, they continue to "touch" another point on the model to try again. This allows for targeted treatment targeting to be done on the computer beforehand, rather than just in the operating room.

The heart contracts thanks to its internal electrical system. This system generates and transmits electrical impulses, helping the heart chambers contract in the correct order to pump blood throughout the body.

If a disorder occurs, most commonly ventricular tachycardia, the heart can beat too fast. This is because an electrical "wave" in the heart short-circuits in the two ventricles. As a result, the ventricles no longer pump blood effectively to the body. The heart then almost only "vibrates" instead of contracting normally. Other organs may be deprived of blood supply for a very short time, greatly increasing the risk of serious complications.

The primary treatment method currently used (cardiac ablation) aims to destroy areas of heart tissue that cause the heart's electrical signals to malfunction. However, precisely identifying the area to be ablated is not straightforward. This process is still somewhat trial-and-error, as patients must remain under anesthesia for many hours while doctors explore and determine the necessary intervention site.

Because it is difficult to determine the treatment goal from the outset, many patients require lengthy consultations. A significant number also need implanted defibrillators as a preventative measure.

A research team at Johns Hopkins University, based on a trial involving 10 volunteers, shifted the targeting of cardiac ablation to a simulation system, rather than relying on manual detection. More than a year after treatment, 8 patients no longer experienced arrhythmias. The remaining 2 had only one brief episode during their recovery.

According to Dr. Jonathan Chrispin, the lead author of the study, these results are better than the typical success rate of around 60%. In addition to shortening the time to find a treatment plan, the new method burns less heart tissue because it targets only the areas believed to be truly crucial.

Despite positive initial results, the study remains small-scale. The Johns Hopkins team says they hope to continue researching this approach in a larger trial involving more hospitals. They have also begun a trial using "digital clones" to treat atrial fibrillation, a more common type of heart rhythm disorder , and even cancer.