Exploring key breakthroughs in VT ablation
Advances in cardiac mapping technology and the development of new energy sources are reshaping ablation therapies for ventricular tachycardia (VT), according to Roderick Tung, MD, chief of cardiology at the University of Arizona College of Medicine and director of the Banner Heart Institute.
Speaking with Cardiovascular Business, Tung said the field has made significant progress in understanding the electrical circuits that sustain VT. While early research in the 1970s and 1980s established that VT is driven by reentrant electrical circuits, today's sophisticated electrophysiology (EP) mapping systems allow physicians to visualize those circuits in unprecedented detail.
"We know what the animal looks like that we're hunting," Tung said. "Now it's about how do we destroy it, because that's how we're actually helping people."
Modern electro-anatomic mapping platforms can process thousands of electrical signals, helping electrophysiologists better identify the precise location, size and 3D structure of arrhythmia circuits. Physicians can now determine whether circuits lie on the inner lining of the heart, the outer surface or extend through the heart muscle, allowing for more targeted treatment.
While mapping has become increasingly precise, Tung said the next major challenge is improving the ability to create durable lesions that eliminate these circuits.
New ablation technologies aim for deeper lesions
One of the biggest areas of investigation is adapting pulsed field ablation (PFA) for ventricular arrhythmias. PFA has generated significant excitement for treating atrial fibrillation because it selectively destroys heart muscle while minimizing injury to surrounding tissues. However, Tung explained that the thicker ventricular myocardium presents a different challenge.
"If you've got a wall here and we only treat one surface, it's not enough," he said. "You need to get a full-thickness treatment."
Researchers are evaluating higher-voltage PFA systems that may produce deeper lesions capable of treating ventricular tissue. However, increasing energy delivery also raises important questions about maintaining the technology's favorable safety profile.
Another promising approach is ultra-low-temperature cryoablation, which freezes tissue to temperatures approaching minus 200 degrees Celsius in an effort to penetrate deeper into the ventricular wall.
Tung said both technologies share the same objective of creating deeper lesions that completely eliminate the abnormal electrical pathways responsible for VT.
Complex patients make VT ablation particularly challenging
Unlike many atrial fibrillation patients, individuals undergoing VT ablation often have advanced structural heart disease, weakened heart muscle and multiple medical comorbidities. These procedures frequently last several hours and require physicians to intentionally induce VT, which Tung said is the most dangerous arrhythmia, to identify and treat the abnormal circuits.
Because of the complexity and risks involved, VT ablation remains one of the most technically demanding procedures in cardiac electrophysiology and is not performed by large numbers of clinicians. Tung said ongoing improvements in mapping technology are helping with the identification of potential targets before arrhythmias are even induced. By recognizing scar patterns and electrical abnormalities during normal heart rhythm, physicians can better predict where VT circuits are likely to exist.
Better EP mapping visualization broadens VT expertise
Tung said newer generations of mapping systems also make complex arrhythmias much easier to interpret. Improved signal processing and automated annotation allow physicians to see electrical activation more clearly than on previous systems, reducing reliance on the procedural experience of individual electrophysiologists alone.
The resulting three-dimensional maps have become increasingly common in educational presentations and on social media, reflecting how much the imaging of arrhythmia circuits has improved.
"We've never been able to image the circuit better," Tung said.
For more, watch the video interview with Tung at the top of the article
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: [email protected]