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Researchers map rotating spiral waves in live human hearts

Researchers map rotating spiral waves in live human hearts
A spiral wave in a human heart. Credit: Georgia Tech

Electrical signals tell the center to contract, however when the signals form spiral waves, they are able to result in dangerous cardiac events like tachycardia and fibrillation. Researchers at the Georgia Institute of Technology and clinicians at Emory University School of Medicine are bringing a fresh understanding to these complicated conditions with the initial high-resolution visualizations of stable spiral waves in human ventricles.

“Clinicians have known for many years that spiral waves of electrical activity may appear in the , and researchers did experiments in animal and human hearts before,” said School of Physics Professor Flavio Fenton. “However, this is actually the first-time the evolution of relatively stable spiral waves of voltage and calcium in the ventricles of human hearts have already been mapped at high spatial and .”

Studying live hearts from provides rare window in to the detailed behavior of the center during conditions which are difficult to take care of like fibrillation. Because of this, doctors can gain an improved knowledge of how spiral waves begin and so are sustained, that may result in new therapies.

Today’s work has been section of a decade-long collaboration between your Georgia Tech School of Physics and the Emory School of Medicine. The researchers published their latest findings, “Direct observation of a well balanced spiral wave reentry in ventricles of a complete human heart using optical mapping for voltage and calcium” and “Spiral wave breakup: Optical mapping within an explanted human heart shows the transition from ventricular tachycardia to ventricular fibrillation and self-termination,” in the journal Heart Rhythm.

A spiral wave in a human heart. Credit: Georgia Tech

Mapping the center

To create the conditions for spiral waves, the researchers applied timed electric shocks to the center. Then, to visualize and record the spiral waves, they injected florescent dyes for voltage and calcium in to the blood substitute that keeps the center alive. The changes in light intensity enable them to record signals over the heart tissue, a method referred to as .

“In this manner we are able to visualize simultaneously the calcium and electrical waves in the center by measuring the changes in as direct changes in calcium and voltage in the cardiac cells,” said Ilija Uzelac, a physics research scientist at Georgia Tech. “The amazing thing concerning this technique is that with a high-resolution camera, we are able to obtain measurements of voltage and calcium at high spatial and temporal resolutions which could not be possible even using a large number of recording electrodes round the heart.”

Each heart includes a slightly different condition resulting in the necessity for a transplant, therefore the researchers can investigate the dynamics of spiral waves with different kinds and severities of disease.

Collaborating with Clinicians

Fenton’s group has been studying spiral waves in hearts for a lot more than 2 decades. Spiral waves certainly are a good candidate for the physics field of nonlinear dynamics, where systems that seem to be unpredictable aren’t random but chaotic. Methods could be developed to regulate and terminate spiral waves to avoid fibrillation with little energy, as Fenton’s group demonstrated theoretically earlier this season.

Previously, the group spent some time working with fish, reptiles, amphibians, plus some mammalian hearts. However, because of the partnership with Emory, they are in a position to study 10 human hearts from transplant patients who’ve received a fresh heart during the past year.

“We’re very fortunate to possess this strong collaboration between Emory and Georgia Tech to execute these experiments,” Fenton said. “You can find hardly any physicians that, along with treating patients, desire to partner with physicists to research arrhythmias.”

The study in addition has been eye-opening from the medical standpoint.

“I had a simplistic view of ventricular fibrillation predicated on what I see in the clinic and what I’ve read, but actually considering ventricular fibrillation directly through these experiments provides different perspective of the complexity and of what’s happening making use of their dynamics,” said Shahriar Iravanian, an Emory cardiologist in the group.

“Mapping electrical and chemical waves simultaneously in the isolated human heart supplies a unique possibility to research mechanisms of sudden cardiac death at a fresh functional level also to associate the dynamic electrical changes characterizing malignant arrhythmias to the precise and individual pathology of patients,” Said Dr. Andr G. Klber, Professor of Pathology in the condition Biophysics Group at the A. Paulson School of Engineering and SYSTEMS, Harvard University.

The researchers are continuing to review explanted hearts and desire to tailor the experiments not merely for basic science but improving treatments. For instance, most arrythmias are treated through ablation, by burning the substrate of faulty circuits, or , which research will make such treatments more targeted and also personalized. Such advances may have enormous implications for future years of the treating cardiac arrhythmias, a significant reason behind death in the U.S.

“It really is difficult to map due to patient instability and complexity of signals,” said Neal Bhatia, an assistant professor of medicine at Emory and person in the collaboration. “This research has potential significant clinical complications. By detailed mapping of spiral wave dynamics, we are able to better understand their evolution and ultimately identify if and the way the heart could be treated with better catheter ablation strategies.”



More info: Ilija Uzelac et al, Direct observation of a well balanced spiral wave reentry in ventricles of a complete human heart using optical mapping for voltage and calcium, Heart Rhythm (2022). DOI: 10.1016/j.hrthm.2022.06.015

Ilija Uzelac et al, Spiral wave breakup: Optical mapping within an explanted human heart shows the transition from ventricular tachycardia to ventricular fibrillation and self-termination, Heart Rhythm (2022). DOI: 10.1016/j.hrthm.2022.07.013

Citation: Researchers map rotating spiral waves in live human hearts (2022, September 8) retrieved 8 September 2022 from https://medicalxpress.com/news/2022-09-rotating-spiral-human-hearts.html

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