Researchers from UC San Diego, the University of California Los Angeles and Indiana University report having found, for the first time, that atrial fibrillation or irregular heart rhythms is caused by small electrical sources within the heart, in the form of electrical spinning tops ("rotors") or focal beats. Importantly, they found a way of detecting these key sources, then precisely targeting them for therapy that can shut them down in minutes with long lasting results.
The team, which included cardiologists, physicists and bioengineers, report the findings in the July issue of the Journal of the American College of Cardiology as the CONFIRM trial (Conventional Ablation for Atrial Fibrillation With or Without Focal Impulse and Rotor Modulation).
Currently, many patients treated for atrial fibrillation with standard therapies will experience a recurrence due to the difficulty of finding the source of the arrhythmia. The new findings will help cardiologists better target and treat arrhythmias.
The CONFIRM study examined 107 patients with atrial fibrillation referred for a non-surgical catheter ablation procedure. During this procedure, doctors thread a wire with a metal-tipped catheter inside the body, from a vein in the groin, to apply heat to the area of the heart that is producing the arrhythmia to stop it.
In one group of patients, the team used the new technique to help perform precise burns, called Focal Impulse and Rotor Modulation (FIRM) that were aimed directly at the fundamental source of the arrhythmia – tiny electrical disturbances in the heart called rotors or focal sources that look like mini tornadoes or spinning tops.
Remarkably, this new procedure shut down atrial fibrillation or very significantly slowed it in 86 percent of patients in an average of only 2.5 minutes.
In comparison, conventional catheter procedures were performed in a second group of patients. Since this approach is less targeted, it involved hours of treatment over larger regions in the heart and often did not shut down the atrial fibrillation.
To track outcomes, patients received an implanted ECG monitor that very accurately assessed their heart rhythms over time. Researchers found that after two years, the FIRM-guided group had an 82.4 percent freedom from atrial fibrillation episodes, compared to only 44.9 percent freedom in the group that received standard therapy.
The new targeted method demonstrated an 86 percent improvement over the conventional method in the study.
"We are very excited by this trial, which for the first time shows that atrial fibrillation is maintained by small electrical hotspots, where brief FIRM guided ablation can shut down the arrhythmia and bring the heart back to a normal rhythm after only minutes of ablation," said lead author Sanjiv Narayan, MD, PhD, professor of medicine at UC San Diego Sulpizio Cardiovascular Center, director of Electrophysiology at the San Diego Veterans Affairs Medical Center and visiting professor at the UCLA Cardiac Arrhythmia Center.
"The results of this trial, with an 80 percent ablation success rate after a single procedure, are very gratifying. This is the dawn of a new phase of managing this common arrhythmia that is mechanism-based," said Kalyanam Shivkumar, MD, PhD, director of the UCLA Cardiac Arrhythmia Center, and professor of medicine and radiological sciences at UCLA.
This study also represents a successful example of technology transfer from U.S. researchers supported by U.S. research funding to a small U.S. enterprise. The science behind this work was funded by grants to Narayan from the National Institutes of Health, including a grant awarded as part of the American Recovery and Reinvestment Act, and by the Doris Duke Charitable Foundation.
These discoveries, owned by the Regents of the University of California, were then licensed to a local startup company, Topera Medical, which has recently obtained FDA clearance for the mapping system it developed (RhythmViewTM) from this early science. Narayan is a co-founder with equity interest in Topera. Wouter-Jan Rappel, PhD, holds equity interest in Topera. John Miller, MD, has received modest honoraria from Topera. Shivkumar is an unpaid advisor to Topera, and the other authors report no relationship with Topera.
Other authors included John Miller, MD, chief of electrophysiology at Indiana University; David Krummen, MD, associate professor of medicine with UC San Diego Sulpizio Cardiovascular Center and associate director of electrophysiology at the San Diego Veterans Affairs Medical Center; Wouter-Jan Rappel, PhD, University of California San Diego Department of Theoretical Biological Physics; and Paul Clopton from the San Diego Veterans Affairs Medical Center Department of Statistics.
Kim Edwards | EurekAlert!
Penn vet research identifies new target for taming Ebola
12.01.2017 | University of Pennsylvania
The strange double life of Dab2
10.01.2017 | University of Miami Miller School of Medicine
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction