Implanted defibrillators save lives by shocking hearts back into a normal rhythm. But sometimes a defibrillator can go off when it's not necessary, delivering a shock that feels like a kick in the chest.
The study found reprogramming defibrillators to be less sensitive to irregular heart rhythms reduced the number of inappropriate shocks, while also reducing mortality. The study was presented at a meeting of the American Heart Association Scientific Sessions and is being published in the New England Journal of Medicine.
"Inappropriate shocks can be painful and psychologically traumatic to patients," said cardiologist Dr. Peter Santucci, medical director of Loyola's Implant Device Program. "It's important to reduce these shocks, and results of this study will help us to do this, while also potentially improving patients' survival."
Santucci enrolled Loyola patients in the multicenter international trial. Dr. David Wilber, director of Loyola's Cardiovascular Institute, is a co-author of the paper.The trial is known as MADIT-RIT (Multicenter Automatic Defibrillator Implantation Trial - Reduce Inappropriate Therapy). First author is Dr. Arthur J. Moss of the University of Rochester Medical Center.
An implantable cardioverter defibrillator (ICD) is about the size of a pocket watch and is implanted below the collarbone. Wire leads connect to the heart. The device is designed to protect against tachyarrhythmias - quivering, superfast heartbeats that prevent the heart from pumping blood effectively.
When the heart goes into a tachyarrhythmia, the ICD's pacemaker is activated. If the pacemaker fails to restore a normal rhythm, the ICD then delivers a powerful electric shock that jolts the heart back into a normal rhythm. But previous research, cited in the new paper, found that ICDs are inappropriately activated in between 8 percent and 40 percent of patients.
Under conventional programming, an ICD may be activated if the heart rate reaches 170 to 199 beats per minute for 2.5 seconds or at least 200 beats per minute for 1 second. If the heart rate does not slow within 5 to 10 seconds, a shock may be delivered.
The study included 1,500 patients who were randomly assigned to three groups. The first group had ICDs with conventional programming. In the second group, the ICDs would not activate unless the heart rate was at least 200 beats per minute. In the third group, the ICDs were programmed to have longer delays before activation (for example, a 60-second delay when the heart rate was at 170 to 199 beats per minute).
After an average follow-up of 1.4 years, patients in the second group had a 79 percent reduction in first-time inappropriate ICD activation. Patients in the third group had a 76 percent reduction in first-time inappropriate activation.
There was a 55 percent reduction in deaths in the second group and a 44 percent reduction in deaths in the third group.
Wilber is a professor and Santucci is an associate professor in the Department of Medicine, Division of Cardiology of Loyola University Chicago Stritch School of Medicine.
Jim Ritter | EurekAlert!
Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland
Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
29.03.2017 | Materials Sciences
29.03.2017 | Physics and Astronomy
29.03.2017 | Earth Sciences