Atrial Fibrillation Study Builds on Mapping of Rotors, Focal Drivers

Sanjiv Narayan Abbott pic
Sanjiv Narayan

A professor of cardiovascular medicine at Stanford University, Dr. Sanjiv M. Narayan is working to develop the Stanford Arrhythmia Center, which focuses on creating innovative bioengineering-based treatments for complex heart rhythm disorders. As a bioengineer, Sanjiv Narayan also applies his background in neural networks, machine learning, and artificial intelligence to the field of cardiology at the Computational Arrhythmia Research Laboratory.

After extensive work that resulted in discovery of the role of focal drivers and rotors in heart fibrillation, Dr. Narayan coauthored a paper on what independent mapping techniques showed about the presence of rotational activation. The paper was published in the January 29, 2018, issue of the Journal of Cardiovascular Electrophysiology.

The authors of the paper worked with the goal of finding out how, during the process of ablation, atrial fibrillation terminates close to the pulmonary veins prior to pulmonary vein isolation. This research represents the first full study of that phenomenon, as well as the first study of how patients with pulmonary vein reconnection can be free of arrhythmias.

The study involved patients with atrial fibrillation who had been scheduled for ablation. The researchers examined specific electrograms from these patients using two distinct mapping methods. In all patients studied, ablation at locations close to the pulmonary veins resulted in a termination of atrial fibrillation before the isolation of the pulmonary veins.

The researchers concluded that surgeons may be able to use these mapping techniques to create pulmonary vein lesion groups and lessen the occurrence of atrial fibrillation.

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Apple Watch Sales Up 50 Percent over Last Year

 

Apple Watch pic
Apple Watch
Image: techcrunch.com

Dr. Sanjiv Narayan serves as a professor of medicine at Stanford University, where he is the co-founder and co-director of the Stanford Arrhythmia Center. In his personal life, Dr. Sanjiv M. Narayan maintains an interest in wearable technologies like the Apple Watch.

During an early August investor call, Apple CEO Tim Cook revealed that the company’s Apple Watch has seen sales rise more than 50 percent from last year’s figures. Creative Strategies analyst Ben Bajarin estimates the company’s flagship wearable sold somewhere between 2 to 3 million units.

Though the reason for the uptick in sales is uncertain, TechCrunch suggests two potential reasons. First is compatibility with the company’s wireless AirPod earbuds. The other possible reason is the general downturn in sales for other wearables from companies like Fitbit and Jawbone, the latter of which is poised to go out of business.

Apple is currently planning the release of watchOS 4, which will further integrate Siri and also promises “an entirely new music experience.” WatchOS 4 is scheduled for release sometime in the fall of 2017.

New Study Reveals WiSE-CRT Technology as Safe

Heart Rhythm Society pic
Heart Rhythm Society
Image: hrsonline.org

With a medical career spanning more than 25 years, Dr. Sanjiv M. Narayan has been recognized as a leading a physician and a researcher in the field of cardiology. He is a faculty member at Stanford University, where he co-directs the school’s new Stanford Arrhythmia Center. Committed to active engagement in his field, Dr. Sanjiv Narayan is a longtime member of the Heart Rhythm Society.

According to a first-of-its-kind study presented at a Heart Rhythm Society scientific event, Wireless Stimulation Endocardially for cardiac resynchronization therapy (WiSE-CRT) has been proven to be safe for patients who were studied two years after having the device implanted. These tiny devices are the only current means of controlling heart pacing from inside the left ventricle of the heart, making use of ultrasound signals transmitted to an electrode placed in the ventricle itself. The study’s lead author, Simon James, MRCP, expressed pleasure with the study’s results, which represent the first real glimpse at the long-term feasibility of WiSE-CRT implants.

ACC Journal Examines Blood Thinner Prescription in A-Fib Patients

 

 A-Fib Patients pic
A-Fib Patients
Image: news.heart.org

For over a decade, Dr. Sanjiv Narayan has been a leading voice in cardiology, both as a physician and a researcher. As a faculty member at Stanford University, he is responsible for overseeing the brand-new Stanford Arrhythmia Center, an incubator that will serve to help spawn innovative treatments in arrhythmia medicine. In addition to his work as an educator and clinician, Dr. Sanjiv Narayan is a fellow of the American College of Cardiology.

Recently published research in the Journal of the American College of Cardiology reveals that patients diagnosed with atrial fibrillation typically do not get the blood thinners they need to reduce their stroke risk. Because these patients are at a particularly elevated risk for stroke, they are usually prescribed oral anticoagulants to reduce this risk. But in studying more than 600,000 patient files through the National Cardiovascular Data Registry PINNACLE Registry, the study authors found that there was only a small increase in usage of these drugs among atrial fibrillation patients over the course of approximately seven years.

Approximately 40 percent of these patients are still not receiving prescriptions for these medications from their doctors. And even when they do, some research has shown that they are getting too low a dosage to adequately address their stroke risk. Consequently, some strokes are happening in atrial fibrillation patients that could have been otherwise prevented. The lead author of this research study, Lucas N. Marzec, MD, urged further study to determine why these important medications are not being prescribed properly.

Cardiac Abnormalities – Heart Arrhythmias

Heart Arrhythmias pic
Heart Arrhythmias
Image: heart.org

Dr. Sanjiv Narayan is a cardiologist who teaches medical students in his capacity as professor of medicine at Stanford University, where he’s working to improve patient outcomes and create a center dedicated to innovation in the treatment of heart arrhythmias. Before joining Stanford, Dr. Sanjiv Narayan established his own health-technology company focusing on the anti-arrhythmia market, and its success drew interest from Abbott Laboratories, which acquired the company and incorporated it into the Abbott family of firms.

In healthy people, the heart beats according to a set rhythm that helps ensure blood is properly circulated throughout the body. The heart functions in part thanks to a finely tuned electrical system that tells its muscles when to contract and when to relax. Sometimes, the cells that determine the heart’s electrical impulses start to behave abnormally, leading to heart rhythm problems or “arrhythmias.”

A variety of factors can give rise to arrhythmias. For example, in people with partially-blocked arteries, heart cells may become starved of vital oxygen, causing them to malfunction and the heart to beat improperly. The problem can also be in the heart’s nerves responsible for conducting the electrical signals telling the heart to beat. In addition, certain drugs like caffeine and amphetamines can cause arrhythmias.

Doctors use modern diagnostic tools like echocardiograms and electrophysiological studies to determine whether or not patients have arrhythmias and to investigate their origins in order to best devise a stratagem for treatment.

Treating Atrial Fibrillation

atrial fibrillation (AF)
atrial fibrillation (AF)

 

In his goal to deliver good patient outcomes in the treatment of atrial fibrillation (AF), Dr. Sanjiv Narayan led the development of an innovative therapy known as Focal Impulse and Rotor Modulation (FIRM). Dr. Sanjiv Narayan also founded a start-up company that was eventually bought by Abbott Laboratories. The company, Topera, Inc., enabled Abbott to enter the field of treating individuals with AF.

Topera created a rotor identification system using mapping software and an innovative diagnostic catheter. This system assists physicians in finding and targeting the definitive locations of an individual’s heart that are causing atrial fibrillation. An independent study has shown that the system with catheter ablation results in better long-term outcomes and requires fewer procedures than other methods of treatment.

In an ablation procedure, a catheter is positioned in a targeted area of the heart. Energy is then used to disturb the unusual electrical activity in that area associated with AF.

AF is the most prevalent cardiac arrhythmia (abnormal heart rhythm). Around 2.7 million to 6.1 million adult Americans are estimated to have AF. Individuals having this condition are three times more likely to experience heart failure.

The Computational Arrhythmia Research Laboratory at Stanford

Stanford University Image: stanford.edu
Stanford University
Image: stanford.edu

 

Dr. Sanjiv Narayan cofounded medical device startup Topera, Inc., which was later purchased by Abbott Laboratories. The acquisition enabled Abbott to enter the large and expanding catheter-based electrophysiology market. A professor of medicine at Stanford University, Dr. Sanjiv Narayan is also the director of the Computational Arrhythmia Research Laboratory based at the same academic institution.

The research laboratory seeks to improve the treatment of patients with cardiac arrhythmias, focusing on atrial fibrillation (AF), as well as on ventricular fibrillation. It develops bioengineering solutions to raise the mechanistic understanding of the disorder, as well as enhance its clinical treatment.

Mapping cardiac fibrillation through the creation of clinical tools has been a major development of the laboratory. This form of mapping is computationally close to the optical mapping yardstick, which at present is not yet available to patients.

Focal Impulse and Rotor Mapping (FIRM) was pioneered by the laboratory, which led to the discovery that localized circuits (rotors) perpetuate human AF. The FIRM approach is increasingly utilized in treating AF, and its results have been supported by many other clinical techniques and by basic science studies in many human and and animal models .

The research program receives funding from the National Institutes of Health.