What You Need to Know About Atrial Fibrillation and Stroke Risk

Sanjiv Narayan Abbott pic
Sanjiv Narayan

As co-founder and co-director of the Stanford Arrhythmia Center, cardiologist Sanjiv M. Narayan, MD, Ph.D., works to develop world-class therapies for heart rhythm disorders like atrial fibrillation (Afib). Formerly a professor at the University of California, San Diego, Dr. Sanjiv Narayan’s most important achievements include the development of a new cardiac ablation treatment called Focal Impulse and Rotor Modulation (FIRM), which allows cardiac surgeons to eliminate disruptive heart tissue with greater precision and efficiency.

One of the main reasons cardiologists are concerned with finding a permanent treatment for Afib is that people with this type of arrhythmia are five times more likely to experience a stroke. Resulting from a blocked or burst blood vessel in the brain, a stroke can have effects ranging from severe, permanent damage to the brain to death. Other important facts to know about Afib and strokes include:

1. Each year, about 700,000 Americans have a stroke. Of these, about 15-20% are due to Afib.

2. Roughly 35% of people with Afib will experience a stroke over their lifetime.

3. Afib risk increases with age, doubling every decade after the age of 55.

4. Women account for 61% of stroke deaths in the US, and they are at higher risk of death from Afib than men.


About the 40th Annual Heart Rhythm Scientific Sessions

Heart Rhythm Scientific Sessions pic
Heart Rhythm Scientific Sessions
Image: hrssessions.org

A cardiologist and professor of cardiovascular medicine at Stanford University in California, Sanjiv M. Narayan, MD, PhD, is a prolific researcher in the area of atrial fibrillation. A former faculty member at UC San Diego, Dr. Sanjiv Narayan is a longtime member of the Heart Rhythm Society.

The Heart Rhythm Society will hold Heart Rhythm Scientific Sessions on May 8-11, 2019, at the Moscone Center in San Francisco. This will mark the organization’s 40th annual conference for scientific sessions.

The opening day of the conference will kick off with two featured symposia. The first will focus on new developments in atrial fibrillation (AF) screening, with talks given by experts in the field. After the lecture, attendees will have the opportunity to ask questions of the presenters in an interactive panel.

The second symposium will focus on the findings of the CABANA trial, a 2018 landmark trial comparing AF ablation to drug therapy. To learn more or register for the Heart Rhythm Scientific Sessions, visit www.hrssessions.org.

Stanford AI Outperforms Cardiologists in Arrhythmia Detection

iRhythm Technologies pic
iRhythm Technologies
Image: irhythmtech.com

Sanjiv M. Narayan, MD, PhD, and professor of cardiovascular medicine at Stanford University in California, concentrates his research on the use of bioengineering techniques to treat cardiac arrhythmias at the Computational Arrhythmia Research Laboratory. A former professor of medicine at UC San Diego, Sanjiv Narayan is co-director of the Stanford Arrhythmia Center.

Stanford’s long-time reputation as a focus for next-generation computational and artificial intelligence work applied to medicine continues. Stanford university’s recent work in this field includes using artificial intelligence to detect arrhythmias by members of the Stanford Machine Learning Group. The group created a deep learning algorithm that has shown greater success in identifying arrhythmias than a control group consisting of human cardiologists. The algorithm is able to diagnose more than a dozen subsets among heart rhythm disorders. In addition, it can work with data from more remote communities in which many residents lack access to cardiologists.

The model developed by the Machine Learning Group, in collaboration with the company iRhythm Technologies, diagnoses rhythm disorders based on single-lead electrocardiogram signals.

According to researchers, the particular excitement inherent in this project lies in the algorithm’s ability to provide speed and accuracy of diagnosis across so many arrhythmia types, an accomplishment that had not previously been possible.

2017 Article Identifies Rotating Waves during Atrial Fibrillation


Atrial Flutter pic
Atrial Fibrillation
Image: webmd.com

Stanford University professor Dr. Sanjiv M. Narayan is an expert in atrial fibrillation (AF), a medical condition defined by an irregular and often accelerated heartbeat. One of Dr. Sanjiv Narayan’s recent studies on the topic appeared in the June 2017 issue of the Journal of Cardiovascular Electrophysiology.

Entitled “Two Independent Mapping Techniques Identify Rotational Activity Patterns at Sites of Local Termination during Persistent Atrial Fibrillation,” the study addressed uncertainties in the general medical understanding of AF that arise as the result of inconsistent mapping techniques. It accomplished this by comparing two independent AF mapping techniques that measured results in the same patients.

The first study of its kind to use more than one AF mapping method, it identified stable rotational activation at specific sites in the heart that drove AF for multiple cycles. Both mapping methods confirmed these results. Researchers developed a new computer program to chart their findings and subsequently released this program for free on the Internet.

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.

Study Examines Relationship between AT and AF


Sanjiv Narayan Abbott pic
Sanjiv Narayan

Dr. Sanjiv M. Narayan is a cardiac research scientist and a professor of medicine at Stanford University, where he founded the Stanford Arrhythmia Center. In his research for new treatment methods, Dr. Sanjiv Narayan participates in leading research projects.

Atrial fibrillation (AF) and atrial tachycardia (AT) often convert to and from one another, but little research has been performed on whether the two conditions are related on a mechanistic basis. Dr. Narayan and other researchers recently conducted a trial in which they hypothesized that critical areas related to AT may have a correlation to regional sources of AF in patients who experience both conditions.

The researchers tested their hypothesis with spatial mapping techniques on 26 different patients who experience AF to AT conversion. The researchers concluded that overlap may exist in atrial regions related to the mechanisms that cause both AF and AT. The researchers suggest that future studies should examine the rate at which accelerated AT causes AF.

An Overview of Atrial Flutter


Atrial Flutter pic
Atrial Flutter
Image: stanfordhealthcare.org

Dr. Sanjiv M. Narayan serves as a professor of medicine and the director of the Stanford Arrhythmia Center at Stanford University. Over the course of his career, Dr. Sanjiv Narayan’s research on atrial fibrillation has been cited in multiple studies pertaining to the condition and related disorders, such as atrial flutter.

Atrial flutter is a cardiac abnormality wherein the upper chambers of the heart beat too fast, causing muscles in the area to contract and fall out of sync with the heart’s lower chambers. The heart beats an average of 250 to 400 times per minute, as opposed to the healthy rate of 60 to 100. Compared to atrial fibrillation, the rapid heartbeat occurs in a regular, more organized manner and appears as a sawtooth pattern on electrocardiogram tests.

Because the rapid heartbeat stays at a steady pace for people with atrial flutter, some individuals will not notice any symptoms. Those who do may experience shortness of breath, chest discomfort, heart palpitations, fainting, and dizziness or lightheadedness. While not life-threatening, the condition can potentially lead to more series complications if left untreated. For instance, it increases the risk for blood clots, which can in turn cause stroke or heart failure.