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.

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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.

Acutus and Stereotaxis Partner to Improve Electrophysiology Tools

 

Stereotaxis’s Niobe system pic
Stereotaxis’s Niobe system
Image: stereotaxis.com

A Heart Rhythm Society member and advocate, Dr. Sanjiv Narayan is a cardiac research scientist and Southern California professor who has published on subjects related to mapping and ablation of atrial fibrillation (AF). Past studies co-authored by Dr. Sanjiv Narayan showed that mapping AF can identify drivers, which supports the work of groundbreaking firms like Acutus Medical, which announced in mid-2018 an important collaboration with robotic technology company Stereotaxis.

The goal of this agreement is to support the work of electrophysiology physicians and improve levels of care for cardiac arrhythmia patients by integrating Acutus Medical AcQMap technology with the Niobe Magnetic Navigation System by Stereotaxis.

Acutus first received FDA approval for its AcQMap technology in October 2017. The technology is a high-resolution 3D imaging system that relies on ultrasound technology combined with dipole density mapping to visualize heartbeats in real time. It gives physicians a tool to monitor a patient’s heart moment-to-moment during ablation procedures.

Stereotaxis’s Niobe system is a magnetic navigation system that gives physicians more exact, steady remote control over instruments used during procedures, including the catheters necessary for the ablation process. Leadership from both Acutus and Stereotaxis praised the “interoperability” of the two systems in a press release, contending the integration of the technologies will improve physician workflow, and has the potential to significantly improve the experience of cardiology patients.

Studying Atrial Fibrillation Terminated by Local Ablation

Atrial Flutter pic
Atrial Fibrillation
Image: webmd.com

An experienced researcher specializing in atrial fibrillation, Dr. Sanjiv M. Narayan, professor of medicine at Stanford University, is responsible for developing innovative assessment tools for diagnosing heart arrhythmia conditions. Dr. Sanjiv M. Narayan’s research recently focused on the mechanisms of and relationship between localized ablation and persistent atrial fibrillation termination.

As part of a clinical trial, researchers hypothesized that local ablation sites where AF persistently terminates have certain indicators that can be analyzed through activation mapping techniques. To test this theory, they closely studied activation patterns that occurred solely in instances of AF termination via ablation.

After examining the results, the research team found patterns of either rotational or focal activity when mapping termination sites. Computer simulations also revealed rotational activation sequences, but the sequences were found to have increased sensitivity to activation timing, especially in areas where slow conduction was a factor. Based on these observations, the researchers stated that many currently used tools to map AF may not detect important regions, including sites of termination, and further studies should compare mapping approaches to guide ablation.

Acutus Medical Launches AcQMap Imaging and Mapping System

Acutus Medical pic
Acutus Medical
Image: acutusmedical.com

A professor of Medicine at Stanford University, Dr. Sanjiv M. Narayan is a well established atrial fibrillation (AF) researcher who has created technology-driven solutions for assessing complex heart arrhythmia conditions. Dr. Sanjiv M. Narayan’s foundational work has informed studies that apply novel technologies to map AF and find localized ablation targets.

In May 2018, Acutus Medical announced the launch of the high-resolution AcQMap imaging & mapping system, as well as a 3-D mapping catheter. Used together, these pieces of equipment generate real time ultrasound-enabled 3-D heart chamber images. Detecting and displaying charge-source and voltage-based maps, the AcQMap system is described as enabling physicians to better view “complex, irregular arrhythmias.”

With a clinical study of AcQMap having been launched, the potential for the FDA-approved system in enhancing AF retreatment ablation procedures is of intense interest. Acutus Medical also entered into a partnership with Stereotaxis in incorporating the latter firm’s magnetic navigation system within its AcQMap mapping and imaging system.