Friday, March 25, 2022

App. of AI in Cardiovascular Medicine

A cardiologist and professor of medicine at Stanford University, Sanjiv M. Narayan, MD, is highly recognized in San Diego for treating numerous veterans with life-threatening heart rhythm disorders. Dr. Sanjiv Narayan attended the University of Birmingham, where he received his MD and PhD. He also takes an interest in various clinical interests, such as machine learning and AI.

Machine learning (ML)-based artificial intelligence systems are revolutionizing cardiovascular medicine. These systems have to offer added precision and timely delivery of crucial care to mitigate the future emergence of debilitating and potentially lethal heart problems. For the most part, ML-embedded AI is trained with ECG data to familiarize underlying algorithms with the concepts of diagnosis and prognosis of cardiovascular abnormalities. With this knowledge, AIs can streamline workflow in clinical settings by helping clinicians perform some tasks that traditionally require the skills of a cardiovascular expert.

To comprehend how useful AIs can be in the field of cardiovascular settings, consider how Mayo Clinic scientists have successfully automated the cardiovascular examination of patients. Mayo Clinic uses AI systems to detect warning signs of dangerous heart problems through ECGs. The Mayo Clinic database has over seven million ECG records. The art of diagnosis was taught to machines by feeding the systems with data. Of course, each patient's ID was removed before relaying the data to computer systems for training to avoid violation of privacy.

The ML-embedded AI systems demonstrated accuracy in detecting weak heart pumps from ECG analysis with the data. Weak heart pumps are warning signs of heart failure in the future. These predictions also come at a lower cost than what would be required if human experts made the diagnosis. The systems also boast faster results, as each evaluation takes just a couple of seconds.

Saturday, July 25, 2020

Detecting Atrial Fibrillation Using Video Technology in Mobile Devices

Tuesday, May 19, 2020

T Wave Alternans Can Help Detect Potential Heart Defects

Board-certified in Clinical Cardiac Electrophysiology, Dr Sanjiv Narayan serves as the professor of cardiovascular medicine at the Stanford University Medical Center. Sanjiv Narayan, PhD, has written several medical papers, including the role of alternating repolarization in causing rhythm problems.

Repolarization changes can cause arrhythmias. This was previously part of the surface electrocardiogram phenomenon of "T wave (repolarization) alternans" and is now increasingly noticed in the atrium. This is detectable using clinical tools but also several research tools. These are being explored to better understand the heart rhythm problem, and also to improve therapy of patients.

Ventricular arrhythmia can cause asymptomatic heart failure, leading to death without prior notice. In some cases, however, ventricular arrhythmia may present with less potent lethal complications such as ventricular fibrillation and ventricular tachycardia. Current treatments for ventricular arrhythmia involve device therapy and ablation. These can be effective, but it is difficult to identify which patients may benefit from each form of therapy.

Tuesday, April 28, 2020

Can Heart Attacks Trigger Arrhythmia?

A member of the Heart Rhythm Society, Dr. Sanjiv Narayan is a professor of cardiovascular medicine at Stanford University. Sanjiv M Narayan is dedicated to helping cardiologists develop cutting-edge therapies for treating patients with arrhythmia.

A condition that occurs when electrical impulses in the heart become irregular, arrhythmia results in the heart beating too slow, too fast, or without a normal pattern. Symptoms of arrhythmia may include sweating, chest pain, dizziness, or shortness of breath. Certain medical conditions, such as diabetes, sleep apnea, high blood pressure, or thyroid disease can increase a person's chance of having an arrhythmia.

At the University of California, a group of researchers has also investigated the potential genetic link between heart attacks and arrhythmia, as these two medical issues only occur in a subset of the population. During the research study, the actions of mutated versions of a gene called 9p21 were investigated. It was discovered that when a heart attack occurs, the mutated gene activates a signaling protein called JNK that performs a key role in triggering arrhythmia. JNK sends signals that break the connection between heart cells, thus causing the heart to beat irregularly

Tuesday, November 12, 2019

Acutus Medical Gains $170M Funding for Its Intracardiac Mapping System

Human Heart Model Photo by Robina Weermeijer on Unsplash

A longtime California cardiologist with a background in San Diego and at Stanford University, Sanjiv M. Narayan, MD, PhD, is recognized for his innovations in the area of atrial fibrillation (AF) care, including a next generation FIRM-assisted ablation approach. Dr. Sanjiv M. Narayan’s work over 15 years generated FIRM, Focal Impulse and Rotor Modulation, and has led to work such as that carried out by Acutus Medical.

Based in Carlsbad, California, Acutus focuses on improving outcomes among patients who live with complex atrial arrhythmias. The core platform at work is an intracardiac mapping system that incorporates dynamic arrhythmia visualization techniques. The underlying electrophysiology technology platform is designed to allow for adaptive, personalized approaches to therapy.

The AcQMap stands as the sole cardiac mapping and imaging system that utilizes “precision ultrasound atrial anatomy reconstruction” in tandem with “high-definition non-contact charge density mapping” in ways that are highly reproducible.

In June 2019, Acutus Medical announced completion of a $170 million financing round that included a $70 million credit facility and $100 million in Series D equity investments. The aim of this new funding is to accelerate commercialization activities, while ensuring the development of a robust global business.

Friday, June 7, 2019

Phase Mapping vs. Electrogram-Based Mapping in Ablation

Sanjiv M. Narayan, MD, PhD, is a professor of cardiovascular medicine at Stanford University in California, where he researches bioengineering techniques for the treatment of cardiac arrhythmias. A former professor of medicine at UC San Diego, cardiologist Sanjiv Narayan is a member of several other research teams as well, focused on advancing understanding of atrial fibrillation (AF).

One such team published a study in Pacing and Clinical Electrophysiology, a peer-reviewed journal, entitled, “Comparison of phase mapping and electrogram-based driver mapping for catheter ablation in atrial fibrillation.” Ablation is a procedure that scars or destroys the heart tissue that allows incorrect electrical signals to be sent to the heart and cause atrial fibrillation. 

After studying 175 articles in the PubMed database, the researchers concluded that one specific method of ablation (driver-guided) showed better outcomes than standard ablation therapies. Additionally, the researchers found that phase mapping is better for guiding ablation than electrogram-based mapping. This supports many studies of AF driver based ablation by many techniques.

Wednesday, March 13, 2019

Addressing Ongoing Challenges in Dealing with Sudden Cardiac Arrest

Cardiologist Sanjiv M. Narayan, MD, PhD, serves as a professor of cardiovascular medicine at Stanford University and founder of the Stanford Arrhythmia Center, where he leads a team working on bioengineering techniques to treat cardiac arrhythmias. Formerly a faculty member at the University of California, San Diego, Dr. Sanjiv Narayan is a researcher who has published numerous articles in leading peer-reviewed medical journals.

One of the leading causes of heart-related deaths worldwide is sudden cardiac arrest (SCA), which only 10 percent of patients survive when it occurs outside of a hospital setting. There has been extensive research into the condition, yet challenges remain. Recently, Dr. Narayan was among a team of researchers to address the hurdles to attacking the SCA epidemic worldwide. This was covered in a recent study by Dr. Narayan in the Journal of the American College of Cardiology, which discussed SCA, new approaches and the use of artificial intelligence to integrate new technologies in the space. 

One practical way they have identified to improve response involves increased community access to technology such as automated external defibrillators. Additionally, the disease may be better understood by further refining SCA classification and by looking at how pathology and physiology determine how the disease presents and progresses. It is also vital that public leaders, lawmakers, and other stakeholders work together to formulate public health policy to adequately address the epidemic.

Saturday, February 16, 2019

FDA Approves TactiCath SE for Ablation Treatment

Longtime professor of medicine Dr. Sanjiv M. Narayan has held teaching roles at colleges throughout California, including UC San Diego. He is currently a faculty member at Stanford University and the director of the Stanford Arrhythmia Center. A committed cardiologist and researcher, Sanjiv Narayan, MD, PhD, is a leading authority in the diagnosis and treatment of atrial fibrillation.

In January 2018, the United States Food and Drug Administration gave approval for the use of a new type of ablation catheter for the treatment of atrial fibrillation. Developed by Abbott, the TactiCath Contact Force Ablation Catheter SE (Sensor Enabled) discourages the electrical stimulations that can scar heart tissue. 

Physicians who have tried the catheter have praised it as a major advance in ablation therapy. Srijoy Mahapatra, MD, of Abbott says the TactiCath SE is the latest innovation in the company’s mission to advance ablation therapy by making it safer and easier to perform.

Monday, February 4, 2019

The Heart Rhythm Society Provides an Online Resource for Professionals

Sanjiv M. Narayan, MD, PhD, is a cardiologist serving Stanford University as a professor of medicine who focuses on innovative bioengineering solutions for treating arrhythmias and other cardiovascular conditions. A former professor of medicine at UC San Diego, Sanjiv Narayan additionally supports professional organizations such as the Heart Rhythm Society (HRS), which encourages the highest possible standards in the delivery of healthcare as part of its mission of education and the promotion of research and heart-healthy public policy. 

The society, based in Washington D.C., serves the professional cardiology community and the general public as a major destination for information on electrophysiology and cardiac pacing. Its membership includes professionals from dozens of nations who focus on studying and treating heart arrhythmias. 

As part of its educational efforts, HRS offers a range of continuing medical education courses for professionals in the field, with registration information detailed at its website’s Learning Center. 

Among these courses is one on atrial fibrillation ablation, providing a full review of the topic, as well as information on emerging procedures. Another course discusses mapping in the treatment of AF, and still another provides updates on the use of medical devices to treat heart conditions.

HRS also provides select access to online discussion portals, such as one offering hundreds of hours of presentations taken from the organization’s latest annual Scientific Sessions conference, held in May 2018 in Boston. 

San Francisco will be the site of the 2019 Scientific Sessions in May, with full details provided on the HRS website.

Sunday, November 11, 2018

Examining Ablation in Concert with PVI for Treating AF

An accomplished educator and researcher, Dr. Sanjiv M. Narayan serves as a professor of medicine and the director of the Stanford Arrhythmia Center. Dr. Sanjiv Narayan has studied numerous aspects of atrial fibrillation (AF), including ablation of AF drivers and its clinical implications. 

Pulmonary vein isolation, or PVI, is a procedure used to stop abnormal electrical signals in the heart that cause atrial fibrillation. PVI as a treatment for AF has been met with less-than-optimal outcomes, however, and the impact of adding lesion sets--additional surgical treatments for AF--has yet to be adequately explored. 

Some recent studies suggest that AF driver ablation, through which doctors intentionally scar tissues by sending irregular electric signals to the heart, may be a preferable treatment option to couple with PVI, but others suggest otherwise. In an effort to gain a clearer perspective, Dr. Narayan and a team of researchers conducted a comprehensive meta-analysis of all the literature on the subject.

The research team found that supplementing PVI treatment with AF driver ablation may be an option to improve patient outcomes, with several studies supporting this approach using several techniques. They suggest randomized clinical trials conducted at different research centers to study the treatment in further detail.

Tuesday, October 23, 2018

Atrial Fibrillation Treatments at the Stanford Arrhythmia Center

Wednesday, October 3, 2018

Dipole Density Mapping Study Mirrors Work of Dr. Sanjiv Narayan

A leading researcher in atrial fibrillation (AF), Dr. Sanjiv M. Narayan operates as a professor of medicine and bioengineering at Stanford University, as well as director of the school’s electrophysiology research and atrial fibrillation programs. In 2017, a research group from Cambridge University published the study “Dipole Density Mapping of Atrial Fibrillation,” which reproduced many of the same results Dr. Sanjiv Narayan and his team had discovered in the 2012 paper, “Treatment of Atrial Fibrillation By the Ablation of Localized Sources.”

First published in the medical text European Heart Journal, the team responsible for the 2017 paper was led by Professor Andrew Grace, PhD, of Cambridge University. The researchers contend that a process known as dipole density mapping provides scientists with a more accurate representation of complex arrhythmias than the standard electrocardiogram. This is because the electrocardiogram is a voltage-based mapping system that can obscure complex patterns in arrhythmia by blending activities the dipole density mapping method is capable of delineating. Dipole density mapping delineates by measuring local charge-sources within the interior surface of the heart chamber being tested.

Wednesday, September 26, 2018

Studying Localized Drivers in Persistent Atrial Fibrillation

Dr. Sanjiv M. Narayan helped spearhead medical results that led to a technology acquired by Abbott Laboratories. Currently a Stanford University professor of medicine, Dr. Sanjiv M. Narayan has been at the forefront of research that examines the mechanisms governing persistent atrial fibrillation.

Previously, the drivers of persistent atrial fibrillation have not been easily traceable or understood. For a recent clinical trial, the research team operated on the hypothesis that putative AF drivers may have a dynamic synergy with disorganized zones across small time frames. They examined these types of interactions across long periods of time with an emphasis on areas where mapping methods were able to indicate regions of termination via ablation. 

Among the 55 patients who participated in the study, AF termination points via ablation had organized activation that varied across different time points when interacting with fibrillatory waves and/or organized zones, but showed more consistent recurrence in conserved spatial areas. Researchers concluded these results show that mapping the atrium in each patient undergoing AF ablation may help to understand the interaction between important sites (AF drivers) and hence guide ablation. These tools should be integrated with other AF mapping methods.