Basics of Atrial Fibrillation


Atrial Fibrillation pic
Atrial Fibrillation

Sanjiv M. Narayan has served as a professor of medicine at Stanford University since 2014. Sanjiv M. Narayan has published extensively on topics related to atrial fibrillation, an ongoing heart irregularity, with over two hundred articles and book chapters. His laboratory works to define mechanistic networks that can cause this condition, and his recent research focuses on ablation treatment focused at small ‘driver’ or ‘rotor’ regions that sustain the disorganization of atrial fibrillation.

Atrial fibrillation is a form of irregular and rapid heart rate in which the heart’s upper chambers stop synchronizing with the lower chambers. Beats can be chaotic and irregular, and often manifest as heart palpitations, shortness of breath, and generalized weakness. Individuals with atrial fibrillation may deal with the condition constantly, or have occasional episodes. While not life-threatening, it can require emergency treatment in certain circumstances.

Atrial fibrillation can also cause further complications. The irregularities in the heartbeat can lead to the formation of blood clots inside the heart, which can migrate around the body and block blood flow. This can cause a stroke if the blood clot lodges in the brain. Heart failure can occur if the irregularities weaken or exhaust the heart, causing the heart to circulate insufficient blood to serve the body.


Quick Tips for First-Time Cyclers


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Dr. Sanjiv M. Narayan, a graduate of the University of Birmingham medical program, joined Stanford University as a professor of medicine in 2014. In this position he has played a driving role in the development of the Stanford Arrhythmia Center. Outside of work, Dr. Sanjiv Narayan stays active by cycling and swimming.

Cycling is a great way to experience new places while receiving a comprehensive workout. However, first-time cyclers may face a number of unexpected challenges.

For those who seek to get right into group cycling, for instance, riding in a paceline can be an unnerving experience. It takes some time to get used to riding so close to other cyclists. Instead of attempting to overcome anxieties associated with potentially crashing into other riders, individuals can simply hang near the back of the line, making use of the additional space and easier pace. As riders grow more confident in their positioning, they can move further up the line.

A more generalized tip is to effectively manage one’s recovery. Rest days are highly important, especially for new and young riders with less endurance. Cycling is an enjoyable, beneficial hobby, but cramming too many group and solo rides into one weekend can result in difficult riding conditions at best, and serious injuries at worst. Riders can consult with more experienced cyclists, and their physician, on an appropriate ride and rest cycle.

Understanding the Causes and Symptoms of Arrhythmia


Atrial Flutter pic

Sanjiv M. Narayan is a well-established cardiologist and medical researcher who has developed innovative atrial fibrillation solutions. In his position as a professor of Stanford University, Sanjiv M. Narayan is in the process of establishing a center focused on arrhythmia research and therapy. Arrhythmia is a condition that causes the heart to beat irregularly.

With a variety of symptoms, including a fluttering or racing heart, arrhythmia is caused by the electrical signals used to coordinate the heartbeat failing to work in sync. Common symptoms include a sense of breathlessness and dizziness. The causes of the condition range from mental stress to diabetes, as well as harmful habits, such as smoking and alcohol consumption. Arrhythmia with no apparent symptoms may be detected through EKGs or routine exams.

Medications can control, but do not generally cure arrhythmia. One traditional treatment involves the use of cardioversion, or an electrical shock used to reset the heart to its proper rhythm. Ablation therapy involves the movement of catheters through one’s blood vessels, so that the catheter tube destroys or scars small sections of problem heart tissue.

Mechanisms of Atrial Flutter


 Atrial Flutter pic
Atrial Flutter

Dr. Sanjiv M. Narayan directs both the electrophysiology research program and the atrial fibrillation program at Stanford University. From 2002 to 2017, Dr. Sanjiv Narayan has published papers that analyzed cardiac rhythm patterns in patients with atrial fibrillation and flutter.

A person’s heartbeat stems from activity in the sinoatrial (SA) node, a structure located in the right atrium of the heart. The Sino-atrial node generates an impulse that travels through the heart, pausing for a moment at the atrioventricular (AV) node to allow the blood to move from the top half of the heart to the bottom.

In the case of atrial flutter, a specific organized type of abnormality develops in the pathway that the electrical impulse follows. This causes the impulse to travel in a circular motion, which makes the atria of the heart beat more rapidly than the ventricles.

A heart with atrial flutter cannot pump blood as effectively as it should. Insufficient blood flow can then cause vital organs to receive insufficient oxygen and nutrients, which may lead to organ failure. There is also a risk of heart attack, stroke, and congestive heart failure.

Atrial Fibrillation Study on Ablation and Pulmonary Veins Isolation


Atrial Fibrillation pic
Atrial Fibrillation

A respected California cardiologist, Dr. Sanjiv M. Narayan was responsible for developing new atrial fibrillation treatments that were acquired by Abbott Laboratories. Presently a Stanford University professor focused on establishing an arrhythmia center, Dr. Sanjiv M. Narayan has coauthored papers such as “Independent mapping methods reveal rotational activation near pulmonary veins where atrial fibrillation terminates before pulmonary vein isolation” (Journal of Cardiovascular Electrophysiology, 2018).

Atrial fibrillation involves the upper chambers of the heart beating irregularly, which disrupts the effective movement of blood into the ventricles. Blood clot is a common cause, and stroke can result in cases where the clot breaks off and gets stuck in the artery that leads to the brain. The procedure known as AF ablation involves carefully destroying or scarring targeted heart tissue in a way that disrupts the defective electrical signals that cause arrhythmia.

The study focused on exploring mechanisms through which, prior to pulmonary veins (PV) isolation, atrial fibrillation (AF) can be terminated in the vicinity of the PV during ablation. The study included 22 patients and found that localized rotational (‘whirlpools’) or focal activity was present at the site near the Pulmonary Veins in each case where AF was terminated by ablation. This may explain the benefit of PV ablation in AF. Through mapping such sites, PV lesion sets can potentially be tailored for each patient, and sites outside the PVs can be targeted.

Blockchain and AI Underlie New Medical Data-Sharing Systems


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With a focus on research and product development, Dr. Sanjiv M. Narayan’s areas of interest include signal processing, medical device technology, wearable devices and machine learning. Dr. Sanjiv M. Narayan founded a startup which was acquired by sale to Abbott Laboratories and presently serves as a professor of medicine at Stanford University.

Several studies from many groups are beginning to speak to machine learning in biometric signals. A recent article in Nature brought attention to the new use of the same blockchain technology that underlies the cryptocurrency Bitcoin for sharing medical data. Employing artificial intelligence (AI) algorithms, patients can share medical data in simple, secure, and user-friendly ways.

A system created at the University of California, San Francisco, was designed to collect the data from three to five million mammograms in this way and utilize it to train an AI algorithm in the detection of cancer. Blockchain is ideal because it is by design decentralized, anonymous, and secure, and it provides an unparalleled level of data-identity control.

Another blockchain-based project at Harvard University is creating a health-records-sharing system called MedRec, which will sync data from Fitbits and other wearable electronic devices. The massive quantities of data collected and analyzed, with patient permission, should enable optimal treatments to be developed.

Possible Signs of Sleep Apnea


Sleep Apnea pic
Sleep Apnea

Dr. Sanjiv M. Narayan joined Stanford University as a professor of medicine in 2014. In this position, Dr. Sanjiv Narayan plays a driving role in the development of the Stanford Arrhythmia Center. He also has experience in area of sleep apnea.

Are a number of physical and psychological symptoms may suggest an individual is experiencing some form of sleep apnea. While an individual is sleeping, symptoms include persistent, loud snoring and patterns of irregular breathing, particularly in the event of obstructive sleep apnea. A person with central sleep apnea, meanwhile, may deal with suddenly waking up and struggling with shortness of breath. Individuals might also experience insomnia or hypersomnia.

During waking hours, sleep apnea can manifest symptoms such as early-morning headaches, dry mouth, and throat soreness. Behavioral changes related to sleep apnea can range from increased irritability to difficulty maintaining focus. Any individual with these symptoms should contact a physician excelling in areas of sleep apnea and similar sleeping disorders.