Posted tagged ‘cardiovascular medicine’

Atrial fibrillation more common than previously reported, study finds

May 15, 2017

Photo by BruceBlaus

Atrial fibrillation (Afib), the most common type of heart arrhythmia, affects millions of Americans. People with Afib can experience an irregular heartbeat, heart palpitations, shortness of breath, lightheadedness, fatigue and chest pain.

However, some patients with Afib have no symptoms — making it difficult to diagnose the disease early enough to overcome the increased risk of life threatening conditions such as heart failure and stroke. New research suggests this may be a bigger problem than previous thought.

“The incidence and prevalence of Afib have not been well defined as patient symptoms are not a reliable indicator of Afib,” said Javed Nasir, MD, a Stanford cardiac electrophysiology fellow. “Most Afib episodes are asymptomatic and most symptoms thought by patients to be Afib are actually not associated with the arrhythmia. Furthermore, Afib is an intermittent disease and doesn’t lend itself to robust detection with traditional intermittent monitoring modalities, such as ECG or Holter monitors.”

To see just how widespread undetected Afib may be, Nasir led a screening trial using insertable cardiac monitors (ICMs). ICMs are single-lead ECG monitoring devices, about one-third the size of an AAA battery, that are inserted under the skin of the chest. The devices can automatically detect and record Afib episodes and can remotely transmit the data to a doctor’s office.

“Recently there have been significant advances in technology and we now have very small ICMs with the ability to continuously monitor for Afib for years,” Nasir said. “We started this trial with the hopes of using this technology to identify a population with a high risk of Afib.”

The research team used ICMs to screen almost 250 elderly people with a mean age of 74 years and with no history of atrial fibrillation. They followed the patients for 18 months with monthly remote analysis of the ICM data that was reviewed by cardiologists. As recently reported in Heart Rhythm, they found that 22 percent of the participants were newly diagnosed with atrial fibrillation.

“While classically we could give a 40 year old adult a 25% chance of developing Afib in their lifetime, in our trial we nearly saw this with only 18 months of monitoring,” Nasir said.

The study also demonstrated that the majority of these newly diagnosed Afib patients were then treated with oral anticoagulants, which have been shown to significantly reduce the risk of stroke in patients with Afib detected with pulse palpation or an ECG.

Yet more research is needed, Nasir said:

“We have begun to appreciate that stroke risk varies with the amount of Afib, and the Afib found with ICM screening tends to be brief and asymptomatic. Before we recommend routine screening for Afib with ICMs, it is important to wait for the results of on-going trials that are evaluating the risks and benefits of oral anticoagulants in patients with device detected Afib. And we will need to carefully consider the costs of screening with ICMs.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

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Stanford researchers develop simulations to improve heart surgeries

February 9, 2017

MRI or CT scans provide physicians with a detailed picture of their patients’ internal anatomy. Heart surgeons often use these images to plan surgeries.

Unfortunately, these anatomical images don’t show how the blood is flowing through the vessels — which is critical, according to Alison Marsden, PhD, a Stanford associate professor of pediatrics and of bioengineering. In the video above, she explains that many surgeons currently use a pencil and paper to sketch out their surgical plan based on the patient’s images. She hopes to change this.

Marsden and her colleagues at Stanford’s Cardiovascular Biomechanics Computational Lab are developing a new technique — using imaging data and specialized simulation software — to predict what is likely to happen during heart surgery.

“What we’re trying to do is bring in that missing piece of what are these detailed blood flow patterns and what might happen if we go in and make an intervention, for example, opening up a blocked blood vessel or putting in a bypass graft,” Marsden said in a recent Stanford Engineering news story.

Their open source software, called SimVascular, loads the imaging data, constructs a 3D anatomical model of the heart and then simulates the patient’s blood flow. It has already been used to help design the surgical plan for several babies born with a severe form of congenital heart disease, Marsden said. However, more research is needed to determine whether the technique improves patient outcomes before it can be widely used in the clinic.

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Genetic counselor offers insights on testing for inherited heart conditions

December 27, 2016
Illustration by waldryano

Illustration by waldryano

Genetic tests are now available for many conditions — everything from Alzheimer’s to familial hypercholesterolemia. But genetic testing isn’t necessarily the best option for everyone, and some of the tests aren’t highly accurate yet.

However, clinicians agree that genetic testing is important for people with hereditary heart conditions in their families. That’s why Stanford created the Stanford Center for Inherited Cardiovascular Disease, which specializes in caring for patients and their families with genetic disorders of the heart and blood vessels. Genetic counseling is a key part of the center, so I spoke with Colleen Caleshu, MSc, their lead genetic counselor to learn more.

What inspired you to become a genetic counselor?

“When I was in college, I was very interested in the science and molecular basis of disease. I was considering a PhD in genetics, but I was also drawn to peer counseling and psychology courses. When I looked at genetic counseling programs, they required an unusual combination of science and humanities such as psychology, ethics, genetics and biochemistry. Before going to graduate school, I spent a year with a research team that focuses on the psychological impact of familial breast cancer risk — that experience solidified that genetic counseling was what I wanted to do. For me, it comes down to a combination of loving the science and being intellectually challenged by a field that is moving really quickly, while also really being able to help people.”

What cardiovascular diseases does genetic testing identify?

“Genetic testing isn’t yet useful for all diseases or for all people. For cardiology, we recommend genetic testing when a patient is diagnosed with an inherited disease. The two most common inherited cardiac diseases are familial hypercholesterolemia and hypertrophic cardiomyopathy. We also care for patients with several other inherited heart muscle, arrhythmia and aorta diseases. If you put all of these genetic cardiac diseases together, greater than one in a 100 people have one in their genes.”

What is a typical genetic counseling appointment like?

“The clinic appointment is about an hour long. It involves establishing a relationship with the patient and their family to understand: Who are they? What are they experiencing? What are their values? What do they most need help with right now? Then we often shift to the medical side of things with a comprehensive four-generation family history. This involves a lot of detective work with the patient and afterwards — calling family members and searching medical records, death certificates and autopsy reports. The rest of the visit is a mixture of medical and genetics education, as well as psychological counseling. All medical conditions can have a psychological impact, but the genetic nature of these diseases mean they can strike healthy people at an unusually early age compared to most heart diseases. And they have reproductive and family planning implications.

Our genetic counselors also function within a broader, multidisciplinary team, including a cardiologist who gives his assessment, diagnosis and management recommendations. And all of this is based on a separate, hour-long intake appointment with a nurse that happens prior to the clinic appointment. “

How can genetic counseling help?

“Genetic counseling definitely benefits both the patient and the patient’s family — by helping them cope better with the familial heart condition and by helping healthy family members get the necessary medical workup and tests.

For example, a patient came to us a few years ago after being diagnosed with hypertrophic cardiomyopathy. Several generations of his family had the disease, and two of his siblings died suddenly from it a few years apart. He was really wrestling with whether or not to get an implanted defibrillator. He came to our center to get everything we offer.

We had several visits with him and his family members. At one point we had more than 10 family members in the room — the patient, siblings, nieces and nephews — grappling with a lot of pain and grief. We provided grief counseling and we addressed what it meant medically and psychologically for each family member. Using genetic testing, we were able to identify a disease-causing genetic variant in the original patient and his family. By proactively checking the heart of other family members, we were also able to diagnose people who didn’t know they had the disease — including members who went on to get implanted defibrillators to protect them from sudden death. Genetic counseling can absolutely save lives.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Can social media shed light on cardiovascular disease? Possibly, Stanford journal editors write

October 6, 2016
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Illustration by Clker-Free-Vector-Images

Clearly social media is part of our every day lives, recording our personal communications in a way previously unimaginable.

Researchers are now analyzing this wealth of social media data to better understand what people think and say about their health. Recently, researchers at the University of Pennsylvania sifted through 10 billion English-language tweets to identify and study more than 550,000 US-based tweets related to cardiovascular disease, as reported in JAMA Cardiology.

The research team found that people who tweeted about five cardiovascular conditions — high blood pressure, heart attack, diabetes, heart failure and cardiac arrest — were more likely to be older and female compared to the general population of Twitter users. They also tweeted within minutes or hours in response to events, such as celebrity deaths or to mark World Diabetes Day. 

This study was discussed in the issue’s Editor’s Note by Stanford journal editors Mintu Turakhia, MD, an assistant professor of medicine, and Robert Harrington, MD, a professor and the chair of the Department of Medicine. In the editorial, they acknowledged that the Penn Twitter study was atypical research to include in JAMA Cardiology but noted that digital health is now a major priority for the journal. They explained:

“We accepted [the paper] because it highlights the potential for using these emerging data sources such as Twitter for cardiovascular research, in this case to evaluate public communication about cardiovascular medicine in a manner not previously possible on such a scale.”

Turakhia, the journal’s associate editor of digital health, elaborated in an email: “Twitter and other social media data allow us to examine daily interactions in a connected life in ways not possible before,” he said. “Previously, in order to gain insight on the public’s perception or interest in cardiovascular disease, we were limited to examine historical news and media archives or direct surveys.”

Although the editors believe that Twitter is a new and important research tool, they raised a few questions about future studies. They wrote in the editorial, “The use of Twitter and other social media platforms for cardiovascular research is in an early, proof-of-concept stage. Many important questions remain: Is there signal in the noise? Are these data or results… from the ‘Twitterverse’ generalizable to a broader population?” They also emphasized the need to establish analysis standards and overcome any ethical issues in linking the data with medical or clinical information. Turakhia added:

“Twitter users do not represent the broader population, but that’s not really its purpose. Twitter allows us to examine a highly connected subset of society and learn how cardiovascular disease might manifest in their connected world.”

Ultimately, researchers hope to use this new information to improve their patients’ health, but the research is in its infancy, he said, adding:

“We haven’t yet figured out how Twitter or social media can be definitely used to improve health and health care. The obvious avenues would be through social and community engagement. Although sharing of personal information is at the cornerstone of the success of social media, I’m not sure that society is ready to be as open with posting health information, as they are with selfies or pictures of kids. However social media could be used to gamify health care behavior by providing incentives, and that won’t need disclosure.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Electrocardiogram: Blog illustrates value of old, but still vital cardiac test

September 23, 2016

Stephen Smith, MD, an emergency medicine physician at Hennepin County Medical Center in Minnesota, is passionate about using electrocardiograms to save lives. He even writes a popular blog called Dr. Smith’s ECG Blog to train others to more accurately interpret them.

If you’re one of the 735,000 Americans that had a heart attack in the last year, you almost certainly had your heart evaluated with an electrocardiogram, or ECG for short, as soon as you were brought into the emergency room. The heart produces small electrical impulses with each beat, which cause the heart muscle to contract and pump blood throughout your body. The ECG records this electrical activity using electrodes placed on the skin, allowing physicians to detect abnormal heart rhythms and heart muscle damage.

On the surface, an ECG just produces a simple line graph based on technology that was invented over a century ago. So why does it still play such a vital role in the clinic? And how can a physician diagnose a heart condition from a little blip on the line? I recently spoke with Smith, who is also a professor affiliated with the University of Minnesota Twin Cities, about the importance and subtleties of interpreting ECGs.

How do you use ECGs in your medical practice?

“I work full time as an emergency medicine physician and see thousands of patients per year. In the emergency room, the ECG is the first test that we use on everyone with chest pain because it’s the easiest, most non-invasive and cheapest cardiac test. Most of the time when someone is having a big heart attack (myocardial infarction), the ECG will show it. So this is all about patient care. It’s a really amazing diagnostic tool.”

Why did you start your ECG blog?

“Every day I use ECGs to improve the care of my patients, but the purpose of my blog is to help other people do so. I write it for cardiologists, cardiologist fellows, emergency medicine physicians, internal medicine physicians and paramedics — anyone who has to record and interpret ECGs — in order to improve their training and expertise. It’s easy to interpret a completely normal ECG, but many physicians fail to look at all aspects of the ECG together and many abnormalities go unrecognized. Reading ECGs correctly requires a lot of training.

For instance, one of my most popular blog posts presented the case of a 37-year-old woman with chest pain after a stressful interpersonal conflict. She was a non-smoker, with no hyperlipidemia and no family history of coronary artery disease. Her ECG showed an unequivocal, but extremely subtle, sign of a devastating myocardial infarction due to a complete closure of the artery supplying blood oxygen to the front wall of the heart. Her blood testing for a heart attack didn’t detect it, so she was discharged and died at home within 12 hours. It was a terrible outcome, but it demonstrates how training caregivers to recognize these subtle findings on the ECG can mean the difference between life and death.

I get very excited when I see an unusual ECG, and I see several every day. In 2008, I started posting these subtle ECG cases online and, to my surprise, people all over the world became interested in my blog. In July, I had 280,000 visits to my blog and about 90,000 visits to my Facebook page. People from 190 countries are viewing and learning from my posts. And I get messages from all over the world saying how nice it is to have free access to such a high-quality educational tool. I spend about eight hours per week seeking out interesting ECG cases, writing them up and answering questions on my blog, Facebook and Twitter.”

Will ECGs ever be obsolete?

“I don’t think ECGs will ever be outdated, because there is so much information that can be gleaned from them. We’re also improving how to interpret them. The main limitation is having good data on the underlying physiology for each ECG, which can be fed into an artificial intelligence computer algorithm. An AI could learn many patterns that we don’t recognize today.

Right now I’m working with a startup company in France. They’re a bunch of genius programmers who are creating neural network artificial intelligence software. We’re basically training the computer to read ECGs better. We need many, many good data sets to train the AI. I’ve already provided the company with over 100,000 ECGs along with their associated cardiologist or emergency medicine physician interpretations. We’re in the process of testing the AI against experts and against other computer algorithms.

My only role is to help direct the research. I receive no money from the company and have no financial interests. But I do have an interest in making better ECG algorithms for better.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.


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