Featured Research

from universities, journals, and other organizations

Sudden Death From Stress Linked To Wonky Signals In The Brain

Date:
January 12, 2005
Source:
University College London
Summary:
Sudden cardiac death from emotional stress may be triggered by uneven signals from the brain to the heart, according to a study by University College London (UCL) scientists published in the January issue of Brain.

Sudden cardiac death from emotional stress may be triggered by uneven signals from the brain to the heart, according to a study by University College London (UCL) scientists published in the January issue of Brain.

UCL researchers have discovered that a system which normally coordinates signalling from the brain to different parts of the heart may be disrupted in some people, making them vulnerable to potentially fatal abnormal heart rhythms during mentally taxing tasks or emotional events such as family gatherings.

This is particularly true of people who already have heart disease, but it is the brain that may be most responsible. The new study suggests that uneven brain activity, in a region where nerves link directly to the heart, seems to result in an uneven distribution of signals across the heart, which stops the heart from contracting normally.

Around a third of the 300,000 sudden cardiac deaths which occur each year in the US arise from a blood clot in a major artery, which leads to a fatal heart attack. Mental stress is thought to be responsible for a further 20 per cent of these deaths, but scientists have been baffled by the exact mechanisms by which stress can bring on a fatal short-circuiting of the heart.

In the UCL study, volunteers with a history of heart disease were given stressful mental tasks while their brain activity was monitored using PET imaging. Electrical waves travelling across their heart were monitored using electrocardiogram analysis. The study showed that stress-induced changes in electrical currents in the heart were accompanied by uneven activity within the lower brain, in an area known as the brainstem.

The brainstem is connected on the left and right side to the heart by nerve pathways, known as autonomic nerves. These autonomic nerves control heart rate during physical or mental activity.

To maintain a regular heartbeat, the electrical currents that travel across the heart and initiate the heartbeat should be smooth and even. If these electrical waves travel slower or faster in parts of the heart, this can result in a short circuit which leads to arrhythmia - an irregular heartbeat.

Normally, the output from the brainstem to the heart via left and right autonomic nerves is symmetrical and does not disrupt heart rhythm, even during stress. However, UCL scientists think that, in some cases, the autonomic nerves fire unevenly during stress, which disturbs the smooth electrical pattern across the heart and could ultimately induce an irregular, and eventually fatal, heartbeat.

Dr Peter Taggart from UCL's Centre for Cardiology says: "Some people are at risk of sudden death from stress, mainly people who already have heart disease. In these cases the combination of heart and brain irregularities means that heart failure could occur during a stressful or emotional event like a family gathering or even a boisterous New Year party."

"Efforts to prevent the development of potentially dangerous heart rhythms in response to stress have focused on drugs which act directly on the heart, but results have so far been rather disappointing. Our research focuses on what is happening upstream, in the brain, when stress causes these heart rhythm problems. The results so far are very encouraging.

"It may soon be possible to identify which people are particularly at risk and even to treat a heart problem with a drug that works on the brain."

Dr Hugo Critchley from UCL's Institute of Neurology says: "The next stage of our research is to explore how signalling from the brain becomes uneven. It seems that emotions and stress may particularly activate the right hemisphere in the upper brain, but this is usually balanced out into a symmetrical signal produced lower down in the brainstem, possibly though a mechanism that works as a protective balancing relay.

"Some patients with epilepsy produce strong one-sided brain activity during fits and may also show asymmetric changes in the heart, suggesting that the relay system is by-passed. In apparently healthy people, it is possible that massive amounts of stress may also overload the system so that the brain's normal conversion to a balanced symmetric heart response is overcome, leading to arrhythmia."

"Ultimately we would like to establish whether there might be a therapeutic target in the brain for people at risk of stress-induced heart problems. Some medicines already reduce emotional stress responses and help reduce the risk of sudden heart problems, but we hope to develop more selective treatments that eliminate the need to dampen emotional responses in order to reduce the risk of arrhythmia and sudden death."


Story Source:

The above story is based on materials provided by University College London. Note: Materials may be edited for content and length.


Cite This Page:

University College London. "Sudden Death From Stress Linked To Wonky Signals In The Brain." ScienceDaily. ScienceDaily, 12 January 2005. <www.sciencedaily.com/releases/2005/01/050111175254.htm>.
University College London. (2005, January 12). Sudden Death From Stress Linked To Wonky Signals In The Brain. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2005/01/050111175254.htm
University College London. "Sudden Death From Stress Linked To Wonky Signals In The Brain." ScienceDaily. www.sciencedaily.com/releases/2005/01/050111175254.htm (accessed October 1, 2014).

Share This



More Health & Medicine News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Cases Keep Coming for Monrovia's Island Hospital

Ebola Cases Keep Coming for Monrovia's Island Hospital

AFP (Oct. 1, 2014) A look inside Monrovia's Island Hospital, a key treatment centre in the fight against Ebola in Liberia's capital city. Duration: 00:34 Video provided by AFP
Powered by NewsLook.com
Ebola Puts Stress on Liberian Health Workers

Ebola Puts Stress on Liberian Health Workers

AP (Oct. 1, 2014) The Ebola outbreak is putting stress on first responders in Liberia. Ambulance drivers say they are struggling with chronic shortages of safety equipment and patients who don't want to go to the hospital. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Doctors Reassure Public Ebola Patient Won't Cause Outbreak

Doctors Reassure Public Ebola Patient Won't Cause Outbreak

Newsy (Sep. 30, 2014) After the announcement that the first U.S. patient had been diagnosed with Ebola, doctors were quick to say a U.S. outbreak is highly unlikely. Video provided by Newsy
Powered by NewsLook.com
TX Hospital Confirms Patient Admitted With Ebola

TX Hospital Confirms Patient Admitted With Ebola

AP (Sep. 30, 2014) Medical officials from Texas Health Presbyterian Hospital confirm they are treating a patient with the Ebola virus, the first case found in the US. (Sept. 30 Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins