'Broken heart syndrome' protects the heart from adrenaline overload
A condition that temporarily causes heart failure in people who experience severe stress might actually protect the heart from very high levels of adrenaline, according to a new study published in the journal Circulation. The research provides the first physiological explanation for Takotsubo cardiomyopathy, also called "broken heart syndrome" because it affects people who suffer severe emotional stress after bereavement, and suggests guidance for treatment.
Around 1-2% of people who are initially suspected of having a heart attack are finally discovered to have this increasingly recognised syndrome.
The Imperial College London study, which simulated the condition in an animal model, suggests that the body changes its response to adrenaline by switching from its usual role in stimulating the heart to reducing its pumping power. Although this results in acute heart failure, most patients make a full recovery within days or weeks.
The researchers propose that the switch in the heart's response to adrenaline might have evolved to protect the heart from being overstimulated by the particularly high doses of adrenaline that the body releases during stress.
Patients with Takotsubo cardiomyopathy, most often older women, experience symptoms that resemble a heart attack, but heart tests reveal no blockage in the coronary arteries; instead the heart has a balloon-like appearance caused by the bottom of the heart not contracting properly. The same condition is sometimes seen in people who are injected with adrenaline to treat severe allergic reactions.
In this new research, the authors simulated the condition by injecting high doses of adrenaline in anaesthetised rats. In these rats, as in Takotsubo patients, heart muscle contraction was suppressed towards the bottom of the heart. The researchers found that these rats were protected from an otherwise fatal overstimulation of the heart, indicating that adrenaline acts through a different pathway from usual, and that this switch protects the heart from toxic levels of adrenaline.
The study also examined drugs that might be useful for treating Takotsubo cardiomyopathy. Some beta blockers, used to treat high blood pressure, angina and heart failure, reproduced or enhanced the features of Takotsubo, giving new insights into the protective effects of these drugs. Levosimendan, a different type of drug given in heart failure to stimulate the heart without going through the adrenaline receptor pathways, had a beneficial effect.
"Adrenaline's stimulatory effect on the heart is important for helping us get more oxygen around the body in stressful situations, but it can be damaging if it goes on for too long," said Professor Sian Harding, from the National Heart and Lung Institute (NHLI) at Imperial College London, who led the study. "In patients with Takotsubo cardiomyopathy, adrenaline works in a different way and shuts down the heart instead. This seems to protect the heart from being overstimulated."
Study co-author Dr Alexander Lyon, also from the NHLI at Imperial, and consultant cardiologist at Royal Brompton Hospital, set up one of the first specialist services in the UK to look after people who have experienced Takotsubo cardiomyopathy. "Currently it is not fully known how to treat these patients," he said. "Insights from this work show that the illness may be protecting them from more serious harm. We've identified a drug treatment that might be helpful, but the most important thing is to recognise the condition, and not to make it worse by giving patients with Takotsubo cardiomyopathy more adrenaline or adrenaline-like medications."
"At the Royal Brompton Hospital and Imperial College London we are leading a European initiative to bring together experts to understand this recently recognised cardiac syndrome, and we hope the findings from this work will lead to new treatment strategies for these patients during the acute phase of their illness, and to prevent recurrence".
The study was funded by the British Heart Foundation (BHF), the Wellcome Trust, the Biotechnology and Biological Sciences Research Council (BBSRC) and the Academy of Medical Sciences.
Dr Shannon Amoils, Research Advisor at the BHF, said:
"This is a fascinating study which presents a possible explanation for the signs of Takotsubo cardiomyopathy, a rare condition that's usually preceded by intense emotional or physical stress. Patients usually have symptoms that resemble those of a heart attack but nearly all fully recover after a short time.
"The study also provides new insights into how the heart may protect itself from stress, which opens up exciting avenues of exploration for research. We must remember though that this is a study in rats, and the findings need to be confirmed in people before we can be sure of their relevance to patients."
More information: H Paur et al. 'High levels of circulating epinephrine trigger apical cardiodepression in a β2-1 adrenoceptor/Gi-dependent manner: a new model of Takotsubo Cardiomyopathy' Circulation, published online 25 June 2012.
Journal reference: Circulation
Provided by Imperial College London
- Women more likely to have 'broken heart syndrome' Nov 16, 2011 | not rated yet | 0
- 'Popeye' proteins help the heart adapt to stress Feb 24, 2012 | not rated yet | 0
- Mending a broken heart: Study offers closer look at 'broken heart syndrome' Mar 26, 2009 | not rated yet | 0
- Is there really such a thing as a broken heart? Feb 08, 2012 | not rated yet | 0
- The leading cause of death for diabetics: Getting to the heart of problem Feb 13, 2012 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Question of reflection and transmission of TEM wave in normal incidenc
1 hour ago Suppose TEM wave in +z normal to a boundary on xy plane at z=0. We know *E* & *H* are tangential to the boundary. Let ##\vec E_i=\hat x E##, be the...
the rudyak-krasnolutski effective potencial
1 hour ago Hi ... anyone now how to calculate or the formula of the rudyak-krasnolutski EFFECTIVE potencial ? the effective potencial includes the angular...
Normal force for a lever model
3 hours ago My model is a lever on a table top. One arm is horizontal on the table, while the other arm is raised at an angle alpha. I'm assuming the weight of...
gravity is std. therefore can we rate a 'mass at height' by watts?
8 hours ago For example.... wind turbines are primarily listed by their wattage (1.5MW etc.) Presumably their output is varied according to rotational speed, so...
Calculating on-axis elements of a solenoid
20 hours ago I wanted to mention that this solenoid has many winds over many layers. The thickness of the windings is 2.4 inches coming off of the engineering...
latitude & longitude & air pressure
21 hours ago Hi there, I have a peculiar question. Imagine that you are in a earth position, obtained by google, that gives you the latitude and longitude....
- More from Physics Forums - Classical Physics
More news stories
UCLA researchers examining outcomes for advanced heart-failure patients over the past two decades have found that, coinciding with the increased availability and use of new therapies, overall mortality has decreased and sudden ...
Cardiology 1 hour ago | not rated yet | 0
22 May 2013, Paris, France: The Lotus Valve, a second-generation transcatheter aortic valve implantation (TAVI) device, was successfully implanted in all of the first 60 patients in results from REPRISE II reported at EuroPCR ...
Cardiology 6 hours ago | not rated yet | 0
Costs to treat stroke are projected to more than double and the number of people having strokes may increase 20 percent by 2030, according to the American Heart Association/American Stroke Association.
Cardiology May 22, 2013 | not rated yet | 0
Blood thinners are the preferred treatment option to prevent heart attacks, blood clots and stroke, but they are not without risk, and not just because of their side effects. These high-risk drugs, known as anticoagulants, ...
Cardiology May 22, 2013 | not rated yet | 0
Results from a large observational study reported at EuroPCR 2013 today question whether bivalirudin is superior to heparin in the absence of GPIIb/IIIa blockade, showing similar 30-day mortality in patients with non-ST segment ...
Cardiology May 22, 2013 | 5 / 5 (1) | 0
Even while being dragged to its destruction inside a cell, a cancer-promoting growth factor receptor fires away, sending signals that thwart the development of tumor-suppressing microRNAs (miRNAs) before it's dissolved, researchers ...
59 minutes ago | not rated yet | 0 |
Breast cancer characterized as "triple negative" carries a poor prognosis, with limited treatment options. In some cases, chemotherapy doesn't kill the cancer cells the way it's supposed to. New research from Western University ...
5 minutes ago | not rated yet | 0
Mayo Clinic researchers have used next generation genomic analysis to determine that some of the more aggressive prostate cancer tumors have similar genetic origins, which may help in predicting cancer progression. The findings ...
8 minutes ago | not rated yet | 0
(HealthDay)—A shortage of a critical tuberculosis drug has hampered the efforts of health departments across the United States to contain the spread of the highly infectious lung disease, federal officials ...
9 minutes ago | not rated yet | 0
Finnish researchers unveiled new data Thursday to link the Pandemrix flu vaccine to a higher risk of the sleeping disorder narcolepsy in adults.
59 minutes ago | not rated yet | 0
Maintaining a heart healthy lifestyle may also help protect chronic kidney disease patients from developing kidney failure and dying prematurely, according to a study appearing in an upcoming issue of the Journal of the Am ...
29 minutes ago | not rated yet | 0