Nav: Home

New research could reduce the risk of sudden cardiac death

January 20, 2020

Around 26 million people worldwide suffer from heart failure, with more than 50 per cent dying suddenly most likely due to the spontaneous onset of a heart rhythm problem, known as an arrhythmia. The link between the electrical signal that triggers the heart cell to contract (action potential) and consequent ability of the heart to pump blood has been known for nearly 40 years but understanding how and why the heart's electrical rhythm becomes disturbed has remained a major research problem. New research has shown that by changing the time course of voltage change early in action potential it is possible to both withhold a potentially lethal electrical disturbance and improve the strength of cardiac contraction in heart failure at the same time.

The research led by the University of Bristol and funded by the Medical Research Council (MRC) is published today [20 January] in the Proceedings of the National Academy of Sciences (PNAS).

At the cellular level, an identified initiator of cardiac arrhythmias are early after-depolarizations (EADs), but the cellular trigger for EADs in heart failure is unclear. EADs occur during the repolarization phase of the cardiac action potential (AP) where several ionic currents interact to control repolarization. EADs may be produced by reactivation of ionic currents during AP repolarization when the potassium currents forming the "repolarization reserve" are insufficient to maintain the repolarization trajectory of the AP, although why this should occur spontaneously within a steady train of APs is uncertain. Spontaneous calcium (Ca2+) waves inside the cell have also been implicated in EAD generation, but it is unclear how such waves might be initiated.

The study has shown that the reduction in synchronous Ca2+ release early in the AP of failing heart muscle cells promotes the appearance of "late Ca2+ sparks" (microscopic Ca2+ release events) which can propagate, forming Ca2+ ripples and waves. These, in turn, produce an inward sodium-calcium exchange current which opposes AP repolarization. Restoration of AP phase 1 repolarization improved Ca2+ release synchrony and reduced late Ca2+ spark rate, suggesting an entirely new approach to reducing the risk of sudden death in heart failure.

Professor Mark Cannell, Chair in Cardiac Cell Biology in the University of Bristol's School of Physiology, Pharmacology and Neuroscience, who led the research, said: "Our findings suggests that new therapies should be developed with the aim of improving early Ca2+ release by restoring AP phase 1 repolarization and/or restoring t-tubule regularity. This will reduce the risk for potentially lethal heart rhythm problems as well as mitigating the defective excitation-contraction coupling seen in heart failure. Our research proposes an entirely new approach to reducing the risk of sudden death in heart failure and the next step will be to move towards a clinical trial of new drugs."

'Arrhythmogenic late Ca2+ sparks in failing heart cells and their control by action potential configuration' by Ewan D. Fowler, Nan Wang, Melanie Hezzell, Guillaume Chanoit, Jules C. Hancox & Mark B. Cannell in the Proceedings of the National Academy of Sciences (PNAS)

University of Bristol

Related Heart Failure Articles:

Autoimmunity-associated heart dilation tied to heart-failure risk in type 1 diabetes
In people with type 1 diabetes without known cardiovascular disease, the presence of autoantibodies against heart muscle proteins was associated with cardiac magnetic resonance (CMR) imaging evidence of increased volume of the left ventricle (the heart's main pumping chamber), increased muscle mass, and reduced pumping function (ejection fraction), features that are associated with higher risk of failure in the general population
Transcendental Meditation prevents abnormal enlargement of the heart, reduces chronic heart failure
A randomized controlled study recently published in the Hypertension issue of Ethnicity & Disease found the Transcendental Meditation (TM) technique helps prevent abnormal enlargement of the heart compared to health education (HE) controls.
Beta blocker use identified as hospitalization risk factor in 'stiff heart' heart failure
A new study links the use of beta-blockers to heart failure hospitalizations among those with the common 'stiff heart' heart failure subtype.
Type 2 diabetes may affect heart structure and increase complications and death among heart failure patients of Asian ethnicity
The combination of heart failure and Type 2 diabetes can lead to structural changes in the heart, poorer quality of life and increased risk of death, according to a multi-country study in Asia.
Preventive drug therapy may increase right-sided heart failure risk in patients who receive heart devices
Patients treated preemptively with drugs to reduce the risk of right-sided heart failure after heart device implantation may experience the opposite effect and develop heart failure and post-operative bleeding more often than patients not receiving the drugs.
How the enzyme lipoxygenase drives heart failure after heart attacks
Heart failure after a heart attack is a global epidemic leading to heart failure pathology.
Novel heart pump shows superior outcomes in advanced heart failure
Severely ill patients with advanced heart failure who received a novel heart pump -- the HeartMate 3 left ventricular assist device (LVAD) -- suffered significantly fewer strokes, pump-related blood clots and bleeding episodes after two years, compared with similar patients who received an older, more established pump, according to research presented at the American College of Cardiology's 68th Annual Scientific Session.
NSAID impairs immune response in heart failure, worsens heart and kidney damage
Non-steroidal anti-inflammatory drugs, or NSAIDs, are widely known as pain-killers and can relieve pain and inflammation.
Heart cell defect identified as possible cause of heart failure in pregnancy
A new Tel Aviv University study reveals that one of the possible primary causes of heart failure in pregnant women is a functional heart cell defect.
In heart failure, a stronger heart could spell worse symptoms
Patients with stronger-pumping hearts have as many physical and cognitive impairments as those with weaker hearts, suggesting the need for better treatment.
More Heart Failure News and Heart Failure Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Clint Smith
The killing of George Floyd by a police officer has sparked massive protests nationwide. This hour, writer and scholar Clint Smith reflects on this moment, through conversation, letters, and poetry.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at