Tag: defibrillation

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A Model for Gentler Defibrillation for the Heart

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Using light pulses as a model for electrical defibrillation, Göttingen scientists developed a method to assess and modulate the heart function. This has paved the way for an efficient and direct treatment for cardiac arrhythmias. This may be an alternative for the strong and painful electrical shocks currently used.

Cardiac arrhythmias account for around 15-20% of annual deaths worldwide. In case of acute and life-threatening arrhythmias, defibrillators can be used to restart the regular beating of the heart. A strong electrical pulse brings cardiac activity to a brief standstill before it can be resumed in an orderly way. Whereas this treatment can save lives very effectively, the strong electrical pulses can also have negative side effects such as damage of the heart tissue or strong pain.

“We developed a new and much milder method which allows the heart to get back into the right rhythm,” says Stefan Luther, Max Planck Research Group leader at the MPI-DS and professor the University Göttingen Medical Center. “Our results show that it is possible to control the cardiac system with much lower energy intensity,” he continues.

To test their method, the scientists, from the Max Planck Institute for Dynamics and Self-Organization (MPI-DS) and the University Göttingen Medical Center, used genetically modified mouse hearts that can be stimulated by light. In this setting, a sequence of optical light pulses is triggered using a closed-loop pacing algorithm. Each pulse is triggered in response to the measured arrhythmic activity.

With this pacing protocol, the team was able to effectively control and terminate cardiac arrhythmias even at low energy intensities that do not activate the heart, but only modulate its excitability.

“Instead of administering a single high-energy shock to restore normal heart rhythm, we use our understanding of the dynamics of cardiac arrhythmias to gently terminate them.” explains Sayedeh Hussaini, first author of the study.

“This results in a subtle treatment method with far less energy per pulse, more than 40 times less compared to the conventional strategy” she reports.

The research team will also use these findings to improve the control of arrhythmias using electrical pulses. This may result in advanced defibrillators causing less pain and side-effects for patients.

Source: Max Planck Institute for Dynamics and Self-Organization

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Better Survivor Outcomes One Year after Cardiac Arrest When Bystanders Perform Defibrillation

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Survivors of out-of-hospital cardiac arrest (OHCA) who received initial bystander defibrillation with a nearby automated external defibrillator (AED) reported better outcomes at 12 months after arrest compared with those initially defibrillated by paramedics, according to a new study from Monash University which appears in Heart.

The retrospective study recruited adult non-traumatic OHCA with initial shockable rhythms between 2010 and 2019. Survivors at 12 months after arrest were invited to participate in structured telephone interviews. Outcomes were identified using the Glasgow Outcome Scale-Extended (GOS-E), EuroQol-5 Dimension (EQ-5D), 12-Item Short Form Health Survey and living and work status-related questions.

Of 6050 patients, 3211 (53.1%) had a pulse on hospital arrival, while 1879 (31.1%) were discharged alive. Survival rates were highest with bystander defibrillation (52.8%), followed by dispatched first responders (36.7%) and paramedics (27.9%). Of the survivors, 1802 (29.8%) survived to 12-month post-arrest; of these 1520 (84.4%) were interviewed. 1088 (71.6%) were initially shocked by paramedics, 271 (17.8%) by first responders and 161 (10.6%) by bystanders. Bystander-shocked survivors reported higher rates of living at home without care (87.5%), upper good recovery (GOS-E=8) (41.7%) and EQ-5D visual analogue scale (VAS) ≥ 80 (64.9%) compared with first responder and paramedics, respectively. After adjustment, initial bystander defibrillation was associated with higher odds of EQ-5D VAS ≥ 80 (adjusted OR (AOR) 1.56), good functional recovery (GOS-E ≥ 7) (AOR 1.53), living at home without care (AOR 1.77) and returning to work (AOR 1.72) compared with paramedic defibrillation.

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Better Outcomes with Earlier Adrenaline Treatment in Cardiac Arrest

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Earlier adrenaline treatment during a cardiac arrest is linked to better recovery compared to later treatment, according to preliminary research to be presented at the American Heart Association’s Resuscitation Science Symposium (ReSS) 2021.

“Our study’s findings should guide emergency medical services professionals towards earlier administration of epinephrine [adrenaline] during out-of-hospital cardiac arrest management,” said lead study author Shengyuan Luo, MD, MHS, an internal medicine resident physician at Rush University Medical Center in Chicago.

Previous research found that only about 1 in 5 people survive a cardiac arrest outside of the hospital and those who do survive often have long-term impairment in the ability to perform daily living tasks.

During a cardiac arrest, immediate CPR (cardiopulmonary resuscitation) is critical. For some types of cardiac arrest, an AED (automated external defibrillator) also is used to deliver an electric shock through the chest to the heart to restore a heartbeat. For these ‘shockable’ cardiac arrests, adrenalineis injected to help restore blood flow. Previous research indicated that adrenaline should be given after three unsuccessful electric shocks with an AED, however, it was unclear whether it should be given even earlier – such as after the first electric shock.

To compare the effects of earlier versus later administration of adrenaline, the researchers examined medical records to compare epinephrine timing to patient recovery. Study subjects included 6416 multi-ethnic adults across North America who had an out of hospital cardiac arrest with shockable initial rhythm from 2011-2015. They were an average age of 64 years, and most were men.

Overall, adrenaline administration within four minutes after the first shock from an AED was associated with greater chances of recovery, while administration after four minutes was associated with reduced chances. Specifically, people who received adrenaline after four minutes were nearly half as likely to have heartbeat and blood flow restored before hospital admittance and half as likely to survive to hospital discharge or be able to perform daily tasks, as measured by a standard test, at discharge. Additionally, the risks of later adrenaline treatment rose with each minute of delayed treatment.

“It is crucial that whenever a cardiac arrest event is suspected, the emergency medical system be notified and activated immediately, so that people with cardiac arrest receive timely, life-saving medical care,” Dr Luo said.

These findings support the latest American Heart Association CPR and Emergency Cardiovascular Care Guidelines, which were released in October 2020. The guidelines indicate adrenaline should be administered as early as possible to maximise good resuscitation outcome chances. The guideline recommendation was based on previous observational data that suggest better outcomes when adrenaline is given sooner.

Source: EurekAlert!