News | Implantable Cardiac Monitor (ICM) | March 14, 2017

Heart Monitoring Technology Reveals Risks for Climbers at High Altitudes

Findings reveal 50 percent of the subjects experienced significant pauses in their heartbeat over the course of 51 days

heart monitoring technology, climbers, high altitudes, Circulation study, cardiac diagnostics, Medtronic, Reveal LINQ

March 14, 2017 — Climbing above 4,000 meters can provoke abnormal heart rhythms in otherwise healthy mountaineers, with the abnormalities increasing with altitude, new research has shown.

The study, by sports scientists at Leeds Beckett University (U.K.) and cardiologists at Poole Hospital, found that in a team of 16 healthy mountaineers without a previous history of heart disease, more than half (56.3 percent) experienced rhythm disturbances at altitudes of 4,100 meters or above.

These were either significant pauses in their heartbeat — where the heart stops for three seconds or more — or very fast or irregular heartbeats. The pauses generally took place at night, while the climbers were asleep. All identified abnormalities disappeared once climbers descended below 4,100 meters.

The research, published in the journal Circulation, was carried out with a team of military volunteers from the Defence Medical Services during an expedition to climb Nepal’s Mount Dhaulagiri, in the Himalayas.

The research is the first to continually monitor climbers’ heartbeat over an extended period and shows the potential for such technologies to help with medical diagnoses in remote locations.

The group was studied over a period of at least four months, both before, during and after the 51-day expedition, using implantable cardiac monitors, called Reveal LINQ. Similar in size to a AAA battery the devices were developed by Medtronic. They are typically used in clinical care to detect rare cardiac events but had not previously been tried at high altitude.

Heart rate and activity data were continuously recorded by the device and could be uploaded to a remote stored server by a cellular signal or manually for analysis. The climbers could also trigger the device to specifically store extended recordings of their heartbeat if they experienced any concerning symptoms, such as severe palpitations, which was observed among half the participants. Additional data on the climbers’ blood oxygen levels and physical condition were also collected.

The most commonly identified cardiac abnormality were significant pauses, which were recorded on 81 occasions and affected 50 percent of the subjects. Both the frequency and duration of the pauses increased the higher the climbers went, with the longest pause lasting seven seconds. One climber experienced an episode of a sustained symptomatic irregular fast heartbeat known as atrial fibrillation that lasted for nearly five hours and had kept him awake at night, and another developed a fast abnormal heart rhythm know as a supraventricular tachycardia (SVT) lasting 31 seconds while he attempted to lift a heavy load.

Chris Boos, M.D., visiting professor at Leeds Beckett University and consultant cardiologist at Poole Hospital, who led this study explained: “Our research has delivered a unique and fascinating insight into cardiac physiology at high altitude, showing what happens to the heart rate and rhythm while you sleep and exercise at very high altitude.

“For the majority of mountaineers, there should be no cause for concern, as the pauses during sleep may simply represent normal physiological adaptation to the significant challenges of the very high altitude environment. However, going above 4,000 meters could potentially exacerbate any pre-existing conditions which climbers may or may not already be aware of, and this should be taken into account when planning expeditions.”

He added: “Our study also shows the potential of this kind of technology for delivering medical diagnoses to people in extremely remote locations.”

The team plans to continue its investigations with larger groups of subjects and using even more recent advances in cardiac non-invasive monitoring technology, which will enable even greater detail to be recorded without the need for devices to be implanted.

For more information:

Related Content

Male Triathletes May Be Putting Their Heart Health at Risk
News | Cardiac Diagnostics | January 09, 2018
Competitive male triathletes face a higher risk of a potentially harmful heart condition called myocardial fibrosis,...
ERT Acquires iCardiac Technologies
News | Cardiac Diagnostics | December 19, 2017
ERT recently announced it has acquired iCardiac Technologies, a provider of centralized cardiac safety and respiratory...
New Study Suggests Protein Could Protect Against Coronary Artery Disease

Patients with no obstructed blood flow in the coronary arteries had higher levels of CXCL5 (blue) compared to patients with moderate levels (green) or lower levels (yellow) of CXCL5, who had increased severity of coronary obstructions (indicated by the arrows). Credit: Schisler lab

News | Cardiac Diagnostics | December 07, 2017
December 7, 2017 — The buildup of plaque in the heart’s arteries is an unfortunate part of aging.
E-cigarettes Most Likely to be Used by Alcohol Drinkers and Former Cigarette Smokers, at American Heart Association (AHA), #AHA2017.
News | Cardiac Diagnostics | December 06, 2017
December 6, 2017 — Electronic cigarettes are more frequently used by people who recently quit smoking and alcohol dri
Lack of sleep may cause heart disease in older women. American heart Association, #AHA2017
News | Cardiac Diagnostics | December 06, 2017
December 6, 2017 — Older women who do not get enough sleep were more likely to have poor cardiovascular health, accor
New Tool Predicts Risk of Heart Attack in Older Surgery Patients
News | Cardiac Diagnostics | December 05, 2017
A tool designed to more accurately predict the risk of heart attack in older patients undergoing non-cardiac surgery...
EPIC Norfolk prospective population study showed any physical activity is better than none in older adults in preventing cardiovascular disease.

The EPIC Norfolk prospective population study showed any physical activity is better than none in older adults in preventing cardiovascular disease.

News | Cardiac Diagnostics | November 24, 2017
November 24, 2017 — Any physical activity in the elderly is better than none at all for reducing cardiovascular risk,
Analytics 4 Life Presents Clinical Data on Machine-Learned Cardiac Imaging Technology at TCT 2017
News | Cardiac Diagnostics | November 01, 2017
Analytics 4 Life announced it will be presenting new clinical data on the company's ongoing Coronary Artery Disease...
American Heart Association, Verily and AstraZeneca Launch One Brave Idea Science Innovation Center
News | Cardiac Diagnostics | October 20, 2017
The American Heart Association, Verily and AstraZeneca announced the opening of the One Brave Idea Science Innovation...
Overlay Init