ADVERTISEMENT

Fragmentation Of The Heartbeat: Probing The Breakdown Of Biologic Time With Aging And Disease

The trace of the human heartbeat, a dynamical signature of life itself, is regulated by an exquisitely complex “clock” called the sino-atrial (SA) node. The cells comprising this cardiac timekeeper, like those in all biologic pacemakers, are nonlinear oscillators. It is widely assumed that the SA node beats with metronomic regularity.

However, even under resting conditions and during sleep, the time period between beats shows subtle, non-random fluctuations. These correlation properties give the healthy heartbeat a kind of swaying or “fluent” appearance in time series graphs.

ADVERTISEMENT

While the variations in heart rate have been of interest for decades or longer, this signal continues to reveal surprising properties that may provide useful information about health status, as well as about how the body’s oscillators break down with senescence and pathology.

From basic and translational perspectives, tracking the behavior of the heart’s intrinsic pacemaker is uniquely valuable. Heartbeat recordings are among the most accessible biologic signals, requiring only continuous recordings of the electrocardiogram (ECG). Furthermore, the variations in heartbeat dynamics under healthy conditions are self-regulated by an orchestral ensemble, including neurohormonal, respiratory, and cardiac components. Thus, the heartbeat cadence may provide a portal through which to unlock key aspects of our systems biology in physiologic and pathologic settings.

Our recent work on heartbeat dynamics has uncovered an intriguing class of abnormalities, grouped under the rubric of heart rate fragmentation, which appears to provide biomarkers of electrophysiologic instability. The basic mechanisms of heart rate fragmentation remain to be delineated but likely relate to electrophysiologic, inflammatory and mechanical perturbations, singly or in combination.

Of note, clinicians are very unlikely to diagnose fragmentation patterns from clinical ECG displays, which are only 10-sec in duration, or even from visual inspection of longer cardiac monitors recordings obtained in critical care units. But the jagged profiles of fragmentation, reflecting abrupt changes in heart rate acceleration not attributable physiologic control mechanisms, are clearly evident in heart rate time series.

ADVERTISEMENT

Follow-up studies are now aimed at validating these findings and seeing if proposed new measures of heart rate fragmentation can be used to enhance the prediction of adverse outcomes due to cardiovascular and other systemic diseases, as well as to assess the aging process.

These two studies, Heart Rate Fragmentation: A New Approach to the Analysis of Cardiac Interbeat Interval Dynamics and Heart Rate Fragmentation: A Symbolic Dynamical Approach were recently published in the journal Frontiers in Physiology.

Comments

READ THIS NEXT

The Use Of Emotions Can (Also) Be Learned, According To A Twin Study

Whether you suppress your emotions or look at them from a different angle to make them less painful depends to […]

How Many Weeks On Average Are In A School Year?

How many weeks are there in an average school year? The instruction time per school year varies from state to […]

The Formation Of Mars’ Juventae Chasma

Mars is a planet of geological curiosities that often have no parallels on Earth. Among these include the largest and […]

Changing Luminance Levels Affects Color Discrimination Abilities In Dogs

A common myth suggests that dogs don’t see color, that they exclusively see the world in shades of grey. Dogs […]

The Fate Of Urban Springs: Pumping-Induced Seawater Intrusion In An Underwater Cave 

Human populations are concentrated on coasts, where they often depend on aquifers as primary sources of water for drinking, agriculture, […]

Can Childhood Experiences Alter Your DNA and Make You Prone to Illness?

It has always been thought that our DNA is set in stone from the moment we are conceived and that […]

Studying Negative Experiences During Meditation

More than 25% of people who regularly meditate have had a “particularly unpleasant” psychological experience including feelings of anxiety and […]

Science Trends is a popular source of science news and education around the world. We cover everything from solar power cell technology to climate change to cancer research. We help hundreds of thousands of people every month learn about the world we live in and the latest scientific breakthroughs. Want to know more?