3D Data Shows What Makes the Heart Beat – in High-Resolution Detail

Heart CT scan

I’ve often read the phrase “my heart skipped a beat” in novels where it was used to describe a giddy, romantic feeling. I understand what authors are going for, but I can’t imagine that your heart actually skipping a beat, or having any kind of irregular rhythm, is a good thing; in fact, atrial fibrillation, an irregular and often rapid heartbeat, affects 1.4 million people in the UK. While it’s possible to wear your 3D printed heartbeat on your finger, and even use 3D printing to create a patch of beating heart cells or a medical model to guide complex valve procedures, it’s hard to get a really good look at the cardiac conduction system, which are the special cells that make our hearts beat. But a team of scientists from multiple universities in Europe are working on a new study, and developed a way to produce 3D data that shows this heartbeat system in extremely specific detail. The results of their work could help surgeons fix hearts without damaging tissue.

The researchers are from Liverpool John Moores University (LJMU), The University of Manchester, and Newcastle University in England, and Aarhus University in Denmark. The 3D data shows exactly where the system that produces a heartbeat is located (spoiler alert, it’s really close to the aortic valve). In addition it gives the team a more accurate framework for computer models of a heartbeat, and it should be able to improve doctors’ ability to understand conditions and heart rhythms like atrial fibrillation.

Micro-CT allows objective discrimination of the human sinus node. This figure demonstrates high resolution micro-CT data from part of the right atrium containing the sinus node.

According to a paper the team published about their study in Scientific Reports, titled “High resolution 3-Dimensional imaging of the human cardiac conduction system from microanatomy to mathematical modeling,” there’s a good reason why it’s hard to get detailed visuals of the cardiac conduction system.

“The specialised cardiomyocytes, known as the cardiac conduction system, are anatomically discrete from the working myocardium, and cannot be visualised using traditional non-invasive techniques,” the paper explains.

This system ensures that the parts of a heart contract in a coordinated, regular way. It generates and sends out a wave of electrical activity, which stimulates the heart muscle to contract. If something damages this system and causes one part to contract out of time with the other parts, efficiency goes down.

“The 3D data makes it much easier to understand the complex relationships between the cardiac conduction system and the rest of the heart. We also use the data to make 3D printed models that are really useful in our discussions with heart doctors, other researchers and patients with heart problems,” explained Professor Jonathan Jarvis, with the LJMU School of Sport and Exercise Sciences.

“New strategies to repair or replace the aortic valve must therefore make sure that they do not damage or compress this precious tissue. In future work we will be able to see where the cardiac conduction system runs in hearts that have not formed properly. This will help the surgeons who repair such hearts to design operations that have the least risk of damaging the cardiac conduction system.”

In addition to Professor Jarvis, co-authors of the paper include:

• Robert S. Stephenson, Aarhus University
• Robert H. Anderson, Newcastle University
• Jichao Zhao, University of Auckland
• Mike Bateman and Paul A. Iaizzo, University of Minnesota
• Filip Perde, National Institute of Legal Medicine in Romania
• Andrew Atkinson, Halina Dobrzynski, Fatemeh Jafarzadeh, Petros Kottas, and Henggui Zhang, The University of Manchester

The 3D anatomy of cardiac conduction system in the intact human heart. This figure demonstrates high resolution (73 × 73 × 73 µm3) micro-CT data.

The abstract of the paper reads:

“Cardiac arrhythmias and conduction disturbances are accompanied by structural remodelling of the specialised cardiomyocytes known collectively as the cardiac conduction system. Here, using contrast enhanced micro-computed tomography, we present, in attitudinally appropriate fashion, the first 3-dimensional representations of the cardiac conduction system within the intact human heart. We show that cardiomyocyte orientation can be extracted from these datasets at spatial resolutions approaching the single cell. These data show that commonly accepted anatomical representations are oversimplified. We have incorporated the high-resolution anatomical data into mathematical simulations of cardiac electrical depolarisation. The data presented should have multidisciplinary impact. Since the rate of depolarisation is dictated by cardiac microstructure, and the precise orientation of the cardiomyocytes, our data should improve the fidelity of mathematical models. By showing the precise 3-dimensional relationships between the cardiac conduction system and surrounding structures, we provide new insights relevant to valvar replacement surgery and ablation therapies. We also offer a practical method for investigation of remodelling in disease, and thus, virtual pathology and archiving. Such data presented as 3D images or 3D printed models, will inform discussions between medical teams and their patients, and aid the education of medical and surgical trainees.”

The researchers exhibited that micro-CTs, enhanced by contrast, offer a non-destructive way to get high-resolution maps of the 3D disposition of the cardiac conduction system. This kind of detailed imaging could result in important benefits, such as further understanding the differences between healthy, aging, diseased, and congenitally malformed hearts, and creating biophysically and anatomically-detailed mathematical models of the heart, which can then be used to develop 4D simulations of cardiac conductions.

“This is just the beginning. The British Heart Foundation is supporting my group to visualise this system in 3D from aged and failing hearts,” said Dr. Dobrzynski, who has spent 20 years working on the anatomy of the cardiac conduction system. “With my research assistant Andrew Atkinson and working with Professor Jonathan Jarvis, Robert Stephenson and others, we will produce families of data from aged and failing hearts in 3D.”

Discuss in the 3D Data Heartbeat forum thread at 3DPB.com.