NZ scientists create 3D heart model

The 3D model will allow better treatment of heart problems, particularly those with an irregular heartbeat. Photo / Getty Images

Game-changing research by Kiwi scientists - producing world-first 3D models - will help doctors better recognise and treat potentially fatal heart problems.

A newly completed programme, funded by the Health Research Council of New Zealand, has given international experts never-before-seen detail into the heart's upper chambers, or atria, and what tissue changes occur after heart attacks.

University of Auckland research fellow Dr Jichao Zhao has spent the past two years processing data from 700 thin image "slices" of the atria to build into a 3D computer model.

It has shown for the first time a detailed and realistic 3D image of the arrangement of muscle fibres throughout the heart's atrial chambers, down to the cellular level.

Previous models had only been able to reproduce the atria's shape and wall thickness.

The model is being used to examine the mechanisms behind persistent atrial fibrillation - a debilitating heart condition that causes an irregular heartbeat which doesn't go away.

Research suggests about a quarter of New Zealanders older than 40 would develop this condition in their lifetime, putting them at higher risk of not only heart failure, but also thrombosis and stroke.

Patients with persistent atrial fibrillation commonly have treatment to remove the tissue thought to be causing the atria's electrical signals to go haywire. But the method clinicians use to map these signals was time-consuming and unreliable. Dr Zhao has been working with Auckland City Hospital clinician Dr Nigel Lever to develop a method that can record electrical signals simultaneously across the inner surfaces of both atrial chambers.

"By combining novel multi-site mapping catheters with state-of-the art imaging, it will be possible to get a snapshot of what's going on in real time and with much greater anatomical precision than is currently achievable," Dr Zhao said.

Researchers have also used 3D modelling to produce a clearer picture of how an attack affects a "border zone" formed when the affected part of the heart develops scar tissue and butts up against normal tissue.

A team from the university's Auckland Bioengineering Institute and School of Medical Sciences have mapped the area with a high-resolution computer model.

"We've been able to show that rhythm disturbances, which give rise to very rapid heart rates and increase the risk of sudden death, are caused by abrupt changes in the arrangement of the surviving heart muscle cells in the border zone affected by a heart attack," senior research fellow Dr Mark Trew said.

Dr Trew said a wave of international partnerships were being set up.

"It is cutting edge because no one else has been able to do the required imaging of the upper heart to the extent that you can actually measure the orientations of groups of cells.

"From an electrical behaviour point of view, the way these cells are lined up is fundamental to rhythm problems in the heart - and understanding how you might go ahead and treat these things."