Scientists have shown how a complex mesh of muscle fibres that line the inner surface of the heart play a vital role in its function by increasing the efficiency of blood flow through the organ.
The researchers, led by the Medical Research Council (MRC) London Institute of Medical Sciences, based at Imperial College London, say they are the first to show this.
They hope the findings, published in the journal Nature, could help to identify people most at risk of heart failure.
The findings could also inform research into new treatments for the disease, which is one of the leading causes of death worldwide, and currently affects around 920,000 people in the UK.
Leonardo da Vinci sketched these intricate muscles inside the heart half a millennium ago, and it is only now that we are beginning to understand how important they are to human health
Study leader Dr Declan O’Regan, from the MRC London Institute of Medical Sciences, said: “Leonardo da Vinci sketched these intricate muscles inside the heart half a millennium ago, and it is only now that we are beginning to understand how important they are to human health.
“Da Vinci was also intrigued by the link between maths and nature, so it’s fitting that we found that fractal patterns in the heart are so important for its function.
“This work offers an exciting new direction for understanding the heart and shows the potential for bringing together ideas in maths and biology to medical research.”
The findings show how these muscles, called trabeculae, form a repeating geometric pattern known as a fractal, which is seen in other structures like trees and snowflakes.
In the 16th century, da Vinci was the first to sketch the muscles, speculating that they warm the blood as it flows through the heart; however, their true importance has not been recognised until now.
According to the research, the intricate meshwork of muscle fibres that cover the internal surface of the heart’s chambers are critical to the organ’s performance.
It suggests that these fibres allow blood to flow more efficiently during each heartbeat, just like the dimples on a golf ball help it to travel further through the air.
Researchers also discovered six regions in human DNA which affect how the fractal patterns in the muscle fibres develop.
They further found that two of these genes also regulate branching of nerve cells, suggesting a similar mechanism at work in the developing brain as well as the heart.
According to the study, trabeculae may influence the risk of heart disease.
Using genetics to analyse data from 50,000 patients, the scientists found that different fractal patterns in these muscles affected the risk of developing heart failure.
The study, funded by the Medical Research Council (MRC), with additional support from the British Heart Foundation and Wellcome, used artificial intelligence to analyse 25,000 MRI scans of the heart from the UK Biobank study.
The scans revealed the intricate structure of the muscle fibres and allowed researchers to investigate their role in heart function.
Dr O’Regan said: “This network of muscles lies between fast-flowing blood inside the heart and the contracting heart muscle.
“We also found that these fibres influence how fast electrical impulses travel through the heart – so they may be important for more than one aspect of how the heart works.”
The scientists said more research is needed on the intricate muscles inside the heart, with the hope that it could lead to new directions for understanding how common heart diseases develop and how they are treated.