Scientists Uncover Heart's Hidden Geometry to Revolutionize ECG Interpretation

A study by scientists at King's College London has found that the physical orientation of the heart in the chest significantly influences the electrical signals recorded on an electrocardiogram (ECG) - a discovery that could pave the way for more personalised and accurate diagnosis of heart disease.

Using data from more than 39,000 participants in the UK Biobank project, this is one of the largest population-based studies to date examining the relationship between the heart’s anatomy and its electrical activity. By combining 3D cardiac imaging with ECG data, the team created simplified digital twins of each participant’s heart.

These personalized models allowed the researchers to study how the anatomical position of the heart, known as the anatomical axis, relates to a spatial measure of electrical activity, or the electrical axis. The study is published in the journal PLOS Computational Biology.

Digital twins are becoming a powerful tool in cardiovascular research, allowing scientists to model and study the structure and function of the heart in unprecedented detail. In this study, they played a key role in revealing how natural variations in the orientation of the heart, shaped by factors such as body mass index (BMI), gender and hypertension, can significantly affect ECG readings.

“Large-scale biomedical resources such as the UK Biobank are paving the way for patient-centric characterisation of diseases by allowing detailed analysis of anatomical and electrophysiological variations in the population.

This work demonstrated differences in cardiac axes between healthy and diseased individuals, highlighting the potential for increased personalization of digital twins and improved prognosis and disease characterization, ultimately allowing for more personalized clinical care,” says Mohammad Kayyali.

The researchers proposed new, standardized definitions for both anatomical and electrical axes based on their alignment in 3D space. They found that people with higher BMI or high blood pressure tend to have hearts that are positioned more horizontally in the chest, and this shift is reflected in their ECG signals.

The study also found clear differences between men and women: men's hearts tend to have a more horizontal orientation than women's, and this structural difference is reflected in the surface electrical activity. These gender differences highlight the need for a more individualized approach to ECG interpretation.

By identifying and quantifying this variability across a large population, the study highlights the importance of distinguishing between normal anatomical features and early signs of disease. This may help clinicians identify conditions such as hypertension, conduction abnormalities, or early changes in the heart muscle earlier and more accurately, especially in patients whose cardiac orientation deviates from standard assumptions.

“The ability to create personalised models (i.e. digital twins) of the cardiovascular system is an exciting area of research where we hope to find new parameters that can better inform the prevention, diagnosis and risk of cardiovascular disease. In this work, we begin to explore these unexplored areas and hope to soon offer new ways to detect conditions such as electrical conduction disorders early,” says Professor Pablo Lamata.

The findings point to a future where ECGs are no longer interpreted in a one-size-fits-all manner, but are tailored to each patient’s unique anatomy. This personalized approach could reduce diagnostic errors and support earlier, more accurate interventions.