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Approved Research

Sex and age-specific cardiac strain and contractility

Principal Investigator: Mx Sarah St. Pierre
Approved Research ID: 89726
Approval date: August 25th 2022

Lay summary

While many people have studied heart disease, fewer have studied how healthy male and female hearts differ across age. The female heart is not just a smaller version of the male heart. The sex and age differences in the heart are complex and include the shape of the heart and its ability to pump blood efficiently. Over the course of 3 years, I will study functional sex and age differences in cardiac biomechanics in more detail. My first aim is to determine how the geometry and function of male and female hearts influence the degree of deformation of the myocardial tissue, a parameter known as strain. I will do this by using a neural network, which takes in inputs such as geometry, function, sex, and age and learns an output, in this case, strain. The neural network will use the strains from previous UK Biobank studies to optimize its prediction. Once the neural network can make reliable predictions, I will be able to analyze how important each of the input parameters is to determining sex and age-specific strain.

My second aim is to determine the contractility of heart tissue. First, I will use a simple physics relationship called the Law of Laplace which connects blood pressure and the geometry of the heart chambers to the passive stiffness in the walls of the chambers. To find the active stiffness, I will use a more complex physics relationship that takes in the pressure in the heart when it is fully filled. This will allow me to determine the contractility of the heart, which determines how much blood the heart is able to output. My study will characterize the age and sex-specific cardiac strains and contractility in a large, healthy population for the first time.

A better understanding of sex and age differences in the human heart is critical to designing sex and age-specific training plans that improve human performance and prevent cardiac injuries in athletes and to establish sex and age-specific diagnostic criteria that accurately identify cardiac disease and improve cardiac health.