Electrical activity from 30 healthy hearts in people over 75 was combined into a three-dimensional atlas

Electrical activity from 30 healthy hearts in people over 75 was combined into a three-dimensional atlas

On August 5, the authors of a preprint used MRI scans and recordings from a 256-electrode vest to build mathematical heart models for 30 participants over 75. They combined the models into a common map and compared them with data from 47 people of the same age who had early hypertension.

Each heartbeat begins with an electrical wave. The wave travels through the heart muscle, after which the cells recover their readiness for the next impulse. To distinguish age-related changes in this process from early disease, researchers must first measure it in older people selected as healthy.

The authors used MyoFit46, a cardiac study of a British cohort of 5 362 people born during the same week in March 1946. The healthy subgroup included 30 participants with normal blood pressure, hearts that pumped blood normally, and only small areas of scar tissue in the heart muscle.

For each participant, MRI showed the shape of the two ventricles, the chambers that pump blood out of the heart. A vest with 256 electrodes recorded signals from the body surface, which the researchers used to reconstruct the electrical pattern on the surface of the heart. A mathematical model then estimated where the wave began and how quickly it traveled through the muscle. It also assessed how different regions recovered after contraction.

In all 30 models, the authors supplemented the standard parameters of an adult heart with a setting that varied the duration of the cell's electrical impulse across different regions of the heart. The atlas shows how these settings are distributed throughout the heart muscle.

In maps from 47 people of the same age with early hypertension, 12 of 15 ventricular regions more often showed a pattern that corresponds in the model to a longer cellular electrical impulse. The atlas provides a reference distribution against which the electrical map of an individual heart from a person of the same age can be compared.