Uncovering ECG Changes during Healthy Aging using Explainable AI

Cardiovascular diseases remain the leading global cause of mortality. This necessitates a profound understanding of heart aging processes to diagnose constraints in cardiovascular fitness. Traditionally, most of such insights have been drawn from the analysis of electrocardiogram (ECG) feature changes of individuals as they age. However, these features, while informative, may potentially obscure underlying data relationships. In this paper, we employ a deep-learning model and a tree-based model to analyze ECG data from a robust dataset of healthy individuals across varying ages in both raw signals and ECG feature format. Explainable AI techniques are then used to identify ECG features or raw signal characteristics are most discriminative for distinguishing between age groups. Our analysis with tree-based classifiers reveal age-related declines in inferred breathing rates and identifies notably high SDANN values as indicative of elderly individuals, distinguishing them from younger adults. Furthermore, the deep-learning model underscores the pivotal role of the P-wave in age predictions across all age groups, suggesting potential changes in the distribution of different P-wave types with age. These findings shed new light on age-related ECG changes, offering insights that transcend traditional feature-based approaches.