Exploratory Association Between Wearable Electrocardiogram-derived Temporal Parameters and Pulse Wave-based Cardiac Output in Healthy Young Adults

Cardiac output (CO) is a crucial indicator for assessing hemodynamic status in intensive care units and clinical settings. However, conventional reference methods like echocardiography are limited by equipment accessibility and the challenges associated with repeated measurements. This study aimed to quantitatively analyze the relationships between physiological parameters derived from wearable electrocardiogram (ECG) devices and pulse wave-derived CO. The goal was to explore the feasibility of developing a wearable ECG-based CO estimation algorithm. The study included 30 healthy university students in their 20s, comprising both males and females, with no history of cardiovascular disease. The RR interval, QRS duration, and PR interval demonstrated statistically significant correlations with CO. Simple linear regression analysis revealed the following: a 1-ms increase in the RR interval was associated with an estimated decrease of 0.0072 L/min in CO; a 1-ms increase in the QRS duration was associated with an estimated increase of 0.0513 L/min; and a 1-ms increase in the PR interval was associated with an estimated decrease of 0.0346 L/min in CO. Our findings confirm that physiological parameters extracted from wearable ECG devices exhibit significant linear relationships with pulse wave-based CO. This supports the technical feasibility of noninvasive CO estimation using wearable ECG signals.