Background.Seismocardiography (SCG) is a non-invasive, wearable technology that captures mechanical vibrations of the heart, offering a potential low-cost tool for assessing cardiac function. While conventional imaging modalities such as transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) provide detailed structural and volumetric measures, they are operator-dependent and require specialized training. This study aimed to evaluate the correlation between SCG, TTE and CMR markers of systolic and diastolic function in healthy individuals and those with cardiovascular disease (CVD).Methods.Twenty-six subjects (age 45 ± 16 years and 77% male) were included, 10 healthy subjects and 16 subjects with CVD. All subjects underwent SCG, TTE, and CMR measurements before and after intravenous infusion of 2.0 l isotonic saline. SCG signals were segmented into individual heartbeats, and fiducial points were automatically detected and manually validated.Results.SCG amplitudes Cd-to-Dd and Dd demonstrated moderate correlations with the diastolic parametere' from TTE (r= 0.42-0.66), while SCG time intervals Gs-Bd and Ls-Bd correlated moderately with LVET (r= 0.51-0.66). These associations were consistent across both healthy participants and patients with CVD.Conclusion.SCG-derived measures correlate moderately with TTE markers of diastolic (e') and systolic (LVET) function, and these associations are preserved in both healthy and CVD subgroups, indicating robustness across clinical phenotypes. The findings in this study support SCG's potential as a non-invasive tool for assessing mechanical cardiac function. However, further validation in real-world wearable settings is required.