Based on the monitoring data of wearable devices, with cardiac output (CO) as the gold standard, this study intends to develop a non-invasive evaluation model of CO based on wearable data, and optimize the parameters to realize the cardiac capacity detection function in resting and exercise states on the wearable device.

Inclusion Criteria:

• Over 18 years old
• Left ventricular ejection fraction (Left ventricular ejection fraction, LVEF) < 50%(200 subjects)
• Left ventricular ejection fraction (Left ventricular ejection fraction, LVEF) ≥50% (100 subjects)
• Able to use smart phones and operate wearable devices such as wristbands/watches

Exclusion Criteria:

• Patients with pacemaker implantation
• No smartphone
• Currently participating in other clinical trials
• Lactating women
• Pregnant Women
• Unable to run and ride due to personal physical and external reasons (subjects participating in the exercise state cardiac output model study)
• Physical examination results in the past year have clear cardiovascular, metabolic, bone and joint related diseases that have exercise risk, or have diseases and related potential health risks confirmed by the self-examination form of physical status before exercise (participants in the exercise state cardiac output model study)
• No informed consent was obtained

Two hundred HF patients with an left ventricular ejection fraction (LVEF) of less than 50% and 100 normal cardiac function subjects with an LVEF of 50% or greater were enrolled