This trial is a Phase II, multicenter clinical study. The purpose of this trial is to evaluate the safety and efficacy of MiSaver, a cellular therapy product, in patients who have experienced an acute myocardial infarction (AMI). Specifically, the study aims to assess the improvement in left ventricular function of the heart following the administration of MiSaver, as well as to determine the safety of using stem cell therapy in these patients.

This trial will employ a single-blind design (subject-blinded), meaning that the participants will not be aware of whether they are receiving MiSaver or standard treatment, while the researchers will have this information. This design helps ensure transparency and adherence to ethical standards while also providing valuable clinical insights.

By utilizing randomization, we can enhance the reliability and comparability of the study results. A portion of the participants will receive MiSaver, while the others will undergo standard treatment. This allows for a direct comparison of the two therapeutic approaches to determine their respective efficacy.

The primary objective of this trial is to evaluate the safety and efficacy of MiSaver, in the treatment of patients with acute myocardial infarction (AMI). To achieve this, we will collect comprehensive participant data, including assessments of cardiac function, records of cardiac events, and quality-of-life surveys. By analyzing these data, we aim to gain a deeper understanding of the benefits and limitations of this treatment approach.

The investigators will enroll patients who have been diagnosed with acute myocardial infarction (AMI) within a timeframe of 36 hours to 7 days after the initial diagnosis. Eligible participants must be hemodynamically stable at the time of enrollment. Hemodynamic stability is defined as not requiring vasopressor support within the past 24 hours, having a systolic blood pressure (SBP) of less than 80 mmHg for no more than one hour, and not experiencing a resting heart rate of over 100 beats per minute for more than one hour.

Additionally, eligible patients must have undergone successful reperfusion therapy or coronary angiography confirming the absence of infarction at the time of screening. Only patients who are willing to receive MiSaver cellular therapy will be included in the study.

Inclusion Criteria:

1. Age ≥ 45 years, BMI ≤ 32
2. Patients diagnosed with acute myocardial infarction by a cardiologist, within 36 hours to 7 days post-diagnosis, and able to complete cell infusion within this period.
3. Left ventricular ejection fraction (LVEF) ≤ 45%, hemodynamically stable patients who do not require vasopressor support within 24 hours.
4. Patients with a history of coronary artery disease, who have previously undergone percutaneous coronary intervention or coronary artery bypass graft surgery, may also be included upon evaluation by a cardiologist.
5. Patients deemed unsuitable for percutaneous coronary intervention or coronary artery bypass graft surgery by a cardiologist.
6. Must agree to sign the informed consent form.
7. Subjects must use effective contraception during the study observation period and for 6 months after its conclusion to ensure no pregnancy occurs during the study. (Primarily for women of childbearing potential).
8. Agree to and comply with the required outpatient visits and examinations during the study observation period.

Exclusion Criteria:

1. Age < 45 years, BMI > 32.
2. Women who are planning to become pregnant, are pregnant, or are breastfeeding
3. Immunodeficiency diseases caused by infection , such as Human Immunodeficiency Virus (HIV).
4. Patients diagnosed as needing coronary artery bypass surgery or potentially requiring coronary revascularization surgery within the next 6 months.
5. Severe aortic or mitral valve stenosis.
6. Life-threatening arrhythmias.
7. Malignant tumors, including all categories and cancer conditions.
8. Hematologic disorders or other severe organ diseases with an expected survival of less than one year.
9. Chronic kidney disease (eGFR < 30 mL/min/1.73m²) or patients undergoing dialysis.
10. Patients with autoimmune diseases or those who have already received immunotherapy.
11. Patients who have undergone tumor treatment or require immunosuppressive therapy within the last three years.
12. History of transfusion reactions.
13. Recipients of bone marrow or organ transplants.
14. Liver dysfunction (bilirubin > 2.5 mg/dL or transaminases > 5x the upper limit of normal).
15. Patients who have previously received growth factors, cytokines, gene therapy, or stem cell therapy.
16. Subjects participating in more than one clinical trial.
17. Inability to sign the consent form or comply with outpatient follow-up after infusion therapy.
18. Patients with a known allergy to this product or its excipients (e.g., dimethyl sulfoxide, cell preservation solution).