After a heart attack (also called myocardial infarction), the heart forms a scar as part of its healing process. This can sometimes lead to dangerous complications like heart failure or heart rhythm disorders. The immune system, particularly B cells interacting with other cells like monocytes and platelets, plays a crucial role in this healing process. Most research on this topic comes from mouse studies, but how it applies to humans is unclear. This project, centered on the recently initiated PHENO-HEART MI study, aims to understand the human B-cell-centered immune response after a heart attack. By studying patients, their blood samples and immune patterns, the researchers aim to identify better ways to identify at-risk patients and develop new treatments.