Heart failure with preserved ejection fraction (HFpEF) is a massive public health issue that is now more common than the traditional form of heart failure (HFrEF). While doctors have long noted that women and men experience HFpEF differently—especially as they age or deal with metabolic issues like diabetes—a new study analyzing actual heart tissue samples discovered that these differences aren’t strictly based on a person’s biological sex. Instead, by looking at the heart’s proteins, researchers found that HFpEF actually splits into two entirely distinct molecular blueprints, or “clusters.” One cluster shows major changes in the heart’s physical pumping structure, while the other shows breakdown in how heart cells communicate with their surrounding supportive tissue. By uncovering these two specific protein profiles rather than viewing HFpEF as a single disease, scientists now have a precise map to design targeted, personalized drugs for patients based on their specific molecular type.