This study is checking if the drug zilebesiran can lower the risk of serious heart problems in people with high blood pressure not well controlled. High blood pressure is when the force of blood against your artery walls is too high. Zilebesiran will be compared to a placebo (a "fake" treatment that looks like the real medicine but isn't) to see if it helps reduce heart-related issues like heart attacks, strokes, or heart failure. Participants need to have heart disease or be at high risk for it and already take certain blood pressure medicines.

• Participants must be at least 18 years old with heart disease or 55 or older with high risk.
• The study will last until enough important heart events have been recorded.
• Some health conditions may prevent joining, such as other types of high blood pressure or liver issues.