Omecamtiv mecarbil is primarily used in the treatment of heart failure, specifically for patients with reduced ejection fraction. It works by directly targeting cardiac myosin, a key protein involved in muscle contraction, enhancing its activity. This leads to improved systolic function, allowing the heart to pump blood more effectively. It is particularly beneficial for patients who do not respond adequately to standard heart failure therapies. Clinical trials have shown that it can increase the time the heart spends in systole, improving cardiac output without significantly increasing oxygen demand. This makes it a promising option for managing heart failure symptoms and improving overall cardiac performance.