sounds of the heart

The sounds of the heart are caused by the closing of its valves during each heartbeat. The first sound, "lub," occurs when the mitral and tricuspid valves close as the heart contracts to pump blood out. The second sound, "dub," happens when the aortic and pulmonary valves close as the heart relaxes to fill again. These sounds can vary with heart rate, blood flow, or valve function. Listening to these sounds helps doctors assess how well the heart is working and whether there are any abnormal sounds, such as extra clicks or murmurs, that might indicate issues like valve problems.