Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Heart Murmur ?
    ### Response:
    A heart murmur is an extra or unusual sound heard during a heartbeat. Murmurs range from very faint to very loud. Sometimes they sound like a whooshing or swishing noise.
                
Normal heartbeats make a "lub-DUPP" or "lub-DUB" sound. This is the sound of the heart valves closing as blood moves through the heart.
    