Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Left ventricular noncompaction ?
    ### Response:
    Left ventricular noncompaction (LVNC) is a rare heart condition. In LVNC the inside wall of the heart is spongy or grooved, instead of smooth. Signs and symptoms of LVNC vary, but may cause life-threatening abnormal heart rhythms and weakness of the heart muscle.
    