My sister, who temporarily returned to Japan for a health checkup from studying abroad, had a simple health check for her brother, who is a medical student, for the time being... The older brother puts the stethoscope to his chest and tilts his head. Apparently multiple heartbeats were confirmed... Moreover, it was completely different from the sound of a human heart... My brother palpated to confirm the abnormality ... However, I don't know the cause at all ...