Add spaces: Volumeoverloadoftheleftheart(themitralvalveontheleftsideoftheheart,separatingtheleftatriumfromtheleftventricle):

Answer: Volume overload of the left heart (the mitral valve on the left side of the heart, separating the left atrium from the left ventricle):

Add spaces: ContemporaryChineseArtistHeSenOilPaintingArtAppreciation–SmokingGirl→

Answer: Contemporary Chinese Artist He Sen Oil Painting Art Appreciation – Smoking Girl →

Add spaces: OutdoorrecreationImagesinsport

Answer:
Outdoor recreation Images in sport