These terms purely describe the anatomic position of the left ventricular apex in the chest and their use does not indicate anything about the structure of the heart or the body situs. Thus, whilst levocardia is ‘normal’ in situs solitus, it would be regarded as abnormal in situs inversus, although the latter situation is very rare 3. Conversely in situs inversus, dextrocardia is usually ‘normal’, whilst dextrocardia is clearly abnormal in those with normal body orientation. Mesocardia is usually seen in situs solitus, rarely in situs inversus 3.
Conversely the term cardiac displacement is used for any change in the position of the heart caused by extrinsic factors, such as lung collapse or a large pleural effusion. This may occur, of course, to any heart regardless of its cardiac position.
- dextroposition: shift to the right
- mesoposition: central heart
- levoposition: shift to the left