The following information may help to address your question:
Isolated levocardia is a type of situs inversus where the heart is located in the normal position, but there is a mirror-image reversal of other internal organs. Isolated levocardia may occur alone or with heart defects, heart rhythm abnormalities (sick sinus syndrome or atrioventricular node disorder), spleen defects (absent, underdeveloped, or extra spleen), and intestinal malrotation. Long term outlook varies depending on the presence/absence of associated abnormalities, particularly heart defects. The cause of isolated levocardia is not known. It is not usually associated with chromosome abnormalities.
The overall outlook for infants born with isolated levocardia will vary depending largely on the absence/presence of heart defects. You can find grim estimates for long term survival in dated literature (published in the 1960’s and 70’s). These statistics do not account for mild cases of isolated levocardia diagnosed as a result of improved technologies and detection.