Chest X-Ray - dextrocardia
Normally, the heart is a midline structure found just posterior to the sternum where 35-40% of the heart mass in the right side of the thorax (chest), and the rest (60-65%) is in the left side of the thorax. In this normal condition the apex of the heart faces slightly inferior and to the left. In fact, there are many books and websites that state (wrongly) that the heart is normally in the “left side of the chest”.
If the above mentioned situation is reversed, we are in the presence of dextrocardia, that is, the heart is still in the midline, but most of the mass of the heart is in the right side of the thorax, and the apex points inferiorly and to the right.
The word dextrocardia is a derivate of the Latin [dexter], meaning “right”, and the Greek term [kardia], meaning “heart”. The word dextrocardia literally means “right-sided heart”.
Dextrocardia is a congenital condition, can be completely asymptomatic and present as an isolated condition. It can also be part of a complex genetic condition called “situs inversus” where the whole body is a mirror image of itself and all organs, including the heart are mirrored. A complete situs inversus is rare, but when present it usually does not cause problems.
The problems start when only part of the body and organs are reversed and others are not, causing an incredible number of potential anatomical variations and associated problems.
The prevalence of dextrocardia is about 1 in 12,00 pregnancies. The reported incidence is about 0.22%. Depending on the situation, dextrocardia can present with additional cardiac congenital disorders.
Sources:
1. “Dextrocardia: an incidental finding” Yusuf SW, Durand JB, Lenihan DJ, Swafford J. Tex Heart Inst J 2009;36(4):358-9.
2. Garg N, Agarwal BL, Modi N, Radhakrishnan S, Sinha N. Dextrocardia: an analysis of cardiac structures in 125 patients. Int J Cardiol 2003;88(2–3):143–56
3. Bernasconi A, Azancot A, Simpson JM, Jones A, Sharland GK. Fetal dextrocardia: diagnosis and outcome in two tertiary centres. Heart 2005;91(12):1590–4.