Dextrocardia

Dextrocardia (from Latin dexter, meaning “right,” and Greek kardia, meaning “heart”) is a rare congenital condition in which the apex of the heart is located on the right side of the body. There are two main types of dextrocardia: dextrocardia of embryonic arrest (also known as isolated dextrocardia) and dextrocardia situs inversus. Dextrocardia situs inversus is further divided.

Classification

Dextrocardia of embryonic arrest

In this form of dextrocardia, the heart is simply placed further right in the thorax than is normal. It is commonly associated with severe defects of the heart and related abnormalities including pulmonary hypoplasia.

Dextrocardia situs inversus

Dextrocardia with situs inversus refers to the heart being a mirror image situated on the right side. For all visceral organs to be mirrored, the correct term is dextrocardia situs inversus totalis.

Although statistically people with dextrocardia do not have any medical problems from the disorder, they may be prone to a number of bowel, esophageal, bronchial and cardiovascular disorders (such as double outlet right ventricle, endocardial cushion defect and pulmonary stenosis). Certain cardiovascular and pulmonary disorders related to dextrocardia can be life-threatening if left unchecked (see reference).

Kartagener syndrome may also be present in patients with dextrocardia but this must be in the setting of situs inversus and may include male infertility.

Diagnosis

Medical diagnosis of the two forms of congenital dextrocardia can be made by ECG or imaging.

Technical dextrocardia

Technical dextrocardia refers to an ECG reading that has no basis in the patient’s anatomy. This apparent presentation is typically caused by the accidental lead placement of the left and right arm electrodes. Usually this would show as an extreme axis deviation.

Management

ECG leads must be placed in reversed positions on a person with dextrocardia. In addition, when defibrillating someone with dextrocardia, the pads should be placed in reverse positions. That is, instead of upper right and lower left, pads should be placed upper left and lower right.

When heart transplantation is required in a person with situs inversus, reconstruction of the venous pathways to accommodate a normal donor heart is a major, but not insurmountable, challenge.

Epidemiology

Dextrocardia is believed to occur in approximately 1 in 12,019 pregnancies.

A Japanese study of 1,753 fetal cardiac echocardiograms over five years only revealed two cases.