Chapter 34

    The heart is in the right hemithorax and the apex is deviated to the right side. The heart chambers and the abdominal viscera, in particular the liver, are positioned in an inverted manner (mirror image of all viscera). In dextrocardia, the arterial atrium is located in the right side, and will be connected through the mitral valve to the arterial ventricle which is located to the right of the venous ventricle.
    About 35% of the patients with situs inversus will present with associated heart malformations as VSD, ASD, Tetralogy of Fallot, Tricuspid atresia or Pulmonary stenosis. However, transposition of the great arteries is probably the most commonly seen malformation in conjunction with dextrocardia. Single ventricle can be seen in 10% of these patients.
    Dextrocardia should be distinguished from Dextrorotation of the heart and in this regard the analysis of the position of the liver, the gastric chamber and the P wave configuration in the ECG is helpful. In case of dextrorotation complex, heart malformations will be encountered almost as a rule in 100% of patients. The triad of bronchiectasis, sinusitis and dextrocardia is known as Kartagener's Syndrome. Polysplenia was described many times. Asplenia is not uncommon.

PHYSICAL FINDINGS

    Heart apex (PMI) palpable in the right hemithorax. Liver palpable in the left side. No other abnormalities necessarily are to be seen. The patient may present another associated congenital heart disease.

ELECTROCARDIOGRAM

    Negative P wave in I,II, AVL. Positive P wave in right precordial leads. Negative P wave in traditional left hemithorax precordial leads. The QRS axis is deviated to the right and inferiorly (mirror -image of the ECG).
    The associated malformations however can distort these classical findings.

CARDIAC CATHETERIZATION AND ANGIOGRAPHY

    It is essential when an accurate diagnosis is necessary but many times is difficult to interpret, particularly when complex heart malformations are associated.

ROENTGENOGRAM

    It is important to localize the liver, gastric chamber, status of the pulmonary circulation and cardiac size, which will be helpful in selecting possible cases with associated malformations.

DEXTROROTATION OF THE HEART

    The appearance of the heart and location in the roentgenogram may simulate dextrocardia, but the gastric chamber and the liver will be normally located.
    The electrocardiogram will depict positive P waves in 1,11, and AVL with positive P wave in the left precordial leads.
    The main ORS axis over the frontal plane may be deviated toward the right.
    These patients usually present complex heart malformations, complete transpositions, and single ventricle is particularly frequent.

Roentgenogram showing Dextrorotation in an infant who has Trisomy D and large ASD.

Dextrocardia. 44 year-old male with no symptoms.