Morning Report: Dextrocardia and Situs Inversus

Here’s Dr. Carmelli with today’s Morning Report!

Dextrocardia and Situs Inversus

Definitions

• Situs solitus: Normal position of organs/structures
• Situs inversus: Opposite or reverse of normal position of organs/structures
• Levocardia: Cardiac apex pointing to the left
• Dextrocardia: Cardiac apex pointing toward the right
• Cardiac displacement: A secondary shift of heart 2/2 eventration of a hemidiaphragm, agenesis of a lung, congenital absence of the pericardium…

Background

• The incidence of Situs Inversus with dextrocardia is about 1/8000-1/25,000.
• Unclear cause??? Sometimes its an autosomal recessive genetic condition, while other times it can be X-linked

Types

Associated Illness

• Situs inversus with dextrocardia: Often with structurally normal heart. However, 3-10% have a congenital heart disease:
  • Double outlet right ventricle, Endocardial cushion defect, Pulmonary stenosis, Single ventricle, Transposition of the great vessels (most common), Ventricular septal defect
• Situs inversus w/ levocardia is rare, but 95% have a congenital heart disease

Kartageners

• In 1933, Kartagener noticed a triad of sinusitis, bronchiectasis, and situs inversus, called Kartagener’s syndrome
• This is a subgroup of primary ciliary dyskinesia, Prevalence of around one in 20,000 to 40,000 individuals, affecting 20% of patients with situs inversus
• Of note, only 50% of pts with primary ciliary dyskinesia have situs inversus

Symptoms

• Situs inversus with dextrocardia and a structurally normal heart is otherwise asymptomatic and has normal life longevity
• However, note typical illness pain will be reversed:
  • Ischemic heart pain on the right, appendicitis pain on the LLQ, biliary colic pain on LUQ…etc

Diagnosis

• Percussion and palpation – gastric tympany/cardiac dullness- right, hepatic dullness- left, and heart sounds are louder on the right. Apical pulse found on right LSB
• Auscultation-1^st/ 2^nd heart sounds are louder on the right with S2 Splitting on the right. Cardiac murmur sites are the mirror images of normal.

CXR/ CT scan

• Most Dextrocardia patients diagnosed after random CXR.
• Look at apex, look for liver, stomach bubble, aortic arch, diaphragm height, IVC vs descending aorta…etc

EKG

• Right axis deviation
• Positive QRS complexes (with upright P and T waves) in aVR and maybe V1
• Lead I: inversion of all complexes, (inverted P wave, QRS, T wave)- Limb lead reversal***
• Absent R-wave progression in the chest leads (dominant S waves throughout)

Echo

Treatment

• Without Heart defects, no treatment required.
• If heart defects are present, usually may need surgery during infancy.
• Children with Kartagener syndrome will need repeated Tx with antibiotics for sinusitis

References

• Situs Inversus. Wikipedia. https://en.wikipedia.org/wiki/Situs_inversus
• Wilhelm A. Karani J. Situs Inversus Imaging. http://emedicine.medscape.com/article/413679-overview#showall
• Kaneshiro N, Zieve D. Dextrocardia. MedlinePlus. http://www.nlm.nih.gov/medlineplus/ency/article/007326.htm
• Webb G. Smallhorn J. Therrien J, Redington A. Congenital Heart Disease. Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine, 62, 1391-1445
• Perloff J, Marelli A. Cardiac Malpositions. Clinical Recognition of Congenital Heart Disease, Chapter 3, 15-40
• UpToDate.com: Primary ciliary dyskinesia (immotile-cilia syndrome)
• UpToDate.com: ECG tutorial: Miscellaneous diagnoses
• Lifeinthefastlane.com: Dextrocardia, ECG basics.

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Jay Khadpe MD

• Editor in Chief of "The Original Kings of County"
• Assistant Professor of Emergency Medicine
• Assistant Residency Director
• SUNY Downstate / Kings County Hospital

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