Skip to content
How It Works
Explore
Resources Ask a Question
Who It's For
Patients Caregivers Providers
Log In Ask a Question
PubMed This is a summary of 89 peer-reviewed journal articles Updated
Cardiology

Understanding Right Isomerism: A Guide for Parents

At a Glance

Right Isomerism is a congenital condition where a baby's internal organs develop two "right" sides. It typically involves severe heart defects requiring staged surgeries and an absent spleen that requires daily preventative antibiotics. Multidisciplinary care is essential for managing this condition.

Receiving a diagnosis of Right Isomerism can feel like entering a world of complex medical jargon and high-stakes decisions. While the term sounds technical, it simply describes how a baby’s internal organs are organized [1]. In most people, the body has a distinct left and right side (like the heart being on the left and the liver on the right). In Right Isomerism, also known as heterotaxy syndrome or asplenia syndrome, the body develops with a “bilateral right-sidedness” [2][3].

This means that instead of having a typical left side and a right side, the body essentially tries to create two right sides [2]. While this is a serious and complex condition, understanding the facts can help you navigate the journey ahead with your medical team.

Three Stabilizing Facts for Families

When you first hear this diagnosis, it is easy to feel overwhelmed. Here are three facts to ground your perspective:

  1. There is a Roadmap: Although the condition is complex, there are established, staged surgical pathways (such as the single-ventricle pathway) that surgeons use to help the heart function effectively [4][5].
  2. Multidisciplinary Expertise: Modern care involves a team of specialists—including cardiologists, infectious disease experts, and surgeons—who work together to address every aspect of your child’s health, from their heart to their immune system [6][7].
  3. Advancing Outcomes: While Right Isomerism presents significant challenges, medical and surgical advancements in neonatal care have led to improved outcomes and better survival rates than in previous decades [8][9].

Understanding “Bilateral Right-Sidedness”

In a typical body (situs solitus), organs are arranged asymmetrically [1]. Right Isomerism is a form of heterotaxy, a term derived from Greek meaning “different arrangement” [10].

  • The Lungs: Instead of having one right lung (with three lobes) and one left lung (with two lobes), a child with Right Isomerism often has two right-sided lungs (both with three lobes) [11][7].
  • The Spleen: A hallmark of Right Isomerism is asplenia, the absence of a spleen [12]. Since the spleen is a “left-sided” organ, a body with “two right sides” often does not develop one [12][13].
  • The Heart: The heart is often the most complex area of concern. It may have a “single ventricle” (one main pumping chamber instead of two) and other defects like AVSD (a large hole in the center of the heart) or TAPVR (veins from the lungs connecting to the wrong place) [14][12].

For more details on the biological causes and anatomy, see The Blueprint of Right Isomerism.

What to Expect After Birth

Immediately after birth, your baby will likely be cared for in the Neonatal Intensive Care Unit (NICU) or a cardiac intensive care unit [15][16]. The focus will be on stabilizing the baby and gathering detailed information about their unique anatomy.

Immediate Medical Steps

01

Protecting Your Child: Managing Life Without a Spleen

Learn how to protect your child with Right Isomerism and asplenia. Understand daily antibiotics, extra vaccines, and why a fever is a medical emergency.

02

The Digestive System and Right Isomerism: Malrotation Risks

Learn how right isomerism causes intestinal malrotation. Understand the risks of midgut volvulus, symptoms like bilious vomiting, and Ladd procedure options.

The Surgical Pathway

Most children with Right Isomerism will require a series of heart surgeries. The most common route is the single-ventricle pathway, which typically involves three staged operations (such as the Norwood, Glenn, and Fontan procedures) to help the heart pump blood to the body and lungs more efficiently [4][9]. Your surgical team will determine the best timing and approach based on your baby’s specific heart structure [21][22]. See Surgery and Care for Right Isomerism for a detailed breakdown of these stages and what to expect.

Common questions in this guide

What does a single ventricle mean for my baby's heart?
A single ventricle means the heart has one main pumping chamber instead of the typical two. Babies with this condition usually require a series of three staged heart surgeries to help the heart pump blood effectively to the body and lungs.
Why do babies with right isomerism need preventative antibiotics?
A hallmark of right isomerism is the absence of a spleen, known as asplenia. Because the spleen is a critical part of the immune system, doctors prescribe preventative antibiotics to protect your baby from serious bacterial infections.
What is intestinal malrotation and why is it checked?
Intestinal malrotation is a condition where the intestines are not positioned correctly in the abdomen. Because organs are arranged differently in heterotaxy, the medical team checks the digestive system early to prevent potential blockages.
What immediate care will my baby receive in the NICU?
In the NICU, your baby may receive a medication called prostaglandin to keep essential blood vessels open. The care team will also perform detailed imaging, like echocardiograms, to map out your baby's unique heart and organ anatomy.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Does my baby have a 'single ventricle' heart, and what does that mean for their long-term surgical path?
  2. 2.Is my baby's spleen present and working, and what steps should we take to prevent infections?
  3. 3.Has my baby been checked for 'intestinal malrotation' or other issues with how the digestive system is arranged?
  4. 4.Can you draw a diagram of my child's specific heart anatomy so I can better visualize what we are discussing?
  5. 5.How many babies with Right Isomerism does this hospital treat each year, and what multidisciplinary specialists will be on our care team?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (22)
  1. 1

    Cardiac and Non-Cardiac Abnormalities in Heterotaxy Syndrome.

    Mishra S

    Indian journal of pediatrics 2015; (82(12)):1135-46 doi:10.1007/s12098-015-1925-x.

    PMID: 26612104
  2. 2

    Laparoscopic sleeve gastrectomy in polysplenia syndrome/left isomerism: A case report.

    Jeragh F, Aljazzaf I, Al Khayyat H

    International journal of surgery case reports 2020; (75()):488-491 doi:10.1016/j.ijscr.2020.09.079.

    PMID: 33076202
  3. 3

    Unravelling the complexity of heterotaxy syndrome.

    Bilamge A, Vallabhaneni P, Didel S, Rajagopal R

    BMJ case reports 2023; (16(10)) doi:10.1136/bcr-2023-256198.

    PMID: 37907318
  4. 4

    Pulmonary venous obstruction after extracardiac total cavopulmonary connection in right atrial isomerism.

    Kugo Y, Iwai S, Ishimaru K, et al.

    General thoracic and cardiovascular surgery 2020; (68(9)):969-974 doi:10.1007/s11748-020-01316-3.

    PMID: 32036565
  5. 5

    The posterior tunnel Fontan: A different approach to lateral tunnel Fontan.

    Aydin MI, O'Hara R, Bishnoi A, d'Udekem Y

    European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery 2025; doi:10.1093/ejcts/ezaf408.

    PMID: 41289089
  6. 6

    Heterotaxy Syndrome: Discordant Growth.

    Yadav P, Ajmera P, Krishnamurthy S, Nandivada NB

    Cureus 2021; (13(4)):e14766 doi:10.7759/cureus.14766.

    PMID: 34094731
  7. 7

    From multiple spleens to absence: Insights from two cases of heterotaxy syndromes.

    Paudel S, Banjade RR, Sharma NK, et al.

    Radiology case reports 2026; (21(3)):1217-1223 doi:10.1016/j.radcr.2025.11.066.

    PMID: 41542032
  8. 8

    Improved Surgical Management of Complex Neonates With Heterotaxy Syndrome.

    Mills AC, Dawson AE, Scott MC, et al.

    World journal for pediatric & congenital heart surgery 2026; (17(1)):28-35 doi:10.1177/21501351251345791.

    PMID: 40641439
  9. 9

    Early- and Middle-Term Surgical Outcomes in Patients with Heterotaxy Syndrome.

    Chen W, Ma L, Cui H, et al.

    Cardiology 2016; (133(3)):141-6 doi:10.1159/000440947.

    PMID: 26571485
  10. 10

    Fetal Magnetic Resonance Imaging of Malformations Associated with Heterotaxy.

    Loomba R, Shah PH, Anderson RH

    Cureus 2015; (7(5)):e269 doi:10.7759/cureus.269.

    PMID: 26180693
  11. 11

    Ultrasound and computed tomography angiography diagnosis of fetal right atrial isomerism with cardiac total anomalous pulmonary venous connection and intestinal malrotation: a case report and literature review.

    Gao J, Ou H, Xing H, et al.

    Pediatric radiology 2024; (54(8)):1399-1404 doi:10.1007/s00247-024-05938-0.

    PMID: 38750327
  12. 12

    Characterisation of computed tomography angiography findings in paediatric patients with heterotaxy.

    Ugas Charcape CF, Alpaca Rodriguez LR, Matos Rojas IA, et al.

    Pediatric radiology 2019; (49(9)):1142-1151 doi:10.1007/s00247-019-04434-0.

    PMID: 31165901
  13. 13

    Clinical profile, prenatal detection and predictors of outcome of heterotaxy syndromes in Western Australia.

    MacDonald B, Vetten Z, Ramsay J, et al.

    International journal of cardiology. Congenital heart disease 2023; (14()):100472 doi:10.1016/j.ijcchd.2023.100472.

    PMID: 39712988
  14. 14

    Characterization of ultrasound and postnatal pathology in fetuses with heterotaxy syndrome.

    Wu Q, Guo S, Huang B, et al.

    Frontiers in cardiovascular medicine 2023; (10()):1195191 doi:10.3389/fcvm.2023.1195191.

    PMID: 37485264
  15. 15

    Renal replacement therapy with a cytokine-adsorbing hemofilter after neonatal open-heart surgery.

    Shimada M, Hoashi T, Imai K, Ichikawa H

    Journal of artificial organs : the official journal of the Japanese Society for Artificial Organs 2021; (24(3)):398-401 doi:10.1007/s10047-020-01241-5.

    PMID: 33416978
  16. 16

    Unique foetal diagnosis of aorto-pulmonary collaterals in right atrial isomerism.

    Mawad W, Dutil N, Thakur V

    Cardiology in the young 2021; (31(2)):303-305 doi:10.1017/S1047951120003649.

    PMID: 33239120
  17. 17

    Complex congenital cardiac anomalies in the setting of right isomerism in a 31-month-old infant: a case report.

    Lyimo FR, Pallangyo P, Majani N, et al.

    Journal of medical case reports 2018; (12(1)):324 doi:10.1186/s13256-018-1835-4.

    PMID: 30352615
  18. 18

    Low immunoglobulin M memory B-cell percentage in patients with heterotaxy syndrome correlates with the risk of severe bacterial infection.

    Chiu SN, Shao PL, Wang JK, et al.

    Pediatric research 2016; (79(2)):271-7 doi:10.1038/pr.2015.221.

    PMID: 26524717
  19. 19

    Specific cardiovascular morphology on computed tomography angiography in patients with right isomerism.

    Tomita Y, Muneuchi J, Sugitani Y, et al.

    Pediatrics international : official journal of the Japan Pediatric Society 2025; (67(1)):e70234 doi:10.1111/ped.70234.

    PMID: 41133277
  20. 20

    Ivemark syndrome-a rare entity with specific anatomical features.

    Hrusca A, Rachisan AL, Lucian B, et al.

    Revista medica de Chile 2015; (143(3)):383-6.

    PMID: 26005826
  21. 21

    Cardiac Laterality: Surgical Results of Right Atrial Isomerism.

    Ortega-Zhindón DB, Pérez-Hernández N, Rodríguez-Pérez JM, et al.

    Diseases (Basel, Switzerland) 2023; (11(4)) doi:10.3390/diseases11040170.

    PMID: 37987281
  22. 22

    Letter to the Editor: Cardiac surgery in patients with atrial isomerism: Long-term results and outcomes.

    Ahmed S, Sohaib M

    Journal of cardiac surgery 2022; (37(6)):1796 doi:10.1111/jocs.16484.

    PMID: 35365903

This guide to Right Isomerism is for informational purposes only. Always consult your child's pediatric cardiologist and multidisciplinary medical team for specific medical advice and treatment planning.

Get notified when new evidence is published on Right isomerism.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.