Criss-Cross Atrioventricular Relationship

Criss-Cross Atrioventricular Relationship (Criss-Cross Heart)

Criss-cross atrioventricular (AV) relationship is a rare congenital spatial arrangement in which the right- and left-sided AV inflow axes do not run in parallel, but instead cross because the AV junction (and ventricular mass) is rotated/twisted along the long axis of the heart. The result is a characteristic “criss-cross” geometry in which inflow vectors may become markedly angulated—sometimes approaching ~90°—and conventional planar thinking (e.g., a single “standard” 4-chamber view) becomes unreliable. [1,2]

1) Core concept

“Crossed inflow tracts” is the definition—not a fixed set of segmental connections

A helpful mental model is to separate connections from geometry:

1. AV connections (who connects to whom)
• Can be concordant or discordant; the criss-cross label does not automatically define AV discordance. [3]
2. AV inflow geometry (how blood enters the ventricles)
• The defining feature is intersecting inflow axes caused by rotation/twisting of the AV junction, not merely “malposition” of chambers. [1,2]

Take-home: Criss-cross is primarily a 3D rotational problem. Diagnosis and management hinge on what else comes with it: AV valve integrity/straddling, VSD routing options, outflow anatomy, and ventricular adequacy. [2,7]

2) Morphologic hallmarks

What you should “see in your head” before you open the echo probe

Common structural signatures include:

• Crossed inflow streams
• The RA→RV and LA→LV inflow vectors are twisted and intersect, rather than running side-by-side. [2]
• Superior–inferior ventricles (frequent partner anatomy)
• A superior RV / inferior LV configuration is common, often with a nearly horizontal ventricular septum. In a clinical series, superior–inferior ventricles were seen in ~90% of patients with criss-cross anatomy. [2]
• “Non-coplanar AV valves”
• The two AV valve annuli may not be visualized in a single conventional plane—this is why the anatomy can feel “elusive” unless you track inflow direction. [4]

3) Typical associations

The lesion rarely travels alone—and these associations drive strategy

In one representative series of criss-cross anatomy, associated lesions were strikingly common: [2]

• Ventricular septal defect (VSD): ~100% [2]
• Abnormal ventriculo-arterial (VA) connections: common
• Including TGA and DORV patterns. [2]
• Right ventricular outflow tract obstruction (RVOTO): ~60% [2]
• AV valve straddling/overriding: ~50% (often the pivotal determinant of biventricular feasibility) [2]
• Additional frequent findings: ASD (~40%), RV hypoplasia (~30%) [2]

Clinical implication: The “criss-cross” label is rarely the surgical problem by itself; the repair conversation is shaped by (i) AV valve anatomy, (ii) VSD routability, (iii) outflow relationships, and (iv) ventricular size/function. [2,7,8]

4) Imaging approach

Diagnose it without getting “tricked” by standard views

Because standard imaging planes can be misleading, the most reliable approach is sequential segmental analysis + inflow tracking.

Practical echocardiography checklist

1. Anchor orientation
• Establish situs and atrial morphology; then define ventricles by trabeculations/moderator band and AV valve morphology. [4,5]
2. Track each AV inflow axis (color Doppler is your compass)
• Normal: inflows are broadly parallel.
• Criss-cross: inflows are twisted and intersect; crossed inflow streams are a defining feature (reported ~100% in one series). [2]
3. Actively look for the “missing 4-chamber” phenomenon
• A classic clue is the inability to obtain a conventional 4-chamber view showing both AV valves together, because the AV valves are not coplanar. [4]
4. Define associated lesions early
• AV valve straddling/overriding, VSD location/size, RVOTO, and VA connections (DORV/TGA patterns). [2,5]

When echo leaves uncertainty (or when surgical planning needs a true 3D map)

• Cardiac MRI can clarify AV segmental anatomy, the horizontal septal plane, inflow crossing, and associated malformations; high diagnostic agreement with reference studies has been reported in dedicated series. [1,3]
• CT/MRI can be especially helpful for spatial relationships and routing feasibility when contemplating biventricular repair. [1,3]

5) Surgical implications

Why this diagnosis changes the “repair conversation”

Criss-cross heart is a classic “decision lesion”: the main question is not what to call it, but whether a durable physiology can be built.

A) Key decision points (biventricular vs single-ventricle pathway)

1. Is biventricular repair anatomically achievable?

Depends heavily on:

1. AV valve straddling/overriding severity (and whether repair would distort the valve or create regurgitation) [2,7]
2. VSD geometry and routability (position, size, and ability to construct a non-obstructive pathway) [2,7]
3. Ventricular adequacy (balanced size/function; absence of prohibitive hypoplasia) [2,7]
4. VA connections + RVOTO (what must be reconstructed and what obstruction risks are created) [2,7]
2. If biventricular repair is possible, what is the “price”?

Complex intraventricular routing can increase risk of:

1. LVOT/RVOT obstruction (long/angulated tunnels; competing outflow geometry) [7,8]
2. AV valve distortion/regurgitation (especially with straddling) [2,7]
3. Conduction vulnerability (septal malalignment + extensive patch work in the AV junctional region) [7]
3. If biventricular repair is not favorable
• A single-ventricle strategy may offer a safer and more durable pathway, particularly when AV valve straddling or ventricular imbalance dominates. [7,8]

B) Outcomes are physiology-driven

Long-term trajectory depends less on the “criss-cross” geometry alone and more on the associated hemodynamic burden and the quality/durability of the chosen repair pathway. Adult series emphasize the importance of underlying anatomy/physiology in determining natural history and outcomes. [6]

6) “Textbook-ready” summary (drop-in paragraph)

Criss-cross atrioventricular relationship is a rare congenital cardiac configuration caused by rotation/twisting of the AV junction and ventricular mass, producing crossed (often near-orthogonal) AV inflow axes rather than parallel inflow tracts. [1,2] A superior–inferior ventricular arrangement with a nearly horizontal septum is common, and diagnosis often requires sequential segmental analysis with deliberate inflow tracking, as standard 4-chamber imaging planes can be misleading or unobtainable. [2,4] The lesion is frequently associated with large VSD, abnormal VA connections (e.g., DORV/TGA), RVOTO, and AV valve straddling/overriding, which together determine feasibility of biventricular repair versus a single-ventricle pathway and largely govern outcomes. [2,6,7]

References

[1] Yoo SJ, Seo JW, Lim TH, Park IS, Hong CY, Song MG, Kim SH, Choe KO, Cho BK, Lee HJ. Hearts with twisted atrioventricular connections: findings at MR imaging. Radiology. 1993;188(1):109-113. (PubMed)

[2] Fang F, Li ZA, Yang Y, Zheng CH, Lam YY. Deciphering the mysteries of crisscross heart by transthoracic echocardiography. Echocardiography. 2011;28(1):104-108. (PubMed)

[3] Zhu M, Zhong Y. Magnetic resonance evaluation of criss-cross heart. Pediatr Cardiol. 2008;29(2):359-365. (PubMed)

[4] Yang YL, Wang XF, Zhang H, et al. Echocardiographic characteristics of the criss-cross heart. Int J Cardiol. 2010;140(2):133-137. (PubMed)

[5] Carminati M, Valsecchi O, Borghi A, Balduzzi A, Bande A, Crupi G, Ferrazzi P, Invernizzi G. Cross-sectional echocardiographic study of criss-cross hearts and superoinferior ventricles. Am J Cardiol. 1987;59(1):114-118. (PubMed)

[6] Hoffman P, Szymański P, Różański J, et al. Crisscross hearts in adults: echocardiographic evaluation and natural history. J Am Soc Echocardiogr. 2009;22(2):134-140. (PubMed)

[7] Gajjar T, Rao JN, Desai N. Crisscross heart—Morphology, clinical diagnosis, and management options. J Card Surg. 2017;32(1):49-56. (PubMed)

[8] de Oliveira ÍM, Aiello VD, Mindêllo MMA, Martins YdeO, Pinto VC Jr. Criss-cross heart: report of two cases, anatomic and surgical description and literature review. Rev Bras Cir Cardiovasc. 2013;28(1):93-102. (PubMed)

[9] Ngeh N, Allain D, Hornung T. Criss-cross heart: report of three cases with double-inlet ventricles diagnosed in utero. Ultrasound Obstet Gynecol. 2008;31(4):461-465. (PubMed)