Available online 8 May 2025

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Atrial right to left shunt (aRL) after repair of TOF is common, but not well understood

The relationship of aRL to outcomes and echo metrics of diastole are unclear

Large single center cohort inclusive of neonatal, staged, and elective repair

aRL is associated with better atrial function, rather than RV noncompliance alone

In elective TOF repair, aRL is also associated with shorter length of stay

Atrial right to left (aRL) shunting is often identified on echocardiograms in the early postoperative period following repair of tetralogy of Fallot (TOF) and thought to reflect poor right ventricular (RV) compliance, but to be possibly beneficial in serving as a “pop off” for the RV. We aimed to investigate the relationship between aRL shunting to echocardiographic diastolic function and early postoperative outcomes, hypothesizing that aRL would be associated with worse diastolic function, and with post-operative length of stay (LOS).

Single center cohort study of patients who underwent repair of TOF. Echocardiograms were obtained 2-5 days after repair. Patients were grouped as “elective” if repaired after 30 days of age without prior palliation, “staged” if they had a neonatal palliation prior to repair, or as “neonatal” repair if repaired <30 days age. aRL shunting was compared to all others: bidirectional, left to right, and no atrial shunt detected. Linear regression tested the relationship of aRL with right atrial volumes and right atrial emptying fraction (RAEF), RV inflow/tissue Doppler velocities, and RA peak longitudinal strain and early strain rate. Multivariable negative binomial regression tested the association between aRL with LOS, stratified by repair group.

There were 197 TOF patients (60% male, 74% White), most (127, 64%) had elective, 41 (21%) staged, and 29 (15%) neonatal repair. aRL was present in 68 patients (35%). In the overall cohort, aRL shunting was associated with lower RA end diastolic volume, higher RAEF, higher A wave peak velocity, and higher RA peak longitudinal strain. In the subgroup analysis, aRL was associated with higher RAEF and peak longitudinal strain in the elective repair group only, where aRL was also associated with shorter LOS.

Conclusions: aRL after TOF repair is associated with better atrial function, and possibly with a combination of robust atrial function in the presence of RV noncompliance, and shorter LOS in patients undergoing elective rTOF, but not in those undergoing a neonatal intervention.

2025 Published by Elsevier Inc. on behalf of the American Society of Echocardiography.