Atrial Switch Operation (Senning) — #1 Indications

Atrial Switch Operation (Senning) — Indications and Contemporary Role

The atrial switch operation (Senning; historically Mustard) is a physiology-redirecting repair: it reconstructs atrial inflow pathways so that systemic venous return (SVC/IVC) and pulmonary venous return are delivered to the intended ventricle. In current congenital practice, Senning is rarely a “destination operation.” Instead, it is most valuable as the atrial component of an anatomic (double-switch) strategy, particularly for ccTGA, and as a selective fallback in d-TGA when an arterial switch is not feasible.

1) Core principle: venous redirection to the appropriate ventricle

What Senning “fixes” (flow architecture):

1. Systemic venous blood → morphologic LV (by constructing a systemic venous baffle).
2. Pulmonary venous blood → morphologic RV (by directing PV return across the atrial pathways).

Why this matters clinically

• It restores correct inflow–ventricle pairing, which is the enabling step for downstream anatomic correction (i.e., placing the LV in the systemic position) when a double-switch pathway is selected.

2) Primary modern indication: ccTGA as the atrial engine of an anatomic repair

A) The problem Senning helps solve in ccTGA

ccTGA is “physiologically corrected,” but the systemic ventricle is a morphologic RV, which is vulnerable to chronic systemic afterload (progressive systemic RV dysfunction and systemic AV valve regurgitation over time).

B) The contemporary solution: Double-Switch (atrial + arterial/outflow correction)

Senning provides the atrial (inflow) correction, paired with an outflow procedure that places the morphologic LV in the systemic position:

• Senning + ASO (arterial switch)

When ventriculo-arterial anatomy and coronary transfer are suitable.

• Senning + Rastelli (LV-to-aorta tunnel ± VSD enlargement + RV-PA conduit)

When LVOT obstruction and/or VSD geometry favors a Rastelli-type outflow reconstruction.

This “pairing logic” is central: associated lesions determine the outflow partner, while Senning ensures the venous streams are aligned with the repaired outflows. [1, 3]

C) What “good candidates” tend to share (ccTGA selection themes)

• Systemic RV risk trajectory is meaningful (declining function, dilation, worsening systemic AV valve regurgitation, or expected progression).
• LV readiness is adequate (native preparedness or a deliberate training strategy when appropriate).
• Anatomic coherence: venous anatomy, atrial geometry, and the chosen outflow plan can be integrated without creating long-term obstruction or an “unserviceable” pathway for future interventions.

D) Contemporary outcomes (what recent series highlight)

• In a large modern cohort of double-switch patients (median age ~2 years), early and mid-term outcomes can be excellent, with high transplant-free survival at 5 years, but a notable burden of conduction disease and resynchronization needs (pacemaker/CRT) and the possibility of reintervention (e.g., neoaortic valve/aortic root issues). [1]
• Multicenter data similarly support good survival after anatomic repair of ccTGA, while reinforcing that late morbidity remains driven by arrhythmia/conduction disease and ventricular/valve-related issues. [2]

3) d-TGA: a highly selected indication in the modern era

For d-TGA, Senning was historically definitive, but it is no longer first-line because long-term outcomes and complication profiles are generally superior with ASO when feasible. [4]

Where Senning still appears on the decision tree (typical scenarios):

1. Late presenter with a regressed LV
• An ASO may be prohibitive without LV retraining, and timing/condition may not permit a safe training pathway.
2. Contraindication to coronary transfer / ASO
• “Complex” coronary patterns or other anatomic constraints may make ASO unsafe in select cases.

Clinical framing: In d-TGA today, atrial switch is best viewed as a problem-solving operation, not the default strategy. [4]

4) Preoperative decision checklist (what must be mapped before committing)

Because Senning is fundamentally a flow-reconstruction operation, preoperative planning must be unusually explicit.

A) Venous anatomy (make obstruction a “never event”)

• Systemic venous variants: LSVC, interrupted IVC/azygos continuation, anomalous hepatic drainage.
• Pulmonary venous return: partial/total anomalous PV return; atypical PV confluence geometry.

B) Atrial geometry and septal history

• Restrictive atrial septum, prior septostomy, atrial size/asymmetry (especially in complex ccTGA physiology).

C) Conduction system vulnerability (anticipate pacing needs)

• Baseline rhythm, AV conduction status, and surgical plan relative to conduction tissue.
• Set expectations early: conduction disease and pacing therapy remain a major “cost of doing business” in atrial switch pathways. [1, 5]

D) Outflow integration (“build the baffle for the next operation”)

• Senning must be designed with the planned ASO vs Rastelli pathway in mind, including:
• unobstructed systemic venous channel,
• non-turbulent pulmonary venous pathway,
• adequate atrial volume/geometry to reduce late pathway narrowing,
• future catheter/EP access strategy.

5) Late issues after atrial switch: what actually drives follow-up intensity

Across long-term series of Mustard/Senning survivors, late morbidity is dominated by a familiar triad:

1. Arrhythmias and sinus node dysfunction (atrial tachyarrhythmias, bradyarrhythmias). [6–8]
2. Systemic ventricular failure risk (systemic RV for classic d-TGA atrial switch; systemic LV after double-switch depends on anatomy and downstream lesions). [6,10]
3. Baffle-related problems (systemic or pulmonary venous pathway obstruction, residual shunts).
• Comparative data suggest different “profiles” between Mustard and Senning for specific late events, reinforcing the need for anatomy-based surveillance rather than a one-size-fits-all follow-up script. [11]

6) One-line contemporary takeaway

• ccTGA: Senning is primarily the atrial engine of anatomic repair (double-switch)—redirecting venous return so the LV can be positioned as the systemic ventricle, with modern series showing excellent survival but meaningful late burdens from conduction disease/arrhythmia and selected reinterventions. [1–3]
• d-TGA: Senning is a selective fallback when ASO is not an option (late LV regression or ASO contraindications such as complex coronaries). [4]

References (PubMed-indexed)

[1] Marathe SP, Celermajer DS, Cho A, et al. Contemporary outcomes of the double switch operation for congenitally corrected transposition of the great arteries. J Thorac Cardiovasc Surg. 2022;164(3):915-927.e5.

[2] Mainwaring RD, Hanley FL, Reddy VM, et al. Contemporary outcomes after the double switch operation. Ann Thorac Surg. 2024;118(1):243-251.

[3] Barron DJ, Kilby MD, Davies B, Wright JG, Jones TJ, Brawn WJ. The Senning procedure as part of the double-switch operations for congenitally corrected transposition of the great arteries. Prog Pediatr Cardiol. 2011;31(1):39-43.

[4] Kirzner J, Pirmohamed A, Ginns J, Singh HS. Long-term Management of the Arterial Switch Patient. Curr Cardiol Rep. 2018;20(8):68.

[5] Ferro G, Murthy R, Sebastian VA, Guleserian KJ, Forbess JM. Single-Center Experience With the Senning Procedure in the Current Era. Semin Thorac Cardiovasc Surg. 2016;28(2):514-520.

[6] Vejlstrup N, Sørensen K, Mattsson E, et al. Long-Term Outcome of Mustard/Senning Correction for Transposition of the Great Arteries in Sweden and Denmark. Circulation. 2015;132(8):633-638.

[7] Moons P, Gewillig M, Sluysmans T, et al. Long term outcome up to 30 years after the Mustard or Senning operation: a nationwide multicentre study in Belgium. Heart. 2004;90(3):307-313.

[8] Dos L, Teruel L, Ferreira IJ, et al. Late outcome of Senning and Mustard procedures for correction of transposition of the great arteries. Heart. 2005;91(5):652-656.

[9] Sarkar D, Bull C, Yates R, et al. Comparison of long-term outcomes of atrial repair of simple transposition with implications for a late arterial switch strategy. Circulation. 1999;100(19 Suppl):II176-II181.

[10] Dennis M, Kotchetkova I, Cordina R, Celermajer DS. Long-Term Follow-up of Adults Following the Atrial Switch Operation for Transposition of the Great Arteries: A Contemporary Cohort. Heart Lung Circ. 2018;27(3):304-313.

[11] Khairy P, Landzberg MJ, Lambert J, O'Donnell CP. Long-term outcomes after the atrial switch for surgical correction of transposition: a meta-analysis comparing the Mustard and Senning procedures. Cardiol Young. 2004;14(3):284-292.