Ebstein Anomaly — Pathophysiology After Infancy
Hemodynamics as PVR normalizes.
As pulmonary vascular resistance (PVR) falls after the neonatal period, antegrade RV–pulmonary arterial flow typically predominates; cyanosis recedes if the functional RV generates sufficient forward stroke volume and any PFO/ASD is small or restrictive [1]. When an interatrial communication persists, shunt direction varies with loading: right-to-left during exertion/dehydration (rises in RA pressure) and left-to-right when right-sided pressures decrease, further loading the right heart [1].
Chronic tricuspid regurgitation and right-heart remodeling.
Apical displacement of the septal and inferior tricuspid leaflets and atrialization of the proximal RV yield moderate–severe TR, sustained volume overload, and progressive RA and functional RV dilation with rising RA pressure [1]. Children may show exercise intolerance, hepatomegaly, failure to thrive, and, if right-to-left shunting persists, exertional desaturation and clubbing [1].
Ventricular interdependence and left-sided effects.
Marked right-sided enlargement and RV volume load shift the septum leftward—especially in diastole—impairing LV filling and systemic output despite preserved LV systolic function. Tachyarrhythmias or hypovolemia that shorten diastolic filling time accentuate these interactions and can precipitate hypotension or low-output symptoms [1].
Interatrial shunting and its consequences.
An ASD/PFO often functions as a pressure “relief valve” for the RA. Right-to-left shunt sustains cyanosis and exposes patients to paradoxical embolization, whereas left-to-right shunt aggravates right-sided volume load and TR progression; management must therefore address both the tricuspid valve lesion and atrial septal physiology [1].
Arrhythmias and the conduction substrate.
Accessory AV pathways (e.g., WPW) and substantial atrial dilation create a substrate for re-entrant SVT and atrial flutter/fibrillation. In series of young patients undergoing cone repair, the burden of clinically significant postoperative arrhythmia is low when preoperative EPS/ablation is targeted to those with WPW or documented/suspected arrhythmia (only ~5% remained on antiarrhythmic medication at follow-up) [3].
Natural history and triggers for intervention.
Unchecked TR drives a cycle of annular enlargement, leaflet malcoaptation, RA/RV dilation, and rising RA pressure with escalating symptoms, cyanosis, and arrhythmias. Contemporary indications for surgery include symptomatic or progressive TR with RV enlargement/dysfunction; cyanosis from right-to-left interatrial shunting; recurrent/drug-refractory tachyarrhythmias; diminished objective exercise capacity; or paradoxical embolic events [1,4,6].
Surgical strategy after infancy: the Cone repair.
For suitable anatomy, the cone procedure is the preferred operation, mobilizing and delaminating leaflet tissue circumferentially to construct a 360° leaflet cone coapting at the true annulus; adjuncts include annular remodeling, plication/resection of the atrialized RV, RA reduction, and closure/fenestrated closure of an ASD to balance right-sided filling [1,6]. Across institutional experiences, cone repair provides near-anatomic restoration of valve function with excellent early–intermediate outcomes: freedom from tricuspid reintervention after cone repair is ~97%, 91%, and 91% at 2, 4, and 6 years, respectively, and RV function is better preserved than after tricuspid valve replacement [2]. Large series also demonstrate very low early mortality, sustained reductions in RV size (favorable reverse remodeling), and durable TR reduction as programs progress along the learning curve [5]. Valve replacement is reserved for severely deficient leaflet tissue or salvage situations; it carries a higher risk of later reoperation and tricuspid stenosis with worse RV function than repair [2].
Peri- and postoperative considerations.
Preoperative optimization centers on rhythm evaluation/ablation strategy, preload and pulmonary vasoreactivity. Intraoperatively, protecting the conduction system and preserving RV geometry are pivotal. Postoperatively, meticulous management of preload, rhythm, and pulmonary pressures supports RV recovery. Long-term follow-up tracks TR recurrence, RV size/function, residual shunting, and arrhythmia surveillance [1,5,6].
References
[1] Neumann S, Rüffer A, Sachweh J, et al. Narrative review of Ebstein’s anomaly beyond childhood: Imaging, surgery, and future perspectives. Cardiovasc Diagn Ther. 2021;11(6):1310-1323. PubMed
[2] Boyd R, Kalfa D, Nguyen S, et al. Comparative outcomes and risk analysis after cone repair or tricuspid valve replacement for Ebstein’s anomaly. JTCVS Open. 2023;14:372-384. PubMed
[3] Wackel P, Cannon B, Dearani J, et al. Arrhythmia after cone repair for Ebstein anomaly: The Mayo Clinic experience in 143 young patients. Congenit Heart Dis. 2018;13(1):26-30. PubMed
[4] Brown ML, Dearani JA, Danielson GK, et al. The outcomes of operations for 539 patients with Ebstein anomaly. J Thorac Cardiovasc Surg. 2008;135(5):1120-1136; 1136.e1-7. PubMed
[5] Holst KA, Dearani JA, Said S, et al. Improving results of surgery for Ebstein anomaly: Where are we after 235 cone repairs? Ann Thorac Surg. 2018;105(1):160-168. PubMed
[6] Dearani JA, Mora BN, Nelson TJ, Haile DT, O’Leary PW. Ebstein anomaly review: what’s now, what’s next? Expert Rev Cardiovasc Ther. 2015;13(10):1101-1109. PubMed