Problems in the diagnosis of discordant atrioventricular with concordant ventriculo-arterial connections: anatomical considerations, surgical management, and long-term outcome

Background Discordant atrioventricular with concordant ventriculo-arterial connections is a rare cardiac defect. When isolated, the haemodynamics resemble transposition of the great arteries. In complex heart defects such as heterotaxy, haemodynamics guide the surgical approach. Objective To report a series of eight patients with discordant atrioventricular and concordant ventriculo-arterial connections focussing on anatomical and diagnostic difficulties, surgical management, and follow-up. Methods A retrospective review was carried out from 1983 to 2013. Anatomical description was based on segmental analysis. Emphasis was placed on the venoatrial connections. Results Segmental arrangement was {I, D, S} in six patients, all with spiralling great vessels. There were two patients with parallel great vessels of whom one had {S, L, D} and the other had {S, L, A} arrangement. Of eight patients, five had heterotaxy syndrome. Median age at repair surgery was 1.4 years (with a range from 1.1 months to 8.1 years). The repair surgery finally performed was the atrial switch procedure in seven out of eight patients. The main post-operative complications were two cases of baffle obstruction and one sick sinus syndrome needing pacemaker implantation. There were two early post-operative deaths and six late survivors. Median follow-up was 4.2 years (with a range from 3.9 to 26.7 years) with good functional status in all survivors. Discussion Diagnosing discordant atrioventricular with concordant ventriculo-arterial connections remains challenging. There are ongoing controversies about the definition of atrial morphology and heterotaxy syndrome animating the anatomic discussion of these complex heart defects. Haemodynamically, the atrial switch procedure is the surgical method of choice with an encouraging long-term follow-up despite rhythm disturbances and baffle obstruction.