The spectrum of atrioventricular discordance. A clinical study.

The clinical, investigative, and surgical findings were reviewed in 47 patients with atrioventricular discordance who presented to the Brompton Hospital between January 1962 and June 1981. Although the unifying feature was the atria connecting to morphologically inappropriate ventricles, the hearts differed widely in other respects. In most cases there was the usual visceral and atrial arrangement, but six had a mirror image arrangement of the atria and viscera. Among those patients with usual atrial arrangement (solitus) the aorta was not always anterior and left sided, and ventricular "inversion" was not invariable. Only 35 of the 47 patients also had a discordant ventriculoarterial connexion, the majority of the remainder having a double outlet right ventricle. The specific diagnosis of atrioventricular discordance depended on echocardiographic and angiographic examination. The other investigations did not distinguish between different ventriculoarterial connexions and were not specific even for the presence of atrioventricular discordance. For those patients with the usual atrial arrangement the anticipated right heart border was present in only just over one third, and the reversal of Q wave progression in the precordial leads of the standard electrocardiogram was found in under a half. Many patients with atrioventricular discordance progressed normally to adult life. In 20 cases no surgery was performed. The results of total correction showed a mortality of 25% (three cases), including two deaths after a modified Fontan procedure for exceedingly complex associated lesions. The results of surgery in the survivors were excellent, and awareness of the disposition of the atrioventricular conduction tissue made it possible to avoid atrioventricular dissociation.