OBJECTIVEThe investigators compared the outcome of infants and children having right atrial isomerism with normal pulmonary venous drainage to those with anomalous drainage and determined factors associated with poor outcome. They further determined the prevalence of symptomatic cardiac arrhythmia in these patients and its relation to long-term morbidity and mortality.

METHODSThe authors made a retrospective review of management and outcome of 116 infants and children diagnosed to have right atrial isomerism between January 1980 and December 2000. The type, timing and precipitating factors of symptomatic cardiac arrhythmia that occurred in patients, among a cohort of 85 who had or are awaiting surgical interventions, were noted.

RESULTSThe 116 patients presented at a median of 1 day (range 1 day to 3.7 years) with cyanosis in the majority (96%). No interventions were planned in 31 (27%) patients who all died. The early surgical mortality for pulmonary venous repair was 25% (2/8), Fontan procedure 26% (5/19), cavopulmonary shunting 8% (1/13) and systemic-pulmonary arterial shunt insertion 2% (1/53). Late mortality was related to infection (n = 10), sudden death of unknown aetiology (n = 7) and documented arrhythmia (n = 1). Patients with obstructed anomalous pulmonary venous drainage had poor survival (P < 0.001). The mean (SEM) survival estimates for those with normal pulmonary venous drainage at 1, 5, 10 and 15 years were 81 (5)%, 67 (7)%, 60 (8)% and 43 (12)%, respectively, similar to those of patients with non-obstructed anomalous drainage (P = 0.06). Independent risk factors for mortality included pulmonary venous obstruction (relative risk RR 3.8, P = 0.001) and a single ventricle (RR 2.9, P = 0.016). Symptomatic cardiac arrhythmia occurred in 15/85 (18%) patients; 11 of whom had supraventricular tachycardia, and 1 atrial tachycardia, 1 atrial flutter, 1 ventricular tachycardia and 1 congenital complete heart block. The arrhythmias occurred before surgery in 4, early after surgery in 5, and late after surgery in 6 patients. Freedom from arrhythmia at 1, 5, 10, 15 and 20 years was (93 +/- 3)%, (86 +/- 4)%, (80 +/- 6)%, (73 +/- 9)% and (48 +/- 15)%, respectively. Logistic regression failed to identify any risk factors for symptomatic arrhythmia.

CONCLUSIONThe long-term outcome of infants and children with right atrial isomerism, whether associated with normal or anomalous pulmonary venous drainage, remains unfavourable. Sepsis and sudden death are major causes of late mortality. While symptomatic cardiac arrhythmias are not uncommon. They do not seem to relate to the overall high mortality and occurrence of sudden death in this patient group. Nonetheless, detailed assessment and aggressive management of cardiac arrhythmias once they occur are warranted in light of the precarious single ventricular haemodynamics.