Sinoatrial conduction in children: An index of sinoatrial node function

The premature atrial stimulus technique was used to evaluate sinoatrial conduction (SAC) in 50 children (age range 6 months to 21 years; median 6.5 years) to obtain normal values of sinoatrial conduction time (SACT) and to determine the usefulness of the technique in evaluation of sinoatrial node (SAN) dysfunction in children. The results in the normal group (n =20) were compared with those of patients with documented SAN dysfuncton (group 1,n = 20) or at risk to develop SAN dysfunction because of a previous intracardiac operation (group 2, n = 10). Among the 30 patients in groups 1 and 2, 23 had undergone an intracardiac operation - 13 Mustard operations and five closures of an atrial septal defect. In group 1, the mean value of total SACT was 172 msec ± 42 (SD) compared with 124 msec ± 38 in the normal group (p < 0.001). Each of the 20 patients in group 1 had abnormal SAN automaticity (prolonged corrected sinus node recovery time, CSNRT) and 13 of the 20 had abnormal SAC. While each of the 10 patients in group 2 had normal CSNRT, two of them had abnormal SAC. We conclude that the evaluation of SAC should be included in the assessment of children with suspected SAN dysfunction.