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) dysfunc-tion in children. The results in the normal group (n =20) were compared with those of patients with documented SAN dysfunction (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 intra-cardiac 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 nor-mal group (p < 0.001). Each of the 20 patients in group 1 had abnormal SAN automaticity (prolonged cor-rected 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.