Atrial pacing to estimate total sinoatrial conduction time in children

Abstract

No data exist concerning the total sinoatrial conduction time (TSACT) in children that compare values determined by the atrial extrastimulation technique (TSACT S ) with those generated by the atrial pacing method (TSACT N ). In this study, TSACT in 55 patients, age 0.2–18.5, was measured using both techniques. TSACT N was performed at a mean 90% (TSACT N−90 ) ( n =32) or a mean 95% (TSACT N−95 and ( n =38) of sinus cycle length (SCL). When data generated during determination of TSACT N−90 and TSACT S were compared, SCL and recovery cycle length (REC) were similar for both techniques. Likewise, TSACT S (128±40 ms) and TSACT N−90 (126±74 ms) were not significantly different. Coefficient of correlation was r =0.82, p <0.001. Chi-square analysis demonstrated a strong association of normal and abnormal values between TSACT S and TSACT N−90 . In contrast, when values generated during TSACT N−95 and TSACT S were compared, TSACT S exceeded TSACT N−95 (137±38 vs 105±58 ms; p <0.001). Values for SCL and REC were similar while correlation between TSACT determined by the two techniques remained strong ( r =0.82, p <0.001). Despite a good correlation between TSACT N−90 and TSACT S , individual differences in magnitude and direction were noted between the two techniques.