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Atrial pacing to estimate total sinoatrial conduction time in children
R M Campbell1, M Dick, D C Crowley
1Department of Pediatrics, University of Michigan, Ann Arbor.
Insights
Total sinoatrial conduction time (TSACT) in children can be reliably estimated using atrial pacing at 90% of sinus cycle length (TSACTN-90), which closely approximates atrial extrastimulation (TSACTS). TSACTN-90 is preferred over TSACTN-95 for accurate pediatric sinoatrial conduction assessment.
Area of Science:
- Pediatric Cardiology
- Electrophysiology
- Cardiac Electrophysiology
Background:
- No prior studies have compared total sinoatrial conduction time (TSACT) measurements in children using atrial extrastimulation (TSACTS) versus atrial pacing (TSACTN).
- Accurate assessment of sinoatrial node function is crucial for diagnosing and managing pediatric cardiac arrhythmias.
Purpose of the Study:
- To compare TSACT values obtained by TSACTS and TSACTN in pediatric patients.
- To determine the optimal atrial pacing method for estimating TSACT in children.
Main Methods:
- TSACT was measured in 55 pediatric patients (age 0.2-18.5 years) using both TSACTS and TSACTN.
- TSACTN was performed at 90% (TSACTN-90, n=32) and 95% (TSACTN-95, n=38) of sinus cycle length (SCL).
- Statistical analyses included correlation (r), p-values, and Chi-square analysis.
Main Results:
- TSACTS (128 ± 40 ms) and TSACTN-90 (126 ± 74 ms) showed no significant difference, with a strong correlation (r=0.82, p<0.001).
- TSACTS (137 ± 38 ms) was significantly longer than TSACTN-95 (105 ± 58 ms) (p<0.001), despite a similar strong correlation (r=0.82, p<0.001).
- TSACTN-90 demonstrated a strong association for normal/abnormal values compared to TSACTS.
Conclusions:
- TSACTN-90 provides a reliable approximation of TSACTS in children, suggesting its utility for pediatric sinoatrial conduction assessment.
- TSACTN-90 is preferable to TSACTN-95 due to potentially better sinus node capture during pacing.
- Direct recording of sinus node activity is needed for more precise sinoatrial conduction evaluation.
Abstract:
No data exist concerning the total sinoatrial conduction time (TSACT) in children that compare values determined by the atrial extrastimulation technique (TSACTS) with those generated by the atrial pacing method (TSACTN). In this study, TSACT in 55 patients, age 0.2-18.5, was measured using both techniques. TSACTN was performed at a mean 90% (TSACTN-90) (n = 32) or a mean 95% (TSACTN-95 and (n = 38) of sinus cycle length (SCL). When data generated during determination of TSACTN-90 and TSACTS were compared, SCL and recovery cycle length (REC) were similar for both techniques. Likewise, TSACTS (128 +/- 40 ms) and TSACTN-90 (126 +/- 74 ms) were not significantly different. Coefficient of correlation was r = 0.82, p less than 0.001. Chi-square analysis demonstrated a strong association of normal and abnormal values between TSACTS and TSACTN-90. In contrast, when values generated during TSACTN-95 and TSACTS were compared, TSACTS exceeded TSACTN-95 (137 +/- 38 vs 105 +/- 58 ms; p less than 0.001). Values for SCL and REC were similar while correlation between TSACT determined by the two techniques remained strong (r = 0.82, p less than 0.001). Despite a good correlation between TSACTN-90 and TSACTS, individual differences in magnitude and direction were noted between the two techniques. In summary, TSACTN-90 approximates TSACTS in children. TSACTN-90 is preferable to TSACTN-95, probably due to more complete sinus node capture during atrial pacing. However, the behavior of the sinus node in response to extrastimuli (single or train) precludes favoring one technique over the other. More precise evaluation of sinoatrial conduction will require direct recording of sinus node activity.