Key result
Evaluation of the PR/RR ratio during incremental atrial pacing yielded a mean maximum ratio of 1.17 in AVNRT patients versus 0.82 in controls (P<0.00001), with 88% sensitivity and 96% specificity.
Why the study?
Does the PR/RR ratio during incremental atrial pacing from the proximal coronary sinus accurately diagnose AVNRT and serve as an endpoint for slow pathway ablation?
Observational (n=398)
Does the PR/RR ratio during incremental atrial pacing from the proximal coronary sinus accurately diagnose AVNRT and serve as an endpoint for slow pathway ablation?
Absolute Event Rate: 1.17% vs 0.82%
p-value: p=<0.00001
The PR/RR ratio >= 1 during proximal coronary sinus pacing is a highly sensitive and specific marker for AVNRT and its elimination can serve as a surrogate endpoint for successful slow pathway ablation.
May support proximal CS pacing with isoproterenol for PR>RR identification in AVNRT; hypothesis-generating and requires prospective validation before adoption.
PURPOSE: During incremental atrial pacing in patients with atrioventricular nodal reentrant tachycardia, the PR interval often exceeds the RR interval (PR > RR) during stable 1:1 AV conduction. However, the PR/RR ratio has never been evaluated in a large group of patients with pacing from the proximal coronary sinus and after isoproterenol challenge. Our study validates new site of pacing and easier method of identification of PR > RR. MATERIAL AND METHODS: A prospective protocol of incremental atrial pacing from the proximal coronary sinus was carried out in 398 patients (AVNRT-228 and control-170). The maximum stimulus to the Q wave interval (S-Q = PR), SS interval (S-S), and Q-Q (RR) interval were measured at baseline and 10 min after successful slow pathway ablation and after isoproterenol challenge (obligatory). RESULTS: The mean maximum PR/RR ratios at baseline were 1.17 ± 0.24 and 0.82 ± 0.13 (p < 0.00001) in the AVNRT and controls respectively. There were no PR/RR ratios ≥1 at baseline and after isoproterenol challenge in 12.3% of the AVNRT group and in 95.9% of the control group (p < 0.0001). PR/RR ratios ≥1 were absent in 98% of AVNRT cases after slow pathway ablation/modification in children and 99% of such cases in adults (P = NS). The diagnostic performance of PR/RR ratio evaluation before and after isoproterenol challenge had the highest diagnostic performance for AVNRT with PR/RR > = 1 (sensitivity: 88%, specificity: 96%, PPV-97%, NPV-85%). CONCLUSIONS: The PR/RR ratio is a simple tool for slow pathway substrate and AVNRT evaluation. Eliminating PR/RR ratios ≥1 may serve as a surrogate endpoint for slow pathway ablation in children and adults with AVNRT.
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Śledź et al. (2018) conducted an observational in Atrioventricular nodal reentrant tachycardia (AVNRT) (n=398). PR/RR ratio evaluation during incremental atrial pacing vs. Controls without AVNRT was evaluated on Mean maximum PR/RR ratio at baseline (p=<0.00001). Evaluation of the PR/RR ratio during incremental atrial pacing yielded a mean maximum ratio of 1.17 in AVNRT patients versus 0.82 in controls (P<0.00001), with 88% sensitivity and 96% specificity.
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