Published in:
01-11-2018
The relationship between the P wave and local atrial electrogram in predicting conduction block during catheter ablation of cavo-tricuspid isthmus-dependent atrial flutter
Published in: Journal of Interventional Cardiac Electrophysiology | Issue 2/2018
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Purpose
The endpoint for radiofrequency catheter ablation (RFA) of cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL) is complete conduction block along the CTI. The purpose of this study is to evaluate the utility of the temporal relationship between the P wave and the local atrial electrograms in determining complete CTI block.
Methods
RFA of CTI was performed in 125 patients (age 63 ± 11 years). During pacing from the coronary sinus (CS), the intervals from the peak of the P wave (Ppeak) in lead V1 to the second component of the local atrial electrogram (A2) along the ablation line (Ppeak-A2) and from the end of the P wave (Pend) to A2 (Pend-A2) were investigated before and after complete block in the first 100 patients (training set). In the next 25 patients (validation set), Ppeak-A2 and Pend-A2 intervals were prospectively assessed to determine CTI block.
Results
The mean Ppeak-A2 and Pend-A2 immediately before complete block were − 15±24 and − 39±23 ms compared to 49 ± 17 and 21 ± 16 ms after CTI block (P < 0.0001). Ppeak-A2 ≥ 20 ms and Pend-A2 ≥ 0 ms predicted CTI block with 98% sensitivity and 95% specificity and 96% sensitivity and 100% specificity, respectively. In the validation set, the positive and negative predictive values of Ppeak-A2 ≥ 20 ms or Pend-A2 ≥ 0 ms were 100 and 96%, respectively. The diagnostic accuracy was 98%.
Conclusions
During pacing from the CS, the temporal relationship between the P wave in lead V1 and A2 is a simple and reliable indicator of complete block during RFA of CTI-AFL.