Validation of Coronary Sinus Activation Pattern During Left Atrial Appendage Pacing for Beat‐to‐Beat Assessment of Mitral Isthmus Conduction/Block

Abstract

CS activation sequence was used to assess conduction in 39 of 40 patients (unable to advance CS catheter distally in one case). MI block was achieved in 36 of 39 cases. The mean MI conduction time (LAA to distal CS) was 92.9 +/- 25.9 ms prior to ablation and 178.4 +/- 59.9 ms after MI block was confirmed. The mean step-out in conduction time at point of block was 80.8 +/- 40.6 ms. In all individuals in whom CS activation indicated block, there was concordance with endocardial activation, differential pacing and, where detectable, presence of widely split double potentials. CS lesions were required to achieve block in 24 of 36 (67%) successful cases. Radiofrequency application time and procedure time to achieve MI block were 10.8 +/- 6.0 minutes and 21.1 +/- 15.3 minutes, respectively.