Novel Approach to Reproducible Atrial Fibrillation Cycle Length Measurement

Noting that previous studies on pulmonary vein (PV) atrial fibrillation (AFib) cycle length (CL) measurement returned inconsistent results when predicting the efficacy of PV isolation (PVI), researchers developed a simple method to characterize atrial activity rate using the average of 10 consecutive Fastest Atrial Repetitive Similar morphology signal (FARS₁₀)-CL. Their study, published in the Journal of Cardiovascular Electrophysiology, found that FARS₁₀-CL measurements were more reproducible than traditional measuring of AFib-CL using continuously fragmented coronary sinus signals (CS).

Francesco Spera, the study’s lead author, noted that “patients with high burden of [spontaneous low voltage zone (LVS)] have longer Fastest PV-FARS₁₀-CLs.” Moreover, the study’s collaborators identified that a Fastest PV-FARS₁₀-CL ≤140 ms was associated with a high success rate of the wide antral PVI-only ablation approach in patients with persistent AFib.

The prospective trial compared the reproducibility of FARS₁₀-CL and traditional AFib-CL measurements. A total of 100 consecutive patients with AFib undergoing wide antral PVI-only ablation were enrolled and the researchers measured their PV-FARS₁₀-CLs measured and tracked their long-term outcomes.

According to the report, the Kendall area correlation between repeated traditional measurements was –0.006, while the correlation between repeated FARS₁₀-CL measurements in the left and right atrial appendages, CS, and PVs were 0.944, 0.859, 0.882, 0.675–0.955, respectively. Additionally, both patients with recurrent atrial tachyarrhythmia had significantly longer Fastest PV-FARS₁₀-CL (172±41 vs. 156±41 ms; p = 0.047) and those with high spontaneous LVS burden had significantly longer Fastest PV-FARS₁₀-CL. The recurrent tachyarrhythmia-free rate at 24 months was 85% versus 59% in patients a with Fastest PV-FARS₁₀-CL ≤140 ms versus those with >140 ms (p = 0.0018). Finally, the authors’ multivariable analysis indicated that Fastest PV-FARS₁₀-CL ≤140 was the “only significant predictor of freedom from recurrent tachyarrhythmia.”

Overall, the authors presented their novel approach to simple and reproducible measurement of atrial fibrillation cycle length as superior to the traditional method. In future practice, the prospective method may be able to identify patients who could benefit from PVI-only ablation as well.