Objective: To investigate the optimal range of quantitative
ablation index (AI) value during superior vena cava (SVC) electrical
isolation by radiofrequency catheter ablation (RFCA). Methods:
First, in a development cohort of patients with atrial fibrillation
(AF), the RFCA with 40W was performed to complete SVC isolation guided
by the conduction breakthrough point from the right atrium to SVC. Then,
the range of AI value was calculated by offline analysis on different
segments of SVC. Lastly, for the validation of AF patients, the safety
and effectiveness of SVC isolation with the optimized target range of AI
value were evaluated with an additional adenosine test.
Results: A total of 101 patients with AF were included in the
study (44 patients in the development cohort / 57 in the validation
cohort). The segmental ablation strategy was applied in 70% of the
patients. According to the offline analysis of the AI values in the
development cohort, the target AI value range was set as 350-400. The
success rate of SVC isolation in the validation cohort was significantly
higher than that in the exploration cohort (100% vs 90.9%, P = 0.02),
and no complications occurred in the exploration cohort. During the
adenosine test, the recovery rate of electrical conduction in SVC was
significantly lower than that in the pulmonary vein (3.5% vs 17.5%).
Conclusion: The target AI value with a range from 350 to 400 is
safe and effective for high-power RFCA to complete SVC isolation.