Ablation Index Predicts Successful Ablation of Focal Atrial Tachycardia: Results of a Multicenter Study

Abstract

A radiofrequency energy lesion transmurality marker incorporating power, contact force, and time (Ablation Index, AI) was shown to be associated with outcomes of catheter ablation (CA) of multiple arrhythmias, but was never systematically assessed in the CA of focal atrial tachycardias (AT). We aimed to evaluate the role of AI as a predictor of outcomes in focal AT CA, and therefore, retrospectively included 45 consecutive patients undergoing CA for focal AT in four referral electrophysiology laboratories. Clinical and procedural information were collected. For each patient, maximum and mean (by averaging maximum AI values for each radiofrequency ablation lesion) AI were measured. The primary outcome was focal AT-free survival, and was systematically assessed with periodical Holter monitors or cardiac implantable electronic devices. CA was acutely effective in each case; however, 20% (n = 9) of the study population experienced a focal AT recurrence over a median follow-up of 288 days. Both maximum and mean AI values were significantly higher among patients without AT recurrences (maximum AI = 568 ± 91, mean AI = 426 ± 105) than in patients with AT relapses (maximum AI = 447 ± 142, mean AI = 352 ± 76, p = 0.036, and p = 0.028, respectively). The optimal cutoffs associated with freedom from recurrences were 461 for maximum AI (sensitivity, 0.89; specificity, 0.56) and 301 for mean AI (sensitivity, 0.97; specificity, 0.44). In a time-to-event analysis, maximum AI was significantly associated with survival free from AT recurrence (p = 0.001), whereas mean AI was not (p = 0.08). In summary, maximum AI is the best procedural parameter associated with the outcomes of CA for focal AT, and may help standardize the procedural approach.

Microelectrode voltage mapping for substrate assessment in catheter ablation of ventricular tachycardia: A dual‐center experience

“…Radiofrequency energy was delivered in a temperature‐controlled fashion (QMODE TM ; Biosense Webster), power setting 40−50 W, and recommended contact force 5−20 g; the choice of power, contact force, and duration of radiofrequency energy delivery were left at the discretion of operators. An automated lesion tagging module (Visitag Module; Biosense Webster) was used to mark the location of each radiofrequency lesion with the following settings: catheter stable for at least 3 s within a 3 mm range and at least 3 g of contact force for 25% of the stability time 10,11 . For each case, we recorded the number of Visitags, minimum and maximum power, as well as maximum and mean ablation index values, as previously described 10,12 .…”

“…An automated lesion tagging module (Visitag Module; Biosense Webster) was used to mark the location of each radiofrequency lesion with the following settings: catheter stable for at least 3 s within a 3 mm range and at least 3 g of contact force for 25% of the stability time. 10,11 For each case, we recorded the number of Visitags, minimum and maximum power, as well as maximum and mean ablation index values, as previously described. 10,12 In inducible patients, PES was repeated at end procedure; complete procedural success was defined as absence of any VT inducibility; partial procedural success was defined as nonclinical VT inducibility; procedural failure was defined as persistent inducibility of clinical VT.…”

Posterior wall ablation for persistent atrial fibrillation: Very-high-power short-duration versus standard-power radiofrequency ablation

“…In this study, we sought to investigate whether use of the vHPSD ablation mode impacts the procedural, safety, and efficacy outcomes of patients with persistent AF undergoing PVI plus posterior wall ablation (PWA) compared to standard power (SP), contact force–sensing, and ablation index (AI)–guided radiofrequency (RF) CA. 9 , 10 , 11 Furthermore, we aimed to formally assess the impact of microelectrode mapping on characterization of the atrial substrate by exploring the voltage correlation between microbipolar and standard bipolar mapping. 8 , 12 …”