The isthmus characteristics of scar‐related macroreentrant atrial tachycardia in patients with and without cardiac surgery

Abstract

Introduction Identifying the critical isthmus (CI) in scar‐related macroreentrant atrial tachycardia (AT) is challenging, especially for patients with cardiac surgery. We aimed to investigate the electrophysiological characteristics of scar‐related macroreentrant ATs in patients with and without cardiac surgery. Methods A prospective study of 31 patients (mean age 59.4 ± 9.81 years old) with scar‐related macroreentrant ATs were enrolled for investigation of substrate properties. Patients were categorized into the nonsurgery (n = 18) and surgery group (n = 13). The CIs were defined by concealed entrainment, conduction velocity less than 0.3 m/s, and the presence of local fractionated electrograms. Results Among the 31 patients, a total of 65 reentrant circuits and 76 CIs were identified on the coherent map. The scar in the surgical group is larger than the nonsurgical group (18.81 ± 9.22 vs. 10.23 ± 5.34%, p = .016). The CIs in surgical group have longer CI length (15.27 ± 4.89 vs. 11.20 ± 2.96 mm, p = .004), slower conduction velocity (0.46 ± 0.19 vs. 0.69 ± 0.14 m/s, p < .001), and longer total activation time (45.34 ± 9.04 vs. 38.24 ± 8.41%, p = .016) than those in the nonsurgical group. After ablation, 93.54% of patients remained in sinus rhythm during a follow‐up of 182 ± 19 days. Conclusion The characteristics of the isthmus in macroreentrant AT are diverse, especially for surgical scar‐related AT. The identification of CIs can facilitate the successful ablation of scar‐related ATs.

Procedural Feasibility and Long-Term Efficacy of Catheter Ablation of Atypical Atrial Flutters in a Wide Spectrum of Heart Diseases: An Updated Clinical Overview

“…As shown in Table 1 , 33 studies [ 4 , 5 , 7 , 9 , 10 , 14 , 21 , 31 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ] published from 1996 [ 10 ] to 2021 [ 58 ] were collected. One-thousand-six-hundred-and-forty-one patients undergoing CA for AAFL were analyzed in different clinical settings.…”

“…Moreover, AAFL are complex arrhythmogenic circuits sustained by double or multiple loops in up to 60% of cases, which would make an ablation strategy based on conventional mapping particularly challenging [ 10 ]. To overcome these issues, three-dimensional electroanatomic mapping systems have been progressively implemented in cardiac electrophysiology to guide mapping [ 36 , 46 , 58 ] and to achieve effective radiofrequency ablation of these complex circuits [ 7 , 9 , 44 , 46 , 49 , 55 , 57 ]. In fact, when these systems are used, the peri-procedure success rate spans from 65% [ 37 ] to 100% [ 9 , 49 , 53 , 57 ], with better results observed in patients with a history of non-surgical PVI or in case of no structural heart disease [ 48 , 53 , 58 ].…”

“…To overcome these issues, three-dimensional electroanatomic mapping systems have been progressively implemented in cardiac electrophysiology to guide mapping [ 36 , 46 , 58 ] and to achieve effective radiofrequency ablation of these complex circuits [ 7 , 9 , 44 , 46 , 49 , 55 , 57 ]. In fact, when these systems are used, the peri-procedure success rate spans from 65% [ 37 ] to 100% [ 9 , 49 , 53 , 57 ], with better results observed in patients with a history of non-surgical PVI or in case of no structural heart disease [ 48 , 53 , 58 ]. Moreover, by preventing electrode–tissue interface boiling and reducing coagulum and char formation, open-irrigation-tip catheters seem associated with even higher acute success rates with less X-ray exposure and radiofrequency delivery in the setting of AAFL ablation [ 47 ].…”

“…The older the publication date, the greater the incidence of arrhythmia recurrence. This would suggest that the recent implementation of dedicated mapping tools [ 57 ] and irrigated-tip catheters [ 42 , 49 ] could help the cardiac electrophysiologist to achieve a greater long-term SR maintenance after an initially successful CA procedure [ 51 , 57 ]. The adoption of dedicated, tachycardia-oriented strategies for mapping and ablation of AAFL seem associated with even better results [ 46 , 51 ].…”

Electrophysiological characteristics of epicardial breakthrough during catheter ablation of perimitral atrial flutter

“…Local EGM intervals of CS were measured from initial activation to electrogram termination during perimitral atrial flutter, and the percentage of CS local EGM was calculated by CS interval dividing tachycardia cycle length in both groups before ablation of mitral AFL, or VoM alcoholization ( 16 ). Local conduction velocity in CS was defined by the distance between the two adjacent points divided by the activation time difference according to the isochronal line that was aligned with the directional vectors by the coherent map, Carto mapping system (Biosense-Webster Inc.; Diamond Bar, CA, USA), or obtained with UHD mapping directly by the Ensite Navigation System (St. Jude Medical, Minneapolis, MN, USA) ( 17 ).…”