Slow Potential at the Entrance of the Slow Conduction Zone in the Reentry Circuit of a Verapamil‐Sensitive Atrial Tachycardia Originating From the Atrioventricular Annulus

Abstract

BackgroundSlow conduction zone in a verapamil‐sensitive reentrant atrial tachycardia originating from atrioventricular annulus is composed of calcium channel–dependent tissue. We examined whether there was a slow potential (SP) at the entrance of the slow conduction zone.Methods and ResultsWe first identified the pacing site from where manifest entrainment and orthodromic capture of the earliest atrial activation site were demonstrated in 40 atrioventricular annulus patients with atrioventricular annulus. Radiofrequency energy was then delivered 2 cm proximal to the earliest atrial activation site in the direction of entrainment pacing site and gradually advanced toward the earliest atrial activation site until atrial tachycardia termination to localize the entrance of the slow conduction zone. Electrogram characteristics were analyzed at successful and unsuccessful ablation sites. During sinus rhythm, SP was observed at all 40 successful sites, but was observed at only 12 unsuccessful sites (P<0.0001). During sinus rhythm, there was no significant difference in electrogram amplitude nor width of atrial electrogram between successful and unsuccessful sites (0.407±0.281 versus 0.487±0.447 mV [P=0.1989] and 37.0±9.2 versus 38.9±8.0 ms [P=0.1773]); however, SP amplitude and width at successful sites were significantly greater than those at unsuccessful sites (0.110±0.049 versus 0.025±0.046 mV [P<0.0001] and 38.8±13.4 versus 8.1±13.2 ms [P<0.0001]). During atrial tachycardia, SP amplitude was significantly attenuated (0.088±0.042 versus 0.110±0.049 mV, P<0.001) and SP width was significantly prolonged (47.8±14.1 versus 38.8±13.4 ms, P<0.0001) at successful sites.Conclusions SP was observed during sinus rhythm at the entrance of the slow conduction zone; however, SP amplitude was attenuated and SP width was prolonged during atrial tachycardia, suggesting that SP reflects the characteristics of calcium channel–dependent tissue involved in atrioventricular annulus reentry circuit.

Outcomes of deep sedation for catheter ablation of paroxysmal supraventricular tachycardia, with adaptive servo ventilation

“…Most of the patients in this study (133 of 145 (92%)) had reentrant tachycardias as a mechanism of PSVT, such as AVNRT (77) and AVRT (51), including 5 patients with perinodal ATP‐sensitive AT of which the mechanism is supposed to be reentry 12,20 . Based on our results, it appears that PSVT with reentrant mechanism also have preserved inducibility under deep sedation.…”

“…In patients with AT, the earliest activation site indicated by electroanatomical mapping was targeted for ablation. As for perinodal ATP‐sensitive AT of which the mechanism is considered to be macro‐reentry, ablation was tried at the reentrant site outside of Koch's triangle first, and then the earliest activation site was targeted 11,12 . Either of non‐irrigated or irrigated catheters were used in AVRT and AT ablation by physician choice, with maximum power up to 35 W.…”

Target potential for ablation in adenosine-sensitive atrial tachycardia originating from the vicinity of the atrioventricular node identified by the LUMIPOINT software

“…In this case, SKYLINE demonstrated the underlying AT mechanism was localized reentry and highlighted the successfully ablated site, located 8 mm away from the EAAS, showing a low amplitude and fractionated potential, consistent with a previous report. 9 These findings indicate that the effective ablation site for the AVN-AT is the exit site of the SCZ, as highlighted by the LUMIPOINT. The distance between the successfully ablated site and HB was also similar to previous findings.…”

“…A previous study demonstrated that the atrial electrogram at the successfully ablated site appeared 15 ms later than the HB electrogram during AVN-AT. 9 This delay in electrogram detection is attributed to the low amplitude of the electrogram, which may not be accurately detected by the ablation catheter. Additionally, the annotation algorithm of LUMIPOINT software, which is unique and unlike any other 3D mapping systems, helps to identify the mechanism of this arrhythmia.…”

Atrioventricular Ring Tachycardias: Atypical Fast-Slow Atrioventricular Nodal Reentrant Tachycardia and Atrial Tachycardia Share a Common Arrhythmogenic Substrate—A Unifying Proposal

“…Yamabe et al . [ 86 ] have described low-frequency, late potentials following local atrial activation during sinus rhythm, probably reflecting a delayed activation of the tachycardia origin, near the site of successful ablation, in patients presenting with atrial tachycardia originating from the tricuspid annulus. The presence of these potentials suggests a slowly conducting, common arrhythmogenic substrate of these tachycardias.…”