Kenichi Tokutake

Dormant pulmonary vein conduction induced by adenosine in patients with atrial fibrillation who underwent catheter ablation

BACKGROUND intravenous administration of adenosine triphosphate (ATP) is used to induce transient pulmonary vein (PV) reconduction (dormant PV conduction) following PV isolation. This study investigated the detailed characteristics of dormant PV conduction in patients with atrial fibrillation (AF) who underwent catheter ablation. METHODS two hundred sixty consecutive patients (235 men; mean age, 54 ± 10 years) who underwent catheter ablation of their AF were included in this study. ATP was injected following PV isolation to induce dormant PV conduction, which was then eliminated by radiofrequency application. RESULTS dormant PV conduction was induced by ATP in 60.4% (157/260) of the patients and in 25.3% (258/1,021) of the isolated PVs. This transient PV reconduction was more frequently observed in the left superior PV in comparison with other PVs (P < .0001). There was no significant difference in the prevalence of the dormant PV conduction among patients with paroxysmal AF, persistent AF, and long-lasting AF (62%, 66%, and 48%, respectively; P = .13). During the follow-up period, repeat AF ablation was performed in 70 patients with recurrent AF. The dormant PV conduction was less frequently induced in the repeat procedure than in the initial procedure (60.4% vs 31.4%, P < .0001). CONCLUSIONS dormant PV conduction was evenly induced among AF types. The repeat PV isolation led to the decrease in incidence of the ATP-induced acute transient pharmacological PV reconduction.

The role of successful catheter ablation in patients with paroxysmal atrial fibrillation and prolonged sinus pauses: outcome during a 5-year follow-up

AIMS Although patients with paroxysmal atrial fibrillation (AF) and prolonged sinus pauses [tachycardia-bradycardia syndrome (TBS)] are generally treated by permanent pacemaker, catheter ablation has been reported to be a curative therapy for TBS without pacemaker implantation. The purpose of this study was to define the potential role of successful ablation in patients with TBS. METHODS AND RESULTS Of 280 paroxysmal AF patients undergoing ablation, 37 TBS patients with both AF and symptomatic sinus pauses (age: 62 ± 8 years; mean maximum pauses: 6 ± 2 s) were analysed. During the 5.8 ± 1.2 years (range: 5-8.7 years) follow-up, both tachyarrhythmia and bradycardia were eliminated by a single procedure in 19 of 37 (51%) patients. Repeat procedures were performed in 14 of 18 patients with tachyarrhythmia recurrence (second: 12 and third: 2 patients). During the repeat procedure, 79% (45 of 57) of previously isolated pulmonary veins (PVs) were reconnected to the left atrium. Pulmonary vein tachycardia initiating the AF was found in 46% (17 of 37) and 43% (6 of 14) of patients during the initial and second procedure, respectively. Finally, 32 (86%) patients remained free from AF after the last procedure. Three patients (8%) required pacemaker implantation, one for the gradual progression of sinus dysfunction during a period of 6.5 years and the others for recurrence of TBS 3.5 and 5.5 years after ablation, respectively. CONCLUSION Catheter ablation can eliminate both AF and prolonged sinus pauses in the majority of TBS patients. Nevertheless, such patients should be continuously followed-up, because gradual progression of sinus node dysfunction can occur after a long period of time.

Substrate Modification by Pulmonary Vein Isolation and Left Atrial Linear Ablation in Patients with Persistent Atrial Fibrillation: Its Impact on Complex‐Fractionated Atrial Electrograms

PV and Linear Ablation for CFAEs. Introduction: Linear ablations in the left atrium (LA), in addition to pulmonary vein (PV) isolation, have been demonstrated to be an effective ablation strategy in patients with persistent atrial fibrillation (PsAF). This study investigated the impact of LA linear ablation on the complex‐fractionated atrial electrograms (CFAEs) of PsAF patients.

Adenosine testing during cryoballoon ablation and radiofrequency ablation of atrial fibrillation: A propensity score–matched analysis

BACKGROUND The infusion of adenosine triphosphate after radiofrequency (RF) pulmonary vein (PV) isolation (PVI), which may result in acute transient PV-atrium reconnection, can unmask dormant conduction. OBJECTIVE The purpose of this study was to compare the incidence and characteristics of dormant conduction after cryoballoon (CB) and RF ablation of atrial fibrillation (AF). METHODS Of 414 consecutive patients undergoing initial catheter ablation of paroxysmal AF, 246 (59%) propensity score-matched patients (123 CB-PVI and 123 RF-PVI) were included. RESULTS Dormant conduction was less frequently observed in patients who underwent CB-PVI than in those who underwent RF-PVI (4.5% vs 12.8% of all PVs; P < .0001). The incidence of dormant conduction in each PV was lower in patients who underwent CB-PVI than in those who underwent RF-PVI in the left superior PV (P < .0001) and right superior PV (P = .001). The site of dormant conduction was mainly located around the bottom of both inferior PVs after CB-PVI. Multivariable analysis revealed that a longer time to the elimination of the PV potential (odds ratio 1.018; 95% confidence interval 1.001-1.036; P = .04) and the necessity of touch-up ablation (odds ratio 3.242; 95% confidence interval 2.761-7.111; P < .0001) were independently associated with the presence of dormant conduction after CB-PVI. After the elimination of dormant conduction by additional ablation, the AF-free rate was similar in patients with and without dormant conduction after both CB-PVI and RF-PVI (P = .28 and P = .73, respectively). CONCLUSION The results of the propensity score-matched analysis showed that dormant PV conduction was less frequent after CB ablation than after RF ablation and was not associated with ablation outcomes.

Adenosine-induced atrial tachycardia and multiple foci initiating atrial fibrillation eliminated by catheter ablation using a non-contact mapping system.

A 47-year-old male with both atrial tachycardia and atrial fibrillation underwent catheter ablation. During the procedure, rapid administration of adenosine triphosphate induced atrial tachycardia. A non-contact mapping system revealed a focal atrial tachycardia originating from the lateral right atrium, which was successfully ablated. Following the ablation of tachycardia, atrial fibrillation was induced by the injection of adenosine along with multiple extra pulmonary vein foci, which were eliminated by the application of radiofrequency under the guidance of a non-contact mapping system.

Real-Time Dominant Frequency Analysis of the Pulmonary Vein in Patients with Paroxysmal Atrial Fibrillation

Background:  Paroxysmal atrial fibrillation (PAF) can be treated with pulmonary vein isolation (PVI). A spectral analysis can identify sites of high‐frequency activity during atrial fibrillation (AF). We investigated the role of the PVs on AF perpetuation by dominant frequency (DF) analysis.

Incidence and Factors Associated With the Occurrence of Pulmonary Vein Narrowing After Cryoballoon Ablation

Background— In contrast with traditional radiofrequency ablation, little is known about the influence of cryoballoon ablation on the morphology of pulmonary veins (PVs). We evaluated the influence of cryoballoon ablation on the PV dimension (PVD) and investigated the factors associated with a reduction of the PVD. Methods and Results— Seventy-four patients who underwent cryoballoon ablation for paroxysmal atrial fibrillation were included in the present study. All subjects underwent contrast-enhanced computed tomography both before and at 3 months after the procedure. The PVD (cross-sectional area) was measured using a 3-dimensional electroanatomical mapping system. Each PV was evaluated according to the PVD reduction rate (&Dgr;PVD), which was calculated as follows: (1−post-PVD/pre-PVD)×100 (%). Ninety-two percent of the PVs (271/296) were successfully isolated only by cryoballoon ablation; the remaining 8% of the PVs required touch-up ablation and were excluded from the analysis. Mild (25%–50%), moderate (50%–75%), and severe (≥75%) &Dgr;PVD values were observed in 87, 14, and 3 PVs, respectively, including 1 case with severe left superior PV stenosis (&Dgr;PVD: 94%) in a patient who required PV angioplasty. In multivariable analysis, a larger PV ostium and lower minimum freezing temperature during cryoballoon ablation were independently associated with PV narrowing (odds ratio, 1.773; P=0.01; and odds ratio, 1.137; P<0.001, respectively). Conclusions— A reduction of the PVD was often observed after cryoballoon ablation for atrial fibrillation. A larger PV ostium and lower minimum freezing temperature during cryoballoon ablation were associated with an increased risk of PVD reduction.

Pulmonary vein re-mapping after cryoballoon ablation for atrial fibrillation

Aims Establishment of pulmonary vein isolation (PVI) during cryoballoon (CB) ablation is generally confirmed by use of an octapolar inner-lumen mapping catheter (Achieve®). The aim of this study is to evaluate the residual PV potential (PVP) using the conventional circular catheter after CB-PVI. Methods and results A total of 105 consecutive patients (418 PVs) with paroxysmal AF who underwent the initial CB-PVI were prospectively included in this study. Of those, 305 (73%) PVs with real-time recordings of PVP elimination by Achieve® catheter during successful PVI were included. After isolation of all 4 PVs, PV antral remapping by conventional circular mapping catheter was performed. After CB-PVI, residual PVP was detected in 4.3% (13/305) of PVs (1.2% of left-superior PV, 2.5% of left-inferior PV, none of right-superior PV, and 20% of right-inferior PV). Almost 60% of residual PV potential was located around the bottom portion of the right-inferior PV. In PVs with residual potential, PV trunk was shorter (12.7 ± 5.7 mm vs. 18.7 ± 7.9, P = 0.001), minimal balloon temperature was higher (-46.6 ± 5.9 °C vs. -50.9 ± 8.2, P = 0.02), and balloon warming time was shorter (35.6 ± 17.8 s vs. 50.0 ± 22.8, P = 0.006) than those without. All residual potentials were eliminated by additional touch up ablation. After the initial ablation procedure, 1-year AF-free rate was 79.5%. Conclusion PV remapping after CB-PVI revealed residual antral PVP in 4.3% of PVs and in 20% of RIPVs in particular. The Achieve® catheter sometimes fails to detect complete PV antral isolation.

Pulmonary vein stenosis after second-generation cryoballoon ablation for atrial fibrillation

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for atrial fibrillation (AF), especially in paroxysmal 1 AF patients. In addition to a radiofrequency ablation catheter, a cryoballoon has been proven as an effective technology in PVI for AF. Recently several randomized trials have shown that cryoballoon ablation was noninferior to radiofrequency ablation with respect to efficacy for the treatment of patients with drug-refractory paroxysmal AF, and there was no significant difference between the 2 methods with regard to overall safety. Pulmonary vein (PV) stenosis was one of the major complications after PVI.

Paradoxical responses to pacing maneuvers differentiating atrioventricular node reentrant tachycardia and junctional tachycardia

A 40-year-old female presented at our hospital because of heart palpitations. During an electrophysiological study, atrioventricular (AV) conduction showed dual AV nodal physiology. Three types of supraventricular tachycardia (SVT) were induced. The initiation of SVT was reproducibility dependent on a critical A–H interval prolongation. An early premature atrial contraction during SVT repeatedly advanced the immediate His potential with termination of the tachycardia, indicating AV node reentrant tachycardia (AVNRT). However, after atrial overdrive pacing during SVT without termination of the tachycardia, the first return electrogram resulted in an AHHA response, consistent with junctional tachycardia. The mechanism of paradoxical responses to pacing maneuvers differentiating AVNRT and junctional tachycardia was discussed.