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 (ΔPVD), 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%) ΔPVD values were observed in 87, 14, and 3 PVs, respectively, including 1 case with severe left superior PV stenosis (ΔPVD: 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.

Impact of deep sedation on the electrophysiological behavior of pulmonary vein and non-PV firing during catheter ablation for atrial fibrillation.

PURPOSE: Catheter ablation for atrial fibrillation is performed with and without deep sedation, which could affect the arrhythmogenic activity during the procedure. We investigated the impact of sedation on electrophysiological properties in patients with AF who underwent catheter ablation. METHODS: This study consisted of 255 consecutive patients with atrial fibrillation (229 males, persistent: 105 patients) who underwent a single-catheter ablation procedure. The patients were divided into the following two groups according to the depth of sedation during the procedure: group M (mild sedation with flunitrazepam in 138 patients) and group D (deep sedation with propofol in 117 patients). Peripheral oxygen saturation was continuously monitored via pulse oximetry throughout the procedure. RESULTS: A spontaneous dissociated pulmonary vein activity after pulmonary vein isolation occurred more frequently in group M than in group D (29.1 vs 15.7%, P < 0.01). Adenosine-induced dormant pulmonary vein conduction was more frequently observed in group M than in group D (19.2 vs 13.0% P = 0.01). There were no significant differences in the incidence of non-pulmonary vein triggers between groups M and D (15.2 vs 11.1%, P = 0.53). The atrial fibrillation recurrence rate following the single procedure did not differ between the two groups (29.0 vs 26.5%, in groups M and D, P = 0.85). CONCLUSIONS: Although deep sedation reduced the incidence of a dissociated pulmonary vein activity and dormant pulmonary vein conduction following pulmonary vein isolation, it did not affect the recurrence rate for atrial fibrillation after the procedure.

Total absence of pulmonary vein potentials in a patient with paroxysmal atrial fibrillation: was it really isolated?

We herein present a case (72 years, male) with total absence of pulmonary veins (PVs) potentials at the beginning of the first procedure for paroxysmal atrial fibrillation (AF), demonstrating dormant conduction between the left atrium and all PVs revealed by adenosine triphosphate provocation with relation to the incidence of AF. He was free from atrial arrhythmias during 1 year follow-up after complete PV isolation with the elimination of multiple transient dormant conductions by circular mapping catheter guide ablation.

Influence of the concomitant use of heparin on the effects of warfarin during catheter ablation for atrial fibrillation.

Warfarin is widely used to perform catheter ablation for atrial fibrillation (AF). Heparin is usually administered during this procedure to prevent thromboembolic events, while protamine is used to reduce the incidence of bleeding complications. The purpose of this study was to investigate the influence of heparin and protamine administration on the effects of warfarin and its safety. The subjects included 226 AF patients (206 males, 54.9 ± 9.1 years, paroxysmal/persistent AF: 118/108) undergoing AF ablation with the discontinuation of warfarin administration over 2 days. Heparin was administered to achieve an activated clotting time (ACT) above 300 s during the procedure. Several parameters of the coagulation status, including the prothrombin time international normalized ratio (PT-INR) and ACT values, measured immediately before and after protamine infusion were compared. The mean value of PT-INR prior to ablation was 1.9 ± 0.6. At the end of the procedure, the mean ACT and PT-INR values were 348.0 ± 52.9 and 2.9 ± 0.7, respectively. Following the infusion of 30 mg of protamine, both the ACT and PT-INR values significantly decreased, to 159.6 ± 31.0 (p < 0.0001) and 1.6 ± 0.3 (p < 0.0001), respectively. No cases of symptomatic cerebral infarction were observed, although femoral hematomas developed in 17 (7.5 %) of the patients without further consequence. The concomitant use of heparin augments the effect of warfarin. Meanwhile, protamine administration immediately reverses both the ACT and PT-INR, indicating the applicability of protamine for AF ablation in patients under the mixed administration of heparin and warfarin.

Predictors of ectopic firing from the superior vena cava in patients with paroxysmal atrial fibrillation.

PURPOSE: Although catheter ablation targeting the pulmonary vein (PV) is a well-known therapy for patients with paroxysmal atrial fibrillation (PAF), ectopic firings from the superior vena cava (SVC) can initiate PAF. The purpose of this study was to investigate predictors of SVC firing. METHODS: The subjects included 336 consecutive PAF patients (278 males, age 56.1 ± 10.8 years) undergoing atrial fibrillation (AF) ablation. The appearance of SVC firing was monitored throughout the procedure using a decapolar catheter with multiple electrodes to record electrograms of the coronary sinus and SVC. In addition to PV isolation, SVC isolation was performed only in patients with documented SVC firing. RESULTS: SVC firing was observed in 43/336 (12.8 %) of the patients, among whom complete isolation of the SVC was achieved in 40/43 (93 %) patients. A lower body mass index (BMI) (22.8 ± 2.8 vs 24.1 ± 3.1 kg/m(2), p = 0.007) and higher prevalence of prior ablation procedures (58 vs 18 %, p = 0.0001) were related to the presence of SVC firing. In a multivariate analysis, a lower BMI (p = 0.012; odds ratio 0.83, 95 % CI 0.72 to 0.96) and history of prior ablation procedures (p < 0.0001; odds ratio 5.37, 95 % CI 2.71 to 10.63) were found to be independent predictors of the occurrence of SVC firing. Among 96 patients undergoing repeat ablation procedures, less PV-left atrial re-conduction was observed in patients with SVC firing than in those without (2.7 ± 1.2 vs 3.2 ± 0.8, p = 0.02). CONCLUSIONS: The presence of SVC firing in patients with PAF is associated with a history of repeat ablation procedures and lower BMI values.

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.

Repeated provocation of time- and ATP-induced early pulmonary vein reconnections after pulmonary vein isolation: eliminating paroxysmal atrial fibrillation in a single procedure.

BACKGROUND: Recurrence of atrial fibrillation (AF) after successful pulmonary vein isolation (PVI) occurs mainly due to the reconnection of the once isolated PV. Although provocation and elimination of the early pulmonary vein reconnection (EPVR) soon after PVI has been widely performed to improve the outcome, AF recurrence due to subsequent PV reconnections still occurs. In this study, we repeatedly provoked and eliminated the EPVR to determine the appropriate procedural end point. METHODS AND RESULTS: Seventy-five patients with paroxysmal AF underwent PVI. EPVR was provoked by both time and ATP induction every 30 minutes until 90 minutes after the individual isolation of all PVs. The number of reconnected atrio-PV gaps were evaluated and reablated at each provocation step. Although both time- and ATP-dependent EPVR was induced most frequently at 30 minutes after PVI (75 and 76 gaps, respectively), the prevalence of induced EPVR at 60 minutes was still high (64 and 36 gaps induced by time and ATP, respectively). Only a small number of EPVR appeared at 90 minutes after the elimination of all EPVR by 60 minutes (8 gaps, P<0.01). During the mean follow-up period of 370 days, 92% of cases were free from AF without antiarrhythmic drugs. CONCLUSIONS: Provocation and elimination of time- and ATP-induced EPVR not only at 30 minutes but also at 60 minutes is recommended after PVI to improve its efficacy.

Different strategies for performing pulmonary vein isolation in patients with pulmonary vein rhythm.

Pulmonary vein (PV) isolation was performed in atrial fibrillation (AF) patients whose cardiac rhythm was dominated by the ectopic beats originating from the PV. We herein report two cases with dominant PV ectopic rhythm that underwent catheter ablation for the treatment of paroxysmal AF. In one case, a permanent pacemaker implantation was required to treat a symptomatic long sinus pause after the isolation of all four PVs, while no AF was documented during the 5-year period after ablation. However, the isolation of all four PVs except for a PV with a dominant ectopic rhythm was performed in the other case. The latter case was free from both AF and symptomatic bradycardia following the procedure without the implantation of a pacemaker. Selective PV isolation therefore appears to be an effective therapy to both achieve the successful treatment of AF and to prevent the manifestation of sick sinus syndrome.

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.

Relationship between renal function and the risk of recurrent atrial fibrillation following catheter ablation.

BACKGROUND: Although several clinical variables are associated with the recurrence of atrial fibrillation (AF) following catheter ablation, the influence of renal function remains to be determined. OBJECTIVE: To evaluate the association of renal function with the outcome of the paroxysmal AF ablation. METHODS: 224 patients underwent catheter ablation for paroxysmal AF. The relationship between the pre-procedural clinical valuables and ablation outcomes was evaluated. RESULTS: Over the course of 37.4±24.4 months of follow-up of catheter ablation procedures for AF (mean number of procedures 1.33±0.45), 91.1% of patients (204/224) became free from AF without antiarrhythmic drugs. The estimated glomerular filtration rate (eGFR) was lower in patients with recurrent AF than in those without recurrence (66.6±17.5 vs 78.4±16.8 ml/min/1.73 m(2), p=0.003). AF recurred more frequently in patients with low eGFR (<60 ml/min/1.73 m(2)) than in those with high eGFR (>60 ml/min/1.73 m(2); 24.3% vs 6.7%, p=0.006). Among the various clinical factors, low eGFR (p=0.02) and left atrium (LA) dilatation (p=0.002) independently predicted the clinical outcome of ablation in patients with paroxysmal AF. CONCLUSION: Low eGFR and LA dilatation independently influence the outcome of catheter ablation for paroxysmal AF.

Comparison of the clinical outcome after pulmonary vein isolation based on the appearance of adenosine-induced dormant pulmonary vein conduction.

BACKGROUND: The elimination of transient pulmonary vein (PV) reconduction (dormant PV conduction) revealed by adenosine in addition to PV isolation reduced the atrial fibrillation (AF) recurrence after catheter ablation. The dormant PV conduction is induced in approximately half of the AF patients that undergo PV isolation. The present study compared the clinical outcome of AF ablation in patients whose dormant PV conduction was eliminated by additional radiofrequency applications with the outcome in patients without dormant conduction. METHODS: A total of 233 consecutive patients (206 male, 54.2 +/- 10.1 years) that underwent AF ablation were included in the present study. Dormant PV conduction was induced by the administration of adenosine triphosphate after PV isolation and was eliminated by supplemental radiofrequency application. All patients were followed up for >12 months (mean 903 days) after the first ablation. RESULTS: Following PV isolation, dormant PV conduction was induced in 139 (59.7%) of 233 patients and was successfully eliminated in 98% (223/228) of those in the first ablation procedure. After the first procedure, 63.9% (149/233) of patients were free from AF recurrence events. The success rates of a single or final AF ablation in patients with the appearance of the dormant PV conduction were similar to those of patients without dormant conduction (P = .69 and P = .69, respectively). CONCLUSIONS: Dormant PV conduction was induced in over half of the patients with AF. After the elimination of adenosine triphosphate-induced reconnection, the clinical outcome of patients with the dormant PV conduction was equivalent to that of patients without conduction.

Prospective randomized comparison of a steerable versus a non-steerable sheath for typical atrial flutter ablation.

AIMS: Although cavotricuspid isthmus (CTI) ablation can cure typical atrial flutter (AFL), it might be difficult to achieve a bidirectional conduction block in the isthmus in some patients. We investigated the usefulness of a steerable sheath for CTI ablation in patients with typical AFL or atrial fibrillation. METHODS AND RESULTS: A total of 40 consecutive patients (36 males; mean age 55.2 +/- 10.0 years) undergoing CTI ablation were randomized to one of the following two groups: group S (using a steerable long sheath) or group NS (using a non-steerable long sheath). Ablation was performed using an 8 mm tip catheter. The anatomy of the CTI was evaluated by a dual-source computed tomography scan prior to the procedure. The procedural endpoint was the achievement of a bidirectional isthmus conduction block. Bidirectional block in the CTI was achieved in all patients with 485.3 +/- 416.4 s of radiofrequency (RF) application. The CTI anatomy, including the length, depth, and morphology, was similar between the two groups. The duration and total amount of RF energy delivery were significantly shorter and smaller in group S than in group NS (310 +/- 193 vs. 661 +/- 504 s, P = 0.006, and 12,197 +/- 7306 vs. 26,906 +/- 21,238 J, P = 0.006, respectively). CONCLUSION: The use of a steerable sheath reduced the time and amount of energy needed to achieve a bidirectional conduction block in the CTI. For patients in whom the establishment of a conduction block is difficult, a steerable sheath should be considered as a therapeutic option for typical AFL ablation.

Impact of pulmonary vein isolation on the autonomic modulation in patients with paroxysmal atrial fibrillation and prolonged sinus pauses.

AIMS: The efficacy of catheter-based pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF) and prolonged sinus pauses [bradycardia-tachycardia syndrome (BTS)] has been already described. However, the effects of PVI on autonomic modulation in BTS patients remain to be determined. We, therefore, examined the alteration in the autonomic modulation through the PVI procedure by using a heart rate variability (HRV) analysis of 24 h ambulatory monitoring. METHODS AND RESULTS: This study consisted of 26 symptomatic paroxysmal AF patients either with prolonged sinus pauses on termination of AF (>3.0 s, BTS group, n = 11) or without any evidence of sinus node dysfunction (control group, matched for sex and age, n = 15) who underwent PVI. All 11 BTS patients became free from both AF and prolonged sinus pauses without pacemaker implantation (23 +/- 14 months of observation). The mean heart rate significantly increased in the control group (P < 0.05), but not in the BTS group after the PVI procedure, although the HRV parameters of root-mean-square successive differences in the adjacent NN intervals, standard deviation of the NN intervals, and high frequency did significantly decrease in both groups (P < 0.05). CONCLUSION: Although the parasympathetic modulation was significantly attenuated after the PVI procedure, the mean heart rate did not increase in the BTS patients, probably due to the pre-existing sinus node dysfunction.

The dormant epicardial reconnection of pulmonary vein: an unusual cause of recurrent atrial fibrillation after pulmonary vein isolation.

The case of a 65-year-old man with recurrent atrial fibrillation after undergoing segmental pulmonary vein isolation caused by the reconnection of previously isolated pulmonary veins is herein reported. Interestingly, frequent ectopic firings in the left superior pulmonary vein conducted to the left atrium, not through its ostium but through the supposed epicardial pathway at the region of the Marshall ligament, which had been absent during the first treatment session. The reisolation of the left superior pulmonary vein by radiofrequency application in the left atrial appendage thus successfully eliminated the occurrence of atrial fibrillation.

Prevalence, morphological and electrophysiological characteristics of confluent inferior pulmonary veins in patients with atrial fibrillation.

BACKGROUND: Although the common trunk of left pulmonary veins (PVs) has been reported as a relatively popular anatomical variation of PVs, little is known about the coalescence of contralateral PVs. The present study was conducted to reveal the prevalence and electrophysiologic characteristics of the confluent inferior common PVs. METHODS AND RESULTS: Anatomical variation in the PV drainage to the left atrium (LA) was assessed using the multidetector computed tomography scan in 326 patients with atrial fibrillation (AF) who underwent the PV isolation procedure. Coalescence of inferior PVs was observed in 5 cases (1.5%). Both inferior PVs conjoined prior to the junction with the LA in 3 cases, while they coalesced at the LA junction in the other 2 cases. The arrhythmogenic activities of the confluent inferior PVs were generally low in all cases without any ectopic firings triggering the observed AF. All inferior PVs, as well as the superior PVs, were successfully isolated either en bloc at the common trunk or individually at the orifice of each PV. CONCLUSIONS: Confluent inferior PVs were present in 1.5% of cases in patients with AF who underwent the PV isolation procedure. Preoperative recognition of this venous anomaly by 3-dimensional imaging is important for smooth and safe ablation.

Decreased renal function as an independent predictor of re-hospitalization for congestive heart failure.

BACKGROUND: Patients with congestive heart failure (CHF) are often re-hospitalized, worsening both their quality of life and prognosis. Although renal dysfunction reportedly increases the risk of CHF, the association between renal dysfunction and re-hospitalization for CHF remains unclear. METHODS AND RESULTS: Patients with CHF and decreased renal function were reviewed. The estimated glomerular filtration rate (GFR) was calculated with the Modification of Diet in Renal Disease equation. Patients with decreased renal function (estimated GFR on admission <45 ml .min(-1) . 1.73 m(-2)) were re-hospitalized more frequently than were patients with preserved renal function (estimated GFR on admission >or=45). Patients with decreased renal function were older and had higher rates of anemia, worsening renal function during hospitalization, and previous hospitalization for CHF. Independent predictors of re-hospitalization for CHF identified with multivariate analysis were age, previous hospitalization for CHF, decreased renal function, and non-use of an angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker. CONCLUSIONS: Renal dysfunction is an independent predictor of re-hospitalization for CHF, so careful follow-up is needed, even after discharge.

Hypoxemia in inferior pulmonary veins in supine position is dependent on obesity.

RATIONALE: Although arterial oxygen concentration decreases in obese subjects, the mechanism for this remains to be determined. OBJECTIVES: The blood gas level in each pulmonary vein (PV) was measured in supine subjects with diverse body mass index (BMI) values, to determine whether there was a regional insufficiency in gas exchange depending on the subject's BMI. METHODS: Forty subjects with normal cardiopulmonary function who underwent a catheter ablation for atrial fibrillation were included. Before delivering any radiofrequency energy application, blood samples were obtained from each of the four PVs during physiologic breathing in a supine position to measure the PO2 and PCO2 values. Spirometry and ventilation/perfusion lung scintigraphy were also performed. MEASUREMENTS AND MAIN RESULTS: The PO2 value was significantly higher in superior veins than inferior veins (91.8 +/- 13.5, 70.8 +/- 16.3, 92.2 +/- 11.1, and 73.6 +/- 13.7 mm Hg, in the left superior, left inferior, right superior, and right inferior PV, respectively). There was a significant inverse relationship between the PO2 and PCO2 values. Neither the spirometry nor lung scintigraphy could detect any remarkable findings corresponding to the low PO2 values. Among the various clinical characteristics, only the BMI was significantly associated with the decreased PO2 value in the inferior veins. CONCLUSIONS: Hypoxia in obese subjects in a supine position is thus considered to be primarily caused by insufficient gas exchange in the regions of lung linked to the inferior PVs. The inverse relationship between the BMI and PO2 value in the inferior PVs suggests a possible subclinical manifestation of obesity-related respiratory insufficiency.

Renal insufficiency is related to painless myocardial infarction.

BACKGROUND: Acute myocardial infarction (MI) sometimes occurs without painful symptoms and in such cases, prognosis is worsened by delays in diagnosis and revascularization. Renal insufficiency induces many types of neuropathy, but the relation between renal insufficiency and painless MI remains unclear. METHODS AND RESULTS: Patients with MI and elevated creatine kinase levels were retrospectively analyzed. Renal insufficiency (serum creatinine concentration > or =1.5 mg/dl) and other characteristics (age, sex, body mass index, hypertension, smoking, diabetes mellitus, dyslipidemia, history of stroke, previous MI, hemodialysis, and atrial fibrillation) were compared between patients who had MI with painful symptoms (painful MI, n=131) and patients who had MI without painful symptoms (painless MI, n=18). Other variables compared were the time from symptom onset to admission, peak creatine kinase concentration, Killip class, site of MI, emergency coronary angiography, postprocedural Thrombolysis In Myocardial Infarction grade III flow, and in-hospital death. Univariate analysis identified older age, renal insufficiency, and previous MI as predictors of painless MI. Patients with painless MI showed higher rates of Killip class > or =II and in-hospital death and a longer time from symptom onset to admission. However, multivariate analysis identified only renal insufficiency as an independent predictor of painless MI. CONCLUSIONS: MI without painful symptoms frequently develops in patients who have renal insufficiency, so the possibility of painless MI should be evaluated in such patients to ensure early diagnosis and treatment.

Reduction of AF recurrence after pulmonary vein isolation by eliminating ATP-induced transient venous re-conduction.

BACKGROUND: Recent evidence has suggested that the transient re-conduction of the isolated pulmonary vein (PV) induced by the intravenous injection of adenosine (dormant PV conduction) might predict the incidence of subsequent venous reconnection after the procedure, which is the main cause of the atrial fibrillation (AF) recurrence after PV isolation (PVI). We tested the hypothesis that the elimination of these dormant PV conductions by additional radiofrequency (RF) applications can improve the efficacy of the PVI. METHODS AND RESULTS: One hundred forty-eight patients (124 males; mean age 53 +/- 9 years) with drug-refractory AF underwent the PVI procedure. The standard PVI was performed in 94 patients (Group A), whereas the elimination of adenosine triphosphate (ATP)-induced dormant conduction using additional RF energy was performed in addition to the standard PVI in other 54 patients (Group B). Dormant conduction was observed in 56% of the patients (30/54) in Group B and 95% of these transient re-conductions were successfully eliminated by additional RF applications (mean: 1.5 +/- 1.0 times). During the mean follow-up period of 20 months, recurrences of AF after the procedures were observed significantly less frequently in Group B (20%) than in Group A (40%) (P < 0.05). CONCLUSION: The use of additional RF applications to eliminate transient PV reconnection induced by ATP injection led to a reduction of AF recurrence after PVI, most likely due to the minimization of the subsequent PV reconnection.

Segmental pulmonary vein antrum isolation using the "large-size" lasso catheter in patients with atrial fibrillation.

BACKGROUND: The limited efficacy and complications of segmental ostial pulmonary vein isolation (PVI) for treating atrial fibrillation (AF) have been discussed so, in the present study the feasibility and efficiency of performing segmental pulmonary vein (PV) antrum isolation to treat AF were assessed. METHODS AND RESULTS: A total of 187 patients with drug-refractory AF (paroxysmal 120, persistent 67) underwent segmental PVI guided by circumferential 20-electrode catheters (Lasso). Radiofrequency (RF) current was delivered either at the ostium using a regular Lasso (15-20 mm in diameter, 70 patients: Group 1) or at the antrum using a larger Lasso (25-30 mm in diameter, 117 patients: Group 2). A significantly wider region had to be ablated, with a longer RF application time, to isolate all 4 PVs in Group 2 patients than in Group 1 patients. Although the rate of recurrence of AF after the initial session was equal in both groups, a significantly greater number of patients were free from AF after a mean of 1.4 procedures in Group 2 than in Group 1 (93% vs 76% for paroxysmal AF, 78% vs 48% for persistent AF). CONCLUSIONS: Segmental antral PVI using large-sized Lasso catheters was found to be more effective and safer than ostial PVI for the treatment of AF.