Pulmonary Vein Potentials Research Articles

Comparison of 2 Mapping Strategies for Pulmonary Vein Isolation

Pulmonary vein (PV) isolation using a circular catheter (CC) creates an entrance block from the left atrium (LA) to PV to eliminate paroxysmal atrial fibrillation (PAF). We describe a new approach for PV isolation during distal PV pacing using a basket catheter (BC). The purpose of the present study was to compare 2 mapping strategies for PV isolation. Of 100 consecutive patients with PAF, 50 underwent CC-guided PV isolation and 50 underwent BC-guided PV isolation. During CC-guided ablation, the endpoint was the elimination of PV potentials based on the entrance block from the LA to PV. During BC-guided ablation during distal PV pacing, the endpoint was the elimination of bidirectional PV-LA conduction. At 12 months, 62% of patients who underwent CC ablation and 80% of patients who underwent BC ablation were free of symptomatic PAF without the use of antiarrhythmic drugs (p<0.05). The incidence of mild (<50%) PV stenosis in BC ablation was significantly lower than that in CC ablation (12 vs 24%, p<0.01). This new approach for PV isolation during distal PV pacing using BC is useful for confirming a bidirectional PV-LA conduction block and is more effective than CC ablation.

A Clinical Study of Patients with and Without Recurrence of Paroxysmal Atrial Fibrillation After Pulmonary Vein Isolation

Patients with paroxysmal atrial fibrillation (PAF) can be treated by pulmonary vein (PV) isolation. However, the recurrence rate after this procedure is relatively high. We sought to evaluate the quality of life (QOL) of patients with PAF recurrence after PV isolation and to analyze factors related to recurrences. Seventy-two drug-refractory PAF patients (59 men, 13 women, mean age 52 +/- 10) were included. PV isolation was based on the disappearance of PV potentials recorded from a Lasso catheter after segmental ostium ablation. Automatic foci were observed in 47 patients (65.3%) during the procedure. A mean of 3.1 +/- 0.9 PVs was isolated. Patients were followed for a mean of 10.3 +/- 5.1 months, during which 27 experienced >1 episode of PAF. QOL was scored from 0 (situation before ablation) to 10 (no episode after ablation) based on a questionnaire completed by 69 patients (95.8%). QOL was judged very good in 26 patients (none with PAF recurrences), better in 30 (15 with PAF recurrences), unchanged in 11 (10 with recurrences), and worse in 2 patients with PAF recurrences. Longer histories of PAF and a lower percentage of patients with automatic foci identified during the procedure were observed in the group with, than in the group without recurrences (P < 0.05). PV isolation improved QOL in patients with PAF, including in patients with recurrences. The length of PAF history and observation of automatic foci may be of importance for recurrences of PAF during long-term follow-up.

Left Atrial and Pulmonary Vein Ostial Ablation as a New Treatment for Curing Persistent Atrial Fibrillation Initial Experience and Results

Segmental pulmonary vein (PV) isolation has been performed to eliminate paroxysmal atrial fibrillation (AF). However, this technique is not effective in most patients with persistent AF. Left atrial catheter ablation (LACA) was performed by encircling the left- and right-sided PV 1-2 cm from the ostia, guided by an electroanatomical mapping system in 16 patients with persistent AF (>1 month). Twelve patients (75%) had a history of unsuccessful transthoracic cardioversion and prophylactic antiarrhythmic drugs. Ablation lines were also created in the mitral isthmus and posterior LA. PV isolation was also performed for each PV if there were residual PV potentials after the LACA. After LACA, 38 PV (59%) were completely isolated, and complete PV isolation was achieved with only a few radiofrequency energy applications (2.7+/-2.0 min) on a narrow area of the PV ostium (24+/-15%) in the remaining PV. The mean procedure time was 200+/-38 min. During the follow-up period (17+/-3 months), 12 patients (75%) had normal sinus rhythm and were free of symptomatic AF with (n = 10) or without antiarrhythmic drugs (n = 2). One patient had a stroke just after the procedure. No other complications including PV narrowing (>50%) occurred. This approach was effective in persistent AF, however, concomitant use of antiarrhythmic drugs was often required.

Response of pulmonary vein potentials to burst pacing.

Pulmonary vein potentials recorded at the ostia of pulmonary veins (PV) are a useful guide for segmental isolation of the PV in patients with atrial fibrillation (AF). Even during coronary sinus pacing at 600 ms, atrial (A) and PV potentials can overlap in 50-60% of patients making the accurate identification of PV potentials very difficult. Nineteen patients (M:F 15:4) with paroxysmal AF underwent segmental isolation of one or more PV. Coronary sinus (CS) pacing was performed at cycle lengths of 600/550/500/450/400/350/300 ms and bipolar electrograms were recorded from the 10 or 20 pole Lasso catheter placed at the atrial-PV junction in 27 pulmonary veins. Stimulus (S) to A, S-PVP and A-PVP intervals were measured during CS pacing at the different cycle lengths at sweep speed of 200 mm/sec. During CS pacing at 600 ms the A and PV potentials were significantly overlapped (A-PVP < or = 25 ms) in 15 of 27 (55%) veins. During pacing at 300 ms, the A and PV potentials were significantly separated (A-PVP > or = 25 ms) in 9 of the 15 veins where A and PV potentials overlapped and 21 of all 27 (78%) veins. In two patients pacing at 300 ms was associated with 2:1 conduction block from atrial to PV fascicle. Coronary sinus pacing at cycle length of 300 ms demonstrated better separation of A and PV potentials compared to pacing at 600 ms. This strategy is easier and less time consuming compared to extrastimuli testing. It also confirms that the electrophysiological properties of PV fascicles are different from that of the adjacent atrial musculature.

"Dormant" pulmonary vein conduction revealed by adenosine after ostial radiofrequency catheter ablation.

The endogenous nucleoside adenosine is an important intermediate in cellular metabolism, a regulator of function in many organ systems, and a pharmacologic agent with potent electrophysiologic effects. We studied the effects of adenosine on the activation of the pulmonary veins (PVs) after successful ostial isolation in patients with atrial fibrillation (AF). Twenty-nine patients (21 male; mean age 54 +/- 10 years) with refractory highly symptomatic persistent (n = 9) or paroxysmal (n = 20) AF were included in the study. PV isolation was performed using radiofrequency catheter ablation guided by a multipolar basket catheter (Constellation, Boston Scientific). After successful PV isolation, we studied the effects of intravenous adenosine (12-18 mg) on activation of the upper PVs. A total of 83 PVs were successfully isolated. After adenosine, PV activity was recorded in 10 (34%) of 29 left upper PVs studied and in 3 (13%) of 24 right upper PVs, coupled to atrial activity for 20 +/- 7 seconds (adenosine positive). In 8 (62%) of 13 cases, PV potentials were recorded in the distal electrodes of the basket catheter only. Dissociated PV rhythms (N = 8) present after PV isolation disappeared after adenosine for 18 +/- 7 seconds, even if reconduction was missing. In 14 patients (48%), a second EP study was performed for recurrence of AF. Adenosine-positive PVs had a nonsignificant higher rate of recovery of conduction than adenosine-negative veins (71% vs 35%, P = 0.095). Adenosine induces transient conduction in 25% of PVs following successful isolation. Further studies are necessary to determine the physiologic or pathophysiologic role of adenosine-induced reconduction in human hearts or other organ systems.

Electrical current-induced atrial and pulmonary vein action potential duration shortening and repetitive activity.

The influence of threshold electrical currents (EC) during regular drive on pulmonary vein (PV) and atrial myocardial cell action potential (AP) duration (APD) is unknown. We determined the effects of EC on cellular APD of PV, atria, and ventricles in isolated perfused and superfused male rat hearts (Fisher-344 strain, 3-4 mo old) at 37 degrees C (n = 14). We determined APD changes caused by subthreshold and threshold EC synchronized with a distant pacing electrode and delivered nearby cells from which transmembrane APs were recorded with a glass microelectrode. Progressive APD shortening (P < 0.001) and membrane hyperpolarization (P < 0.05) developed over a 20-s interval in the PV and atrial cells when the EC was delivered at <2 mm but not at >4 mm from the microelectrode. No such effects were seen in ventricular muscle cells. APD fully recovered 25 s after the cessation of EC application. Premature stimuli applied during EC-induced shortening of the APD caused rapid repetitive PV and atrial activity lasting two to five beats. Atropine (2 microM, n = 10) prevented, whereas propranolol (2 microM, n = 5) had no effect, on EC-induced APD shortening or repetitive activity. We conclude that EC shortens the APD and hyperpolarizes the membrane by local release of acetylcholine and causes the steep repolarization gradient in the vicinity of the current source leading to repetitive activity in atrial and PV cells during premature stimulation.

Pulmonary vein potentials and atrial fibrillation in human hearts

Pulmonary vein potentials and atrial fibrillation in human hearts

P-024 Interpretation of pulmonary vein potentials by different-site pacing in patients with paroxysmal atrial fibrillation

P-024 Interpretation of pulmonary vein potentials by different-site pacing in patients with paroxysmal atrial fibrillation

P-024 interpretationof pulmonary vein potentials by different-site pacing in patients with paroxysmal atrial fibrillation

P-024 interpretationof pulmonary vein potentials by different-site pacing in patients with paroxysmal atrial fibrillation

Atrial fibrillation: mechanistic insights from biatrial (and triatrial) mapping.

Percutaneous radiofrequency ablation of pulmonary vein potentials has been shown to eliminate atrial fibrillation in a subset of patients characterized by frequent and repetitive paroxysms of atrial fibrillation. However, pulmonary vein disconnection has had only limited success at curing patients with persistent atrial fibrillation. In those patients, left atrial substrate modification and linear ablation strategies have had substantially higher success rates. Furthermore, in other patients, elimination of right atrial triggers (superior vena cava) or modification of right atrial substrate has been required for elimination of atrial fibrillation. Finally, the realization that the coronary sinus is a third atrial chamber that can both initiate and maintain atrial fibrillation has provided new understanding to the pathogenesis of atrial fibrillation. From a clinical perspective, only careful anatomic and mapping strategies specifically aimed at each subset of patients with atrial fibrillation will allow for pattern recognition and establish which mechanisms are responsible for initiation and maintenance of atrial fibrillation. Only the latter will allow for increased long-term success rates of ablation of atrial fibrillation.

Feasibility and Safety of Pulmonary Vein Isolation Using a New Mapping and Navigation System in Patients With Refractory Atrial Fibrillation

Ostial pulmonary vein (PV) isolation by radiofrequency (RF) catheter ablation can cure patients with atrial fibrillation (AF); however, this procedure carries the risk of PV stenosis. The aim of this study was to assess the feasibility of a new mapping and navigation technique using a multipolar basket catheter (BC) for PV isolation in patients with refractory AF and to analyze its safety with regard to PV stenosis at long-term follow-up. We studied 55 patients (mean age, 53+/-11 years; 40 male) with drug-refractory AF (paroxysmal, n=37; persistent, n=18). A 64-pole BC was placed transseptally into each of the accessible PVs. By use of a nonfluoroscopic navigation system, the ablation catheter was guided to the BC electrodes at the PV ostium, with earliest activation during sinus rhythm. RF was delivered by use of maximum settings of temperature at 50 degrees C and power at 30 W. The end point of the procedure was the complete elimination of all distal and fragmented ostial PV potentials. Of 165 targeted veins, 163 were successfully isolated with a mean RF duration of 720+/-301 seconds per vein. At 1-year follow-up, 62% of the patients were in sinus rhythm without antiarrhythmic drugs. Contrast-enhanced magnetic resonance angiography revealed 2 PV stenoses of >25% out of 165 treated vessels. The use of a multipolar BC allowed effective and safe PV isolation by combining 3D mapping and navigation. At 1-year follow-up, 62% of the patients were in sinus rhythm without antiarrhythmic drugs, and the incidence of relevant diameter reduction of the treated PVs was 1.2%.

Pulmonary vein isolation using transvenous catheter cryoablation for treatment of atrial fibrillation without risk of pulmonary vein stenosis

ObjectivesWe sought to evaluate the efficacy and safety of pulmonary vein (PV) isolation using transvenous cryoablation for the treatment of atrial fibrillation (AF). BackgroundAlthough electrical isolation of PVs with radiofrequency energy for the treatment of AF is feasible, it is associated with a significant risk of PV stenosis. Cryoablation is a new alternative therapy allowing ablation of tissue while preserving its underlying architecture. MethodsIn 52 patients with paroxysmal (n = 45) or persistent (n = 7) AF, PV isolation using the CryoCor cryoablation system (CyroCor Inc., San Diego, California) with a 10F deflectable transvenous catheter was performed as guided by ostial PV potentials. Cryoablation was applied twice at each targeted site (2.5 to 5 min/application). Computed tomography (CT) of the thorax was performed at baseline and at 3 and 12 months to evaluate for PV stenosis. ResultsAll targeted PVs were completely isolated in 49 (94%) of 52 of patients. Of 152 PVs targeted, 147 (97%) were successfully isolated (mean 3.0 PVs isolated per patient). After a mean period of 12.4 ± 5.5 months of follow-up, 37 (71%) of 52 patients had no recurrence of AF or were clinically improved, including 29 patients (56%) who had no recurrence of AF with (n = 11) or without the use of anti-arrhythmic drugs. At 3 and 12 months, the CT scan showed no evidence of PV stenosis associated with cryoablation in any patients. ConclusionsTransvenous catheter cryoablation is an effective method to create PV electrical isolation for the treatment of AF. A clinically satisfactory result can be achieved in 71% of patients with AF, without the risk of PV stenosis.

Circumferential mapping and electric isolation of pulmonary veins in patients with atrial fibrillation

Information about the clinical efficacy and complications of the circumferential mapping and isolation of the pulmonary veins (PVs) in patients with atrial fibrillation (AF) is still limited. The present study included 75 patients (mean age 58 ± 11 years, 20 women) with paroxysmal (n = 69) or persistent AF (n = 6). Mapping of PVs was performed with a circumferential mapping catheter. After preferential PV–left atrium (LA) electric inputs were defined, radiofrequency ablation was performed until complete isolation of the PVs from the LA was achieved. A total of 226 PVs were mapped; 195 (86%) showed typical PV potentials. Complete isolation of PVs from the LA was achieved in 173 PVs (89%). Detailed follow-up, including 7-day Holter monitoring at 1, 4, 9, and 12 months after intervention was performed. If AF reoccurred, PVs were mapped and reisolated. After a mean follow-up period of 230 ± 133 days, 38 of 75 patients (51%) were in sinus rhythm. At 1, 4, and 9 months of follow-up, 31 of 65 patients (48%), 36 of 53 patients (68%, p = 0.04 as compared with the first month), and 21 of 28 patients (75%, p = 0.025 as compared with the first month), respectively, were in sinus rhythm. During follow-up, 30 patients (40%) underwent a second ablation procedure due to recurrence. Recurrences were related to resumption of PV muscle–left atrial conduction (27 patients) and/or extra PV foci (12 patients) or nonablated PVs (8 patients). Complications occurred in 17 patients (22%). PV stenosis was detected in 13 patients (25% to 50% in 7 patients and >50% in 6 patients). Pericardial effusion occurred in 4 patients. It was concluded that isolation of the PV from the LA is moderately effective in the prevention of AF recurrence and could be associated with serious acute and long-term complications.

Comparison of amiodarone versus ibutilide for the prevention of immediate recurrences of atrial fibrillation during pulmonary vein isolation

During segmental ostial ablation for pulmonary vein isolation, pulmonary vein potentials are easily identified during sinus rhythm or left atrial pacing. Therefore, maintenance of atrial fibrillation (AF) during the procedure is desirable. However, cardioversion is occasionally followed by an immediate recurrence of AF. This study compared the efficacy of ibutilide and amiodarone in preventing immediate recurrences of AF in patients who underwent pulmonary vein isolation. The subjects of this study were 25 patients (mean age 56 ± 10 years) who underwent pulmonary vein isolation for AF who had an immediate recurrence of AF within 60 seconds after 2 transthoracic cardioversions. The patients were randomized to receive an infusion of either 300 mg of amiodarone over 10 minutes or 1 mg of ibutilide over 5 minutes. Cardioversion was repeated 15 minutes after the drug infusion. If immediate recurrences of AF occurred 2 more times, the alternative study drug was administered, and cardioversion was repeated. Immediate recurrences of AF were suppressed by amiodarone in 8 of 10 patients (80%), and by ibutilide in 9 of 15 patients (60%, p = 0.4). After crossover, immediate recurrence of AF was suppressed in 2 of 6 patients (33%) by amiodarone, and in 1 of 2 patients (50%) by ibutilide (p = 0.6). Ibutilide and amiodarone, when used alone or in combination, prevented immediate recurrences of AF in 20 of 25 patients (80%). There were no adverse drug effects. Ibutilide and amiodarone were equally effective in suppressing immediate recurrences of AF. Overall, immediate recurrences of AF can be prevented by amiodarone and/or ibutilide in 80% of patients.

Mechanistic significance of intermittent pulmonary vein tachycardia in patients with atrial fibrillation.

The significance of intermittent tachycardia within a pulmonary vein (PV) during an episode of atrial fibrillation (AF) is unclear. The aim of this study was to determine the role that intermittent PV tachycardias play in AF. In 56 patients with AF, segmental ostial ablation guided by PV potentials was performed to isolate the PVs. The characteristics of intermittent PV tachycardias and the inducibility of AF before and after PV isolation were analyzed prospectively. During AF, a PV tachycardia (mean cycle length 130 +/- 30 msec) with exit block to the left atrium was present in 93% of left superior, 80% of left inferior, 73% of right superior, and 7% of right inferior PVs. The site of shortest cycle length during AF alternated between the PVs and left atrium 1 to 13 times per minute. Complete isolation was achieved in 168 (94%) of 178 targeted PVs. In 99% of PVs, tachycardia resolved upon isolation. AF was persistent before and after PV isolation in 100% and 27% of patients, respectively (P < 0.001). Intermittent bursts of tachycardia are observed within multiple PVs during persistent AF in a majority of patients. After PV isolation, PV tachycardias almost always resolve, and AF is less likely to be inducible or persistent. These observations suggest a dynamic interplay between the atria and PVs, with intermittent bursts of PV tachycardia being dependent on left atrial input and with the probability of persistent AF diminishing when PV tachycardias are eliminated by PV isolation.

Left Atrial Appendage Activity Masquerading as Pulmonary Vein Potentials

Despite extensive proximal ablation, all potentials frequently cannot be eliminated from the left pulmonary veins (PV). Methods and Results- PV electrograms were analyzed during sinus rhythm, coronary sinus, and left atrial appendage (LAA) pacing, and PV and LAA angiography performed. During pacing, an initial low-amplitude slow potential was recorded on the anterior aspect of the left superior PV and anticipated with shortest activation time by LAA pacing. Its timing coincided with posterior LAA activation, shown to be immediately adjacent to the left superior PV by angiography. In the left inferior PV, the first potential was smaller and less sharp, coinciding with adjacent low LA activation. Angiographically, the LAA was at least 15 mm from the left inferior PV. The second sharper potential in both left PVs was eliminated by proximal ablation. Far field LAA activity consistently adds to PV myocardial electrograms in the left superior PV whereas lower, less sharp extravenous potentials in the left inferior PV originate from the inferior LA. They can be identified by LAA and coronary sinus pacing.

Electrical Connections Between Pulmonary Veins

Electrical disconnection of the myocardial extensions into arrhythmogenic pulmonary veins (PVs) is recognized as a curative technique for paroxysmal atrial fibrillation (AF). However, the presence of electrical connections between the PVs, which may make achievement of PV disconnection difficult, has not been systematically evaluated. Forty-nine consecutive patients with drug-resistant AF underwent ostial radiofrequency (RF) catheter ablation of arrhythmogenic PVs with foci triggering AF. Pacing from inside the targeted PV was performed after each RF delivery to identify the left atrial exit site of the residual venoatrial conduction. Successful PV disconnection was defined as achieving elimination of the PV potentials during sinus rhythm or left atrial pacing, and the loss of left atrial conduction during intra-PV pacing. A total of 112 arrhythmogenic PVs were identified. PV disconnection was achieved with 10+/-6.1 minutes of RF delivery to the ostia of 101 targeted PVs. In 7 left superior (LS) PVs from 7 patients (14%), the earliest atrial activity was recorded from the left inferior (LI) PV ostium during intra-LSPV pacing after 11+/-4.7 minutes of RF delivery to the LSPV ostium. Disconnection of these LSPVs was achieved by LIPV disconnection. In the remaining 4 PVs from 4 patients, PV disconnection could not be achieved. Fourteen percent of the patients had electrical connections between contiguous PVs. In these patients, ostial ablation of an untargeted PV was required for successful targeted PV disconnection.

Pulmonary vein isolation during minimally invasive mitral valve surgery: one-year follow-up

geted for PV isolation. Circumferential PV electrogrems around the PV ostium were acquired simultaneously using a circular catheter and used to guide ablation at ostial sites with the earliest PV potentials during sinus rhythm or coronary sinus pacing. Radiofrequency ablation was performed at 50 C and 20-30 W, The endpoint was the elimination of either AF (42 patients) or atrio-PV conduction based on the abolition of distal PV potentials (38 patients). Results: Focal ablation, PV isolation or both were performed in 42, 19 and 19 patients, respectively. Of the 104 foci identified, 94 triggers (90%) originated from the PV single in 47% and multiple in 53% and 10 originated from the atrial tissue. AF recurred in 42 patients and re-ablation was performed in 24:7 from the same source, 3 from non-PV foci, 2 from a different part of the same PV, 2 from a different PV, 2 from PV ostia proximal to the previous PV isolation, and 8 due to recovery of atrio-PV conduction. During a mean follow-up of 14 ± 9 months, the clinical success rate with combined therapy (69%) was significantly higher than those with focal ablation (57%) or PV isolation (53%) without drugs (p < 0.05). No PV stenosis was observed. Conclusions: Focal ablation did not prevent AF by another focus in the same PV or other PVs. The success rate of PV isolation is relatively low, probably due to unmasked foci from the PV ostial edge or atrial tissue. Combined treatment with focal ablation and PV isolation is more effective for treating AF than either approach alone.

Elimination of pulmonary vein potentials for catheter ablation of focal atrial fibrillation guided by noncontact mapping: comparison of two different approaches

Elimination of pulmonary vein potentials for catheter ablation of focal atrial fibrillation guided by noncontact mapping: comparison of two different approaches

Clinical significance of residual pulmonary vein potentials after pulmonary vein isolation in patients with paroxysmal atrial fibrillation

Clinical significance of residual pulmonary vein potentials after pulmonary vein isolation in patients with paroxysmal atrial fibrillation