Electrical Isolation Of Pulmonary Veins Research Articles

Use of a diode laser balloon ablation catheter to generate circumferential pulmonary venous lesions in an open-thoracotomy caprine model.

Electrical isolation of the pulmonary veins (PVs) can be curative in certain patients with atrial fibrillation. The ability of a diode laser balloon ablation catheter to isolate PVs was assessed in an open-thoracotomy caprine model system. After a median sternotomy, the left atrial appendage was cannulated in 19 goats. A laser balloon catheter was placed at the PV ostia and used to deliver photonic energy to the periostial tissue. The applications were delivered at 3.7, 4.5, or 5.4 W/cm for 90-150 seconds. Electrical continuity of the PV with the left atrium was assessed using a multielectrode mapping catheter. After a single application of photonic energy, electrical isolation of the PVs was achieved in (70%) 19/27 PVs. However, the success of electrical PV isolation did not correlate with the dose or duration of the applications. When reflectance spectroscopy was utilized to ensure adequate orientation and contact of the laser balloon catheter with the left atrial myocardium, complete PV isolation was achieved in 5/5 veins at 3.5 W/cm for 120 seconds. Pathological examination revealed no PV stenosis, no pericardial damage, minor lung lesions without pleural perforation, minimal endothelial disruption, and, in the presence of adequate heparinization, no endocardial charring or overlying thrombus. Effective isolation of the PVs can be achieved by delivery of a continuous circular beam of photonic energy to ablate the left atrial - pulmonary venous junction. The use of reflectance spectroscopy to provide real-time monitoring of the blanching effect of balloon-tissue contact optimizes lesion delivery.

A08-3 Circumferential mapping and electric isolation of pulmonary veins in patients with atrial fibrillation: mid term follow-up results

A08-3 Circumferential mapping and electric isolation of pulmonary veins in patients with atrial fibrillation: mid term follow-up results

A08-3 Circumferential mapping and electric isolation of pulmonary veins in patients with atrial fibrillation: mid term follow-up results

A08-3 Circumferential mapping and electric isolation of pulmonary veins in patients with atrial fibrillation: mid term follow-up results

A35-2 Electrophysiologic effects of adenosine on the pulmonary vein activity and atrio-venous conduction after electrical isolation of the pulmonary veins

A35-2 Electrophysiologic effects of adenosine on the pulmonary vein activity and atrio-venous conduction after electrical isolation of the pulmonary veins

P-287 Pulmonary vein common ostium in patients with atrial fibrillation: A major target for pulmonary vein electrical isolation?

The existence of pulmonary vein (Pv) common ostia in pts with atria1 fibrillation (AF) could suggest a more complex and arrhythmogenic substrate. The aim of this study was to evaluate the prevalence and signiiicance of this anatomic variant in AF pts. Methods: We considered 43 pts (33 males; age 53S p<O.OOOl). EI of arrhythmogenic and non-mhythmogenic PVs (except the right inferior PV that was treated only if involved in arrhyhnogenesis) was achieved with a mean radiofrequency energy delivery of 21&18 min. At a mean follow-up of 5.5&3 months, AF recurred (without antr p: IX). Conclusions: A PV common ostium is frequently documented in pts with AF. Since it is often involved in arrhythmogenesis, it represents a major target for PVEI procedures. Longer follow-up data are required to assess the clinical relevance of this finding.

P-287 Pulmonary vein common ostium in patients with atrial fibrillation: A major target for pulmonary vein electrical isolation?

P-287 Pulmonary vein common ostium in patients with atrial fibrillation: A major target for pulmonary vein electrical isolation?

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.

Intracardiac Doppler echocardiographic quantification of pulmonary vein flow velocity: an effective technique for monitoring pulmonary vein ostia narrowing during focal atrial fibrillation ablation.

Ablation at the pulmonary vein (PV) ostium to isolate triggers for atrial fibrillation (AF) may induce PV narrowing. The AcuNav ultrasound catheter can image PV flow and quantify peak velocity and may be useful in assessing the degree of narrowing of PV ostia. In 93 patients with AF undergoing PV ostial ablation (up to 40 W, 52 degrees C, 90 sec), the ultrasound catheter was placed in the right atrium and PV peak flow velocities were measured during systole and diastole before and after ablation. Ostial PV electrical isolation was achieved in 216 of the 219 targeted PVs. The ultrasound catheter provided flow imaging of all PVs. The ostial peak flow velocities measured 56 +/- 12 cm/sec before ablation and increased to 101 +/- 22 cm/sec after ablation (P < 0.001). Peak velocity >100 cm/sec was detected in 103 (47%) of 219 and > or = 158 cm/sec (estimated pressure gradient 10 mmHg) with turbulent flow features, in 7 (3.2%) of 219 PVs. The highest velocity detected in one PV was 211 cm/sec (17.7 mmHg). Follow-up ultrasound catheter measurements were obtained in 13 patients (30 previously ablated PVs) during repeat ablations. The ostial peak velocity had decreased by 22 +/- 14 cm/sec and in 25 (83%) of 30 PVs was within the baseline range (<100 cm/sec) at a mean follow-up of 4.9 +/- 2.2 months. Follow-up magnetic resonance imaging (MRI) or contrast-enhanced CT was obtained at 7.0 +/- 3.8 months in seven patients with PV velocity > 158 cm/sec after initial ablation. No significant stenosis (<30%) was identified, and no patient suffered clinical symptoms (follow-up 6-18 months) related to the described acute changes in PV flow after an initial ablation procedure. Of 13 patients with repeat ablation, two had PV velocities >100 cm/sec before repeat ablation, and three PVs in two patients had flow velocity >158 cm/sec after repeat ablation. One of these patients developed symptoms of exertional dyspnea; MRI at 4 months showed 50% to 60% ostial narrowing. Ostial ablation for PV isolation may induce a mild-to-moderate increase in PV flow velocity, which can be identified using an ultrasound catheter with Doppler color flow imaging. Increases in PV flow velocity (<158 cm/sec) after a primary ablation procedure appear to be well tolerated, and a return toward baseline flow characteristics should be anticipated by 3 months. A more cautious approach may be required for patients undergoing repeat PV isolation.

Intracardiac echocardiography-guided, anatomically based radiofrequency ablation of focal atrial fibrillation originating from pulmonary veins

ObjectivesIn patients with a pulmonary vein (PV) source for atrial fibrillation (AF), we sought the use of intracardiac echocardiography (ICE) to evaluate PV anatomy, guide radiofrequency (RF) ablation and monitor for acute stenosis during ablation. BackgroundA focal source for AF may be found in the proximal component of the PVs and can be effectively treated by ablative techniques. However, the procedure may be challenging due to the complex anatomy of the left atrium and PVs, uncertain catheter positioning within the PVs and difficulties in mapping atrial extrasystoles, which may be rare or repeatedly induce AF and require cardioversion. MethodsSixty-four patients were referred for RF ablation of a focal source of AF, and 56 were identified as having AF triggers in ≥1 PV. Using ICE guidance, RF lesions were applied around the circumference of the vein near the os until there was electrical isolation. ResultsLesions were placed in 82 veins (36 right superior PV, 33 left superior PV, 9 left inferior PV, 4 right inferior PV); 24 ± 12 lesions per vein were necessary to create electrical isolation with a fluoroscopic time of 11 ± 4 min and a mean of 22% reduction in luminal area. After a follow-up of 13 ± 7 months, 66% of patients remained free of AF, and another 13% responded better to medications. ConclusionsWe describe an anatomic approach to PV electrical isolation in which ICE is used to define the anatomy, guide RF ablation and monitor for acute PV changes.

Immediate and long‐term results of radiofrequency ablation of pulmonary vein ectopy for cure of paroxysmal atrial fibrillation using a focal approach

Atrial fibrillation (AF) is frequently initiated by focal activity originating in the pulmonary veins. We present the early and long-term results of a focal approach to pulmonary-vein ablation for cure of paroxysmal AF. The aim of this study was to establish the effectiveness of focal pulmonary vein radiofrequency ablation (RFA) for cure of paroxysmal AF. Fifty-one consecutive patients (35 male; 45+/-11.4 years) were considered for RFA on the following criteria: (i) symptomatic drug refractory AF, (ii) high-density atrial ectopy, bursts of atrial tachycardia or AF, (iii) absence of structural heart disease and (iv) provision of informed consent. Pulmonary vein mapping and RFA were by single trans-septal puncture, which was only performed in patients with adequate focal activity at the time of procedure. Focal activity was present spontaneously or was elicited by isoprenaline, burst pacing or AF induction and cardioversion. One patient was excluded from the analysis due to non-pulmonary vein triggers. Trans-septal mapping and RFA were not performed in 22 patients (44%) due to: (i) inadequate ectopy (17), (ii) recurrent AF (1), (iii) inability to cross septum (2) and (iv) multiple foci (2). Of 28 patients, RFA was attempted with procedural success in 23 patients (82%), with no acute complications. Mean fluoroscopy time for patients having RFA was 29+/-11.5 mins. Pulmonary vein stenosis occurred in one case. Ten patients had symptomatic recurrence and, of those, two had further RFA. At a mean follow up of 11+/-8 months, 15 patients (54% ablated, 30% of the total cohort) remained free of AF without antiarrhythmics. This series highlights the low long-term success rate of RFA to cure AF by targeting pulmonary vein initiators using a focal approach. Electrical pulmonary vein isolation may provide better long-term results.

Empirical pulmonary vein isolation in patients with chronic atrial fibrillation using a three-dimensional nonfluoroscopic mapping system: long-term follow-up.

The purpose of this study was to assess the feasibility and long-term results of empirical isolation of both superior pulmonary veins in patients with chronic AF. Although localizing and ablating the focal triggers of AF has been proven an effective approach, this strategy is time consuming, often requires multiple procedures, and carries the risk of pulmonary vein stenosis. Whether ostial electrical isolation of the superior pulmonary veins, without initial detailed mapping, is a more efficient approach is not known. The study included 71 consecutive patients who had chronic AF. Using a nonfluoroscopic electroanatomic mapping system, the left and right superior pulmonary veins were ablated circumferentially at the venoatrial junction, with the aim of achieving electrical isolation of the veins. Following ablation, if frequent atrial ectopies were present, mapping and ablation were considered. The patients were periodically followed with 48-hour Holter and loop recorder monitoring. After the ablation of the right and left superior pulmonary veins 59 (83%) of 71 patients maintained sinus rhythm without premature atrial beats. The remaining 12 patients underwent further mapping and ablation including 5 patients who required isolation of the left inferior pulmonary veins. True electrical isolation could be achieved only in 45 (31%) of the 147 targeted veins. At the latest follow-up (mean 29 +/- 8 months), 80% of the patients with upper vein isolation remained in sinus rhythm off medications, 62% of the patients maintained sinus rhythm on previously ineffective medications, and 17% continued to be in AF. Fourteen (20%) patients developed intermittent episodes of left atrial flutter, and mapping in these patients revealed large electrically silent areas in the left atrium. Empirical isolation of pulmonary veins appeared to be an effective approach to help maintain sinus rhythm in patients with chronic AF. True electrical isolation of the pulmonary veins was associated with a higher likelihood of long-term success. Left atrial flutter was seen in a significant number of patients at long-term follow-up.

Pulmonary vein electrical isolation for control of atrial fibrillation: Can one vein suffice? David Schwartzman. Atrial Arrhythmia Center, University of Pittsburgh, Pittsburgh, PA

Pulmonary vein electrical isolation for control of atrial fibrillation: Can one vein suffice? David Schwartzman. Atrial Arrhythmia Center, University of Pittsburgh, Pittsburgh, PA