Segmental Ostial Ablation Research Articles

Pulmonary venous isolation by antral ablation with a large cryoballoon for treatment of paroxysmal and persistent atrial fibrillation: medium-term outcomes and non-randomised comparison with pulmonary venous isolation by radiofrequency ablation

BackgroundTo prevent atrial fibrillation (AF) recurrence after catheter ablation, pulmonary venous isolation (PVI) at an antral level is more effective than segmental ostial ablation. Cryoablation around the pulmonary venous (PV)...

A 50-Year-Old Woman With a History of Atrial Fibrillation Presents With Acute Dyspnea and Pleuritic Chest Pain

A 50-Year-Old Woman With a History of Atrial Fibrillation Presents With Acute Dyspnea and Pleuritic Chest Pain

Segmental pulmonary vein isolation in atrial fibrillation: new insights from the high density mesh mapper technique in an electrophysiologically guided approach

As opposed to fundamental investigations into the nature of atrial fibrillation (AF) current clinical studies of AF ablation techniques sometimes only contain sparse information about the underlying electrophysiological properties. The purpose of this prospective, pilot study was to evaluate acute therapeutic success and clinical outcome after 6 month of segmental ostial ablation (SOA) using the High Density Mesh Mapper catheter (HDMM, BARD Electrophysiology, Lowell, MA, USA) for an electrophysiological guided approach. The HDMM is a novel, single expandable basket electrode catheter for high resolution recordings at the left atrium/pulmonary vein (PV) junction. SOA was performed by irrigated radiofrequency (RF) application around the HDMM. Entry- and exit conduction block, as well as decreased local electrode amplitude, were endpoints for short-term successful ablation. Seventy-two patients with highly symptomatic paroxysmal AF (PAF; 47, 65.2%), persistent AF (12, 16.7%) and permanent AF (13, 18.1%) were studied. Entrance conduction block was obtained in 93%, exit conduction block in 81% of all PV. After 6 month no PV stenosis was observed, 62 patients (86.1%) improved clinically, whereas 52 patients (72.2%) were free from arrhythmias and sinus rhythm was present favoring patients with PAF. In this first prospective study of PV isolation using the HDMM, our findings suggest, that this method is safe and yields good primary success rates and favourable clinical outcome at 6 month. The new technology based on high resolution recordings, offers beside good anatomical orientation a direct electrophysiological control for monitoring of bidirectional conduction block.

Incidence of Adenosine-Induced Pulmonary Vein Reconnection Following Catheter Ablation of Paroxysmal Atrial Fibrillation

Introduction: Adenosine has significant effects on cellular electrophysiology. Previous studies have shown recovery of pulmonary venous (PV) potentials following exogenous administration of adenosine after apparently successful pulmonary venous isolation in 25–56%of veins. The population studied and method and site of ablation may influence the rate of PV reconnection. We sought to characterise adenosine-induced reconnection in a homogeneous group of patients undergoing first catheter ablation for paroxysmal atrial fibrillation utilising three-dimensional mapping systems. Methods: The effect of intravenous adenosine following successful isolation of 64 veins in 17 patients with paroxysmal AF (15male) was studied. Segmental ostial ablation was performed with an irrigated catheter at the venoatrial junction guided by circular mapping catheter and a three-dimensional mapping system. Intravenous adenosine (12–24mg) was administered 20min post-isolation during coronary sinus pacing to achieve at least one nonconducted atrial paced beat. (LVH; wall thickness range 1.4–2.4 cm) and left atrial (LA) enlargementwerepresent in all cases. LV systolic dysfunctionwaspresent in 2/5.Nopatients had lowECG limb lead voltages, neither did any have ECG evidence of LVH by voltage criteria. On the presenting ECG, 4/5 had either AF (1/5), intraventricular conductiondelay (2/5) orfirst degree AV block (2/5). At presentation 1/5 was in chronic AF. During a mean follow-up of 24± 11 months 4/5 developed AF and 3/5 required permanent cardiac pacing for symptomatic heart block. AF was chronic in 3 and paroxysmal in 1. In 2/4 TEE guided AF cardioversion was attempted andbothhadpoorLAappendageemptyingvelocitieswith spontaneous LA echo contrast. Non-cardiac symptoms due to SCA were rare with painful peripheral neuropathy in 2/5. One patient died from progressive heart failure. Conclusion: SCA may be suspected by the presence of echocardiographic LVH without hypertension nor ECG evidence of LVH in an elderly male presenting with shortness of breath. The development of AF and/or heart block appear common during medium term follow-up.

Selective segmental ostial ablation and circumferential pulmonary veins ablation. Results of an individualized strategy to cure refractory atrial fibrillation

Previous studies have analyzed the efficacy of atrial fibrillation (AF) ablation in series of consecutive patients or comparing methods in a randomized way, without taking account individual patient characteristics. The purpose of this study was to evaluate the results of a strategy based on selecting the ablation method according to patient clinical features in drug-refractory paroxysmal or persistent AF. Patients with left atrial diameter < or =40 mm and runs of atrial tachycardia of more than ten beats during Holter recording were selected for selective segmental ostial ablation (SSOA) in order to disconnect only those pulmonary veins with electrical potentials. The remaining patients underwent circumferential pulmonary veins ablation (CPVA) to modify left atrial substrate by extensive linear lesions. A group of 131 consecutive patients were included. Mean follow-up was 21.5 +/- 15.2 months. In paroxysmal AF, 44 and 55 patients were selected for SSOA and CPVA, respectively, and the efficacy of the procedure was similar in the two groups (77 vs 74%; log-rank test p = NS). In persistent AF, 6 and 26 patients underwent SSOA and CPVA, respectively, and greater efficacy was observed in the second group (17 vs 65%; log-rank test p = 0.004). Selecting the ablation method according to patient characteristics achieved good results and reduced the overall amount of ablated atrial tissue in patients with paroxysmal AF. However, in persistent AF the SSOA technique showed very limited efficacy despite the previous patient selection and a CPVA-like procedure may be the appropriate choice in all cases.

AB27-1: Incidence of asymptomatic cerebral embolism associated with cooled-tip pulmonary vein ablation. A study using segmental ostial ablation and cerebral diffusion-weighted magnetic resonance imaging

Diffusion-weighted magnetic resonance imaging (DW-MRI) has shown to be highly sensitive for detection of acute ischemic lesions associated with catheter based interventions. Aim of this study was to examine the incidence of clinically silent cerebral embolism 2nd to segmental ostial pulmonary vein (PV) ablation in a large group of patients (pt).

Different Patterns of the Fall of Impedance as the Result of Heating During Ostial Pulmonary Vein Ablation: Implications for Power Titration

A variety of strategies have been proposed to avoid the risks of pulmonary vein ablation for atrial fibrillation. The fall of impedance during radiofrequency catheter ablation can be used as a real time measure of tissue heating. The aim of this study was to analyze the impedance fall during ostial pulmonary vein ablation and to evaluate whether adjusting power to the fall of impedance may contribute to a reduction of the risk of complications. Analysis of biophysical parameters of ablation and determination of ostial diameters during follow-up were performed in 70 patients undergoing impedance-guided segmental ostial pulmonary vein ablation. Repeat radiographic angiography, local electrograms, and baseline impedance were the criteria to define the position of the 4-mm electrode tip at atrial sites or inside the proximal pulmonary veins. Energy application inside the proximal pulmonary veins led to an increased impedance fall inside the first 5-10 mm of the pulmonary veins (1.1 +/- 0.5 Omega/W) as compared to ablation at atrial sites (0.7 +/- 0.3 Omega/W) (P < 0.01). The analysis of temperature and impedance fall during ostial ablation demonstrated an increased impedance fall with heating at sites inside the proximal pulmonary veins (1.5 +/- 0.6 Omega/ degrees C) as compared to atrial sites (1.2 +/- 0.5 Omega/ degrees C) (P < 0.001). The regression lines analyzing these correlations indicated that adjusting power to a maximum impedance fall of 20 Omega would limit heating at pulmonary venous sites to lower temperatures (average maximum temperature: 48 degrees C) than at atrial sites (average maximum temperature: 63 degrees C). The ablation strategy used for segmental ostial ablation in 70 patients, which involved power limitation to a maximum impedance fall of 20 Omega, allowed isolation of 89% of targeted pulmonary veins with a low rate of impedance rises (0.3% of applications). No pulmonary vein stenoses >30% were detected by follow-up computed tomography analysis. An increased impedance fall as the result of heating during ostial ablation was found inside the proximal pulmonary veins as compared to atrial sites. Adjusting power to the fall of impedance during segmental ostial pulmonary vein ablation contributes to the prevention of overheating inside the pulmonary veins and may lower the risk of coagulum formation and pulmonary vein stenosis.

Incidence of Pulmonary Vein Stenosis in Patients Submitted to Atrial Fibrillation Ablation: A Comparison of the Selective Segmental Ostial Ablation vs the Circumferential Pulmonary Veins Ablation

Pulmonary vein (PV) stenosis is an important complication of the AF ablation and could be underestimated if their assessment is not systematically done. Selective Segmental Ostial Ablation (SSOA) and Circunferential Pulmonary Veins Ablation (CPVA) have demonstrated efficacy in atrial fibrillation (AF) treatment. In this study the real incidence of PV stenosis in patients (pts) submitted to both SSOA and CPVA was compared. Those pts with focal activity and normal left atrial size were submitted to SSOA, remaining pts were submitted to CPVA to treat refractory, symptomatic AF. Contrast enhanced magnetic resonance angiography (MRA) was routinely performed in all patients 4 months after the procedure. A series of 73 consecutive patients (mean age of 51 +/- 11 years; 75% male) were included. SSOA was performed in 32 patients, and the remaining 41 patients underwent to CPVA, obtaining similar efficacy rates (72% vs 76% arrythmia free probability at 12 months; log rank test p = NS). Six patients had a significant PV stenosis, all in SSOA group none in CPVA group (18.8% vs 0%; p = 0.005). All patients were asymptomatic and the stenosis was detected in routine MRA. No predictors of stenosis has been identified analysing patient procedure characteristics. PV stenosis is a potential complication of SSOA not seen in CPVA. The study confirms than MRA is useful for identifying patients with asymptomatic PV stenosis.

Correlation of Symptoms to ECG Diagnosis Following Atrial Fibrillation Ablation

Currently, definition of success following atrial fibrillation (AF) ablation is commonly based on the lack of symptoms. The purpose of this study was to evaluate the correlation between symptoms and the underlying rhythm after AF ablation. Eighty consecutive patients (pts) were treated for paroxysmal episodes of AF by segmental ostial ablation of all pulmonary veins and right atrial isthmus ablation. For 6 months pts transmitted transtelephonic (T-) ECG recordings in combination with comments daily or in the event of symptoms. Eligible comments were classified as: (1) asymptomatic, (2) symptomatic. Analysis was performed at 1-month intervals, defining an acute (first month) and chronic period (second to sixth month) after ablation. Overall 6,835 T-ECGs were analyzed. Of these 5,437 (79.5%) showed sinus rhythm (SR) and 1,398 (20.5%) showed AF. Pts in SR reported symptoms for 593 (10.9%) episodes, whereas 4,844 (89.1%) episodes were asymptomatic. During AF, 646 (46.2%) episodes were associated with symptoms, and 752 (53.8%) episodes remained asymptomatic. Exclusively asymptomatic were 7 (8.8%) pts. In 30 (52.6%) of 57 pts with AF, arrhythmic events were confined to the acute phase. Of the remaining 27 pts 14 (52%) reported an improvement, 12 (44%) the same, and 1 (4%) worsened symptoms after 3 months. A significant change (P < 0.01) toward more asymptomatic episodes from the acute (43.5%) to the chronic (57.5 +/- 4.5%) period was evident. Assessment of success after AF ablation cannot be based on the absence of symptoms due to a high prevalence of asymptomatic episodes.

577 Lower efficacy of segmental ostial ablation than pulmonary veins encircling in vagal atrial fibrillation

577 Lower efficacy of segmental ostial ablation than pulmonary veins encircling in vagal atrial fibrillation

281 Incidence of asymptomatic pulmonary vein stenosis in atrial fibrillation ablation. Segmental ostial ablation versus pulmonary veins encircling

281 Incidence of asymptomatic pulmonary vein stenosis in atrial fibrillation ablation. Segmental ostial ablation versus pulmonary veins encircling

577 Lower efficacy of segmental ostial ablation than pulmonary veins encircling in vagal atrial fibrillation

577 Lower efficacy of segmental ostial ablation than pulmonary veins encircling in vagal atrial fibrillation

281 Incidence of asymptomatic pulmonary vein stenosis in atrial fibrillation ablation. Segmental ostial ablation versus pulmonary veins encircling

281 Incidence of asymptomatic pulmonary vein stenosis in atrial fibrillation ablation. Segmental ostial ablation versus pulmonary veins encircling

Cardiac CT imaging used in conjunction with a non-fluoroscopic navigation system (NavX) for atrial fibrillation ablation

Case: A 55 year old man with paroxysmal AF was referred to our center for catheter ablation of AF. Cardiac CT imaging with a 64-slice scanner was performed 1 week before the procedure. The raw imaging data was processed using proprietary software (Endocardial Solutions, MN) in order to precisely define the anatomic relationship of the left atrium, pulmonary veins, and esophagus. On the day of the procedure, the processed CT image was imported into the NavX navigation system and was used in conjunction with a NavX-generated geometric map [Figure] to guide circumferential ablation around the right and left pulmonary veins. Ablation was performed using an 8-mm tip ablation catheter, and microbubble monitoring was done with intracardiac ultrasound. Careful attention was paid to avoid ablation within the pulmonary veins, as well as near the esophago-atrial interface. Segmental ostial ablation guided by a 10-pole circular mapping catheter was then performed after circumferential ablation to ensure electrical isolation of each vein. There were no complications. At 6 months, the patient has remained free of AF as assessed by symptoms and periodic Holter monitoring.

Mechanism of focal atrial tachycardias occurring after pulmonary veins isolation

Introduction: A proarrhythmic consequence of pulmonary vein isolation (PVI) to treat atrial fibrillation can be a persistent left atrial tachycardia (LAT). We previously described that focal LATs can occur; however it is unclear whether the mechanism of these focal arrhythmias is reentry, triggered activity, or abnormal automaticity. We performed detailed pacing and pharmacologic maneuvers to determine the mechanism of focal LATs occurring after PVI. Methods: PVI was performed by segmental ostial ablation guided by a circular mapping catheter (Lasso). Patients whose recurrent arrhythmia was a LAT that persisted for more then 8 weeks returned for mapping and ablation. Results: Of 15 pts with persistent LAT, three (age 66 14, all male) had focal LAT (cycle length 268 21 ms) that remained stable in response to pacing. Electroanatomic maps demonstrated focal areas of early activation at the septal aspect of the right lower (2 pts) or right upper (1 pt) PV. Adenosine caused transient AV block but no change in tachycardia cycle length (TCL). Entrainment from multiple LA sites (N 23) outside the PVs demonstrated long post-pacing-intervals (PPI) (mean PPI-TCL 73 27 ms, range 46-127 ms). Entrainment from multiple poles around the Lasso catheter had a wide range of PPIs (PPI-TCL 22 18 ms, range -3 to 50 ms), suggesting both isthmus sites and sites outside the circuit. Septal Lasso sites and not lateral sites had PPI TCL. A single beat resetting curve in 2 pts demonstrated a mixed flat-increasing curve, consistent with reentry. In one pt, burst atrial pacing terminated and reinitiated the same tachycardia. Recordings at the critical isthmus demonstrated mid diastolic potentials or a long fractionated signal suggesting slow conduction. Ablation at the site of mid diastolic electrograms or best PPI (PPI-TCL 2 6 ms) resulted in LAT termination. Conclusions: Focal left atrial tachycardias may occur after segmental PVI, particularly at the septal aspect of the right pulmonary veins. Detailed entrainment mapping and resetting confirm that the mechanism of the stable tachycardias we studied is reentry. RF application at the critical isthmus results in tachycardia termination.

“Pseudo”-AV block and right atrial electrical disconnection complicating ablation for typical atrial flutter

avoid ablation within the pulmonary veins, as well as near the esophagoatrial interface. Segmental ostial ablation guided by a 10-pole circular mapping catheter was then performed after circumferential ablation to ensure electrical isolation of each vein. There were no complications. At 6 months, the patient has remained free of AF as assessed by symptoms and periodic Holter monitoring. Conclusions: CT imaging used in conjunction with a non-fluoroscopic navigation system is a new and important tool for AF ablation. By providing a highly detailed anatomic representation of the left atrium, pulmonary veins and esophagus, CT imaging serves to verify the accuracy of NavX-generated geometry. Regions of interest, such as the pulmonary vein ostia, the left atrial roof, the esophago-atrial interface and the isthmus between the left atrial appendage and the left superior pulmonary vein, can be more accurately defined, potentially resulting in a more effective and precise ablation while avoiding serious complications, such as pulmonary vein stenosis and esophago-atrial fistulas.

Mechanisms of recurrent atrial fibrillation after pulmonary vein isolation by segmental ostial ablation

Objectives The aim of this study was to determine the mechanisms responsible for recurrent atrial fibrillation (AF) after pulmonary vein isolation (PV) by segmental ostial ablation. Background Recovery of conduction into a previously isolated PV is a common observation when there is recurrent AF soon after segmental ostial ablation. However, the mechanisms of recurrent AF have been unclear. Methods A repeat ablation procedure was performed in 50 patients who had recurrent paroxysmal AF at a mean of 7 ± 6 months after segmental ostial ablation to isolate the PVs. During the repeat procedure, a ring catheter was inserted into each PV during sinus rhythm and AF to determine whether the veins were still isolated and, if not, whether there were PV tachycardias with a cycle length shorter than in the adjacent left atrium during AF. Results There was recovery of conduction over a previously ablated muscle fascicle in ≥1 PV in 49 patients (98%). There were 10 ± 2 episodes of PV tachycardia per minute in 36 (72%) of the 50 patients during AF. Repeat ablation was performed by segmental ostial ablation (23 patients) or by left atrial catheter ablation to encircle the left- and right-sided PVs 1 to 2 cm from the ostia, with additional ablation lines in the posterior left atrium and mitral isthmus (27 patients). At 6-month follow-up, among 23 patients who underwent repeat ablation by segmental ostial ablation, AF recurred in 4 (21%) of the 19 patients who had PV tachycardias and in 3 (75%) of the 4 patients who did not ( P = .03). Among the 27 patients who underwent left atrial ablation, AF recurred in 2 (12%) of the 17 patients who had PV tachycardias and in 1 (10%) of the 10 patients who did not ( P = 0.7). Conclusions Recovery of conduction in previously ablated muscle fascicles is a common finding in patients with recurrent AF after segmental ostial ablation. The efficacy of repeat segmental ostial ablation depends on the presence of PV tachycardias, whereas left atrial ablation is effective regardless of whether PV tachycardias are present or not during AF.

Pulmonary vein isolation for vagotonic, adrenergic, and random episodes of paroxysmal atrial fibrillation.

Based on the clinical history, paroxysmal atrial fibrillation (PAF) may be classified as vagotonic, adrenergic, or random. It is unclear whether pulmonary vein (PV) isolation is equally effective for these types of PAF. Segmental ostial ablation to isolate the PVs was performed in 188 consecutive patients (mean age 53 +/- 12 years) with PAF. Based on the clinical history, PAF was classified as random in 136 patients (72%), adrenergic in 30 (16%), and vagotonic in 22 (12%). Three or four PVs were targeted for isolation in all patients, and successful isolation was achieved in 96% of targeted PVs. At 1-year follow-up, 69% of patients with random AF, 83% of patients with adrenergic AF, and 50% of patients with vagotonic AF were free from recurrent episodes of AF in the absence of any antiarrhythmic drug therapy. Vagotonic AF was an independent clinical predictor of recurrent AF (P = 0.03). PV isolation has a lower efficacy in patients with vagotonic PAF than in patients with adrenergic or random episodes of PAF, suggesting that the PVs less often play an important role in vagotonic PAF.

Catheter Ablation of Afib: Two Techniques Compared

Remarkable advances have been made recently in catheter ablation techniques for atrial fibrillation (AF). In fact, 2 techniques that specifically target the pulmonary veins (PVs) have had favorable results. Segmental ostial ablation involves electrical isolation of targeted segments of the PV ostia. With circumferential ablation (also known as left atrial ablation), the PVs are completely encircled electrically. …

Segmental ostial ablation to isolate the pulmonary veins during atrial fibrillation. Feasibility and mechanistic insights

Segmental ostial ablation to isolate the pulmonary veins during atrial fibrillation. Feasibility and mechanistic insights