Pulmonary vein stenosis after catheter ablation of atrial fibrillation: emergence of a new clinical syndrome

Cryoablation:. Potentials and Pitfalls

The use of cryoablation in the electrophysiology lab provides some distinct advantages not seen with conventional radiofrequency ablation. Ice mapping allows a functional assessment of a putative ablation site prior to the formation of a permanent lesion. This provides a distinct advantage adjacent to the AV node for para-hisian pathways and difficult cases of AVNRT. Cryoablation also produces minimal endothelial disruption and thrombus formation and causes no collagen shrinkage. This is likely advantageous when ablation is required within venous structures. There is also mounting experimental evidence that cryoablation is safe adjacent to the arterial system, especially within the middle cardiac vein or distal coronary sinus. As the technology evolves and further iterations of the catheter proceed, the role for this new but well-established technology is likely to grow.

Functional Assessment of Pulmonary Vein Stenosis Using Radionuclide Ventilation/Perfusion Imaging

Pulmonary vein (PV) stenosis following catheter ablation of atrial fibrillation (AF) is a new clinical syndrome. The optimal method of assessing this syndrome is not known. We evaluated radionuclide perfusion imaging, anatomic imaging, and direct measurements of PV-left atrial (LA) pressure gradients in patients suspected of having PV stenosis after catheter ablation for the treatment of AF. The study included 11 consecutive patients who were referred to a tertiary referral center for the evaluation of symptoms suggesting or imaging evidence of PV stenosis following catheter ablation for AF. All patients underwent anatomic imaging of their PVs with direct pulmonary venography or CT scanning as well as radionuclide perfusion imaging. PV stenosis (> 50% diameter) was diagnosed by venography in 6 of the 11 patients and in 16 of 44 PVs. All six patients with PV stenosis had perfusion defects in the affected pulmonary lobe. In contrast, all of the patients without anatomic evidence of PV stenosis had normal perfusion. There were 14 PVs with stenoses of > 80% of the luminal diameter, all of which had a corresponding perfusion abnormality ascertained by perfusion scanning. In all 14 PVs with a resting PV-LA gradient of > 5 mm Hg, there was a corresponding perfusion defect. PV stenosis results in decreased perfusion in the affected lobe when the resting PV-LA pressure gradient is at least 5 mm Hg or when there is 80% luminal stenosis. A perfusion scan may serve as an effective screening tool for PV stenosis and may be most useful in assessing the hemodynamic significance of an anatomic PV stenosis.

Predictors of Recurrence Following Catheter Ablation of Atrial Fibrillation Using an Irrigated-Tip Ablation Catheter

INTRODUCTION

The aims of this study were to identify predictors of recurrence after catheter ablation of atrial fibrillation (AF) and to report the safety and efficacy of catheter ablation of AF using an irrigated-tip ablation catheter.

METHODS AND RESULTS

Seventy-five consecutive patients (51 men [68%]; age 54 +/- 13 years) with symptomatic drug-refractory paroxysmal (42 patients), persistent (21 patients), or permanent (12 patients) AF underwent catheter ablation of AF using an irrigated-tip ablation catheter and a standard ablation strategy, which involved electrical isolation of all pulmonary veins (PVs) and creation of a cavotricuspid linear lesion. At 10.5 +/- 7.5 months of follow-up following a single (n = 75) or redo ablation procedure (n = 11), 39 (52%) of the 75 patients were free of AF, 10 were improved (13%), and 26 had experienced no benefit from the ablation procedure (35%). Seventy-six percent of patients with paroxysmal AF were free from recurrent AF. The most significant complications were two episodes of pericardial tamponade, mitral valve injury in one patient, two strokes, and complete but asymptomatic PV stenosis in one patient. Cox proportional hazards multivariate regression analysis identified the presence of persistent AF, permanent AF, and age >50 years prior to the ablation are the only independent predictors of AF recurrence after the first PV isolation procedure.

CONCLUSION

Catheter ablation of AF using a strategy involving isolation of all PVs and creation of a linear lesion in the cavotricuspid isthmus using cooled radiofrequency energy is associated with moderate efficacy and an important risk for complications. The best results of this procedure are achieved in the subset of patients who are younger than 50 years and have only paroxysmal AF.

Pulmonary vein occlusion: An unanticipated complication of catheter ablation of atrial fibrillation using the anatomic circumferential approach

Favorable results of circumferential pulmonary vein (PV) ostial ablation guided by electroanatomic mapping (Carto) have fueled great enthusiasm for this technique. The lesion set for this ablation procedure as described by Pappone et al.(1,2) involves a figure of 8 lesions encompassing the 2 right and 2 left PV ostia with 2 additional linear lesions. Pulmonary vein stenosis/or occlusion has not previously been reported as a complication of this procedure. We describe PV occlusion after this procedure. Based on the occurrence of this previously unreported complication, we no longer create a figure '8' lesion around the right superior and inferior PVs. We anticipate that this complication can be avoided by creating a circular lesion encompassing the 2 PV ostia, while avoiding the linear lesion between the 2 PV ostia.

Technique and Results of Pulmonary Vein Angiography in Patients Undergoing Catheter Ablation of Atrial Fibrillation

INTRODUCTION

Delineation of pulmonary vein (PV) anatomy is an integral part of the PV isolation procedure. The aims of the present study were to (1) describe the technique of selective PV angiography, (2) show the typical fluoroscopic locations and appearance of the PVs, and (3) compare the ostial diameters of PVs measured by angiography and magnetic resonance imaging (MRI).

METHODS AND RESULTS

Twenty consecutive patients undergoing a PV isolation procedure underwent selective PV angiography using a deflectable 8-French lumened catheter (Naviport, Cardima). The left superior PV (LSPV) runs upward and away from the spine in the right anterior oblique (RAO) projection and upward and toward the spine in the left anterior oblique (LAO) projection. The opposite is true for the right superior PV (RSPV). The left inferior PV (LIPV) has a bull's-eye appearance in the RAO projection, and the right inferior PV (RIPV) has a bull's-eye appearance in the LAO projection due to their end-on trajectories. The LIPV in the LAO projection and the RIPV in the RAO projection run horizontally toward the spine. An excellent correlation was noted in PV ostial size as assessed by angiography and MRI (r(2) < 0.90, P < 0.0001).

CONCLUSION

This study describes the technique and results of PV angiography and fluoroscopy. The study also demonstrates good correlation of PV ostial diameters by contrast venography and MRI. PV angiography can be used as an alternate to MRI or computed tomographic imaging, particularly when these tests are unavailable or are contraindicated in the patient.

Pulmonary Vein Stenosis After Radiofrequency Ablation of Atrial Fibrillation

Background— Pulmonary vein (PV) stenosis is a complication of ablation for atrial fibrillation. The impact of different ablation strategies on the incidence of PV stenosis and its functional characterization has not been described.

Methods and Results— PV isolation was performed in 608 patients. An electroanatomic approach was used in 71 and circular mapping in 537 (distal isolation, 25; ostial isolation based on PV angiography, 102; guided by intracardiac echocardiography, 140; with energy delivery based on visualization of microbubbles, 270). Severe (≥70%) narrowing was detected in 21 patients (3.4%), and moderate (50% to 69%) and mild (<50%) narrowing occurred in 27 (4.4%) and 47 (7.7%), respectively. Severe stenosis occurred in 15.5%, 20%, 2.9%, 1.4%, and 0%, respectively. Development of symptoms was correlated with involvement of >1 PV with severe narrowing ( P =0.01), whereas all patients with mild and moderate narrowing were asymptomatic. In the latter group, lung perfusion (V/Q) scans were normal in all but 4 patients. All patients with severe stenosis had abnormal perfusion scans.

Conclusions— V/Q scans are useful to assess the functional significance of PV stenosis. Mild and moderate degrees of PV narrowing are not associated with development of symptoms and seem to have no or minimal detrimental effect on pulmonary flow. The incidence of severe PV stenosis seems to be declining with better imaging techniques to ensure ostial isolation and to guide power titration. Mild narrowing 3 months after ablation does not preclude future development of severe stenosis and should be assessed with repeat imaging studies.

Rate or rhythm control in persistent atrial fibrillation?

Atrial fibrillation (AF) is the most common sustained tachyarrhythmia encountered in clinical practice, with the majority of patients aged > 65 years. With an increasingly ageing population, the burden of AF in society continues to rise. One of the principal controversies in AF management is whether to control the ventricular rate and accept the underlying rhythm, or to attempt to achieve sinus rhythm. Until recently there were no clinical trial data directly comparing a rate versus rhythm strategy, and most physicians have opted for rhythm control, based on its theoretical benefits. We present an up-to-date evidence-based overview of the relative merits of rate versus rhythm control in AF, including data from five recent randomized trials. We draw conclusions from these studies and present evidence-based guidance on when to adopt which approach in routine clinical practice.

Transcatheter angioplasty for acquired pulmonary vein stenosis after radiofrequency ablation

BACKGROUND

Pulmonary vein stenosis has recently been recognized as a complication of radiofrequency ablation for atrial fibrillation. This study evaluates the presentation of affected patients and the role of transcatheter therapy for this patient population.

METHODS AND RESULTS

This study used a retrospective review of data from 19 patients (age, 51+/-13 years) with pulmonary vein stenosis who underwent catheterization and angiography between December 2000 and December 2002. Quantitative perfusion and spiral CT scans were performed for initial diagnosis and follow-up. The median duration between radiofrequency ablation and the reported onset of respiratory symptoms for 18 of 19 patients was 7.5 weeks (0.1 to 48). After the onset of symptoms, all but two patients were initially misdiagnosed with a symptoms-to-diagnosis duration of 16 weeks (2-59). At initial catheterization, 17 of 19 patients had angioplasty in 30 veins with stent placement in 5 vessels when a flap occurred. Overall vessel diameter increased from 2.6+/-1.6 to 6.6+/-2.4 mm (P<0.0001). There were 4 procedure-related adverse events but no long-term sequelae. Immediate follow-up showed improved flow to involved lung segments. At a median follow-up of 43 weeks (2-92), although repeat angioplasty for restenosis was necessary in 8 of 17 patients, 15 of 17 patients currently have no or minimal persistent symptoms.

CONCLUSIONS

Pulmonary vein stenosis after radiofrequency ablation for atrial fibrillation is often misdiagnosed. Although further follow-up is necessary to determine long-term success, our data indicate better pulmonary vein flow and symptomatic improvement in the majority of patients undergoing dilation of postablation pulmonary vein stenosis.

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

OBJECTIVES

We sought to evaluate the efficacy and safety of pulmonary vein (PV) isolation using transvenous cryoablation for the treatment of atrial fibrillation (AF).

BACKGROUND

Although 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.

METHODS

In 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.

RESULTS

All 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.

CONCLUSIONS

Transvenous 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.

Registro Español de Ablación con Catéter. II Informe Oficial de la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología (2002)

INTRODUCTION AND OBJECTIVES

We present the results (success rates and complication rates) for the second consecutive year of the 2002-Spanish Catheter Ablation Registry, developed by the Spanish Society of Cardiology.

MATERIAL AND METHOD

Data were collected retrospectively by questionnaires sent to all interventional cardiology laboratories in Spain. The outcomes and complications of ablation procedures performed during 2002 were classified according to the substrate or mechanism of arrhythmia treated.

RESULTS

Forty-three centers voluntarily submitted completed questionnaires. The number of procedures analyzed was 4970, performed at 42 centers, for a mean of 118 78 procedures per center. Global outcome rates were success in 93%, major complications in 1.2%, and death in 0.04% of the patients. The three main substrates treated were AV nodal reentry (29%), accessory pathways (28%) and common atrial flutter (24%).

CONCLUSIONS

The 2002 Spanish National Catheter Ablation Registry reports the activity of the majority (90%) of interventional cardiology laboratories in Spain. The efficacy of catheter ablation procedures in Spain is high, and the complication and mortality rates are low.