Incidence, management, and outcome in significant pulmonary vein stenosis complicating ablation for atrial fibrillation

Clinical characteristics of patients with atrial fibrillation suffering from pulmonary vein stenosis after radiofrequency ablation

OBJECTIVE

Pulmonary vein stenosis (PVS) is a serious complication in patients with atrial fibrillation (AF) receiving radiofrequency catheter ablation (RFCA). We therefore examined these patients' clinical characteristics in relation to PVS occurrence.

METHOD

We retrospectively analyzed the clinical symptoms, diagnostic procedures, and treatment strategies in patients with AF who developed PVS after RFCA.

RESULTS

Among 205 patients with AF who underwent RFCA, five (2.44%) developed PVS (all men; age 44-64 years; AF history 12-60 months; 2 paroxysmal AF, 3 persistent AF). One patient underwent two RFCA sessions and the others received one. The time to PVS diagnosed by pulmonary vein computed tomography angiography (CTA) was 3 to 21 months. PVS symptoms included dyspnea and hemoptysis. Nine pulmonary veins developed PVS. Single mild PVS occurred in two asymptomatic patients and multiple PVS or single severe PVS in three symptomatic patients who underwent pulmonary vein angiography and stent placement. Symptoms in the three patients significantly improved after stent implantation; however, stent restenosis occurred 1 year later in one case.

CONCLUSION

PVS is a rare complication of RFCA for AF that can be diagnosed by CTA. Pulmonary vein stent implantation can remarkably improve the symptoms, but stent restenosis may occur.

Pulmonary Computed Tomography Parenchymal and Vascular Features Diagnostic of Postablation Pulmonary Vein Stenosis

PURPOSE

The purpose of this study was to define the full spectrum of pulmonary computed tomography (CT) changes characteristic of postablation pulmonary vein stenosis (PVS).

MATERIALS AND METHODS

We retrospectively reviewed our pulmonary vein isolation database. PVS was graded as follows: grade 1:<50%, grade 2: 50% to 75%, grade 3: 76% to 99%, and grade 4: total occlusion. CT parenchymal and vascular changes were detected and correlated with clinical course and nuclear scans.

RESULTS

Of 486 patients who underwent pulmonary vein isolation, 56 patients (11%) were symptomatic, prompting referral to CT evaluation. Grades 1, 2, 3, and 4 PVS were documented in 42, 1, 2, and 11 patients, respectively. Apart from PVS, abnormal CT findings were present only in patients with PVS grades 2 to 4. Pulmonary parenchymal changes (consolidation, "ground glass" opacities, interlobular septal thickening, and volume loss) were found in PVS grades 2 to 4. Pulmonary vascular changes (oligemia, "sluggish flow," and collateral mediastinal vessels) were shown in patients with grades 3 to 4 PVS. Concomitant nuclear scans documented reduced lung perfusion. All findings were located to the lobe drained by the affected vein. Complete resolution of pulmonary findings on follow-up CT scans was demonstrated in 20% of patients. Eleven stents were inserted in 7 patients with PVS grades 2 to 4, none of which demonstrated radiologic or clinical resolution.

CONCLUSIONS

A typical CT complex of both parenchymal and vascular findings in the affected lobe is diagnostic of postablation PVS. Lack of clinical and radiologic resolution in most patients, even after stent insertion, further highlights the importance of early recognition of this underdiagnosed condition.

Spontaneous massive hemothorax presenting as a late complication of stent implantation in a patient with pulmonary vein stenosis following radiofrequency ablation for atrial fibrillation

Catheter ablation for symptomatic and drug-resistant atrial fibrillation is considered as the main acquired cause of pulmonary vein stenosis in adults. Controversy currently exists about the optimal treatment approach of this entity. Stenting seems to achieve lower vessel restenosis rates than isolated balloon angioplasty. However, these techniques are not exempt from complications. We present a case of spontaneous massive haemothorax presenting as a late complication of stent implantation in a patient with pulmonary vein stenosis.

Fibrosing mediastinitis with pulmonary hypertension as a complication of pulmonary vein stenosis: A case report and review of the literature

INTRODUCTION

Fibrosingmediastinitis (FM) is caused by a proliferation of fibrous tissue in the mediastinum encasing the mediastinal viscera that results in compression of mediastinal bronchovascular structures. Pulmonary hypertension (PH) is a severe complication of FM caused by extrinsic compression of pulmonary blood vessels.

CASE PRESENTATION

Here, we present the case of a 47-year-old man who presented with a 10-year history of progressive hemoptysis and a 2-year history of shortness of breath, in whom a diagnosis of FM was made. Occlusion of the superior pulmonary veins was noted, with stenosis of the inferior pulmonary veins, leading to PH. Because the patient was a poor candidate for interventional catheterization, the preferred treatment for FM, his PH has been managed with diuretics, and he remains stable.

CONCLUSIONS

FM is a serious, potentially life-threatening condition that is best managed in specialized centers.

Ablation of Atrial Fibrillation Using Microwave Energy — Early Experience

Between Dec 12, 2002 and Aug 22, 2004, 84 operative patients with chronic atrial fibrillation (AF) were subjected to AF ablation with microwave energy. Of these, 49 patients were female; their ages ranged between 20 and 72 years (mean, 43.1 years). Most patients suffered from mitral disease, accompanied in over one third of cases with tricuspid insufficiency. Thirteen patients had aortic valve disease, mostly with mitral involvement. Three patients had coronary artery disease, three had atrial septal defect and one had a left atrial (LA) myxoma. Seventy-two patients underwent endocardial ablation and 12 patients underwent epicardial ablation. Operative mortality was 4 (4.8%), and there were no major untoward postoperative events. Fifty seven patients (71.3%) had their AF converted to sinus rhythm immediately after surgery. Amiodarone or sotalol was used in all postoperative patients for 6 months, except in 8 who had bradycardia. Electrical defibrillation was utilized in cases of atrial flutter or persistent AF. Seventy patients were followed for at least 6 months. In total, 52 of them (74.3%) are still in sinus rhythm. We believe microwave ablation is a satisfactory and safe method of AF ablation, and because it is brief, it can be added to surgical procedures without undue risk to the patient.

An unusual case of acute respiratory failure in a patient with pulmonary veins stenosis late after catheter ablation of atrial fibrillation: a case report and the review of the literature

Background

Atrial fibrillation (AF) can be treated with percutaneous catheter ablation procedures into the left atrium. Pulmonary veins stenosis (PV) stenosis is a severe complication of this procedure.

Case presentation

we report a case of late hemoptysis secondary to severe PV stenosis in a man who underwent AF ablation 9 months before onset of symptoms. He presented four episodes of bleeding and developed an acute respiratory failure (ARF). Parameters of respiratory mechanics and medical investigation did not show any abnormalities. Only computed tomography (CT) angiography showed stenosis of 3 out of 4 native PVs. PV balloon dilatation in all affected PVs and a stent was implanted in 1 of the 3 PVs with full restoration of respiratory function during 1 year follow-up.

Conclusion

PV stenosis may be the underlying cause of recurrent haemoptysis after AF ablation in the presence of normal respiratory parameters. This diagnosis can be confirmed by means of CT angiography and magnetic resonance imaging can provide accurate localization of stenosis.

Lung Infarction due to Pulmonary Vein Stenosis after Ablation Therapy for Atrial Fibrillation Misdiagnosed as Organizing Pneumonia: Sequential Changes on CT in Two Cases

Pulmonary vein (PV) stenosis is a complication of ablation therapy for arrhythmias. We report two cases with chronic lung parenchymal abnormalities showing no improvement and waxing and waning features, which were initially diagnosed as nonspecific pneumonias, and finally confirmed as PV stenosis. When a patient presents for nonspecific respiratory symptoms without evidence of infection after ablation therapy and image findings show chronic and repetitive parenchymal abnormalities confined in localized portion, the possibility of PV stenosis should be considered.

Management Of Pulmonary Vein Stenosis Following Catheter Ablation Of Atrial Fibrillation

There is limited literature available regarding PV (pulmonary vein) stenosis management. Starting from its incidence, subsequent follow up using imaging technologies to monitor the success and the way of managing different groups pose varied opinions. However, with newer technological advancements and better understanding of mechanism of the atrial fibrillation ablation, the incidence of PV stenosis secondary to catheter ablation is declining. This paper highlights the current trends and future of management of PV stenosis secondary to catheter ablation for atrial fibrillation.

Exercise-induced haemoptysis: a thoroughbred cause?

The authors report a novel case of exercise-induced haemoptysis with an unexpected underlying pathology. The report discusses the case and provides a pragmatic overview of the diagnosis and management of the pulmonary vein stenosis.

Postradiofrequency ablation inflammatory pseudotumor associated with pulmonary venoocclusive disease: case report and review of the literature

Radiofrequency ablation of pulmonary veins is a common therapeutic intervention for atrial fibrillation. Pulmonary vein stenosis and venoocclusive disease are recognized complications, but the spectrum of pathologies postablation have not been previously reviewed. A recent case at our hospital showed a left hilar soft tissue mass in association with superior pulmonary vein stenosis in a patient 4 years postablation. On resection, this proved to be an inflammatory pseudotumor composed of myofibroblasts in an organizing pneumonia-type pattern with adjacent dendriform ossifications. Pulmonary venoocclusive change was a prominent feature. Literature on the histopathology of postradiofrequency ablation complications is limited. The severity of vascular pathology appears to increase with the postablation interval. Although pulmonary vascular changes are the most common late finding, fibroinflammatory changes including pulmonary pseudotumor formation, attributable to thermal injury, should be considered in the differential diagnosis of these cases.

Pulmonary Vein Stenting for Atrial Fibrillation Ablation-Induced Pulmonary Vein Stenosis

Pulmonary vein stenosis (PVS) is a known complication of pulmonary vein isolation in the treatment of atrial fibrillation. Patients with PVS can present with a great variety of symptoms. Clinicians should have a low threshold to evaluate for this potentially morbid and treatable condition. PVS can be treated by stenting affected pulmonary veins via transseptal access to the left atrium and use of bare metal biliary stents.

Safety of pulmonary vein isolation and left atrial complex fractionated atrial electrograms ablation for atrial fibrillation with phased radiofrequency energy and multi-electrode catheters

AIMS

Recently, a multi-electrode catheter system using phased radiofrequency (RF) energy was developed specifically for atrial fibrillation (AF) ablation: the pulmonary vein ablation catheter (PVAC), the multi-array septal catheter (MASC), and the multi-array ablation catheter (MAAC). Initial results of small trials have been promising: shorter procedure times and low adverse event rates. In a large single-centre registry, we evaluated the adverse events associated with multi-electrode ablation catheter procedures with PVAC alone, or combined with MASC and MAAC.

METHODS AND RESULTS

In all, 634 consecutive patients with AF had 663 procedures with multi-electrode ablation catheters, 502 patients with the PVAC alone, 128 patients with PVAC/MASC/MAAC, 29 redo procedures with the PVAC or PVAC/MASC/MAAC, and 4 patients had a complicated transseptal puncture. Major and minor adverse events during 6 month follow-up were registered. In 15 cases (2.3%), major adverse events were seen within the first month after the procedure. These included complicated transseptal puncture (4), stroke (2), transient ischaemic attack (5), acute coronary syndrome (2), femoral pseudoaneurysm (1), and arteriovenous fistulae (1). Minor adverse events were seen in 10.7% at 6 months, mostly due to femoral haematoma (3.9%), and non-significant PV stenosis (5.2%). There was no difference in the occurrence of major adverse events between PVAC alone, or PVAC/MASC/MAAC ablation.

CONCLUSION

Ablation with phased RF and multi-electrode catheters is accompanied by a major adverse event rate of 2.3% within 1 month and a minor event rate of 10.7% at 6 months.

Drug-eluting stents for the treatment of pulmonary vein stenosis after atrial fibrillation ablation

AIMS

Pulmonary vein (PV) stenosis (PVS) is a complication of radiofrequency PV isolation (PVI). Reported restenosis rates after balloon dilatation and bare-metal stent implantation are high. Drug-eluting stent implantation (DES) has not been reported in the setting of PVS.

METHODS AND RESULTS

Patients suspected of having PVS after PVI based on clinical symptoms and transesophageal echocardiography (TEE) follow-up (FU) were referred for PV DES. One or more branches of the affected PV as documented by angiography were stented (paclitaxel or zotarolimus DES). Follow-up consisted of repeat PV angiography and TEE. Over a period of 2 years, five patients were treated with a total of eight DES. A paclitaxel DES was used in seven of eight implants. Mean FU was 12 ± 14 months during which all patients remained asymptomatic. Transesophageal echocardiography Doppler maximal flow velocity (V(max)) of the affected PVs rose from 58 ± 6 cm/s pre-PVI to 207 ± 20 cm/s pre-DES (+358%, P < 0.0001). After DES, V(max) decreased acutely with 86 ± 15 cm/s (-58%, P < 0.01). During FU, V(max) remained stable in three patients and increased moderately in one. Angiography at 3 months confirmed absence of restenosis in the first three patients and moderate (40%) restenosis in one patient. In one patient, an increase of V(max) back to pre-DES values correlated with a 65% peri-stent stenosis, treated with a redo DES. In total, after seven primary DES only one (asymptomatic) proximal margin restenosis required re-stenting.

CONCLUSION

Initial experience with DES for PV stenosis suggests an excellent stent patency rate. Transesophageal echocardiography Doppler measurements provide a viable way of monitoring stent patency.

Complete pulmonary venous occlusion after radiofrequency ablation for atrial fibrillation

Pulmonary vein stenosis is a known, yet under-recognized complication of radiofrequency ablation for atrial fibrillation. We present the case of a patient developing complete left-sided pulmonary venous occlusion following radiofrequency ablation. Recommendations are made to allow earlier diagnosis of this complication.

Why can pulmonary vein stenoses created by radiofrequency catheter ablation worsen during and after follow-up? A potential explanation

Background

Radiofrequency catheter ablation of excitation foci inside pulmonary veins (PV) generates stenoses that can become quite severe during or after the follow-up period. Since severe PV stenoses have most often disastrous consequences, it would be important to know the underlying mechanism of this temporal evolution. The present study proposes a potential explanation based on mechanical considerations.

Methods

we have used a mathematical-physical model to examine the cyclic increase in axial wall stress induced in the proximal (= upstream), non-stenosed segment of a stenosed pulmonary vein during the forward flow phases. In a representative example, the value of this increase at peak flow was calculated for diameter stenoses (DS) ranging from 1 to 99%.

Results

The increase becomes appreciable at a DS of roughly 30% and rise then strongly with further increasing DS value. At high DS values (e.g. > 90%) the increase is approximately twice the value of the axial stress present in the PV during the zero-flow phase.

Conclusion

Since abnormal wall stresses are known to induce damages and abnormal biological processes (e.g., endothelium tears, elastic membrane fragmentations, matrix secretion, myofibroblast generation, etc) in the vessel wall, it seems plausible that the supplementary axial stress experienced cyclically by the stenotic and the proximal segments of the PV is responsible for the often observed progressive reduction of the vessel lumen after healing of the ablation injury. In the light of this model, the only potentially effective therapy in these cases would be to reduce the DS as strongly as possible. This implies most probably stenting or surgery.

Impact of integration of multislice computed tomography imaging into three-dimensional electroanatomic mapping on clinical outcomes, safety, and efficacy using radiofrequency ablation for atrial fibrillation

BACKGROUND

Circumferential radiofrequency catheter ablation (RFCA) around the orifices of the pulmonary veins (PV) is a curative catheter-based therapy of paroxysmal, persistent, and permanent atrial fibrillation (AF). Integration of multislice computed tomography into three-dimensional electroanatomic mapping to guide catheter ablation has been shown to be accurate and feasible. This study investigated whether the use of such sophisticated imaging technology translates into better clinical outcomes, procedural efficacy, and safety in comparison with a control group treated with conventional three-dimensional electroanatomic mapping.

METHODS

A total of 100 consecutive patients (85 male, mean age 55 +/- 9 years) with multi-drug-resistant AF underwent RFCA. In this study we used a wide area circumferential approach with confirmed PV isolation (requiring additional ablations at the ostial level) and further lines as needed.

RESULTS

Comparison of outcome data between the conventional electroanatomic mapping (Carto XP, Biosense Webster, Diamond Bar, CA, USA) and the image integration technology (Carto MERGE, Biosense Webster) resulted in a significant improvement in procedural success for the image integration group (85.1% vs 67.9%; P = 0.018). No single case of significant PV stenosis occurred in the Carto MERGE group versus three significant stenoses in the conventional group (P = 0.098). Both procedure and fluoroscopy times remained unchanged.

CONCLUSION

Multislice computed tomography image integration into electroanatomic mapping significantly improves the success of wide area circumferential ablation with confirmed isolation of the PV and additional lines. In addition, the safety of radiofrequency ablation with regard to the occurrence of PV stenosis is increased in comparison with a control group using conventional electroanatomic mapping alone. Procedural efficacy remains unchanged.

[Nightmares in atrial fibrillation ablation--identification, management, and prevention of complications in radiofrequency ablation of atrial fibrillation]

Radiofrequency ablation is increasingly being established as a curative treatment option for atrial fibrillation refractory to antiarrhythmic drug therapy. Especially catheter ablation of atrial fibrillation is associated with significant procedure-related risks, as this is one of the most complex interventional electrophysiologic procedures. Knowledge about common and infrequent complications, incidence, etiology, and techniques for prevention should minimize risk and help to further increase procedural success. This paper intends to provide a practice-oriented summary of international surveys and consensus documents in comparison with data from our own electrophysiologic laboratory. Great attention will be laid upon early recognition and technical as well as procedure-related possibilities to prevent any complication.

Detection of pulmonary vein stenosis by transesophageal echocardiography: comparison with multidetector computed tomography

OBJECTIVE

The objective of this study is to compare the use of transesophageal echocardiography (TEE) vs multidetector computed tomography (MDCT) for detecting pulmonary vein stenosis.

BACKGROUND

Pulmonary vein isolation is increasingly used to treat atrial fibrillation. Pulmonary vein stenosis remains a potential complication of pulmonary vein isolation and ideal methods for detection of stenosis are still to be determined.

METHODS

Thirty-six subjects who underwent pulmonary vein isolation returned for follow-up MDCT and TEE. Percent diameter loss was reported for each pulmonary vein stenosis by MDCT. A 50% narrowing was considered as an indication of a stenosis. Pulsed-wave Doppler using TEE was used to measure peak velocities of all pulmonary veins.

RESULTS

Multidetector computed tomography and TEE were performed in all subjects (58 +/- 10 years) at 4 +/- 2 months after pulmonary vein isolation. Atrial fibrillation was present in 14% at time of follow-up. Multidetector computed tomography was able to evaluate all 4 (100%) pulmonary veins in 36 subjects, whereas full interrogation by TEE was possible in 138 (96%) of 144 veins. Pulmonary vein stenosis >50% by MDCT was present in 7 pulmonary veins. Analysis of the receiver operating curve for TEE showed that it had optimum detection of pulmonary vein stenosis at peak velocities approximately 100 cm/s with 86% sensitivity and 95% specificity. Area under the curve for TEE was 0.93. Clinically significant stenosis was observed in 2 subjects and was detected by both TEE and MDCT.

CONCLUSIONS

Transesophageal echocardiography was able to detect most pulmonary veins with good sensitivity and specificity in comparison to MDCT. Pulmonary veins may be visualized more frequently by MDCT; however, TEE provides additional data about the functional significance of a pulmonary vein stenosis.

Irreversible intrapulmonary vascular changes after pulmonary vein stenosis complicating catheter ablation for atrial fibrillation

BACKGROUND

Pulmonary vein stenosis is a recognized complication of catheter ablation of arrhythmias emanating from the pulmonary vein; however, there is little information on secondary effects of pulmonary vein stenosis on lung tissue.

METHODS AND RESULTS

A 55-year-old man with a history of paroxysmal atrial fibrillation refractory to antiarrhythmic medication had radiofrequency ablation in April 2003 and July 2003. Although these procedures were successful in resolving the patient's arrhythmia, they were complicated by the development of pulmonary vein stenosis of all four veins and pulmonary hypertension requiring patch annuloplasty of the pulmonary veins in October 2003. The patient was referred to our center for pulmonary vein stent placement in December 2003, June 2004, and August 2004, each time for recurrent hemoptysis. Due to persistent hemoptysis over the next several months, the patient underwent left lower lung lobectomy in September 2005. Microscopic examination of the lung showed marked medial thickening and intimal hyperplasia of large and small pulmonary veins and arteries, as well as focal organizing thrombi in the small arteries. The lung tissue showed extensive hemosiderin deposition indicative of prior hemorrhage.

CONCLUSION

Chronic pulmonary vein stenosis after radiofrequency ablation of atrial fibrillation results in irreversible venous and arterial morphologic changes throughout the lung, including areas both close to, and remote from, the site of catheter ablation. Because there are persistent pathological changes remote from the ablation site causing the pulmonary hypertension, stenting the site of ablation to reopen large pulmonary veins may not be effective in treating the pulmonary hypertension.

Pulmonary vein total occlusion following catheter ablation for atrial fibrillation: clinical implications after long-term follow-up

OBJECTIVES

We present the clinical course and management outcomes of patients with total pulmonary vein occlusion (PVO).

BACKGROUND

Pulmonary vein occlusion is a rare complication that can develop after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). The long term follow-up data of patients diagnosed with PVO are minimal.

METHODS

Data from 18 patients with complete occlusion of at least one pulmonary vein (PV) were prospectively collected. All patients underwent RFA for AF using different strategies between September 1999 and May 2004. Pulmonary vein occlusion was diagnosed using computed tomography (CT) and later confirmed by angiography when intervention was warranted. Lung perfusion scans were performed on all patients before and after intervention. The percent stenoses of the veins draining each independent lung were added together to yield an average cumulative stenosis of the vascular cross-sectional area draining the affected lung (cumulative stenosis index [CSI]).

RESULTS

The patients' symptoms had a positive correlation with the CSI (r = 0.843, p < 0.05) and a negative one with the lung perfusion (r = -0.667, p < 0.05). A CSI > or =75% correlated well with low lung perfusion (<25%; r = -0.854, p < 0.01). Patients with a CSI > or =75% appeared to improve mostly when early (r = -0.497) and repeat dilation/stenting (r = 0.0765) were performed.

CONCLUSIONS

Patients with single PVO are mostly asymptomatic and should undergo routine imaging. On the other hand, patients with concomitant ipsilateral PV stenosis/PVO and a CSI > or =75% require early and, when necessary, repeated pulmonary interventions for restoration of pulmonary flow and prevention of associated lung disease.

An unusual cause of pulmonary vein stenosis: a case report and review of the literature

We describe the case of a patient with the Carney syndrome and several resections for recurrent left atrial myxomas who underwent autotransplantation of the heart with resection of the left and right atria and reconstruction of both atria with bovine pericardium. She subsequently presented with severe shortness of breath, ascites, and peripheral edema. She was found to have stenosis of all four pulmonary veins and severe pulmonary hypertension. We describe the echocardiographic findings and review the literature on assessment of acquired pulmonary vein stenosis.

Assessment of pulmonary venous stenosis after radiofrequency catheter ablation for atrial fibrillation by magnetic resonance angiography: a comparison of linear and cross-sectional area measurements

One of the recognised complications of catheter ablation is pulmonary venous stenosis. The aim of this study was to compare two methods of evaluation of pulmonary venous diameter for follow-up assessment of the above complication: (1) a linear approach evaluating two main diameters of the vein, (2) semiautomatically measured cross-sectional area (CSA). The study population consists of 29 patients. All subjects underwent contrast-enhanced magnetic resonance angiography (CeMRA) of the pulmonary veins (PVs) before and after the ablation; 14 patients were also scanned 3 months later. PV diameter was evaluated from two-dimensional multiplanar reconstructions by measuring either the linear diameter or CSA. A comparison between pulmonary venous CSA and linear measurements revealed a systematic difference in absolute values. This difference was not significant when comparing the relative change CSA and quadratic approximation using linear extents (linear approach). However, a trend towards over-estimation of calibre reduction was documented for the linear approach. Using CSA assessment, significant PV stenosis was found in ten PVs (8%) shortly after ablation. Less significant PV stenosis, ranging from 20 to 50% was documented in other 18 PVs (15%). CeMRA with CSA assessment of the PVs is suitable method for evaluation of PV diameters.

Congenital pulmonary sling, aorto–pulmonary window and pulmonary vein obstruction as a diagnostic and therapeutic challenge in an infant with VACTERL association

In a newborn with anal atresia and urethral valves an incomplete VACTERL association, was diagnosed and a colon anus praeter was placed. Sweating and heart murmur led to cardiac diagnostics. By 2D colour Doppler echocardiography a huge atrial septal defect and pulmonary venous stenoses were diagnosed. Additionally, a pulmonary sling combined with an aortopulmonary window (AoPAw) was suspected and later confirmed by angiography. Heart failure developed and closure of the AoPAw, transplantation of the left pulmonary artery and closure of the atrial septal defect was performed at the age of 4 weeks. But the patient did not improve. Pulmonary hypertension with suprasystemic pressure in the right ventricle originating from a stenosis of the new orifice of the left pulmonary artery and obstruction of the right pulmonary veins was diagnosed by echocardiography and confirmed by angiography. At the age of 8 months the orifice of the left pulmonary artery was enlarged by a patch, the obstruction of left sided pulmonary veins was opened, and the rightsided pulmonary veins were newly implanted into the left atrium. Finally the inter-atrial communication was closed by a patch plastic. Again, postoperatively the patient improved only slightly. At the age of 10 months trans-septal catheterisation was performed. Angiography revealed a successful balloon dilatation of the long obstruction of the right pulmonary veins. Later on, an absorbable magnesium stent was implanted into the right upper pulmonary vein and medication with an endothelin antagonist was started. Temporarily the patient improved significantly. Within 6 weeks, right ventricular systolic pressure was again suprasystemic due to extreme inflow obstruction of the right pulmonary vein diagnosed by echocardiography. Severe heart failure developed and at the age of 1 year the patient died.

Clinical predictors of noninducibility of sustained atrial fibrillation after pulmonary vein isolation

BACKGROUND

Noninducibility of sustained atrial fibrillation (AF) after pulmonary vein isolation (PVI) has been shown to be associated with a better clinical outcome. We evaluated the role of clinical variables that could predict noninducibility of sustained AF after PVI.

METHODS AND RESULTS

Data were collected prospectively from 181 patients (153 male; age 54 +/- 9 years) referred for ablation of drug-refractory symptomatic paroxysmal AF (duration < or =7 days). Clinical variables were evaluated with regard to their ability of predicting noninducibility of sustained AF (< or =10 minutes) after PVI. Univariate analysis was performed on all collected variables followed by multivariate analysis for variables showing a P value <0.1. After PVI, sustained AF was noninducible in 97 (54%) patients. The following clinical variables showed a significant difference between the groups: body weight, longest AF episode, duration of AF history, presence or absence of structural heart disease, left ventricular (LV) hypertrophy, prior cardioversion, left atrial (LA) parasternal, and longitudinal diameters and LV diameters. On multivariate analysis, three independent predictors of noninducibility were identified: a shorter duration of AF episodes (AF <12 hours: RR 0.01 (0.002-0.06), P < 0.001; AF 12-48 hours: RR 0.07 (0.01-0.37), P = 0.001); LA longitudinal diameter <57 mm (RR 0.33 (0.13-0.82), P = 0.016); and absence of LV hypertrophy (RR 0.15 (0.04-0.63), P = 0.01).

CONCLUSIONS

Shorter AF episodes, smaller LA longitudinal diameter, and absence of LV hypertrophy are independent predictors of noninducibility of sustained AF after PVI.

Cardiac computed tomography compared to transthoracic echocardiography in the management of congenital heart disease

OBJECTIVES

To compare cardiac CT and transthoracic echocardiography (TTE) as diagnostic utilities in congenital heart disease (CHD) and to determine their advantages and limitations.

BACKGROUND

TTE is widely used in the evaluation of CHD. Recent reports suggested an increasing role of CT. However, there are few quantitative data on its diagnostic accuracy.

METHODS

We investigated a total of 162 patients (51.24% male; mean age: 16.06 +/-+/- 17.92) with congenital heart defects, who underwent electron beam CT (EBCT) and TTE between March 2002 and June 2005. We retrospectively analyzed a total of 667 findings, stratified for age and anatomic categories.

RESULTS

EBCT and TTE findings are concordant in patients below 1 year of age (85.43% agreement). EBCT had poor sensitivity and specificity in detecting anomalies of cardiac chambers (0.68, 0.58), but was useful for great arteries (0.91, 0.85). Furthermore, sensitivity and specificity were remarkably different in systemic venous return (0.93, 0.3) and coronary vessels (0.8, 0.33) because of "false positive" findings, which were later found to be most likely real findings not detectable by reference standard. The opposite was true for cardiac valves (0.66, 0.89) and septa (0.76, 0.91).

CONCLUSIONS

EBCT delineates findings related to systemic venous return and coronary vessels well due to simultaneous visualization of complex anatomy. This advantage does not seem to apply in patients below 1 year of age with better acoustic windows. TTE was found more suitable for cardiac valves and septal defects because of the availability of flow imaging.

Pulmonary vein stenosis following catheter ablation of atrial fibrillation

PURPOSE OF REVIEW

This review provides an update on the mechanisms, incidence, and current management of significant pulmonary vein stenosis following catheter ablation of atrial fibrillation.

RECENT FINDINGS

Catheter ablation involving the pulmonary veins and the surrounding left atrial tissue is increasingly used to treat atrial fibrillation. In parallel with the fact that these procedures may cure a substantial proportion of patients, severe complications have been observed. Pulmonary vein stenosis is a new clinical entity produced by radiofrequency energy delivery mainly within or at the orifice of the pulmonary veins. The exact incidence is currently unknown because the diagnosis is dependent on the imaging modality and on the rigor with which patients are followed up. The optimal method for screening patients has not been determined. Stenosis of a pulmonary vein may be assessed by combining anatomic and functional imaging using computed tomographic or magnetic resonance imaging, transesophageal echocardiography, and lung scanning. Symptoms vary considerably and may be misdiagnosed, leading to severe clinical consequences. Current treatment strategies involve pulmonary vein dilatation or stenting; however, the restenosis rate remains high. The long-term outcome in patients with pulmonary vein stenosis is unclear. Strategies under development to prevent pulmonary vein stenosis include alternate energy sources and modified ablation techniques.

SUMMARY

Pulmonary vein stenosis following catheter ablation is a new clinical entity that has been described in various reports recently. There is much uncertainty with respect to causative factors, incidence, diagnosis, and treatment, and long-term sequelae are unclear.

Catheter Ablation Therapy for Atrial Fibrillation

Since cases were first reported in 1994, catheter ablation of atrial fibrillation has undergone rapid development and expansion. The procedure began as an attempt to recreate the Maze III operation with a catheter technique. Understanding the contribution of the pulmonary veins to the initiation and maintenance of atrial fibrillation led to dramatic changes in procedural technique. The segmental ostial and the circumferential approaches have emerged as the 2 dominant methods. Efforts continue in academic centers to better understand the pathophysiology of the arrhythmia and to further refine the ablation procedure to improve patient outcomes.

Impedance monitoring during catheter ablation of atrial fibrillation

BACKGROUND

Delivery of radiofrequency energy in proximity of a pulmonary vein can cause vein stenosis. A sudden decrease in impedance as the catheter is moved from the vein into the left atrium (LA) has been used to define the pulmonary vein-LA transition during ablation procedures.

OBJECTIVES

The purpose of this study was to define the variables affecting impedance measurement.

METHODS

In vitro analysis of impedance was performed in a saline bath using sheaths and a plastic stereolithographic model of the LA. Impedance was continuously monitored during a calibrated pullback from the pulmonary vein into the LA in 37 veins of 10 patients referred for catheter ablation. Location of the catheter was confirmed by the following imaging modalities: intracardiac echocardiography, contrast venography, electroanatomic mapping, and computed tomography/magnetic resonance imaging (offline) in all patients.

RESULTS

Larger cross-sectional areas containing the catheter correlated with lower impedance in an exponential manner both with respect to sheath size (R(2) = 0.99) and in the stereolithographic model (R(2) = 0.91). In vivo, the impedance in the pulmonary veins decreased in an exponential manner as the catheter was pulled back into the LA. However, impedance at the vein orifice was not significantly higher than the LA. A defined cutoff value for defining the pulmonary vein-LA transition could not be identified.

CONCLUSION

The primary determinant of impedance is the cross-sectional area of the space containing the catheter. Impedance monitoring alone does not guarantee a catheter tip position outside the pulmonary vein. Intraprocedural imaging confirmation should be considered to avoid radiofrequency application within pulmonary veins.

A Decrease in Pulmonary Vein Diameter After Radiofrequency Ablation Predicts the Development of Severe Stenosis

A decrease in ostial pulmonary vein (PV) diameter was observed in patients on the day after radiofrequency ablation of atrial fibrillation (AF). This study examined whether a relative reduction in PV diameter on day 1 (RRPVD1) after the procedure predicts the late development of severe PV stenosis (PVS). The study included 104 consecutive patients (mean age = 55 years, range 46-61, 34 women) with drug refractory AF. Pulmonary vein diameter was measured using MR angiography (MRA) on the day before and on day 1 after the ablation procedure. The MRA was repeated every 3 months after the procedure. Severe PVS was defined as a >70% diameter reduction from the initial ostial diameter. The cut-off of RRPVD1 was prespecified as 25% decrease in initial diameter. The data are presented as medians and interquartile range. A total of 357 PV were treated. The RRPVD1 was 0.0% (0.0-11.1%). Severe PVS was found in 18 PV during a follow-up of 12 months (range 6-13). The log-rank analysis confirmed a strong association between a RRPVD1 >/=25% and the development of PVS (hazard ratio: 7.1; 95% confidence interval 3.8-13.5, P < 0.0001). By multivariate Cox regression model, after adjustment of procedure variables, RRPVD1 was the strongest predictor of development of severe PVS. RRPVD1 >/=25% was a strong independent predictor of development of severe PVS.