Visualization of pulmonary vein stenosis after radio frequency ablation using multi-slice computed tomography: initial clinical experience in 33 patients

Pre- and post-procedural cardiac imaging (computed tomography and magnetic resonance imaging) in electrophysiology: a clinical consensus statement of the European Heart Rhythm Association and European Association of Cardiovascular Imaging of the European Society of Cardiology

Imaging using cardiac computed tomography (CT) or magnetic resonance (MR) imaging has become an important option for anatomic and substrate delineation in complex atrial fibrillation (AF) and ventricular tachycardia (VT) ablation procedures. Computed tomography more common than MR has been used to detect procedure-associated complications such as oesophageal, cerebral, and vascular injury. This clinical consensus statement summarizes the current knowledge of CT and MR to facilitate electrophysiological procedures, the current value of real-time integration of imaging-derived anatomy, and substrate information during the procedure and the current role of CT and MR in diagnosing relevant procedure-related complications. Practical advice on potential advantages of one imaging modality over the other is discussed for patients with implanted cardiac rhythm devices as well as for planning, intraprocedural integration, and post-interventional management in AF and VT ablation patients. Establishing a team of electrophysiologists and cardiac imaging specialists working on specific details of imaging for complex ablation procedures is key. Cardiac magnetic resonance (CMR) can safely be performed in most patients with implanted active cardiac devices. Standard procedures for pre- and post-scanning management of the device and potential CMR-associated device malfunctions need to be in place. In VT patients, imaging-specifically MR-may help to determine scar location and mural distribution in patients with ischaemic and non-ischaemic cardiomyopathy beyond evaluating the underlying structural heart disease. Future directions in imaging may include the ability to register multiple imaging modalities and novel high-resolution modalities, but also refinements of imaging-guided ablation strategies are expected.

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.

Cardiovascular imaging in cardio-oncology

Cancer therapy may lead to cardiovascular complications and can promote each aspect of cardiac disease manifestation, such as vascular disease including coronary heart disease, myocardial diseases including heart failure, structural heart diseases including valvular heart diseases, and rhythm disorders. All potential complications of cancer therapy onto the cardiovascular system require imaging for diagnostic workup as well as monitoring of therapy. Transthoracic echocardiography (TTE) is the most frequently used tool for assessment of cardiac function during or after cancer therapy in daily clinical routine. With modern techniques like strain analysis, echocardiography allows to detect a variety of cardiac diseases as caused by cancer therapy even at subclinical stages. For further workup, specific imaging techniques including nuclear imaging are needed in a multimodality imaging approach to in detail characterize the underlying pathophysiology and to improve the management of the patients. Therefore, the field of imaging in cardio-oncology is rapidly growing. This review article will give an overview about existing literature regarding the role of imaging in the diagnostic evaluation and management of therapy in patient with prior or ongoing cancer therapy.

Pulmonary veins stenosis after catheter ablation of atrial fibrillation as the cause of haemoptysis: three cases and a literature review

BACKGROUND

Haemoptysis is a common clinical symptom with a complicated aetiology. Patients usually visit pulmonologists initially and are misdiagnosed due to physician ignorance regarding the rare causes of haemoptysis.

METHODS

We report three cases of haemoptysis due to pulmonary vein stenosis accompanied by catheter ablation for atrial fibrillation and review the related literature.

RESULTS

The three patients presented haemoptysis and they all had the history of catheter ablation. They received kinds of non-invasive and invasive diagnostic and therapeutic procedures. Finally they were confirmed to have pulmonary vein stenosis by either pulmonary angiography or thorax computed tomography three-dimensional reconstructions.

CONCLUSIONS

Haemoptysis could be caused by pulmonary vein stenosis secondary to catheter ablation for atrial fibrillation. Doctors should be aware of this rare aetiology.

256-Slice coronary computed tomographic angiography in patients with atrial fibrillation: optimal reconstruction phase and image quality

OBJECTIVES

To assess the optimal reconstruction phase and the image quality of coronary computed tomographic angiography (CCTA) in patients with atrial fibrillation (AF).

METHODS

We performed CCTA in 60 patients with AF and 60 controls with sinus rhythm. The images were reconstructed in multiple phases in all parts of the cardiac cycle, and the optimal reconstruction phase with the fewest motion artefacts was identified. The coronary artery segments were visually evaluated to investigate their assessability.

RESULTS

In 46 (76.7 %) patients, the optimal reconstruction phase was end-diastole, whereas in 6 (10.0 %) patients it was end-systole or mid-diastole, and in 2 (3.3 %) patients it was another cardiac phase. In 53 (88.3 %) of the controls, the optimal reconstruction phase was mid-diastole, whereas it was end-systole in 4 (6.7 %), and in 3 (5.0 %) it was another cardiac phase. There was a significant difference between patients with AF and the controls in the optimal phase (p < 0.01) but not in the visual image quality score (p = 0.06).

CONCLUSIONS

The optimal reconstruction phase in most patients with AF was the end-diastolic phase. The end-systolic phase tended to be optimal in AF patients with higher average heart rates.

KEY POINTS

The optimal reconstruction phase in 76.7 % of patients with atrial fibrillation (AF) was end-diastole. The end-systolic phase was optimal in AF patients with higher heart rates. ECG and heart-rate control are necessary to obtain end-diastolic images with fewer motion artefacts.

The incidence, diagnosis, and management of pulmonary vein stenosis as a complication of atrial fibrillation ablation

PURPOSE

Pulmonary vein isolation (PVI) during ablation of atrial fibrillation (AF) is associated with pulmonary vein stenosis (PVS). Although the reported incidence of PVS has fallen in recent years, the precise rate of PVS is unknown. Coherent guidelines for screening and treatment of PVS are not established. We reviewed literature to investigate the incidence, diagnosis, and management of PVS as a complication of PVI.

METHODS

We reviewed 41 manuscripts that described a total of 4,615 subjects (median, 84 subjects/study).

RESULTS

The incidence of PVS after PVI reported in literature from 1999 to 2004 ranges from 0 to 44% (mean, 6.3%; median, 5.4%), whereas studies after 2004 report an incidence of 0-19% (mean, 2%; median, 3.1%; p < 0.001). PVS symptoms typically occur with reduction of lung perfusion by 20-25%. Variable criteria exist for diagnosis of PVS by magnetic resonance imaging, computed tomography, and perfusion imaging. The restenosis rate for treatment with balloon angioplasty ranges from 30 to 87% (mean, 60%; median, 47%), compared with immediate stenting that ranges from 14 to 57% (mean, 34%; median, 33%).

CONCLUSIONS

Recent peer-reviewed articles suggest that PVI carries a 3-8% risk of developing PVS, but they likely underestimate the incidence of PVS, as specific screening and diagnostic guidelines are not established. Imaging modalities should be used to screen patients after ablation of AF since early recognition of PVS improves treatment outcomes. Treatment with angioplasty and stent placement can improve symptoms and lung perfusion but the benefit of treatment with immediate stent placement remains controversial. It is critical to maintain a high clinical index of suspicion for PVS in at-risk individuals to ensure timely detection and treatment.

Development of site-specific locking plates for acetabular fractures

Site-specific locking plates have gained popularity for the treatment of fractures. However, the clinical use of a site-specific locking plate for acetabular fractures remains untested due to production limits. To design a universal site-specific locking plate for acetabular fractures, the 3-dimensional (3D) photographic records of 171 pelvises were retrospectively studied to generate a universal posterior innominate bone surface. Using 3D photographical processing software, the 3D coordinate system was reset according to bony landmarks and was scaled based on the acetabular diameter to allow a direct comparison between surfaces. The measured surface was separated into measurement units. At each measurement unit, the authors calculated the average z-axis values in all samples and obtained the 3D coordinate values of the point cloud that could be reconstructed into the universal surface. A plate was subsequently designed in 3D photographical processing software, and the orientation and distribution of locking screws was included. To manufacture a plate, the data were entered into Unigraphics NX version 6.0 software (Siemens PLM Software, Co, Ltd, Plano, Texas) and a CNC digital milling machine (FANUC Co, Ltd, Yamanashi, Japan). The resulting locking plate fit excellently with the reduced bone surface intraoperatively. Plate contouring was avoided intraoperatively. Universal 3.5-mm locking screws locked successfully into the plate, and their orientations were consistent with the design. No screw yielded to acetabular penetration. This method of designing a site-specific acetabular locking plate is practical, and the plates are suitable for clinical use. These site-specific locking plates may be an option for the treatment of acetabular fractures, particularly in elderly patients.

Alteration in pulmonary perfusion due to iatrogenic pulmonary vein stenosis: A mimicker of pulmonary embolism

Iatrogenic pulmonary vein stenosis (PVS) is a known, yet rare, complication of atrial radiofrequency ablation. Alterations in pulmonary perfusion may mimic massive pulmonary embolism on a ventilation/perfusion (V/Q) scintigraphy. This is particularly important due to the overlap in presenting clinical symptoms. The present case illustrates the functional significance of PVS and the changes in perfusion in response to angioplasty.

[Cardiac computed tomography and ablation of atrial fibrillation]

Both cardiac computed tomography (CT) and interventional electrophysiology (EP) have evolved considerably in recent years. Technical improvements in CT have significantly reduced the radiation dose in cardiac applications. This imaging technology plays an important role in preprocedural planning and guidance of the procedures in many EP centers worldwide. Furthermore, CT is the imaging modality of choice to diagnose relevant complications in ablation of atrial fibrillation, e.g. pulmonary vein stenosis or atrioesophageal fistula. In anatomically driven ablation procedures, such as balloon-based procedures in atrial fibrillation, detailed analysis of the relevant cardiac structures is absolutely crucial not only to reduce radiation exposure and procedure times but also to improve ablation success and to reduce the occurrence of complications. Current software applications enable 3-dimensional reconstruction of cardiac images and the integration into electroanatomical navigation systems. This article reviews the available evidence in this field and highlights recent developments in image guidance for ablation of atrial fibrillation.

Noninvasive coronary angiography using dual-source computed tomography in patients with atrial fibrillation

OBJECTIVES

Despite constant improvements in scanner technology, reliable visualization of the coronary arteries with multislice spiral CT angiography (CTA) remains a major challenge in patients with atrial fibrillation (AF). The purpose of this study was to assess the image quality of coronary CT angiograms with coronary angiography, using a dual-source CT scanner (DSCT), comparing systolic and diastolic reconstruction techniques. Additionally, we sought to evaluate the diagnostic accuracy of DSCT with coronary angiography as the standard of reference.

MATERIALS AND METHODS

Sixty-eight patients with permanent AF were imaged on a DSCT system, with a temporal resolution of 82 milliseconds. The volume and flow rate of the contrast medium were adapted to the patient's body weight. The patients were not receiving any drugs for heart rate regulation. Each dataset was reconstructed at an absolute delay determined from the R wave at 300 milliseconds (ie, systolic reconstruction), as well as at 70% of the RR-cycle (diastolic reconstruction). Twenty-one patients underwent both DSCT and coronary angiography. Two blinded independent readers assessed significant stenoses (> or =50%), and image quality in terms of visibility and artifacts (4-point rating scale: 1 = excellent, 2 = good, 3 = poor, 4 = insufficient) on a per-patient- and a per-segment-based analysis (15-segment AHA model) for both the systolic and diastolic datasets. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated.

RESULTS

: During 68 DSCT examinations, the mean heart rate ranged between 26 and 181 beats per minute (77 +/- 25). In the patient-based analysis, the image qualities of 64 of 68 CT angiograms (94%) were high enough to permit diagnosis, ie, 4 of 68 (6%) datasets were considered nonevaluable. Segment-based, a total of 898 of 979 coronary artery segments were rated as diagnostically evaluable (92%).In 57 of 68 evaluable patients (84%) the reconstructions in stole had fewer motion artifacts and thus showed superior image quality. The median image quality of all CT datasets was 2. In 21 patients undergoing both coronary angiography and DSCT, the overall sensitivity, specificity, positive predictive value, and negative predictive value for the diagnosis of significant stenoses were 89% (16 of 18), 98% (260 of 265), 76% (16 of 21), and 99% (260 of 262), respectively, in the per-segment analysis (including 283 vessel segments) and 90% (9 of 10), 82% (9 of 11), 82% (9 of 11), and 90% (9 of 10), respectively, in the patient-based analysis.

CONCLUSIONS

The image quality of coronary CT angiograms obtained with a DSCT is satisfactory in most patients with AF. In the majority of patients with high and irregular heart rate, the absolute forward approach with end-systolic reconstruction 300 milliseconds after the R-peak yield a higher image quality than diastolic reconstructions. As a result of a significant improvement in temporal resolution, DSCT coronary angiography is feasible in patients with AF and can be used to exclude coronary artery disease in this patient cohort.

Preablation assessment for the left atrium: comparison of ECG-gated cardiac CT with echocardiography

RATIONALE AND OBJECTIVES

Evaluate the role of two-dimensional echocardiography and electrocardiographically (ECG)-gated contrast-enhanced multislice computed tomographic (MSCT) cardiac imaging to assess cardiac anatomy, specifically pulmonary venous anatomy and left atrial thrombus, in a selected group of patients before catheter-based atrial fibrillation ablation.

MATERIALS AND METHODS

Left atrial anatomy and associated findings in 34 consecutive patients scheduled for electrophysiologic testing who underwent both echocardiography and ECG-gated 16-slice MSCT cardiac imaging were retrospectively compared. Results from two-dimensional transthoracic echocardiography (TTE), cardiac MSCT, electrophysiologic study (EPS), and transesophageal echocardiography (TEE) (when performed) were taken from the official medical record without prior knowledge of this study when interpretation was rendered for clinical use. Electronic record review included: presence of left atrial thrombus (defined as constant filling defect on at least two echocardiographic views or filling defect on computed tomography) and location, pulmonary venous anatomy, and other cardiac, mediastinal, or pulmonary abnormalities.

RESULTS

Left atrial thrombus was identified by cardiac MSCT alone in five patients (15%). Pulmonary venous variants were identified with cardiac MSCT in two patients (6%). Both MSCT and echocardiography were normal in 17 subjects (79%). Echocardiography was better at identifying associated valvular abnormalities that were seen in 10 patients (29%). Cardiac MSCT angiography alone identified other cardiac and noncardiac abnormalities, including suspicious pulmonary malignancy, mediastinal adenopathy, and coronary stenosis in 15 patients (44%).

CONCLUSIONS

Echocardiography and cardiac MSCT angiography often provide complimentary findings during the preprocedural evaluation for patients with atrial fibrillation requiring ablation. Cardiac MSCT may provide significant additional information about the left atrium, mediastinum, coronary circulation, and visualized lung fields. Based on this study, we would advise that patients considered for radiofrequency ablation for uncontrolled right atrial fibrillation have both echocardiography and ECG-gated contrast-enhanced cardiac MSCT performed as part of the preprocedure evaluation.

Superiority of synchrony of 256-slice cone beam computed tomography for acquiring pulsating objects. Comparison with conventional multislice computed tomography

PURPOSE

A prototype 256-slice cone beam computed tomography (CT) provides complete volumetric data within a single gantry rotation (1 s/rotation) with 0.5 mm slice-thickness.

MATERIALS AND METHODS

Calcified phantoms (200-400 HU) were attached to the balloon of a pulsating phantom and moved at a rate of 5-90/min. Acquisition was performed during one to-and-fro motion at each pulsation rate without electrocardiogram (ECG)-gating. Each period was divided into 10 phases, and compared to conventional multislice CT scanning without ECG-gating.

RESULTS

At 5-20/min, the configuration of calcified phantoms continued to the through-plane without gaps. At 60/min, duplicated calcified phantoms at end-systole and end-diastole were observed without motion. At 90/min, motion could be observed without gaps but was more blurred, and total calcified volume, Agatston scores, mean and max CT values of three phantoms were almost equal compared with those at static state. However, at 60/min, total calcified volume, scores, mean and max CT values of three phantoms were decreased to 64%, 37%, 80% and 56%, respectively, compared with those at static state. In multislice CT, even at lower rates, there were gaps in the through-plane. At 60/min, total calcified volume, scores, mean and max CT values of three phantoms were decreased to only 8%, 3%, 79% and 53%, respectively, compared with static state.

CONCLUSION

This new prototype's unique character (synchrony) enables the acquisition of pulsating objects. These can be acquired without gaps in the through-plane even in the absence of ECG-gating. However, its present temporal resolution only permits accurate quantitative evaluation of calcium up to 20/min.

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.

Transesophageal echocardiography: A follow-up tool after catheter ablation of atrial fibrillation and interventional therapy of pulmonary vein stenosis and occlusion

BACKGROUND

Pulmonary vein stenosis (PVS) has been described as a complication after primary catheter ablation of atrial fibrillation (Afib). The purpose of this study was to evaluate the utility of transesophageal echocardiography (TEE) as follow-up tool after catheter ablation of Afib and interventional therapy of PVS and pulmonary vein occlusion (PVO).

METHODS

We report on 28 patients with stenosis (PVS) of 33 pulmonary veins (PVs) and total PVO of 4 veins complicating ablation of Afib assessed by angiography and/or magnetic resonance imaging (MRI). Subsequently, transseptal PV angiograms were performed, followed by recanalization of three totally occluded PVs and balloon dilatation of seven severe PVS (in four cases combined with PV stenting). PVs were analyzed by multiplane TEE in an intraindividual comparison of preablation/preintervention and follow-up measurements of mean and peak flow velocity, velocity time integrals, and diameters.

RESULTS

Of a total of 28 patients, 14 had mild PVS (n = 14), 9 had moderate PVS (n = 10), 6 had severe PVS (n = 8), and 4 patients showed totally occluded PVs (n = 4). In multivariate analysis flow velocities and vessel diameters showed significant differences (mild, moderate, and severe PVS and PVO; p = 0.001). Interventional benefits of balloon dilatation (n = 10) and stent implantation (n = 4), as well as in-stent restenosis could be detected (p = 0.014). In all recanalized vessels TEE showed reestablished flow. In occluded PVs no flow was detectable. The TEE vessel diameters correlated with angiography data (r = 0.87) and computed tomography/MRI (r = 0.90).

CONCLUSIONS

TEE can be used as a follow-up tool after interventional therapy in patients after catheter ablation and acquired PVS/PVO. Restenosis/in-stent restenosis can be identified by analyzing the vessel diameters and blood flow characteristics.

CT of the Pulmonary Veins

Atrial fibrillation (AF) is a common cardiac rhythm disturbance and its incidence is increasing. Radiofrequency catheter ablation (RFCA) is a highly successful therapy for treating AF, and its use is becoming more widespread; however, with its increasing use and evolving technique, known complications are better understood and new complications are emerging. Computed tomography (CT) of the pulmonary veins, or more correctly, the posterior left atrium (LA), has an established role in precisely defining the complex anatomy of the LA and pulmonary veins preablation and has an expanding role in identifying the myriad of possible complications postablation. The purposes of this article are: to review AF and RFCA; to discuss CT evaluation of the LA and pulmonary veins preablation; and to review the complications of RFCA focusing on the role of CT postablation.

Imaging in percutaneous ablation for atrial fibrillation

Percutaneous ablation for electrical disconnection of the arrhythmogenic foci using various forms of energy has become a well-established technique for treating atrial fibrillation (AF). Success rate in preventing recurrence of AF episodes is high although associated with a significant incidence of pulmonary vein (PV) stenosis and other rare complications. Clinical workup of AF patients includes imaging before and after ablative treatment using different noninvasive and invasive techniques such as conventional angiography, transoesophageal and intracardiac echocardiography, computed tomography (CT) and magnetic resonance imaging (MRI), which offer different information with variable diagnostic accuracy. Evaluation before percutaneous ablation involves assessment of PVs (PV pattern, branching pattern, orientation and ostial size) to facilitate position and size of catheters and reduce procedure time as well as examining the left atrium (presence of thrombi, dimensions and volumes). Imaging after the percutaneous ablation is important for assessment of overall success of the procedure and revealing potential complications. Therefore, imaging methods enable depiction of PVs and the anatomy of surrounding structures essential for preprocedural management and early detection of PV stenosis and other ablation-related procedures, as well as long-term follow-up of these patients.

Technology Insight: possible applications of multislice computed tomography in clinical cardiology

With the introduction of four-slice scanners in 1999, multislice CT (MSCT) technology became available for investigative examination of the heart. Since then, MSCT technology has undergone rapid technical progress; temporal and spatial resolutions have been especially improved. The improved diagnostic image quality has led to more possible uses of MSCT being defined. At present, issues such as visualization of coronary artery bypass grafts, detection of stenoses of native coronary arteries, description of coronary anomalies, and calcium scoring, can be investigated reasonably well. Other features, such as plaque imaging and visualization of intracoronary stents, need further evaluation. A large number of factors, however, such as heart rate, atrial fibrillation, breathing artefacts and severe calcification, still influence image quality and reduce validity. In this article we provide a summary of current fields of application of cardiac MSCT. The word 'indication' is consciously avoided because official guidelines for the use of MSCT in heart examination have not yet been issued. Hopefully, prospective multicenter trials will be performed soon, providing more data with which to establish guidelines for both cardiologist and radiologist.