Prospective randomized comparison between the conventional electroanatomical system and three-dimensional rotational angiography during catheter ablation for atrial fibrillation

Intra-procedural three-dimensional rotational angiography in cryoballoon ablation for atrial fibrillation

Cryoballoon (CB) is an established technology for atrial fibrillation (AF) ablation and is usually performed using solely fluoroscopy. We aimed to study the feasibility of three-dimensional rotational angiography (3DRA) as intra-procedural imaging in CB ablation. Analyzed data were retrospectively collected from patients that underwent second generation CB ablation from February 2015 to August 2017. We studied 68 consecutive patients that received 3DRA (3DRA group). Sixty-six patients who received conventional X-ray imaging served as a control group. 3DRA was performed via an introducer placed in the left atrium. Angiographic images were segmented and fused with live fluoroscopy to guide the ablation. We have analyzed 134 CB patients (73.8% male, 56.9 ± 11.4 years). Paroxysmal AF was present in 77.6% of patients. 3DRA was successfully performed in all 3DRA group patients. The mean procedure time was significantly shorter in the control group (82.4 ± 26.3 min) than in the 3DRA group (121.1 ± 21.4 min) (p < 0.0001). Total radiation dose (419.3 ± 317.9 vs 998.3 ± 673 mGy, p < 0.0001) and contrast administration (83.2 ± 22.3 mL vs 191.6 ± 33.4 mL, p < 0.0001) were significantly lower in control group. There was no significant difference in 2-year success rate, 35.2% of patients had AF recurrence in the 3DRA group and 30.3% in the control group (p = 0.584). Major complications occurred in 2.9% and 1.5% of patients in 3DRA group and control group, respectively (p = 1.000). 3DRA is a feasible method of intra-procedural imaging to guide CB ablation. However, it prolongs procedure time, increases radiation dose and contrast administration with no significant effect on procedure outcomes and complication rates.

Esophageal positions relative to the left atrium; data from 293 patients before catheter ablation of atrial fibrillation

Aims

Three-dimensional rotational angiography (3DRA) of the left atrium (LA) and the esophagus is a simple and safe method for analyzing the relationship between the esophagus and the LA during catheter ablation of atrial fibrillation. The purpose of this study is to describe the location of the esophagus relative to the LA and mobility of the esophagus during ablation procedure.

Methods

From 3/2011 to 9/2015, 3DRA of the LA and esophagus was performed in 326 patients before catheter ablation of atrial fibrillation. 3DRAwas performed with visualization of the esophagus via peroral administration of a contrast agent. The positions of the esophagus were determined at the beginning of the procedure, for part of patients also at the end of procedure with contrast esophagography.

Results

The most frequent position is behind the center of the LA (91 pts., 31.9%) The least frequent position is behind the right pulmonary veins (27 pts., 9.4%). The average shift of the esophagus position was 3.36 ± 2.15 mm, 3.59 ± 2.37 mm and 3.67 ± 3.23 mm for superior, middle and inferior segment resp.

Conclusions

The position of the esophagus to the LA is highly variable. The most common position of the esophagus relative to the LA is behind the middle and left part of the posterior wall of the LA. The least frequently observed position is behind the right pulmonary veins. No significant position change of esophagus motion from before to after the ablation procedure in the majority (≥95%) of the patients was observed.

Prospective randomized comparison of rotational angiography with three-dimensional reconstruction and computed tomography merged with electro-anatomical mapping: a two center atrial fibrillation ablation study

PURPOSE

To compare the efficacy and accuracy of rotational angiography with three-dimensional reconstruction (3DATG) image merged with electro-anatomical mapping (EAM) vs. CT-EAM.

METHODS

A prospective, randomized, parallel, two-center study conducted in 36 patients (25 men, age 65 ± 10 years) undergoing AF ablation (33 % paroxysmal, 67 % persistent) guided by 3DATG (group 1) vs. CT (group 2) image fusion with EAM. 3DATG was performed on the Philips Allura Xper FD 10 system. Procedural characteristics including time, radiation exposure, outcome, and navigation accuracy were compared between two groups.

RESULTS

There was no significant difference between the groups in total procedure duration or time spent for various procedural steps. Minor differences in procedural characteristics were present between two centers. Segmentation and fusion time for 3DATG or CT-EAM was short and similar between both centers. Accuracy of navigation guided by either method was high and did not depend on left atrial size. Maintenance of sinus rhythm between the two groups was no different up to 24 months of follow-up.

CONCLUSION

This study did not find superiority of 3DATG-EAM image merge to guide AF ablation when compared to CT-EAM fusion. Both merging techniques result in similar navigation accuracy.

Multi-phase rotational angiography of the left ventricle to assist ablations: feasibility and accuracy of novel imaging

AIMS

Interventional left ventricular (LV) procedures integrating static 3D anatomy visualization are subject to mismatch with dynamic catheter movements due to prominent LV motion. We aimed to evaluate the accuracy of a recently developed acquisition and post-processing protocol for low radiation dose LV multi-phase rotational angiography (4DRA) in patients.

METHODS AND RESULTS

4DRA image acquisition of the LV was performed as investigational acquisition in patients undergoing left-sided ablation (11 men; BMI = 24.7 ± 2.5 kg/m²). Iodine contrast was injected in the LA, while pacing from the RA at a cycle length of 700 ms. 4DRA acquisition and reconstruction were possible in all 11 studies. Reconstructed images were post-processed using streak artefact reduction algorithms and an interphase registration-based filtering method, increasing contrast-to-noise ratio by a factor 8.2 ± 2.1. This enabled semi-automatic segmentation, yielding LV models of five equidistant phases per cardiac cycle. For evaluation, off-line 4DRA fluoroscopy registration was performed, and the 4DRA LV contours of the different phases were compared with the contours of five corresponding phases of biplane LV angiography, acquired in identical circumstances. Of the distances between these contours, 95% were <4 mm in both incidences. Effective radiation dose for 4DRA, calculated by patient-specific Monte-Carlo simulation, was 5.1 ± 1.1 mSv.

CONCLUSION

Creation of 4DRA LV models in man is feasible at near-physiological heart rate and with clinically acceptable radiation dose. They showed high accuracy with respect to LV angiography in RAO and LAO. The presented technology not only opens perspectives for full cardiac cycle dynamic anatomical guidance during interventional procedures, but also for 3DRA without need for very rapid pacing.

[Interventional treatment for paroxysmal atrial fibrillation : which is the optimal ablation approach?]

Atrial fibrillation is one of the most common arrhythmias and effects probably more than 35 million people worldwide. The incidence in patients older than 70 years of age is as high as 10%. One can expect that according to our demographic development this entity will be increasingly important within the next years and decades. Along with the well know and established but at the same time limited opportunities of pharmacological treatment option of this arrhythmia, catheter ablation has evolved as a safe and effective treatment option. Electrical isolation of the pulmonary vein remains the standard of care and results in success rates as high as 80% using modern ablation strategies. Optimization of procedural and ablation techniques has lead to this high success rates. Different energy sources are available, such as radiofrequency, cryoenergy and laser are widely used today to treat patients with symptomatic atrial fibrillation. PV isolation using a so called "single-shot" ablation approach has shown to be effective with a reduced requirement of periprocedural resources and therefore resulting in wider application of this treatment not only in specialized electrophysiological centers. The rapid development in this field leads to the question which approach can be used as the most likely to result in the highest success and least complication rates. This question will be addressed in the following manuscript.

The Growing Culture Of A Minimally Fluoroscopic Approach In Electrophysiology Lab

Most of interventional procedures in cardiology are carried out under fluoroscopic imaging guidance. Besides other peri-interventional risks, radiation exposure should be considered for its stochastic (inducing malignancy) and deterministic effects on health (tissue reactions like erythema, hair loss and cataracts). In this article we analized the radiation risk from cardiovascular imaging to both patients and medical staff and discusses how customize the X-ray system and how to implement shielding measures in the cath lab. Finally, we reviewed the most recent developments and the latest findings in catheter navigation and 3D electronatomical mapping systems that may help to reduce patient and operator exposure.

Cost analysis of periprocedural imaging in patients undergoing catheter ablation for atrial fibrillation

Cardiovascular imaging is an important part of procedural planning and safety for catheter ablation of atrial fibrillation (AF). However, the costs of imaging surrounding catheter ablation of AF have not been described. Medicare fee-for-service data were used to evaluate Medicare expenditures before, during, and after catheter ablation for AF from July 2007 to December 2009. Among 11,525 patients who underwent catheter ablation for AF, the mean overall expenditure on the day of the procedure was $14,455 (SD $7,441). The mean imaging expenditure in the periprocedural period, which included the 30 days before the catheter ablation and the day of the ablation itself, was $884 (SD $455). Periprocedural imaging expenditures varied by the imaging strategy used, ranging from a mean of $557 (SD $269) for patients with electroanatomic mapping only to $1,234 (SD $461) for patients with electroanatomic mapping, transesophageal echocardiogram, and computed tomography or magnetic resonance imaging. Mean patient-level imaging expenditures varied by provider (mean $872, SD $249). Periprocedural imaging expenditures also varied by patient risk, with mean expenditures of $862 (SD $444) for patients with a CHADS2 score of ≥2 compared with $907 (SD $466) for CHADS2 score<2 (p<0.001). In conclusion, periprocedural imaging accounts for approximately 6% of mean Medicare expenditures for catheter ablation of AF. The expenditures for periprocedural imaging vary both at the patient and at the provider level and they are inversely related to stroke risk by CHADS2 score.

Practical ways to reduce radiation dose for patients and staff during device implantations and electrophysiological procedures

Despite the advent of non-fluoroscopic technology, fluoroscopy remains the cornerstone of imaging in most interventional electrophysiological procedures, from diagnostic studies over ablation interventions to device implantation. Moreover, many patients receive additional X-ray imaging, such as cardiac computed tomography and others. More and more complex procedures have the risk to increase the radiation exposure, both for the patients and the operators. The professional lifetime attributable excess cancer risk may be around 1 in 100 for the operators, the same as for a patient undergoing repetitive complex procedures. Moreover, recent reports have also hinted at an excess risk of brain tumours among interventional cardiologists. Apart from evaluating the need for and justifying the use of radiation to assist their procedures, physicians have to continuously explore ways to reduce the radiation exposure. After an introduction on how to quantify the radiation exposure and defining its current magnitude in electrophysiology compared with the other sources of radiation, this position paper wants to offer some very practical advice on how to reduce exposure to patients and staff. The text describes how customization of the X-ray system, workflow adaptations, and shielding measures can be implemented in the cath lab. The potential and the pitfalls of different non-fluoroscopic guiding technologies are discussed. Finally, we suggest further improvements that can be implemented by both the physicians and the industry in the future. We are confident that these suggestions are able to reduce patient and operator exposure by more than an order of magnitude, and therefore think that these recommendations are worth reading and implementing by any electrophysiological operator in the field.

The Role of Three-dimensional Rotational Angiography in Atrial Fibrillation Ablation

Three-dimensional (3D) imaging became the cornerstone of catheter guidance in atrial fibrillation (AF) ablation procedures during the last few years. Multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) have been the technologies of choice for pre-procedural imaging of the left atrium (LA) and the pulmonary veins to make lesions more precisely set in a highly variable and difficult to understand 3D environment. These technologies have been used not only for pre-procedural orientation but have also been overlayed to fluoroscopic views in many fluoroscopy-guided ablation procedures. As image integration into non-fluoroscopic 3D imaging systems became available, 3D reconstructions of MSCT and MRI became the standard approach in many centres. However, 3D imaging is not a cornerstone during ablation as it is not indispensable and ablation can be performed without. Although rare, some very important and key centres do not routinely use 3D imaging during ablation. Being remote to the ablation procedure, these imaging technologies may have the disadvantage of not reflecting the current status of a variable LA volume and scheduling of an additional diagnostic procedure may complicate the workflow of AF ablation procedures. Intra- procedural imaging techniques are likely to overcome both issues. Beside others, rotational angiography has been introduced for proving highly actual imaging by intra-procedural acquisition of 3D shells suitable for overlay to fluoroscopy without need for registration and image integration into 3D mapping systems registered by point-by-point electroanatomical mapping or 3D echocardiographic imaging.

Three-dimensional computed tomography overlay for pulmonary vein antrum isolation: Follow-up and clinical outcomes

BACKGROUND

To facilitate the creation of circumferential lines in pulmonary vein (PV) antrum isolation, three-dimensional (3D) navigation systems are used widely. Alternatively, 3D reconstructions of the left atrium (LA) can be superimposed directly on fluoroscopy to guide ablation catheters and to mark ablation sites.

METHODS

In 71 atrial fibrillation patients circumferential PV ablation was performed. 3D reconstructions of the LA were derived from contrast cardiac-computed tomography and circumferential PV isolation was performed. In subsequent ablation procedures, veins were re-isolated, and defragmentation or linear lesions were performed if necessary.

RESULTS

Adequate 3D reconstructions were formed and registered to fluoroscopy in all patients. All veins, except 2 in one single patient, could be isolated, resulting in freedom of AF in 45 patients (63 %). In 19 patients a second procedure was performed, in which 2.7 ± 1.1 PV per patient were re-isolated; in 3 patients a third procedure was performed. After follow-up of 15 ± 8 months, 51 (91 %) of patients with paroxysmal and 10 (67 %) with persistent AF were free of AF.

CONCLUSIONS

The results of 3D overlay for circumferential PV isolation are good, although the reconduction rate and need for subsequent ablations remains high, and the outcomes of this technique appear to be equivalent to other mapping techniques.

2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design

This is a report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation, developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology and the European Cardiac Arrhythmia Society (ECAS), and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS). This is endorsed by the governing bodies of the ACC Foundation, the AHA, the ECAS, the EHRA, the STS, the APHRS, and the HRS.

Comparison of aortic root measurements in patients undergoing transapical aortic valve implantation (TA-AVI) using three-dimensional rotational angiography (3D-RA) and multislice computed tomography (MSCT): differences and variability

To evaluate for the first time the degree of compliance between conventional multislice computed tomography (MSCT) and three-dimensional rotational angiography (3D-RA) in measuring relevant dimensions of the aortic annulus, the aortic root and the thoracic aorta in patients undergoing TA-AVI. Twenty-seven patients (82 ± 11 years) with severe aortic stenosis received contrast enhanced ECG gated MSCT prior to TA-AVI and intra-procedural rotational angiography. The aortic annulus size, the distance to the coronary ostia and diameters of the aortic root and the thoracic aorta were measured with both methods by two observers blinded to each other. Linear regression and Bland-Altman analysis were performed to determine the degree of compliance between both methods. The limits of agreement were within two standard deviations for all measurements and with high correlation especially for the supra-annular dimensions. Sizing of the aortic annulus revealed lower interobserver variability for MSCT than for 3D-RA with a maximum deviation of 2.1 ± 2.5 and 1.7 ± 2.8 mm for diameter measurements and for the effective diameter, respectively. With current protocols intra-procedural 3D-RA provides good image quality especially for structures above the aortic annulus. Due to a lower interobserver variability in sizing the aortic annulus MSCT remains more suitable for aortic root assessment prior to TA-AVI.

Analysis of electrical and mechanical left atrial properties in patients with persistent atrial fibrillation

The study of left atrial (LA) mechanical function during atrial fibrillation (AFib) can provide valuable information, particularly if such profiling is related to the cavity electrical substrate and conveys prognostic information. To assess if there is any relation between LA mechanical and electrical asynchrony and if such evaluation can be of interest in stratifying AFib patients. 50 patients with persistent AFib who underwent electrical cardioversion (CV) were evaluated with pre-CV atrial electrograms (AEGs). Electrical asynchrony was classified according to Wells' patterns of AEGs, ranging from most organized (I) to most dispersed (III) one. LA mechanical asynchrony was addressed by transthoracic 2D-speckle-tracking echo and quantified according to time-to-peak standard deviation (TP-SD) of wall strains and their peak values (PS) before CV, after 24 h, at 1 month. Pre-CV a linear, inverse relation between TP-SD and PS (p < 0.001) and a direct linear relation between TP-SD and Wells' classes (p = 0.04) were observed. With sinus rhythm TP-SD decreased (p = 0.023) and PS increased (p < 0.001), suggesting improved LA mechanical milieu. A multivariate analysis, testing the effects of baseline variables in predicting post-CV recurrence of AFib, revealed that amount of TP-SD variation pre/24 h post-CV was the only independent predictor at 6 months (p = 0.046). Speckle tracking-derived LA parameters can describe LA wall forces during AFib, categorizing the asynchronous mechanistic profile of AFib that correlates with the degree of the dispersed LA electrical activity. The amount of changes in LA mechanical asynchrony pre/post-CV seems to have prognostic relevance in predicting SR maintenance.

Registration of 3D trans-esophageal echocardiography to X-ray fluoroscopy using image-based probe tracking

Two-dimensional (2D) X-ray imaging is the dominant imaging modality for cardiac interventions. However, the use of X-ray fluoroscopy alone is inadequate for the guidance of procedures that require soft-tissue information, for example, the treatment of structural heart disease. The recent availability of three-dimensional (3D) trans-esophageal echocardiography (TEE) provides cardiologists with real-time 3D imaging of cardiac anatomy. Increasingly X-ray imaging is now supported by using intra-procedure 3D TEE imaging. We hypothesize that the real-time co-registration and visualization of 3D TEE and X-ray fluoroscopy data will provide a powerful guidance tool for cardiologists. In this paper, we propose a novel, robust and efficient method for performing this registration. The major advantage of our method is that it does not rely on any additional tracking hardware and therefore can be deployed straightforwardly into any interventional laboratory. Our method consists of an image-based TEE probe localization algorithm and a calibration procedure. While the calibration needs to be done only once, the GPU-accelerated registration takes approximately from 2 to 15s to complete depending on the number of X-ray images used in the registration and the image resolution. The accuracy of our method was assessed using a realistic heart phantom. The target registration error (TRE) for the heart phantom was less than 2mm. In addition, we assess the accuracy and the clinical feasibility of our method using five patient datasets, two of which were acquired from cardiac electrophysiology procedures and three from trans-catheter aortic valve implantation procedures. The registration results showed our technique had mean registration errors of 1.5-4.2mm and 95% capture range of 8.7-11.4mm in terms of TRE.

Advances in imaging for atrial fibrillation ablation

Over the last fifteen years, our understanding of the pathophysiology of atrial fibrillation (AF) has paved the way for ablation to be utilized as an effective treatment option. With the aim of gaining more detailed anatomical representation, advances have been made using various imaging modalities, both before and during the ablation procedure, in planning and execution. Options have flourished from procedural fluoroscopy, electroanatomic mapping systems, preprocedural computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and combinations of these technologies. Exciting work is underway in an effort to allow the electrophysiologist to assess scar formation in real time. One advantage would be to lessen the learning curve for what are very complex procedures. The hope of these developments is to improve the likelihood of a successful ablation procedure and to allow more patients access to this treatment.