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.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

Twenty-five years of research in cardiac imaging in electrophysiology procedures for atrial and ventricular arrhythmias

Catheter ablation is nowadays considered the treatment of choice for numerous cardiac arrhythmias in different clinical scenarios. Fluoroscopy has traditionally been the primary imaging modality for catheter ablation, providing real-time visualization of catheter navigation. However, its limitations, such as inadequate soft tissue visualization and exposure to ionizing radiation, have prompted the integration of alternative imaging modalities. Over the years, advancements in imaging techniques have played a pivotal role in enhancing the safety, efficacy, and efficiency of catheter ablation procedures. This manuscript aims to explore the utility of imaging, including electroanatomical mapping, cardiac computed tomography, echocardiography, cardiac magnetic resonance, and nuclear cardiology exams, in helping electrophysiology procedures. These techniques enable accurate anatomical guidance, identification of critical structures and substrates, and real-time monitoring of complications, ultimately enhancing procedural safety and success rates. Incorporating advanced imaging technologies into routine clinical practice has the potential to further improve clinical outcomes of catheter ablation procedures and pave the way for more personalized and precise ablation therapies in the future.

Atrial Fibrillation Ablation: Impact of Intracardiac Echocardiography in Reducing Procedure Time and Hospitalization

BACKGROUND

Intracardiac echocardiography (ICE) allows visualization of cardiac structures and recognition of complications during atrial fibrillation ablation (AFA). Compared to transesophageal echocardiography (TEE), ICE is less sensitive to detecting thrombus in the atrial appendage but requires minimal sedation and fewer operators, making it attractive in a resource-constrained setting.

OBJECTIVE

To compare 13 cases of AFA using ICE (AFA-ICE group) with 36 cases of AFA using TEE (AFA-TEE group).

METHODS

This is a single-center prospective cohort study. The main outcome was procedure time. Secondary outcomes: fluoroscopy time, radiation dose (mGy/cm2), major complications, and length of hospital stay in hours. The clinical profile was compared using the CHA2DS2-VASc score. A p-value <0.05 was considered a statistically significant difference between groups.

RESULTS

The median CHA2DS2-VASc score was 1 (0-3) in the AFA-ICE group and 1 (0-4) in the AFA-TEE group. The total procedure time was 129 ± 27 min in the AFA-ICE group and 189 ± 41 min in the AFA-TEE group (p<0.001); the AFA-ICE group received a lower dose of radiation (mGy/cm2, 51296 ± 24790 vs. 75874 ± 24293; p=0.002), despite the similar fluoroscopy time (27.48 ± 9. 79 vs. 26.4 ± 9.32; p=0.671). The median length of hospital stay did not differ; 48 (36-72) hours (AFA-ICE) and 48 (48-66) hours (AFA-TEE) (p=0.27).

CONCLUSIONS

In this cohort, AFA-ICE was related to shorter procedure times and less exposure to radiation without increasing the risk of complications or the length of hospital stay.

Intra- and Postprocedural Multimodality Imaging in Atrial Fibrillation

Multi-modality imaging plays critical roles during and after procedures associated with atrial fibrillation. Transesophageal echocardiography is an invaluable tool for left atrial appendage occlusion during the procedure and at follow-up. Both cardiac computed tomography and cardiac magnetic resonance contribute to postprocedural evaluation of pulmonary vein isolation ablation. The present review is the second of a 2-part series where we discuss the roles of cardiac imaging in the evaluation and management of patients with atrial fibrillation, focusing on intraprocedural and postprocedural assessment, including the clinical evidence and outcomes data supporting this future applications.

Treatment Options in AF Patients with Cancer; Focus on Catheter Ablation

Longer life expectancy along with advancements in cancer and atrial fibrillation (AF) therapies and treatment strategies have led to an increase in the number of individuals with both diseases. As a result, the complicated management of these patients has become crucial, necessitating individualised treatment that considers the bi-directional relationship between these two diseases. On the one hand, giving appropriate pharmaceutical therapy is exceptionally difficult, considering the recognised thromboembolic risk posed by AF and malignancy, as well as the haemorrhagic risk posed by cancer. The alternative pulmonary vein isolation (PVI) ablation, on the other hand, has been inadequately explored in the cancer patient population; there is yet inadequate data to allow the clinician to unambiguously select patients that can undertake this therapeutic intervention. The goal of this review is to compile the most valuable data and supporting evidence about the characteristics, care, and therapy of cancer patients with AF. Specifically, we will evaluate the pharmaceutical options for a proper anticoagulant therapy, as well as the feasibility and safety of PVI in this population.

Cardiac Tomography and Cardiac Magnetic Resonance to Predict the Absence of Intracardiac Thrombus in Anticoagulated Patients Undergoing Atrial Fibrillation Ablation

Background: Pulmonary veins isolation (PVI) is a standard treatment for recurrent atrial fibrillation (AF). Uninterrupted anticoagulation for a minimum of 3 weeks before ablation and exclusion of left atrial (LA) thrombus with transesophageal echography (TEE) immediately before or during the procedure minimize peri-procedural risk. We aimed to demonstrate the utility of cardiac tomography (CT) and cardiac magnetic resonance (CMR) to rule out LA thrombus prior to PVI. Methods: Patients undergoing PVI for recurrent AF were retrospectively evaluated. Only patients that started anticoagulation at least 3 weeks prior to the CT/CMR and subsequently uninterrupted until the ablation procedure were selected. An intracardiac echo (ICE) catheter was used in all patients to evaluate LA thrombus. The results of CT/CMR were compared to ICE imaging. Results: We included 272 consecutive patients averaging 54.5 years (71% male; 30% persistent AF). Average CHA2DS2VASC score was 0.9 ± 0.83 and mean LA diameter was 42 ± 5.7 mm, 111 (41%) patients were on Acenocumarol and 161 (59%) were on direct oral anticoagulants. Anticoagulation was started 227 ± 392 days before the CT/CMR, and 291 ± 416 days before the ablation procedure. CT/CMR diagnosed intracardiac thrombus in two cases, both in the LA appendage. A new CT/CMR revealed resolution of thrombus after six additional months of uninterrupted anticoagulation. No macroscopic thrombus was observed in any patients with ICE (negative predictive value of 100%; p < 0.01). Conclusions: CT and MRI are excellent surrogates to TEE and ICE to rule out intracardiac thrombus in patients adequately anticoagulated prior AF ablation. This is true even for delayed procedures as long as anticoagulation is uninterrupted.

Long-term efficacy and impact on quality of life of atrial fibrillation catheter ablation in competitive athletes

BACKGROUND

Limited data are available on the efficacy of catheter ablation (CA) for sport-associated atrial fibrillation (AF), in particular at long term follow up. Moreover, the impact of AF CA on quality of life (QoL) in this population remains unknown. We aimed to determine AF CA efficacy in athletes, to assess the impact on athletes' QoL (with SF36 score) and on training capabilities in a long term follow up (FU).

METHODS

A total of 1215 AF patients' candidates to CA between January 2007 and December 2012, were retrospectively screened. Athletes were defined as patients performing ≥ 5h/week of vigorous sports, achieving a total of ≥1500 h lifetime sports activity, for at least one year before AF first symptomatic episode.

RESULTS

Out of 1215 AF patients, 133 were considered competitive athletes and underwent to CA. Overall, 43% of our cohort showed typical or atypical atrial flutter, which required a more extensive ablation procedure. Before AF, athletes used to practice for a mean of 8.5±2.7 h/week, while after the first AF episode the mean practice duration decreased to 2.82.5 h/week. At 10-year follow up, 83% of athletes did not present any recurrent event, and training capabilities increased up to 5.6±3.6 h/week after the procedure. Moreover, intense physical activity before AF CA was related to longterm AF recurrence rates (P = 0.05). QoL scores significantly improved in each single domains (P < 0.05).

CONCLUSIONS

AF CA represents an effective procedure to maintain sinus rhythm in athletes, with a significant improvement in QoL.

Applications of multimodality imaging for left atrial catheter ablation

Atrial arrhythmias, including atrial fibrillation and atrial flutter, may be treated through catheter ablation. The process of atrial arrhythmia catheter ablation, which includes patient selection, pre-procedural planning, intra-procedural guidance, and post-procedural assessment, is typically characterized by the use of several imaging modalities to sequentially inform key clinical decisions. Increasingly, advanced imaging modalities are processed via specialized image analysis techniques and combined with intra-procedural electrical measurements to inform treatment approaches. Here, we review the use of multimodality imaging for left atrial ablation procedures. The article first outlines how imaging modalities are routinely used in the peri-ablation period. We then describe how advanced imaging techniques may inform patient selection for ablation and ablation targets themselves. Ongoing research directions for improving catheter ablation outcomes by using imaging combined with advanced analyses for personalization of ablation targets are discussed, together with approaches for their integration in the standard clinical environment. Finally, we describe future research areas with the potential to improve catheter ablation outcomes.

The impact of current strategy using intracardiac echocardiography, lesion index, and minimum substrate ablation on clinical outcomes after catheter ablation procedure for atrial fibrillation

PURPOSE

We developed the intracardiac echocardiography (ICE) technique to minimize radiation exposure and other recent technology during ablation procedure for atrial fibrillation (AF). The aim of this study was to validate the impact of the current strategy using the recent technology for AF ablation on outcomes after procedure.

METHODS

We evaluated the safety and efficacy of the current strategy in consecutive set of patients undergoing first-time ablation for AF (N = 233) compared with the conventional strategy in earlier consecutive set of patients (N = 223). The current strategy included the technique of ICE to reduce radiation exposure, Ablation Index®-guided pulmonary veins isolation, and minimum substrate ablation targeting only for induced AF. Outcome measures were radiation exposure, procedure time, in-hospital adverse outcomes, and event-free survival from tachyarrhythmias.

RESULTS

Puncture-to-ablation time was slightly, but significantly increased in the current strategy than in the conventional strategy (48.0 minutes vs 44.7 minutes, P = .002), although total procedure time was significantly decreased in the current strategy (143.9 minutes vs 156.9 minutes, P < .001). Likewise, radiation time and absorbed dose were significantly decreased in the current strategy (9.8 minutes vs 38.8 minutes, P < .001; 102.3 mGy vs 490.5 mGy, P < .001). The incidence of overall in-hospital adverse outcomes was 3.9% in the current strategy and each complication rate was comparable with the conventional protocol. The event-free survival from recurrent atrial tachyarrhythmias was not significantly different between two groups (72.3% vs 77.1% at 2-year, P = .32).

CONCLUSION

The current strategy using the recent technology with ICE, lesion index, and minimum substrate ablation was feasible and reduced total procedure time and radiation exposure. However, the arrhythmia-free survival could not be improved.

Implementation of a zero fluoroscopic workflow using a simplified intracardiac echocardiography guided method for catheter ablation of atrial fibrillation, including repeat procedures

Objective

Pulmonary vein isolation (PVI) is the cornerstone of the interventional treatment of atrial fibrillation (AF). Traditionally, during these procedures the catheters are guided by fluoroscopy, which poses a risk to the patient and staff by ionizing radiation. Our aim was to describe our experience in the implementation of an intracardiac echocardiography (ICE) guided zero fluoroscopic (ZF) ablation approach to our routine clinical practice.

Methods

We developed a simplified ICE guided technique to perform ablation procedures for AF, with the aid of a 3D electroanatomical mapping system. The workflow was implemented in two phases: (1) the Introductory phase, where the first 16 ZF PVIs were compared with 16 cases performed with fluoroscopy and (2) the Extension phase, where 71 consecutive patients (including repeat procedures) with ZF approach were included. Standard PVI (and redoPVI) procedures were performed, data on feasibility of the ZF approach, complications, acute and 1-year success rates were collected.

Results

In the Introductory phase, 94% of the procedures could be performed with complete ZF with a median procedure time of 77.5 (73.5–83) minutes. In one case fluoroscopy was used to guide the ICE catheter to the atrium. There was no difference in the complication, acute and 1-year success rates, compared with fluoroscopy guided procedures. In the Extension phase, 97% of the procedures could be completed with complete ZF. In one case fluoroscopy was used to guide the transseptal puncture and in another to position the ICE catheter. Acute success of PVI was achieved in all cases, 64.4% patients were arrhythmia free at 1-year. Acute major complications were observed in 4 cases, all of these occurred in the redo PVI group and consisted of 2 tamponades, 1 transient ischemic attack and 1 pseudoaneurysm at the puncture site. The procedures were carried out by all members of the electrophysiology unit in the Extension phase, including less experienced operators and electrophysiology fellows (3 physicians) under the supervision of the senior electrophysiologist. Consequently, procedure times became longer [90 (75–105) vs 77.5 (73.5–85) min, p = 0.014].

Conclusions

According to our results, a ZF workflow of AF ablations can be successfully implemented into the routine practice of an electrophysiology laboratory, without compromising safety and effectivity.

Does merged three-dimensional mapping improve contact force and long-term procedure outcome in atrial fibrillation ablation? (MICRO-AF study): a prospective randomized controlled study

Integration of electroanatomical map (EAM) with preacquired three-dimensional (3D) cardiac images provides detailed appreciation of the complex anatomy of the left atrium (LA) and pulmonary vein (PV). High-density (HD) multi-electrode mapping catheters have enabled creating more accurate EAM reflecting real-time volume-rendered LA-PV geometry during atrial fibrillation (AF) ablation. However, no study has compared the outcomes of AF ablation using HD-EAM versus 3D-merged map. We aimed to investigate the procedural and clinical outcomes of AF ablation with HD-EAM (HD-EAM group) versus 3D-merged map (Merge group). One hundred patients (59.5 ± 11.5 years, 53% with paroxysmal AF [PAF]) were randomly assigned (1:1) to HD-EAM or Merged group. HD multi-electrode mapping and contact force (CF)-sensing catheters were used to create virtual LA-PV chamber and to perform wide antral circumferential ablation (WACA), respectively. The two groups showed no significant differences in baseline characteristics and procedural data including ablation time, fluoroscopy time, LA voltage, and CF. PV isolation with a single WACA line was achieved in 21 (42%) and 27 (54%) patients in the Merge and HD-EAM groups, respectively (P = NS). CF was significantly lower in lesions with gap than lesions without gap after a single WACA (7.3 ± 7.3 g vs. 16.0 ± 8.3, respectively, P < 0.001). During the 12-month follow-up, no significant difference in AF recurrence was observed between two groups, irrespective of AF type. In multivariate analysis, non-PAF was an independent risk factor for AF recurrence. Integration of 3D cardiac imaging did not improve procedural and clinical outcomes. HD-EAM provides an accurate real-time LA geometry.

Saturation recovery-prepared magnetic resonance angiography for assessment of left atrial and esophageal anatomy

OBJECTIVES

Magnetic resonance angiography (MRA) has been established as an important imaging method in cardiac ablation procedures. In pulmonary vein (PV) isolation procedures, MRA has the potential to minimize the risk of severe complications, such as atrio-esophageal fistula, by providing detailed information on esophageal position relatively to cardiac structures. However, traditional non-gated, first-pass (FP) MRA approaches have several limitations, such as long breath-holds, non-uniform signal intensity throughout the left atrium (LA), and poor esophageal visualization. The aim of this observational study was to validate a respiratory-navigated, ECG-gated (EC), saturation recovery-prepared MRA technique for simultaneous imaging of LA, LA appendage, PVs, esophagus, and adjacent anatomical structures.

METHODS

Before PVI, 106 consecutive patients with a history of AF underwent either conventional FP-MRA (n = 53 patients) or our new EC-MRA (n = 53 patients). Five quality scores (QS) of LA and esophagus visibility were assessed by two experienced readers. The non-parametric Mann-Whitney U-test was used to compare QS between FP-MRA and EC-MRA groups, and linear regression was applied to assess clinical contributors to image quality.

RESULTS

EC-MRA demonstrated significantly better image quality than FP-MRA in every quality category. Esophageal visibility using the new MRA technique was markedly better than with the conventional FP-MRA technique (median 3.5 [IQR 1] vs median 1.0, p < 0.001). In contrast to FP-MRA, overall image quality of EC-MRA was not influenced by heart rate.

CONCLUSION

Our ECG-gated, respiratory-navigated, saturation recovery-prepared MRA technique provides significantly better image quality and esophageal visibility than the established non-gated, breath-holding FP-MRA. Image quality of EC-MRA technique has the additional advantage of being unaffected by heart rate.

ADVANCES IN KNOWLEDGE

Detailed information of cardiac anatomy has the potential to minimize the risk of severe complications and improve success rates in invasive electrophysiological studies. Our novel ECG-gated, respiratory-navigated, saturation recovery-prepared MRA technique provides significantly better image quality of LA and esophageal structures than the traditional first-pass algorithm. This new MRA technique is robust to arrhythmia (tachycardic, irregular heart rates) frequently observed in AF patients.

Impact of image integration on clinical and procedural outcomes of radiofrequency catheter ablation of atrial fibrillation: A meta-analysis of randomized controlled trials

BACKGROUND

The purpose of this meta-analysis was to evaluate the impact of image integration technique on clinical and procedural outcomes in patients undergoing radiofrequency catheter ablation of atrial fibrillation with a three-dimensional electroanatomic mapping system.

METHODS

Randomized controlled trials were identified through a systematic literature search of PubMed and CENTRAL databases from inception to April 2020. The primary outcome was arrhythmia recurrence during the follow-up period. The secondary outcomes were the difference in total procedural time and fluoroscopy time.

RESULTS

Four studies with a total of 749 patients were included. The pooled result showed no statistically significant difference between the groups with respect to arrhythmia recurrence (RR, 0.75; 95% CI, 0.47-1.21), fluoroscopy time (MD, -6 minutes; 95% CI, -23.4 to 11.3), and total procedural time (MD, 1.1 minutes; 95% CI, -31.8 to 34.1).

CONCLUSION

Image integration to guide radiofrequency catheter ablation for patients with atrial fibrillation does not improve clinical and procedural outcomes.

CT- und MRT-Bildgebung in der Rhythmologie

Die Anwendung bildgebender Verfahren gewinnt in der interventionellen Elektrophysiologie entgegen der geringen Beachtung in den aktuell geltenden nationalen und internationalen Leitlinien zur Behandlung von Patienten mit Vorhofflimmern und ventrikulären Tachykardien auch über die reine Diagnostik zugrunde liegender struktureller Herzerkrankungen hinaus immer mehr an Bedeutung. Die breite Anwendung der Computertomografie (CT) und der Magnetresonanztomografie (MRT) ergibt sich aus den spezifischen Möglichkeiten dieser bildgebenden Techniken heraus: Gewebecharakterisierung des Myokards auf Vorhof- und Kammerebene mit präziser Darstellung von Infarktnarben, Grenzzonen und vitalem Myokard (MRT inklusive Late-Gadolinium-Enhancement-Darstellung); hochauflösende Darstellung wichtiger anatomischer Strukturen inklusive der Koronararterien und präzise Identifizierung von kritischer ventrikulärer Wandausdünnung im Infarktareal (CT); Identifizierung potenzieller Komplikationen nach Vorhofflimmerablation (Pulmonalvenenstenosen, Ösophagusruptur oder -fistel). Stärken und Schwächen sowie mögliche relative und absolute Kontraindikationen bei der Anwendung dieser beiden Methoden müssen jedoch berücksichtigt werden. Generell kann die Anwendung bildgebender Verfahren insbesondere für die Therapieplanung und -steuerung als wertvolle Ergänzung mit der Möglichkeit der Steigerung von Effektivität und Sicherheit gesehen werden. Prospektive randomisierte Studien liegen jedoch zu wichtigen aktuellen Anwendungsbereichen der CT und MRT noch nicht vor. Wichtigste Grundlage der interventionellen Elektrophysiologie in der Therapie supraventrikulärer und ventrikulärer Arrhythmien wird noch auf lange Sicht die Anwendung klassischer elektrophysiologischer Manöver und Strategien sowie die Verwendung sich immer weiter entwickelnder elektroanatomischer Mappingsysteme bleiben.

Advancements in Imaging for Atrial Fibrillation Ablation: Is There a Potential to Improve Procedural Outcomes?

Since the introduction of atrial fibrillation (AF) ablation in the 1990s, the procedure has continuously evolved, with gradual improvements in outcomes and safety. Recent technological advancements include the introduction of contact force catheters and high-resolution electroanatomical mapping systems, while imaging modalities including transesophageal echocardiography and fluoroscopy have become integral parts of AF ablation procedures. Further, intraprocedural intracardiac echocardiography and the integration of cardiac magnetic resonance and computed tomography images with electroanatomical mapping have shown promise to improve procedural outcomes by reducing radiation exposure and procedural times. However, available data on procedural utility and the reduction in AF recurrence rates associated with these modalities are mixed. This review therefore aims to discuss the current common imaging modalities used in AF ablation and their potential impact on outcomes. In particular, imaging is discussed with respect to the important information it offers before, during, and after the procedure. Perspectives on the future of imaging in AF ablation are also shared.

Use of Cardiac Computed Tomography and Magnetic Resonance Imaging in Case Management of Atrial Fibrillation with Catheter Ablation

Atrial fibrillation (AF) is the most common arrhythmia associated with the risk of morbidity and mortality in clinical patients. AF is considered as an arrhythmia type that develops and progresses through close connection with cardiac structural arrhythmogenic substrates. Since the introduction of catheter ablation-mediated electrical isolation of arrhythmogenic substrates, cardiac imaging indicates improved treatment outcome and prognosis with appropriate candidate selection, ablation catheter guidance, and post-ablation follow-up. Currently, cardiac computed tomography (CCT) and cardiovascular magnetic resonance (CMR) imaging are essential in the case management of AF at both pre-and post-procedural stages of catheter ablation. In this review, we discuss the roles and technical considerations of CCT and CMR imaging in the management of patients with AF undergoing catheter ablation.

Reducing radiation exposure during atrial fibrillation ablation using lectures to promote awareness

Objective

Recently, concern has increased regarding the hazards of radiation exposure in patients and laboratory staff. Since the numbers of complex catheter ablations (CA) performed, duration of procedure times, and need for multiple sessions have increased, radiation exposure during each session needs to be minimised. Our study aimed to assess the impact of awareness on radiation exposure during CA for atrial fibrillation (AF).

Methods

Mini-course lectures was delivered to the physicians and staff in the electrophysiology division. Its effect on the fluoroscopic time and radiation dose during AF ablation before (Group I, n=70), shortly after (Group II: n=70) and remotely after the mini-lecture (Group III, n=70) were evaluated. Patient demographics, preoperative testing and procedural parameters were collected.

Results

The fluoroscopic time significantly reduced after the lecture (Group I and II: 25.1±10.0 and 15.1±7.3 min, respectively (p<0.0001)), and remained so in Group III (13.0±5.4 min), despite the increase in the number of persistent AFs. The radiation dose also significantly reduced (Groups I, II, III: 295.0±263.0, 109.6±103.5 and 110.1±89.6 mGy, respectively (p<0.0001)).

Conclusion

Awareness on radiation exposure led to a significant reduction in fluoroscopic time and radiation dose during CA for AF, the effect of which persisted even to remote periods following the procedure.

The Impact of Advances in Atrial Fibrillation Ablation Devices on the Incidence and Prevention of Complications

The number of patients with atrial fibrillation currently referred for catheter ablation is increasing. However, the number of trained operators and the capacity of many electrophysiology labs are limited. Accordingly, a steeper learning curve and technical advances for efficient and safe ablation are desirable. During the last decades several catheter-based ablation devices have been developed and adapted to improve not only lesion durability, but also safety profiles, to shorten procedure time and to reduce radiation exposure. The goal of this review is to summarise the reported incidence of complications, considering device-related specific aspects for point-by-point, multi-electrode and balloon-based devices for pulmonary vein isolation. Recent technical and procedural developments aimed at reducing procedural risks and complications rates will be reviewed. In addition, the impact of technical advances on procedural outcome, procedural length and radiation exposure will be discussed.

Catheter Ablation of Atrial Fibrillation: A Review of the Current Status and Future Directions

Atrial fibrillation (AF) is one of the most common arrhythmias encountered in clinical practice today. Over the last 20 years, the frequency of use of catheter ablation to treat AF has grown, commensurate with the rise in arrhythmia burden and via a number of technical advancements. These developments can be divided into new techniques for myocardial ablation, improvements in the understanding of AF trigger mechanisms, and advancements in atrial mapping. Progress in these fields has led to a fundamental change in daily practice, and has contributed to a rise, for ablation, from a procedure performed infrequently at select centers to one that is commonplace worldwide. In this article, the data and methods leading to this fundamental change will be presented and discussed.

Fluoroscopy-free AF ablation using transesophageal echocardiography and electroanatomical mapping technology

PURPOSE

Guidelines recommend that radiation exposure during AF catheter ablation procedures should be 'as low as reasonably achievable' (ALARA), particularly since many patients may have multiple procedures. Consequently, avoiding radiation exposure altogether must, if safe to do so, be the ultimate goal. The primary objective was to determine the feasibility and efficacy of fluoroscopy-free AF ablation compared to the fluoroscopy-assisted procedure.

METHODS

Patients underwent AF ablation using commercially available technology with no routine pre-procedural imaging. The use of non-fluoroscopic imaging/mapping technologies permitted us to initially reduce x-ray exposure before eliminating its use altogether. This evolution of our practice proceeded in two stages: a 9-month period of optimising our fluoroscopy-free ablation protocol followed by a 9-month period during which we set out to complete the whole procedure routinely without fluoroscopy. We describe the protocol developed and report salient endpoints, such as complications, procedure times, patient experience, and procedural success rates.

RESULTS

During the study period, fluoroscopy-free AF ablation was attempted in 69 patients: 24 in the 9-month 'development phase' and 45 in the 'implementation phase'. During the development phase, 13 of 24 patients (54%) were treated without the use of fluoroscopy. In the implementation phase, 45 patients underwent AF ablation of which 42 (93.3%) were fluoroscopy-free. A detailed description is given of the three cases in which fluoroscopy had to be used despite an intention not to.

CONCLUSIONS

Fluoroscopy-free complex ablation procedures for the treatment of atrial fibrillation are safe and feasible in most patients.

An automatic and accurate registration method for electro-anatomical map and CT surface

BACKGROUND

Electro-anatomical maps (EAM) and CT surface registration are widely used for catheter navigation in atrial fibrillation ablations. However, few studies have investigated the registration algorithm. Moreover, some of them are semiautomatic, so that physicians must be proficient; some are inaccurate for catheter navigation. A both automatic and accurate registration method is needed.

METHOD

A Hausdorff distance based approach (HD) was proposed for EAM/CT registration. First, using principal axes based registration, EAM/CT pairs were coarsely aligned. Then, using Hausdorff distance as the fine objective function, EAM/CT pairs were finely aligned.

RESULTS

Six real EAM/CT pairs were collected from five patients and 38 simulated pairs were generated. Each pair was aligned using Carto-Merge, a stochastic approach (SA) and HD. Considering the balance of operability, accuracy and robustness, HD obtained the best EAM/CT registration results among the three approaches.

CONCLUSION

Experiments validate that the proposed method registers EAM and CT surface both automatically and accurately.

Reduction in radiation dose for atrial fibrillation ablation over time: A 12-year single-center experience of 2344 patients

BACKGROUND

Pulmonary vein isolation (PVI) is a well-established treatment of atrial fibrillation (AF), with contact force (CF)-sensing catheters joining 3-dimensional mapping systems and image integration as technological advancements over the last decade.

OBJECTIVE

The purpose of this study was to analyze trends in radiation exposure for AF ablation over the last 12 years at our center.

METHODS

We reviewed prospectively collected data of 2344 consecutive PVI procedures for either paroxysmal or persistent AF between January 2004 and December 2015. During this period, all cases used 3-dimensional mapping systems, with 8 software and 2 hardware upgrades. Primary endpoints were fluoroscopy time, absorbed dose (Air Kerma in mGy), and effective dose (mSv).

RESULTS

In total, 1914 patients underwent initial PVI, and 430 patients underwent redo PVI using radiofrequency energy. Fluoroscopy time, and absorbed and effective doses significantly and progressively decreased over the 12-year period for initial PVI as follows: 2004-2006: 61 ± 27 minutes; 2007-2009: 46 ± 14 minutes, 1365 ± 1369 mGy, 11.3 ± 12.5 mSv; 2010-2012: 31 ± 11, 464 ± 339 mGy, 9.0 ± 10.4 mSv; and 2013-2015: 17 ± 9 minutes, 304 ± 758 mGy, 5.5 ± 6.7 mSv. CF-sensing catheters were used for 357/508 PVI only cases between 2014 and 2015. Fluoroscopy times (11 ± 5 vs 21 ± 8 minutes; P <.001) and absorbed dose (200 ± 524 vs 470 ± 1326 mGy; P = .004) were significantly shorter with this catheter.

CONCLUSION

Radiation exposure has dramatically decreased over the last decade for PVI and is related to operator experience, annual case volume, technology evolution, and more recently CF-sensing catheters. This has significant implications for both patient and operator long-term risk.

Who Needs Catheter Ablation And Which Approach?

Catheter ablation therapy for atrial fibrillation (AF) has gained a significant role during maintenance of sinus rhythm compared to anti-arrhythmic medication. Catheter ablation techniques are also improved and progressed over years in parallel to better understanding of disease mechanisms and technological advancements. However, due to invasive nature of the therapy with its pertinent procedural risks, both appropriate patient selection and use of relevant approach should be considered by all electrophysiologists before decide to perform catheter ablation.

Long-term outcomes after ablation of persistent atrial fibrillation: an observational study over 6 years

Objectives

To address the limited long-term outcome data for catheter ablation (CA) of persistent atrial fibrillation (PeAF), we analysed consecutive ablations performed at our centre from 1 January 2008 to 31 December 2010 and followed patients prospectively until January 2014.

Methods

Both arrhythmia recurrence and symptom relief were assessed. Follow-up data were collected from hospital records, supplemented by data from general practitioners and referring hospitals. At the end of the follow-up period, all patients were contacted by phone to determine their up-to-date clinical condition.

Results

188 consecutive patients with PeAF (157 male, mean age 57.3±9.7 years, 20% with long-standing PeAF) underwent a mean of 1.75 procedures (range 1–4). Telephone follow-up was achieved for 77% of surviving patients. Over a mean follow-up of 46±16 months (range 4–72), 139 (75%) patients experienced arrhythmia recurrence after a single procedure and 90 (48%) after their final procedure. Median time to first recurrence was 210 days (range 91–1850). 71% of recurrences were within the first year following ablation and 91% within 2 years. At final follow-up, 82% of patients reported symptomatic improvement. 7 (2.3%) major complications occurred, and there was no procedure-related death or stroke.

Conclusions

CA for PeAF is safe with a low rate of complications. Over a follow-up period of up to 6 years, a large majority of patients experience significant symptomatic improvement but recurrence after the initial procedure is the norm rather than the exception. 2 years' follow-up is sufficient to observe 90% of AF recurrences, but recurrence can occur even after 5 years' remission.

Safety and Feasibility of a Minimally Fluoroscopic Approach for Ventricular Tachycardia Ablation in Patients With Structural Heart Disease: Influence of the Ventricular Tachycardia Substrate

BACKGROUND

We sought to evaluate the safety and feasibility of a minimally fluoroscopic approach using the CARTOUNIVU module during scar-related ventricular tachycardia (VT) ablation.

METHODS AND RESULTS

Consecutive patients with structural heart disease undergoing VT ablation using the CARTOUNIVU module were prospectively included and classified depending on their VT substrate: (1) ischemic VT (IVT) and (2) nonischemic VT and depending on the presence of an epicardial access. Radiation exposure parameters and major and minor procedure-related complications were registered. A near-zero fluoroscopy exposure was defined as those procedures with an effective dose ≤1 mSv. A total of 44 VT ablation procedures were performed in 41 patients (22 IVT and 19 nonischemic VT). The use of the CARTOUNIVU module resulted in low levels of radiation exposure: median total fluoroscopy time and effective dose of 6.08 (1.51-12.36) minutes and 2.15 (0.58-8.22) mSv, respectively. Patients with IVT had lower radiation exposure than patients with nonischemic VT (total fluoroscopy time, 2.53 [1.22-11.22] versus 8.51 [5.55-17.34] minutes; P=0.016). Epicardial access was associated with significantly higher levels of radiation exposure. Complications occurred in 4.9% patients, none of them being related to the use of the image integration tool. A near-zero fluoroscopy ablation could be performed in 14 of 44 procedures (32%), 43% of IVT procedures, and 50% of procedures with endocardial access only.

CONCLUSIONS

The use of the CARTOUNIVU module during scar-related VT ablation resulted in low levels of radiation exposure. A near-zero fluoroscopy approach can be achieved in up to half of the procedures, especially in IVT patients with endocardial ablation.

Integrated x-ray and echocardiography imaging for structural heart interventions

Treatment of structural heart disease (SHD) represents a growing need and, with increasing device availability, an increasing number of SHD can be and will be treated percutaneously. However, interventional treatment of SHD is challenging. Long procedure times and steep learning curves are recognised obstacles. The main difficulties arise, however, from the inability to visualise simultaneously the anatomy and the devices using a single imaging technology. In fact, the majority of percutaneous interventions in SHD are guided by fluoroscopy. On the other hand, a multitude of imaging technologies are presently available to guide the interventionalist. Of these technologies, transoesophageal echocardiography (TEE), and particularly 3-D TEE, is rapidly becoming the imaging modality of choice for many of these procedures because it provides critical insights into soft tissue anatomy. However, adequate visualisation and appreciation of the relationships between the cardiac structures and the devices using various imaging modalities remain a challenge. Hence, the interaction between the operator and imager is a crucial factor in attaining procedural success. Innovative technology that fuses live 3-D TEE with live x-ray in an intuitive way could have an important added value. This new imaging technology seeks to improve the communication between the echocardiographer and the interventionalist, to increase the confidence and anatomical awareness, to assist in guidance, and to increase procedural efficiency.

Electroanatomic Mapping and Transoesophageal Echocardiography for near Zero Fluoroscopy during Complex Left Atrial Ablation

BACKGROUND

We evaluated Carto 3, transoesophageal echocardiography (TOE) and contact force (CF) sensing catheter in atrial fibrillation (AF) ablation.

METHODS

Unselected consecutive ablations performed under general anaesthesia (GA) were studied with modified protocol (cases, n=11) and compared to retrospective consecutive controls (n=10). Patent foramen ovale (PFO) or single transseptal puncture enabled left atrial (LA) access; ablation strategy was stepwise approach. Modified protocol utilised right atrial (RA) electrograms, CF and TOE to localise SmartTouch and create RA and CS electroanatomic map (EAM) without fluoroscopy. Transseptal puncture was performed with fluoroscopy in absence of PFO. Fluoroless pulmonary vein and LA EAM was created using TOE to locate circular-mapping catheter.

RESULTS

Mean age of cases was 57±11 years with 64% male compared with 60±11 (70% male) for controls. Patent foramen ovale was identified in four cases (36%) and two controls (20%). No early complications occurred. Shorter fluoroscopy time (median 36 vs 390seconds; p=0.038) and trend to lower radiation dose (median 17 vs 165 cGym2; p=0.053) was seen in cases, with no increase in total procedure time (p=0.438).

CONCLUSIONS

General anaesthesia, TOE and CF mapping catheters facilitate minimised fluoroscopy for catheter ablation of LA arrhythmias. Zero fluoroscopy is possible in a majority of cases with PFO.

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.