Fluoroscopy usage in contemporary interventional electrophysiology: Insights from a European registry.

BACKGROUND: Fluoroscopy has been an essential part of every electrophysiological procedure since its inception. However, till now no clear standards regarding acceptable x-ray exposure nor recommendation how to achieve them have been proposed. HYPOTHESIS: Current norms and quality markers required for optimal clinical routine can be identified. METHODS: Centers participating in this Europe-wide multicenter, prospective registry were requested to provide characteristics of the center, operators, technical equipment as well as procedural settings of consecutive cases. RESULTS: Twenty-five centers (72% university clinics, with a mean volume of 526 ± 348 procedures yearly) from 14 European countries provided data on 1788 cases [9% diagnostic procedures (DP), 38% atrial fibrillation (AF) ablations, 44% other supraventricular (SVT) ablations, and 9% ventricular ablations (VT)] conducted by 95 operators (89% male, 41 ± 7 years old). Mean dose area product (DAP) and time was 304 ± 608 cGy*cm2 , 3.6 ± 4.8 minutes, 1937 ± 608 cGy*cm2 , 15.3 ± 15.5 minutes, 805 ± 1442 cGy*cm2 , 10.6 ± 10.7 minutes, and 1277 ± 1931 cGy*cm2 , 10.4 ± 12.3 minutes for DP, AF, SVT, and VT ablations, respectively. Seven percent of all procedures were conducted without any use of fluoroscopy. Procedures in the lower quartile of DAP were performed more frequently by female operators (OR 1.707, 95%CI 1.257-2.318, P = .001), in higher-volume center (OR 1.001 per one additional procedure, 95%CI 1.000-1.001, P = .002), with the use of 3D-mapping system (OR 2.622, 95%CI 2.053-3.347, P < .001) and monoplane x-ray system (OR 2.945, 95%CI 2.149-4.037, P < .001). CONCLUSION: Exposure to ionizing radiation varies widely in daily practice for all procedure. Significant opportunities for harmonization of exposure toward the lower range has been identified.

Three-Dimensional Late Gadolinium Enhancement Cardiovascular Magnetic Resonance Predicts Inducibility of Ventricular Tachycardia in Adults With Repaired Tetralogy of Fallot.

BACKGROUND: Adults with repaired tetralogy of Fallot die prematurely from ventricular tachycardia (VT) and sudden cardiac death. Inducible VT predicts mortality. Ventricular scar, the key substrate for VT, can be noninvasively defined with late gadolinium enhancement (LGE) cardiovascular magnetic resonance but whether this relates to inducible VT is unknown. METHODS: Sixty-nine consecutive repaired tetralogy of Fallot patients (43 male, mean 40±15 years) clinically scheduled for invasive programmed VT-stimulation were prospectively recruited for prior 3-dimensional LGE cardiovascular magnetic resonance. Ventricular LGE was segmented and merged with reconstructed cardiac chambers and LGE volume measured. RESULTS: VT was induced in 22 (31%) patients. Univariable predictors of inducible VT included increased RV LGE (odds ratio [OR], 1.15; P=0.001 per cm3), increased nonapical vent LV LGE (OR, 1.09; P=0.008 per cm3), older age (OR, 1.6; P=0.01 per decile), QRS duration ≥180 ms (OR, 3.5; P=0.02), history of nonsustained VT (OR, 3.5; P=0.02), and previous clinical sustained VT (OR, 12.8; P=0.003); only prior sustained VT (OR, 8.02; P=0.02) remained independent in bivariable analyses after controlling for RV LGE volume (OR, 1.14; P=0.003). An RV LGE volume of 25 cm3 had 72% sensitivity and 81% specificity for predicting inducible VT (area under the curve, 0.81; P<0.001). At the extreme cutoffs for ruling-out and ruling-in inducible VT, RV LGE >10 cm3 was 100% sensitive and >36 cm3 was 100% specific for predicting inducible VT. CONCLUSIONS: Three-dimensional LGE cardiovascular magnetic resonance-defined scar burden is independently associated with inducible VT and may help refine patient selection for programmed VT-stimulation when applied to an at least intermediate clinical risk cohort.

[Careers in cardiac electrophysiology]. / Karrierewege in der Rhythmologie.

Cardiac electrophysiology has developed into a broad, exciting, and challenging subdiscipline of modern cardiology. The professional opportunities available to electrophysiologists are diverse and offer a wide variety of career goals. The aim of this article is to show young cardiologists what different career paths can look like if they opt for electrophysiology today. Personal testimonials from five experienced electrophysiologists on their own career paths show decisions, support, obstacles, and destinations of these paths to practice or university professorship. This article aims to support young cardiologists who are considering specialization in electrophysiology during their career planning.

An initial experience of high-density mapping-guided ablation in a cohort of patients with adult congenital heart disease.

AIMS: In the management of both ventricular and supraventricular tachycardia in patients with congenital heart disease (CHD) catheter ablation has now been recognized as one of the mainstays. METHODS AND RESULTS: We review our initial experience of using the Rhythmia mapping system in a cohort of 12 adult CHD patients presenting with multiple arrhythmia substrates. A total of 78 arrhythmia maps were attempted in a total of 15 procedures, but possible due to the dilatation of the target chamber only 44% of maps were able to reconstruct the entire arrhythmia. All patients underwent pre-procedure 3D imaging (either cardiac magnetic resonance or computed tomography), but image integration was suboptimal. A median of two maps per patient were finally analysed and acquisition took in median 22 min with a median number of 12 574 (8230-18 167) mapping points. Procedural data with a total duration amounting to in median 285 (194-403) min, with a median total fluoroscopy exposure of 7.5 (5.2-10.7) min. After a median of 1.5 procedures [median of 12 (8-16 months)], nine patients remained in stable sinus rhythm or atrial paced rhythm, while three patients had further sustained recurrences. One of these passed away in end-staged heart failure. CONCLUSION: This initial experience of using high-density mapping for arrhythmia management in patients with CHD allowed rapid acquisition of multiple maps with high accuracy to identify surgical scars and fibrosis, however, it was limited by large atrial volumes and a high percentage of incomplete maps resulting in modest clinical success.

Arrhythmias in congenital heart disease: a position paper of the European Heart Rhythm Association (EHRA), Association for European Paediatric and Congenital Cardiology (AEPC), and the European Society of Cardiology (ESC) Working Group on Grown-up Congenital heart disease, endorsed by HRS, PACES, APHRS, and SOLAECE.

The population of patients with congenital heart disease (CHD) is continuously increasing with more and more patients reaching adulthood. A significant portion of these young adults will suffer from arrhythmias due to the underlying congenital heart defect itself or as a sequela of interventional or surgical treatment. The medical community will encounter an increasing challenge as even most of the individuals with complex congenital heart defects nowadays become young adults. Within the past 20 years, management of patients with arrhythmias has gained remarkable progress including pharmacological treatment, catheter ablation, and device therapy. Catheter ablation in patients with CHD has paralleled the advances of this technology in pediatric and adult patients with structurally normal hearts. Growing experience and introduction of new techniques like the 3D mapping systems into clinical practice have been particularly beneficial for this growing population of patients with abnormal cardiac anatomy and physiology. Finally, device therapies allowing maintanence of chronotropic competence and AV conduction, improving haemodynamics by cardiac resynchronization, and preventing sudden death are increasingly used. For pharmacological therapy, ablation procedures, and device therapy decision making requires a deep understanding of the individual pathological anatomy and physiology as well as detailed knowledge on natural history and long-term prognosis of our patients. Composing expert opinions from cardiology and paediatric cardiology as well as from non-invasive and invasive electrophysiology this position paper was designed to state the art in management of young individuals with congenital heart defects and arrhythmias.

An efficient cardiac mapping strategy for radiofrequency catheter ablation with active learning.

OBJECTIVE: A major challenge in radiofrequency catheter ablation procedures is the voltage and activation mapping of the endocardium, given a limited mapping time. By learning from expert interventional electrophysiologists (operators), while also making use of an active-learning framework, guidance on performing cardiac voltage mapping can be provided to novice operators or even directly to catheter robots. METHODS: A learning from demonstration (LfD) framework, based upon previous cardiac mapping procedures performed by an expert operator, in conjunction with Gaussian process (GP) model-based active learning, was developed to efficiently perform voltage mapping over right ventricles (RV). The GP model was used to output the next best mapping point, while getting updated towards the underlying voltage data pattern as more mapping points are taken. A regularized particle filter was used to keep track of the kernel hyperparameter used by GP. The travel cost of the catheter tip was incorporated to produce time-efficient mapping sequences. RESULTS: The proposed strategy was validated on a simulated 2D grid mapping task, with leave-one-out experiments on 25 retrospective datasets, in an RV phantom using the Stereotaxis Niobe® remote magnetic navigation system, and on a tele-operated catheter robot. In comparison with an existing geometry-based method, regression error was reduced and was minimized at a faster rate over retrospective procedure data. CONCLUSION: A new method of catheter mapping guidance has been proposed based on LfD and active learning. The proposed method provides real-time guidance for the procedure, as well as a live evaluation of mapping sufficiency.

Utility of noninvasive arrhythmia mapping in patients with adult congenital heart disease.

Arrhythmia management in patients with adult congenital heart disease (ACHD) is a challenge on many levels, as tachycardic episodes may lead to hemodynamic impairment in otherwise compensated patients even if episodes are only transient. Recently several technical advances, including 3-dimensional (3D) image integration, 3D mapping, and remote magnetic navigation, have been introduced to facilitate curatively intended ablation procedures in patients with ACHD. This review attempts to outline the role of a novel technology of simultaneous, noninvasive mapping in this patient cohort, and gives details of the authors' single-center experience.

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.

Radiation exposure and safety for the electrophysiologist.

This review attempts to give practical advice for invasive electrophysiologists on personal radiation protection. Applying all measures of the "As low as reasonably achievable" ALARA concept should be a daily and indeed routine practice for all staff in the electrophysiology laboratory. A substantial number of technical options have been recently introduced which may enable the physician to lower the total radiation exposure significantly, but all require a substantial learning curve. Using these measures can arrive at very low or indeed close to ZERO fluoroscopy exposure even in complex ablation cases.

Catheter ablation of multiple unstable macroreentrant tachycardia within the right atrium free wall in patients without previous cardiac surgery.

BACKGROUND: Macroreentrant atrial tachycardia (AT) involving the right atrial free wall (RAFW) has been reported in patients without atriotomy. Catheter ablation of these ATs remains challenging due to the multiple morphologies of ATs with unstable reentrant circuits in some patients. The purpose of this study was to clarify the electrophysiological characteristics of these ATs and attempt the novel approach for catheter ablation. METHODS AND RESULTS: Electrophysiological study and catheter ablation were performed in 17 patients (14 men; 71 [quartile 1, 67; quartile 3, 76] years) with reentrant ATs originating from the RAFW using 3D mapping. All patients had no history of cardiac surgery. Clinical ATs with stable cycle length and atrial activation were identified in 11 patients (group A). All ATs were successfully ablated. In the remaining 6 patients, clinical tachycardia continuously changed, with a different cycle length and P-wave morphology and atrial activation sequence during mapping or entrainment study (group B). A complete isolation of the RAFW was attempted in group B. After complete isolation was achieved in 5 of 6 patients, ATs were not induced in these 6 patients. The number of previous failed catheter ablations and induced ATs were higher in group B than in group A. During 31 (19; 37) months of follow-up, AT recurrence developed in 27% patients from group A and 33% from group B. CONCLUSIONS: Multiple and unstable macroreentrant ATs from the RAFW can occur in patients without a history of cardiac surgery. The RAFW isolation has the potential to abolish all ATs.

Pulmonary vein isolation by high-intensity focused ultrasound: first-in-man study with a steerable balloon catheter.

BACKGROUND: High-intensity focused ultrasound (HIFU) applied via a steerable balloon catheter (ProRhythm, Ronkonkoma, NY) is a novel technology for pulmonary vein (PV) isolation. OBJECTIVE: The purpose of this study was to assess the short-term and long-term success rates of PV isolation in patients with paroxysmal atrial fibrillation (AF) using the steerable HIFU balloon catheter. METHODS: A total of 15 patients (7 female), mean age 59 +/- 8 years, with a long (8 +/- 5 years) history of drug-refractory, symptomatic paroxysmal AF were enrolled. After double transseptal puncture, a lasso catheter and the 16F HIFU balloon catheter (11F shaft) were inserted into the left atrium (LA). After PV angiography, phrenic nerve (PN) pacing (10 V, 2.9 ms) was conducted. In case of PN capture at the right superior PV ostium, patients were excluded (n = 3). To achieve complete PV isolation, HIFU was repeatedly applied with an acoustic power of 45 W for 40 to 90 seconds. Follow-up included telephonic interviews, transtelephonic Holter electrocardiogram, and office visits after 1, 3, and 6 months. RESULTS: Complete electrical PV isolation was achieved in 41 of 46 (89%) PVs. Median follow-up time was 387 days (range 120 to 424 days). Seven of 12 (58%) patients were free of AF without antiarrhythmic drugs. In 2 patients, only a single AF episode was documented, resulting in an overall chronic success of 75%. Despite negative PN pacing, 2 patients experienced right-sided PN palsy, which had not resolved after 12 months. CONCLUSION: In patients with paroxysmal AF, acute PV isolation can be achieved in 89% using a steerable HIFU balloon; 58% of all patients were free of AF and 75% reached the primary end point defined as a reduction of AF episodes to less than 50%. However, further studies need to improve identification of patients at risk for PN palsy.

Pulmonary vein conduction is the major finding in patients with atrial tachyarrhythmias after intraoperative maze ablation.

INTRODUCTION: Electrophysiological (EP) data from patients with recurrent atrial tachyarrhythmias (ATa) after intraoperative maze ablation are limited. Furthermore, the clinical course after accomplishing pulmonary vein (PV) isolation using the double lasso technique (DLT) is unknown. METHODS AND RESULTS: EP study and catheter ablation (CA) was guided by a three-dimensional electroanatomic mapping system (3-D EA, CARTO, Biosense-Webster) combined with simultaneous ipsilateral PV mapping using the DLT. Defined endpoints were: (1) identification of conduction gaps within the ipsilateral PVs, (2) elimination of all PV spikes, and (3) ablation of clinical ATas. CA was performed in eight patients (four females, 62 +/- 5 years, LA: 50 +/- 6 mm) with drug refractory ATa (9.1 +/- 6.3 years) despite non-"cut and sew" maze operation. Electrical PV conduction was demonstrated in the majority of patients (7/8). All endpoints were achieved. Repeat ablations were required in three patients. Second ablation was due to typical atrial flutter (n = 1) and atrial fibrillation (n = 2). One patient required three ablations due to a left atrial macroreentrant tachycardia. During a mean follow-up of 15.5 +/- 4.8 months, 7/8 patients were free of ATa recurrences. CONCLUSION: Incomplete lesions after non-"cut and sew" maze operation are associated with PV conduction and recurrence of ATas. Electrical isolation of ipsilateral PVs and completion of linear lesions guided by 3-D EA mapping is feasible and successful in maintaining sinus rhythm during mid term follow-up. Completeness of linear lesions using EP endpoints should be confirmed during the initial surgical procedure to minimize ATa recurrences.

A single pulmonary vein as electrophysiological substrate of paroxysmal atrial fibrillation.

INTRODUCTION: It has been demonstrated that pulmonary veins (PVs) play an important role in initiation and maintenance of paroxysmal atrial fibrillation (AF). However, it is not clearly known whether a single PV acts as electrophysiological substrate for paroxysmal AF. METHODS AND RESULTS: This study included five patients with paroxysmal AF. All patients underwent complete PV isolation with continuous circular lesions (CCLs) around the ipsilateral PVs guided by a three-dimensional mapping system. Irrigated radiofrequency (RF) delivery was performed during AF on the right-sided CCLs in two patients and on the left-sided CCLs in three patients. The incomplete CCLs resulted in a change from AF to atrial tachycardia (AT), which presented with an identical atrial activation sequence and P wave morphology. Complete CCLs resulted in AF termination with persistent PV tachyarrhythmias within the isolated PV in all five patients. PV tachyarrhythmia within the isolated PV was PV fibrillation from the left common PV (LCPV) in two patients, PV tachycardia from the right superior PV (RSPV) in two patients, and from the left superior PV in one patient. All sustained PV tachyarrhythmias persisted for more than 30 minutes, needed external cardioversion for termination in four patients and a focal ablation in one patient. After the initial procedure, an AT from the RSPV occurred in a patient with PV fibrillation within the LCPV, and was successfully ablated. CONCLUSION: In patients with paroxysmal AF, sustained PV tachyarrhythmias from a single PV can perpetuate AF. Complete isolation of all PV may provide good clinical outcome during long-term follow-up.

Focal atrial tachycardia originating from the non-coronary aortic sinus: electrophysiological characteristics and catheter ablation.

OBJECTIVES: We sought to investigate electrophysiological characteristics and catheter ablation in patients with focal atrial tachycardia (AT) originating from the non-coronary aortic sinus (AS). BACKGROUND: In patients with failed ablation of focal AT near the His bundle (HB) region, an origin from the non-coronary AS should be considered because of the close anatomical relationship. METHODS: This study included 9 patients with focal AT, in 6 of whom attempted radiofrequency (RF) ablation had previously failed. Activation mapping was performed during tachycardia to identify an earliest activation in the atria and the AS. The aortic root angiography was performed to identify the origin in the AS before RF ablation. RESULTS: Focal AT was reproducibly induced by atrial pacing. Mapping in atria demonstrated that the earliest atrial activation was located at the HB region, whereas mapping in the non-coronary AS demonstrated that an earliest atrial activation preceded the atrial activation at the HB by 12.2 +/- 6.9 ms and was anatomically located superoposterior to the HB in all 9 patients. Also, His potentials were not found at the successful site in the non-coronary AS in all 9 patients. The focal AT was terminated in <8 s in all 9 patients. Junctional beats and PR prolongation did not occur during RF application in all 9 patients. No complications occurred in any of the nine patients. All 9 patients were free of arrhythmias without antiarrhythmic drugs during a follow-up of 9 +/- 3 months. CONCLUSIONS: In patients with focal AT near the HB region, mapping in the non-coronary AS can improve clinical outcome.

Complete pulmonary vein isolation guided by three-dimensional electroanatomical mapping for the treatment of paroxysmal atrial fibrillation in patients with hypertrophic obstructive cardiomyopathy.

AIMS: Evaluation of the clinical outcome of patients with hypertrophic obstructive cardiomyopathy (HOCM) and paroxysmal atrial fibrillation (AF) treated with complete pulmonary vein (PV) isolation guided by three-dimensional (3-D) electroanatomical (EA) mapping. METHODS: Circumferential radiofrequency (RF) ablation and continuous circular lesions (CCLs) around the left and right-sided PVs were performed in 4 highly symptomatic patients (2 males; age 57.5 +/- 8.3 years) with HOCM and anti-arrhythmic drug (AAD) refractory paroxysmal AF. Ablation was guided by 3-D EA mapping combined with conventional circumferential PV mapping. The endpoints of the ablation were defined as: (1) absence of all PV spikes documented with the two Lasso catheters within the ipsilateral PVs; and (2) no recurrence of the PV spikes within all PVs following intravenous administration of adenosine. RESULTS: The ablation endpoints were achieved in all patients. A repeat ablation was performed in one patient due to repetitive atrial tachycardia, 1 month after the initial procedure. During a follow-up of 5.8 +/- 2.7 months, all patients are free of AF recurrence. Short episodes of symptomatic AT were documented after the repeat procedure, and were well controlled with oral amiodarone in the patient. No procedure-related complications were observed. CONCLUSION: The present study demonstrates that complete isolation of ipsilateral PVs guided by 3-D EA mapping is potentially effective for the treatment of highly symptomatic, drug refractory paroxysmal AF in patients with HOCM.

Topographic distribution of focal left atrial tachycardias defined by electrocardiographic and electrophysiological data.

BACKGROUND: Detailed information about the topographic distribution of focal left atrial tachycardias (FLATs) is limited. METHODS AND RESULTS: A total of 143 atrial tachycardia (AT) foci were successfully ablated in 140 patients (56 men, mean age 44.6+/-17.9 years). In 36.4% (52/143 ATs), a left atrial (LA) origin of the tachycardia was identified from the site of successful ablation. In 46% (24/52) of FLATs, the site of origin (SO) was near the ostium of a pulmonary vein (PV), and in 36.5% (19/52), the SO was near the mitral annulus (MA). In the remaining ATs, the SO was in the left atrial appendage (LAA), septum, LA roof and inside the coronary sinus. P waves in V1 showed biphasic morphology with an initial negative component in most FLATs originating from the septal MA, superior MA, and LAA. However, P waves in V1 were positive in all patients with FLATs originating from PVs. Negative P waves in aVL were always observed in FLATs originating from left PVs. The mean cycle length of FLATs from PVs was significantly shorter than that from the MA. CONCLUSION: Knowledge of the topographic distribution, P-wave morphology, and tachycardia cycle length facilitates successful ablation of FLATs.

Modulation of the slow pathway in the presence of a persistent left superior caval vein using the novel magnetic navigation system Niobe.

AIMS: This is the first report of a young female with typical AVNRT in the presence of a persistent left superior caval vein that underwent catheter ablation using the novel magnetic navigation system (MNS) Niobe (Stereotaxis Inc.). METHODS: The MNS consists of two outer permanent magnets (about 0.1 T) that align a third small magnet integrated in the tip of a mapping and ablation catheter along its magnetic field lines. By changing the orientation of the outer magnets, the orientation of the magnetic field lines also change, thereby allowing navigation of the ablation catheter. In combination with an automated advancer system, this novel technique allows for the first time complete remote catheter ablation. RESULTS: Successful slow pathway modulation was performed using a total of seven radiofrequency current applications via the magnetic ablation catheter. No complication occurred. CONCLUSIONS: The novel magnetic navigation system proved to be a safe and feasible tool for remote catheter ablation of common type AVNRT in the presence of a persistent left superior caval vein.