A worldwide survey on incidence, management, and prognosis of oesophageal fistula formation following atrial fibrillation catheter ablation: the POTTER-AF study.

AIMS: Oesophageal fistula represents a rare but dreadful complication of atrial fibrillation catheter ablation. Data on its incidence, management, and outcome are sparse. METHODS AND RESULTS: This international multicentre registry investigates the characteristics of oesophageal fistulae after treatment of atrial fibrillation by catheter ablation. A total of 553 729 catheter ablation procedures (radiofrequency: 62.9%, cryoballoon: 36.2%, other modalities: 0.9%) were performed, at 214 centres in 35 countries. In 78 centres 138 patients [0.025%, radiofrequency: 0.038%, cryoballoon: 0.0015% (P < 0.0001)] were diagnosed with an oesophageal fistula. Peri-procedural data were available for 118 patients (85.5%). Following catheter ablation, the median time to symptoms and the median time to diagnosis were 18 (7.75, 25; range: 0-60) days and 21 (15, 29.5; range: 2-63) days, respectively. The median time from symptom onset to oesophageal fistula diagnosis was 3 (1, 9; range: 0-42) days. The most common initial symptom was fever (59.3%). The diagnosis was established by chest computed tomography in 80.2% of patients. Oesophageal surgery was performed in 47.4% and direct endoscopic treatment in 19.8% and conservative treatment in 32.8% of patients. The overall mortality was 65.8%. Mortality following surgical (51.9%) or endoscopic treatment (56.5%) was significantly lower as compared to conservative management (89.5%) [odds ratio 7.463 (2.414, 23.072) P < 0.001]. CONCLUSION: Oesophageal fistula after catheter ablation of atrial fibrillation is rare and occurs mostly with the use of radiofrequency energy rather than cryoenergy. Mortality without surgical or endoscopic intervention is exceedingly high.

Simple and safe digitoxin dosing in heart failure based on data from the DIGIT-HF trial.

BACKGROUND: The present study aimed to develop a simple dosing score when starting the cardiac glycoside digitoxin in heart failure with reduced ejection fraction (HFrEF) employing first data from the randomized, double-blinded DIGIT-HF trial. METHODS AND RESULTS: In DIGIT-HF, digitoxin was started with a dose of 0.07 mg once daily (o.d.) in all patients. For score derivation, 317 patients were analyzed who had been randomized to digitoxin. In these patients, after scheduled determination of serum levels at study week 6, the digitoxin dose had remained unchanged or had been reduced to 0.05 mg o.d. (97% of patients) to achieve serum concentrations within a predefined range (10.5-23.6 nmol/l). In logistic regression analyses, sex, age, body mass index (BMI), and estimated glomerular filtration rate (eGFR) were associated with need for dose reduction and, therefore, selected for further developing the dosing score. Optimal cut-points were derived from ROC curve analyses. Finally, female sex, age ≥ 75 years, eGFR < 50 ml/min/1.73 m2, and BMI < 27 kg/m2 each were assigned one point for the digitoxin dosing score. A score of ≥ 1 indicated the need for dose reduction with sensitivity/specificity of 81.6%/49.7%, respectively. Accuracy was confirmed in a validation data set including 64 patients randomized to digitoxin yielding sensitivity/specificity of 87.5%/37.5%, respectively. CONCLUSION: In patients with HFrEF, treatment with digitoxin should be started at 0.05 mg o.d. in subjects with either female sex, eGFR < 50 ml/min/1.73m2, BMI < 27 kg/m2, or age ≥ 75 years. In any other patient, digitoxin may be safely started at 0.07 mg o.d.

Electrophysiological findings during atrial fibrillation reablation: Extending from pulmonary vein reconnection to sequential bipolar voltage map information.

BACKGROUND: Left atrial substrate modification targeting low voltage zones (LVZ) is an ablation strategy that-in addition to pulmonary vein (PV) isolation-tries to eliminate arrhythmogenic mechanisms harbored in such tissue. Electrophysiological findings at reablation include (a) PV reconnection, (b) reconnection over previous substrate ablation, and (c) de-novo LVZ. OBJECTIVE: To study, prevalence and contribution of these arrhythmogenic electrophysiological entities in patients with atrial fibrillation (AF) recurrences. METHODS: Consecutive patients with highly symptomatic AF undergoing index and reablation were included (n = 113). In all patients' PV reconnection, reconnection over previous substrate ablation and spontaneous de-novo LVZ were quantitatively assessed and integrated into an individual reablation strategy. Follow-up was based on continuous device monitoring. RESULTS: At re-do procedure, 45 out of 113 (39.8%) patients showed PV reconnection as the only electrophysiological abnormality. Reconduction over previous lines was the only electrophysiological abnormality in 8 out of 113 (7.1%) patients. Spontaneous de-novo LVZ was the only electrophysiological abnormality in 12 out of 113 (10.6%) patients. Combined findings of PV reconnection, line reconduction, and/or spontaneous de-novo LVZ were seen in 40 out of 113 (35.4%) patients. No detectable electrophysiological abnormality was observed in 8 out of 113 (7.1%) patients. In univariate analysis, none of the tested electrophysiological characteristics independently predicted the outcome after re-do. CONCLUSIONS: In patients undergoing reablation, we could show that reconduction over previous substrate ablation as well as the development of new low voltage areas are frequent findings besides classical PV reconnection-without a clear leading cause for recurrences. These findings impact reablation strategies as well as the strategic focus during index procedures.

Real-time magnetic resonance-guided ablation of typical right atrial flutter using a combination of active catheter tracking and passive catheter visualization in man: initial results from a consecutive patient series.

AIMS: Recently cardiac magnetic resonance (CMR) imaging has been found feasible for the visualization of the underlying substrate for cardiac arrhythmias as well as for the visualization of cardiac catheters for diagnostic and ablation procedures. Real-time CMR-guided cavotricuspid isthmus ablation was performed in a series of six patients using a combination of active catheter tracking and catheter visualization using real-time MR imaging. METHODS AND RESULTS: Cardiac magnetic resonance utilizing a 1.5 T system was performed in patients under deep propofol sedation. A three-dimensional-whole-heart sequence with navigator technique and a fast automated segmentation algorithm was used for online segmentation of all cardiac chambers, which were thereafter displayed on a dedicated image guidance platform. In three out of six patients complete isthmus block could be achieved in the MR scanner, two of these patients did not need any additional fluoroscopy. In the first patient technical issues called for a completion of the procedure in a conventional laboratory, in another two patients the isthmus was partially blocked by magnetic resonance imaging (MRI)-guided ablation. The mean procedural time for the MR procedure was 109 ± 58 min. The intubation of the CS was performed within a mean time of 2.75 ± 2.21 min. Total fluoroscopy time for completion of the isthmus block ranged from 0 to 7.5 min. CONCLUSION: The combination of active catheter tracking and passive real-time visualization in CMR-guided electrophysiologic (EP) studies using advanced interventional hardware and software was safe and enabled efficient navigation, mapping, and ablation. These cases demonstrate significant progress in the development of MR-guided EP procedures.

Reduction of radiation exposure during atrial fibrillation ablation using a novel fluoroscopy image integrated 3-dimensional electroanatomic mapping system: A prospective, randomized, single-blind, and controlled study.

OBJECTIVE: We explored whether the use of a novel fluoroscopy image integrated 3-dimensional electroanatomic mapping (F-EAM) system could result in a reduction of overall fluoroscopy time and radiation doses during the whole procedure of atrial fibrillation (AF) ablation. METHODS: Eighty patients (44 men (55%); mean age 63 ± 10 years) who underwent catheter ablation due to paroxysmal AF were recruited consecutively in the present study. Patients were randomized (1:1) into 2 arms for AF ablation: one using a conventional 3-dimensional electroanatomical mapping (EAM) system and the other using the F-EAM system. RESULTS: Fluoroscopy time (10:42 [interquartile range {IQR} 8:45-12:46] minutes:seconds vs 1:45 [IQR 1:05-2:22] minutes:seconds; P < .001) and radiation doses (2440 [IQR 1593-3091] cGy·cm(2) vs 652 [IQR 326-1489] cGy·cm(2); P < .001) in the EAM group were significantly greater than those in the F-EAM group. The majority of reduction of radiation exposure was achieved after transseptal puncture, which was near-zero fluoroscopic exposure. In total, approximately 84% of fluoroscopy time and 73% of radiation doses have been reduced during the AF ablation procedure using the F-EAM system compared to using the conventional EAM system. However, procedure time did not differ significantly (1:39 [IQR 1:18-2:10] hours:minutes vs 1:37 [IQR 1:17-1:50] hours:minutes; P = .362). During follow-up (5.9 ± 1.3 months), 61 patients (76.3%) had no recurrence of atrial arrhythmias. The recurrence rate between the 2 groups did not differ. CONCLUSION: AF catheter ablation using the F-EAM system was safe and resulted in a significant reduction of radiation exposure to patients and staff without complicating the workflow of the procedure. A near-zero fluoroscopic catheter ablation procedure could be performed without compromising acute/mid-term efficacy and safety.

Fluoroscopy integrated 3D mapping significantly reduces radiation exposure during ablation for a wide spectrum of cardiac arrhythmias.

AIMS: Despite the use of established 3D-mapping systems, invasive electrophysiological studies and catheter ablation require high radiation exposure of patients and medical staff. This study investigated whether electroanatomic catheter tracking in prerecorded X-ray images on top of an existing 3D-mapping system has any impact on radiation exposure. METHODS AND RESULTS: Two hundred and ninety-five consecutive patients were either ablated with the guidance of the traditional CARTO-3 system (c3) or with help of the CARTO-UNIVU system (cU): [typical atrial flutter (AFL) n = 58, drug refractory atrial fibrillation (AF) n = 81, ectopic atrial tachycardia (EAT) n = 37, accessory pathways (APs) n = 22, symptomatic, idiopathic premature ventricular complexes (PVCs) n = 56, ventricular tachycardias (VTs) n = 41]. The CARTO-UNIVU allowed a reduction in radiation exposure: fluoroscopy time: AFL c3: 8.6 ± 0.8 min vs. cU: 2.9 ± 0.3 min, P < 0.001; AF c3: 16.0 ± 1.3 min vs. cU: 6.4 ± 0.9 min, P < 0.001; EAT c3: 23.4 ± 3.1 min vs. cU: 9.7 ± 1.7 min, P < 0.001; AP c3: 7.1 ± 1.2 min vs. cU: 6.0 ± 1.5 min, P = 0.59; PVCs c3: 17.6 ± 2.3 min vs. cU: 15.2 ± 2.8 min, P = 0.52; VT c3: 31.4 ± 3.4 min vs. cU: 17.5 ± 2.4 min, P = 0.003. Corresponding to the fluoroscopy time the fluoroscopy dose was also reduced significantly. These advantages were not at the cost of increased procedure times, periprocedural complications, or decreased acute ablation success rates. CONCLUSION: In a wide spectrum of cardiac arrhythmias, and especially in AF and VT ablation, fluoroscopy integrated 3D mapping contributed to a dramatic reduction in radiation exposure without prolonging procedure times and compromising patient's safety. That effect, however, could not be maintained in patients with APs and PVCs.

Nonfluoroscopic catheter visualization in atrial fibrillation ablation: experience from 375 consecutive procedures.

BACKGROUND: A technological platform (MediGuide) has been recently introduced for nonfluoroscopic catheter tracking. No data on the safety of this technology are yet available in a large cohort of patients. METHODS AND RESULTS: Data from a prospective ablation registry were analyzed. All patients undergoing atrial fibrillation ablation procedures supported by nonfluoroscopic catheter visualization technology were included. Patient characteristics and procedural data and complications within the first 3 months were recorded. Between May 2012 and February 2014, a total of 375 patients underwent atrial fibrillation ablation using nonfluoroscopic catheter visualization technology. The patients were predominantly men (68%); the majority were ablated for the first time (71%); left atrium was 43±6 mm; and left ventricular function was normal (59±9%). The median ablation procedure time was 135 (113-170) minutes, median fluoroscopy time 2.8 (1.5-4.4) minutes, and median radiation dose 789 (470-1466) cGy*cm(2). Regression analysis demonstrated a significant decrease of fluoroscopy time, dose, and procedure time. To confirm the result and show overall changes, the initial 50 cases (group 1) to the last 50 cases (group 2) of the series were compared: fluoroscopy time decreased from 6.0 (4.1-10.3) minutes in group 1 to 1.1 (0.7-1.5) minutes in group 2 and radiation dose from 2363 (1413-3475) to 490 (230-654) cGy*cm(2), respectively. Ten patients (2.7%) experienced complications: 5 cardiac tamponades (1.4%), 4 pseudoaneurysms (1.1%), and 1 stroke (0.3%). CONCLUSIONS: Atrial fibrillation ablation using the nonfluoroscopic catheter visualization technology is safe with a rate of complications of 2.7%. Procedure time (135 minutes) is not prolonged. A dramatic reduction in fluoroscopy time and dose was achieved.

Atrial arrhythmias following surgical AF ablation: electrophysiological findings, ablation strategies, and clinical outcome.

BACKGROUND: Intraoperative atrial fibrillation (AF) ablation during cardiac surgery is a well-established treatment. However, tachycardia mechanisms, ablation strategies, and long-term follow-up of atrial arrhythmias (AA) following intraoperative AF ablation (AFA) have not been previously studied in a large cohort of patients. OBJECTIVE: Eighty-two patients (48 male, median age of 65 years) with symptomatic recurrence of AA following intraoperative AFA underwent radiofrequency catheter ablation. METHODS: Regular atrial tachycardias (AT) were mapped using 3-dimensional (3D) color-coded entrainment/activation mapping and eliminated by linear ablation. Pulmonary vein (PV)-isolation (PVI) was achieved in patients with left atrium-PV (LAPV) conduction after AT elimination. RESULTS: In 85 (83%) out of a total of 103 regular ATs, the entire reentrant circuits were localized perimitrally (n = 27), around PVs (left PV [LPV] or right PV [RPV]; n = 9), around left atrial appendage (LAA; n = 1), on left-sided atrial septum (n = 8), on atrioventricular nodal area (n = 1), on the posterior wall of LA (n = 1), along roof-septum-inferoposterior wall (n = 8), at coronary sinus ostium (n = 2), upper loop in RA (n = 1), and as cavotricuspid isthmus-dependent reentrant ATs (n = 27). Sixty-five (79%) patients received PVI. Noninducibility of any AT was reached at the end of all procedures. During a median follow-up time of 18 months, 69 patients (87%) were free of AA. CONCLUSION: Reentrant AT appears in the majority of patients with recurrence of AA following intraoperative AFA. Detailed 3D color-coded entrainment mapping was successfully obtained in the majority of patients suffering from reentrant AT after intraoperative AFA, facilitated the accurate identification of the entire reentrant circuit and selection of optimal ablation lines.

Cardiac resynchronization therapy device implantation using a new sensor-based navigation system: results from the first human use study.

BACKGROUND: Cardiac resynchronization therapy (CRT) device implantation can be challenging, time consuming, and fluoroscopy intense. To facilitate left ventricular lead placement, a novel sensor-based electromagnetic tracking system (MediGuide Technology [MGT], St. Jude Medical) has been developed. We report the results of the First Human Use study evaluating the feasibility, safety, and performance of a novel CRT implantation approach using electromagnetic trackable operation equipment. METHODS AND RESULTS: Fifteen consecutive patients (66±8 years, 53% male) with an established indication for CRT were implanted using the new tracking technology. Demographics, anatomical information, detailed fluoroscopy need, procedure time, and adverse events were collected. Patients were followed up for 4 weeks after implantation. The CRT system was successfully implanted with a lateral or posterolateral left ventricular lead position in all patients. The total procedure time was 116±43 minutes, the median total fluoroscopy time (skin to skin) was 5.2 (Q1-Q3, 3.0-8.4) minutes, and the median fluoroscopy time for left ventricular lead deployment (coronary sinus [CS] cannulation to withdrawal of CS sheath) measured 2.6 (Q1-Q3, 1.6-5.6) minutes. There were no severe complications that required an acute intervention or reoperation during the perioperative and postoperative periods. CONCLUSIONS: Use of the MGT tracking technology allows for safe and successful CRT implantation with the potential for reduced fluoroscopy time. Future randomized studies are needed to validate these data. CLINICAL TRIAL REGISTRATION: URL http://www.clinicaltrials.gov. Unique identifier: NCT01519739.

Catheter ablation of atrial fibrillation supported by novel nonfluoroscopic 4D navigation technology.

BACKGROUND: The MediGuide technology (MGT) represents a novel sensor-based electromagnetic 4-dimensional (4D) navigation system allowing real-time catheter tracking in the environment of prerecorded X-ray loops. OBJECTIVE: To report on our clinical experience in atrial fibrillation (AF) ablation with recently available MGT-enabled ablation catheters. METHODS: The MGT was used in addition to a conventional 3D mapping system in 80 patients with AF (age 61 ± 10 years; 47 men; 40 with persistent AF), who underwent circumferential pulmonary vein isolation and voltage mapping with and without substrate modification. Short native right anterior oblique/left anterior oblique loops were used as background movies for the nonfluoroscopic placement of sensor-equipped diagnostic catheters into the coronary sinus and the right ventricle. After single transseptal puncture, selective angiograms of the pulmonary veins were used as background movies for near nonfluoroscopic left atrial reconstruction. Computed tomography registration as well as mapping/ablation was performed by using the new open-irrigated MGT-enabled ablation catheter. RESULTS: MGT application was not associated with a change in established workflow. Large parts of the procedure (mean entire duration 167 ± 47 minutes) could be done without additional fluoroscopy, whereas median residual fluoroscopy duration of 4.6 (interquartile range: 2.9, 7.1) minutes was mainly used for the acquisition of background loops, transseptal puncture, occasional verification of transseptal sheath position, and manipulation of the circular mapping catheter. Three (4%) minor complications occurred. CONCLUSIONS: The MGT integrates easily into the workflow of standard AF ablation and allows for high-quality nonfluoroscopic 4D catheter tracking. This results in low radiation exposure for patients and staff without complicating the workflow of the procedure.

MediGuide in supraventricular tachycardia: initial experience from a multicentre registry.

AIMS: Currently, fluoroscopy-based catheter visualization is the standard modality in invasive electrophysiological procedures. Recently a new technology for non-fluoroscopic visualization of diagnostic (since 2010) and ablation catheters (since May 2012) has been introduced. The MediGuide™-Technology (MediGuide) projects catheter tips on prerecorded cine loops in a high time resolution. METHODS AND RESULTS: We report on MediGuide-based supraventricular tachycardia (SVT) cases [atrioventricular nodal reentry tachycardia (AVNRT), atrioventricular reentry tachycardia (AVRT), Wolff-Parkinson-White syndrome (WPW), ectopic atrial tachycardia (EAT) and typical atrial flutter) from two European centres. In all patients, diagnostic and/or ablation catheters with a special sensor were used to perform the ablation procedures. All procedural data such as acute success, duration of the procedure, fluoroscopy time, and dose and patients' characteristics were analyzed and compared with conventionally ablated patients (n = 1865). Procedure-related complications during the hospital stay were recorded. A total of 24 consecutive patients were analyzed: no significant difference to the control group was seen in the baseline characteristics. The MediGuide patients were predominantly male (66%), aged 58 ± 14 years and were ablated for 6 AVNRT (25%), 4 AVRT/WPW (17%), 1 EAT (4%), and 13 typical atrial flutter (54%). The acute success rate was 100% (98% in the control group, n.s.). The median fluoroscopy time was 0.5 ± 1.4 min (10.2 ± 9.6 in the control group, P < 0.001), the median fluoroscopy dose was 187 ± 554 cGy cm(2) (996 ± 2593 cGy cm(2), P < 0.05). Mean procedure time was 70 ± 25 min (60 ± 36 min, n.s.). No complications during the hospital stay were recorded. CONCLUSION: In several different forms of supraventricular tachycardias the MediGuide-Technology contributed to a dramatic reduction in irradiation exposure. With a median fluoroscopy time of 30 s all SVT cases were effectively performed with no complications; the fluoroscopy burden can be significantly reduced not only for the patient but also for the nurses and the physicians performing the case. The overall procedure times are not prolonged due to the use of MediGuide Technology compared with a control group of >1800 patients undergoing conventional ablation procedures.

Individually tailored left ventricular lead placement: lessons from multimodality integration between three-dimensional echocardiography and coronary sinus angiogram.

AIMS: Non-responder rates for cardiac resynchronization therapy (CRT) vary from 11% to 46%. Retrospective data imply a better outcome with stimulation of the latest contracting left ventricular (LV) region. Our study analysed the feasibility, safety and clinical outcome of prospectively planned LV lead placement at the site of latest mechanical activation. METHODS AND RESULTS: Thirty-eight heart failure patients with CRT indication were assessed by three-dimensional (3D) transoesophageal echocardiography and rotation angiography of the coronary sinus (CS). Both images were merged into a single 3D-model to identify CS target veins close to the site of latest mechanical activation. Subsequently, LV lead deployment was attempted at the desired target position. Patients were clinically and echocardiographically evaluated at baseline, after 3 and 6 months. The area of latest mechanical activation covered 6 ± 2 segments (38 ± 13% of LV surface) and was found lateral in 24 of 37 (65%), anterior in 11 of 37 (30%), inferior in 2 of 37 (5%), and septal in 1 of 37 (3%) patients. In 36 of 37 (97%) patients an appropriate target vein was identified and successful implantation could be performed in 34 of 37 (92%) patients. Among those patients clinical and echocardiographic response was observed in 91% and 81%, respectively. CONCLUSION: Individualized lead placement at the latest contracting LV site can be performed safely and successfully in the majority of patients. Initial clinical outcome data are encouraging. Identification of target sites requires multimodality integration between LV wall motion data and CS anatomy. Future developments need to improve those technologies and require randomized data on clinical outcome parameters.

Initial experience in ablation of typical atrial flutter using a novel three-dimensional catheter tracking system.

AIMS: Three-dimensional (3D) mapping has been established for clinical routine in an interventional electrophysiology (EP). Recently, a novel sensor-based 3D catheter tracking system has been introduced integrating 3D non-fluoroscopic catheter navigation into the environment of pre-recorded 2D fluoroscopy [MediGuide™ Technology (MG)]. We are reporting on the first clinical experience for ablation of typical atrial flutter. First we aimed to demonstrate safety and feasibility of this new technique. Secondly, procedural aspects such as effectiveness, procedure, and fluoroscopy time should be evaluated. METHODS AND RESULTS: Ten consecutive patients (100% male, age 68 ± 8 years) were ablated using MG technology. Two steerable diagnostic EP catheters (MediGuide Enabled Livewire™ Catheter, SJM) were used for coronary sinus cannulation and anatomical cavo-tricuspidal isthmus (CTI) reconstruction within the EnSite NavX™ System (NavX). Ablation was performed with a conventional 8 mm tip ablation catheter (IBI, SJM). In all 10 patients both sensor-equipped MG catheters could be tracked non-fluoroscopically. Successful anatomical CTI reconstruction was performed and complete isthmus block was documented after the ablation. Total procedure duration was comparable with conventional procedures (55 ± 8 min). Usage of the MG tracking system resulted in a fluoroscopy time of 2.5 ± 2 min. No adverse events occurred during the procedures. CONCLUSIONS: For the first clinical application of the MG technology in an interventional electrophysiology we found a stable system enabling excellent 3D orientation for spatial catheter positioning on the basis of underlying pre-recorded cine loops. Clinically, the MG technology allowed successful procedures with short fluoroscopy times, even though a sensor-equipped ablation catheter was not yet available for use in the study.

Ablation of atrial fibrillation using novel 4-dimensional catheter tracking within autoregistered left atrial angiograms.

BACKGROUND: We describe a novel fluoroscopy coregistered, 4-dimensional catheter tracking technology (MediGuide Technology [MGT]) used for treatment of patients with atrial fibrillation. The aim of the study was to investigate (1) the feasibility of nonfluoroscopic catheter manipulation within dynamic left atrial chamber models; (2) the integration of the technology into an established electroanatomical mapping system; and (3) potential clinical impact. METHODS AND RESULTS: Forty-nine patients received atrial fibrillation ablation using MGT-enabled NavX-EnSite. Matched patients ablated with a conventional NavX-EnSite system served as a control group. MGT was used for the deployment of diagnostic catheters within preacquired cine loops, for nonfluoroscopic chamber mapping within dynamic angiograms, and for 4-dimensional tagging of anatomical landmarks. Integration with the electroanatomical mapping system allowed correction of field distortions and a reference tool to detect and correct map shifts. Catheter ablation was done without MGT because the ablation catheter was not MGT enabled. MGT worked safely and stably in all 49 patients. Catheter deployment within the preacquired cine loops was successfully performed in 45 of 49 (92%) patients. Catheter tracking within dynamic left atrial angiograms allowed nearly nonfluoroscopic creation of NavX-EnSite geometries with subsequent computed tomography model registration in all 49 patients. Overall, MGT significantly reduced total procedural fluoroscopy time (median [quartiles]) from 31 minutes (25, 43 minutes) to 16 minutes (10, 23 minutes) and irradiation dose from 14 453±7403 to 7363±5827 cGy*cm(2) (mean±SD), respectively (P<0.001). CONCLUSIONS: MGT is a tracking technology that allows 4-dimensional visualization of dedicated catheters within moving chamber models. Integration of the MGT with an established electroanatomical mapping system provided algorithms to facilitate mapping in the electroanatomical mapping system environment. As a first measurable clinical impact, MGT was able to reduce fluoroscopy exposure by nearly 50%.

Sustained monomorphic left ventricular outflow tract tachycardia early after aortic valve replacement.

Sustained monomorphic ventricular tachycardia (VT) after valve surgery is uncommon. Cases of focal VT or bundle-branch re-entry after aortic valve surgery have been reported. We present the case of a 60 year-old patient with an incessant outflow tract VT early after aortic valve replacement. We suggest the disease process affecting the valve and adjacent area, and/or the surgical procedure, might somehow relate to VT substrate adjacent to the aortic annulus.

Long-term efficacy of single procedure remote magnetic catheter navigation for ablation of ischemic ventricular tachycardia: a retrospective study.

BACKGROUND: Remote magnetic navigation (RMN) aims to reduce some inherent limitations of manual radiofrequency (RF) ablation. However, data comparing the effectiveness of both methods are scarce. This study evaluated the acute and long-term success of RMN guided versus manual RF ablation in patients with ischemic sustained ventricular tachycardia (sVT). METHODS: One hundred two consecutive patients (age 68 ± 10 years, LVEF 32 ± 12%, 88 men) with ischemic sVT were ablated with RMN (Stereotaxis; 49%) or manually (51%) using substrate and/or activation mapping (Carto) and open-irrigated-tip catheters. All received implantable defibrillators or loop recorders. Acute success was defined as noninducibility of any sVT at the end of the ablation procedure and long-term success as freedom from VT upon follow-up. RESULTS: There was no difference in the baseline characteristics between the groups. Three patients died in hospital. Acute success rate was similar for RMN and manual ablation (82% vs 71%, P = 0.246). RMN was associated with significantly shorter fluoroscopy time (13 ± 12 minutes vs 32 ± 17 minutes, P = 0.0001) and RF time (2337.59 ± 1248.22 seconds vs 1589.95 ± 1047.42 seconds, P = 0.049), although total procedure time was similar (157 ± 40 minutes vs 148 ± 50 minutes, P = 0.42). There was a nonsignificant trend toward better long-term success in RMN group: after a median of 13 (range 1-34) months, 63% in the RMN and 53% in the manual ablation group were free from VT recurrence (P = 0.206). CONCLUSION: RMN guided RF ablation of ischemic sustained VT is equally efficient compared with manual ablation in terms of acute and long-term success rate. These results are achieved with a significantly reduced fluoroscopy time and shorter RF time.

Catheter ablation of atrial fibrillation using remote magnetic catheter navigation: a case-control study.

AIMS: To compare the acute and the 6 month outcome of catheter ablation of atrial fibrillation (AF) using irrigated tip magnetic catheter and remote magnetic cathter navigation (RMN) with manual catheter navigation (MCN) in patients with paroxysmal and persistent AF. METHODS AND RESULTS: In this retrospective analysis 356 patients (235 male, mean age: 57.9 ± 10.9 years) with AF (70.5%, paroxysmal) who underwent catheter ablation between August 2007 and May 2008 using either RMN (n = 70, 46 male, mean age: 57.9 ± 10.1 years, 50% paroxysmal) or MCN (n = 286, 189 male, mean age: 58.0 ± 13.9 years, 75.5% paroxysmal) were included. All patients completed an intensive follow-up strategy. Complete pulmonary vein isolation was achieved in 87.6 and 99.6% of patients in RMN and MCN groups, respectively (P < 0.05). The procedure, fluoroscopy, and radiofrequency application times were 223 ± 44 vs. 166 ± 52 min (P < 0.0001), 13.7 ± 7.8 vs. 34.5 ± 15.1 min (P < 0.0001), and 75.4 ± 20.9 vs. 53.2 ± 21.4 min (P < 0.0001) in RMN and MCN groups, respectively. Seven (10.0%) and 28 (9.8%) patients in RMN and MCN groups received antiarrhythmic medications during the follow-up (P = 0.96). All the patients completed the 6 month follow-up. Freedom from AF at 6 months was achieved in 57.8 and 66.4% of the patients in RMN and MCN groups, respectively (P = 0.196). In patients without previous AF catheter ablation procedure the freedom from AF at 6 months were 68.2 and 60.5% in the MCN and RMN groups, respectively (P = 0.36). CONCLUSION: Catheter ablation using irrigated tip magnetic catheter and RMN is an effective and safe method for catheter ablation of AF. Compared to manual catheter navigation, the procedure and radiofrequency application times were longer and fluoroscopy time was shorter in the RMN group compared with the MCN group.

Catheter ablation of scar-related ventricular tachycardia in patients with electrical storm using remote magnetic catheter navigation.

BACKGROUND: A remote magnetic navigation system (MNS) has been used for ablation of ventricular arrhythmias. However, irrigated tip catheter has not been evaluated in large series of patients. OBJECTIVE: To evaluate acute and long-term efficiency of the newly available irrigated tip magnetic catheter for radiofrequency (RF) ablation of scar-related ventricular tachycardia (VT) in patients with ischemic heart disease. METHODS: Between January 2008 and October 2009, a total of 30 consecutive patients with ischemic heart disease (26 men, age 70.1 ± 8.7 years, left ventricular ejection fraction: 30 ± 9%) and electrical storm due to monomorphic VT underwent RF ablation using a remote MNS and a magnetic irrigated tip catheter. RESULTS: Acute success was defined as noninducibility of any monomorphic VT during programmed right and left ventricular stimulation, and obtained in 24 (80%) patients. A total of 1-6 VTs (mean 2.3 ± 1.2, 394 ± 108 ms, 210-660 ms) were inducible during each procedure. The duration of RF energy application was 41.2 ± 23.3 minutes, with total procedure and fluoroscopy times of 158 ± 47 minutes and 9.8 ± 5.3 minutes, respectively. No acute complications were observed during the procedures. During mean follow-up of 7.8 months, 21 patients (70%) had no recurrence of VT and received no implantable cardioverter defibrillator therapy. Among patients who were noninducible during programmed right ventricular stimulation (n = 25), ≥1 monomorphic VT was inducible during programmed left ventricular stimulation in four (16%) that was ablated successfully in three of them. CONCLUSIONS: Irrigated ablation of scar-related VT using remote MNS is an effective modality for management of the monomorphic VT in patients with ischemic cardiomyopathy with minimal radiation exposure. Programmed left (in addition to right) ventricular stimulation might be necessary to assess acute outcome of the ablation procedure.

Safety of remote magnetic navigation in patients with pacemakers and implanted cardioverter defibrillators.

BACKGROUND: Remote magnetic catheter navigation (MNS) has been shown to be feasible and safe for radiofrequency catheter ablation of various cardiac arrhythmias. However, its safety in patients with implanted pacemakers or cardioverter-defibrillators has not yet been studied. OBJECTIVES: This retrospective case series study intends to assess the acute and short-term safety of remote MNS in patients with implanted pacemakers or cardioverter-defibrillators. METHODS: Between January 2008 and June 2009, a total of 31 patients with implanted pacemakers (n = 5) or cardioverter-defibrillators (n = 26) underwent 32 catheter ablation procedures using the remote MNS. Baseline pacing thresholds, sensed amplitudes, pacing and, if available, shock impedances as well as battery status were measured in all devices before, immediately after, and 1-3 months after catheter ablation. RESULTS: After ablation, no statistically significant difference in atrial sensing (2.7 ± 1.5 mV vs 3.1 ± 1.9 mV, P = 0.18) and impedance (457 ± 104 Ω vs 449 ± 101 Ω, P = 0.37) were observed. After ablation, no statistically significant difference in right ventricular sensing (10.4 ± 3.8 mV vs 10.9 ± 4.9 mV, P = 0.43) and impedance (535 ± 118 Ω vs 534 ± 120 Ω, P = 0.913) were observed. No changes in pacing threshold could be observed in all but 2 patients with biventricular cardioverter-defibrillators who underwent ventricular tachycardia ablation in lateral wall of left ventricle near the implanted epicardial electrode. CONCLUSIONS: Ablation procedures using remote MNS can be performed safely in patients with implanted devices with no significant effects on device system integrity. Long endocardial ablation close to the insertion site of the implanted epicardial left ventricular leads can affect the pacing and/or sensing characteristics of these electrodes.