Ablação de arritmias da câmara de saída do ventrículo direito e esquerdo com sistema de navegação magnética por controlo remoto

Electrocardiographic imaging to guide ablation of ventricular arrhythmias and agreement between two different systems

BACKGROUND AND AIM

A recent study using an epicardial-only electrocardiographic imaging (ECGI), suggests that the agreement of ECGI activation mapping and that of the contact mapping for ventricular arrhythmias (VA) is poor. The aim of this study was to assess the diagnostic value of two endo-epicardial ECGI systems using different cardiac sources and the agreement between them.

METHODS

We performed 69 ECGI procedures in 52 patients referred for ablation of VA at our center. One system based on the extracellular potentials was used in 26 patients, the other based on the equivalent double layer model in 9, and both in 17 patients. The first uses up to 224 leads and the second just the 12‑lead ECG. The localization of the VA was done using a segmental model of the ventricles. A perfect match (PM) was defined as a predicted location within the same anatomic segment, whereas a near match (NM) as a predicted location within the same segment or a contiguous one.

RESULTS

44 patients underwent ablation, corresponding to 58 ECGI procedures (37 with the first and 21 with the second system). The percentage of PMs and NMs was not significantly different between the two systems, respectively 76% and 95%, p = 0.077, and 97% and 100%, p = 1.000. In 14 patients that underwent ablation and had the ECGI performed with both systems, raw agreement for PMs was 79%, p = 0.250 for disagreement.

CONCLUSIONS

ECGI systems were useful to identify the origin of the VAs, and the results were reproducible regardless the cardiac source.

Validation of an electrocardiographic marker of low voltage areas in the right ventricular outflow tract in patients with idiopathic ventricular arrhythmias

BACKGROUND

Previous studies have reported the presence of subtle abnormalities in the right ventricular outflow tract (RVOT) in patients with apparently normal hearts and ventricular arrhythmias (VAs) from the RVOT, including the presence of low voltage areas (LVAs). This LVAs seem to be associated with the presence of ST-segment elevation in V1 or V2 leads at the level of the 2nd intercostal space (ICS).

OBJECTIVE

Our aim was to validate an electrocardiographic marker of LVAs in the RVOT in patients with idiopathic outflow tract VAs.

METHODS

A total of 120 patients were studied, 84 patients referred for ablation of idiopathic VAs with an inferior axis by the same operator, and a control group of 36 patients without VAs. Structural heart disease including arrhythmogenic right ventricular cardiomyopathy was ruled out in all patients. An electrocardiogram was performed with V1-V2 at the 2nd ICS, and ST-segment elevation ≥1 mm and T-wave inversion beyond V1 were assessed. Bipolar voltage map of the RVOT was performed in sinus rhythm (0.5-1.5 mV color display). Areas with electrograms <1.5 mV were considered LVAs, and their presence was assessed. We compared three groups, VAs from the RVOT (n = 66), VAs from the LVOT (n = 18) and Control group (n = 36). ST-elevation, T-wave inversion and left versus right side of the VAs were tested as predictors of LVAs, respective odds ratio (ORs) (95% confidence interval [CI]) and p values, were calculated with univariate logist regression. Variables with a p < .005 were included in the multivariate analysis.

RESULTS

ST-segment elevation, T-wave inversion and LVAs were present in the RVOT group, LVOT group and Control group as follows: (62%, 17%, and 6%, p < .0001), (33%, 29%, and 0%, p = .001) and (62%, 25%, and 14%, p < .0001). The ST-segment elevation, T-wave inversion and right-sided VAs were all predictors of LVAs, respective unadjusted ORs (95% CI), p values were, 32.31 (11.33-92.13), p < .0001, 4.137 (1.615-10.60), p = .003 and 8.200 (3.309-20.32), p < .0001. After adjustment, the only independent predictor of LVAs was the ST-segment elevation, with an adjusted OR (95% CI) of 20.94 (6.787-64.61), p < .0001.

CONCLUSION

LVAs were frequently present in patients with idiopathic VAs. ST-segment elevation was the only independent predictor of their presence.

A simplified approach to radiofrequency catheter ablation of idiopathic ventricular outflow tract premature ventricular contractions

BACKGROUND

Frequently, low voltage areas (LVAs) and diastolic potentials (DPs) are present at ablation site in sinus rhythm in patients with idiopathic premature ventricular contractions (PVCs).

OBJECTIVE

Validate these findings as substrate for PVCs and evaluate the feasibility of a simplified substrate approach based on LVAs and DPs for ablation of idiopathic outflow tract PVCs, in patients with a low PVC burden during the procedure.

METHODS

Prospective single-arm clinical trial at two centers with comparison with a historical group, matched to age and gender. The study group consisted of consecutive patients referred for ablation of frequent idiopathic PVCs with inferior axis, that presented with less than 2 PVCs/min in first 5 minutes of the procedure. The ablation was based on fast mapping of the RVOT in sinus rhythm looking for LVAs and DPs, defined as isolated small amplitude potentials occurring after the T wave of the surface ECG. The area with LVAs and DPs was tagged, and a simplified activation mapping of the PVCs was done in that area. The procedure time, success rate and recurrence rate were compared with the historical group in whom ablation was performed based on activation and pace mapping only. A validation group without PVCs was also studied to assess the prevalence of LVAs and DPs in the general population.

RESULTS

The study (n=38), historical (n=38) and validation (n=38) groups did not differ in relation to age or gender. Prevalence of LVAs and DPs was significantly higher in the study group in comparison with the validation group, respectively, 71% vs 11%, p<0.0001 and 87% vs 8%, p<0.0001. Procedure time was significantly lower in the study group when comparing to the historical group, 130 (100-164) vs 183 (160-203) min, p<0.0001 and the success rate was significantly higher, 90% vs 64%, p=0.013. The recurrence rate in patients with a successful ablation was not significantly different between both groups, Log-Rank=0.125.

CONCLUSION

Prevalence of LVAs and DPs was significantly higher in the study group than in the validation group. The proposed approach proved to be feasible, faster and more efficient than the historical approach. This article is protected by copyright. All rights reserved.

Assessment of wave front activation duration and speed across the right ventricular outflow tract using electrocardiographic imaging as predictors of the origin of the premature ventricular contractions: A validation study

AIMS

Evaluate right ventricular outflow tract (RVOT) activation duration (AD) and speed, invasively and with the electrocardiographic imaging (ECGI), as predictors of the origin of the PVCs, validating the ECGI.

METHODS

18 consecutive patients, 8 males, median age 55 (35-63) years that underwent ablation of PVCs with inferior axis and had ECGI performed before ablation. Isochronal activation maps of the RVOT in PVC were obtained with the ECGI and invasively. Total RVOT AD was measured as the time between earliest and latest activated region, and propagation speed by measuring the area of the first 10 ms of activation. Cut-off values for AD, activation speed and number of 10 ms isochrones to predict the origin of the PVCs, were obtained with the ROC curve analysis. Agreement between methods was done with Pearson correlation test and Bland-Altman plot.

RESULTS

PVCs originated from the RVOT in 11 (61%) patients. The stronger predictor of PVC origin was the AD. The median AD in PVCs from RVOT was significantly longer than from outside the RVOT, both with ECGI and invasively, respectively 62 (58-73) vs 37 (33-40) ms, p < 0.0001 and 68 (60-75) vs 35 (29-41) ms, p < 0.0001. Agreement between the two methods was good (r = 0.864, p < 0.0001). The cut-off value of 43 ms for AD measured with ECGI predicted the origin of the PVCs with a sensitivity and specificity of 100%.

CONCLUSIONS

We found good agreement between ECGI and invasive map. The AD measured with ECGI was the best predictor of the origin of the PVCs.

Prolonged Right Ventricular Outflow Tract Endocardial Activation Duration and Presence of Deceleration Zones in Patients With Idiopathic Premature Ventricular Contractions. Association With Low Voltage Areas

BACKGROUND AND AIMS

The wavefront propagation velocity in the myocardium with fibrosis is characterized by the presence of deceleration zones and late activated zones, that are absent in the normal myocardium. Our aim was to study the right ventricular outflow tract (RVOT) endocardial activation duration in sinus rhythm, and assess the presence of deceleration zones, in patients with premature ventricular contractions (PVCs) and in controls.

METHODS

We studied 29 patients with idiopathic PVCs from the outflow tract, subjected to catheter ablation that had an activation and voltage map of the RVOT in sinus rhythm. A control group of 15 patients without PVCs that underwent ablation of supraventricular arrhythmias was also studied. RVOT endocardial activation duration and number of 10 ms isochrones across the RVOT were assessed. Propagation speed was calculated at the zone with the higher number of isochrones per cm radius. Deceleration zones were defined as zones with >3 isochrones within 1 cm radius. Low voltage areas were defined as areas with local electrogram with amplitude <1.5 mV.

RESULTS

The two groups did not differ in relation to age, gender or number of points in the map. RVOT endocardial activation duration and number of 10 ms isochrones were higher in the PVC group; 56 (41-66) ms vs. 39 (35-41) ms, p = 0.001 and 5 (4-8) vs. 4 (4-5), p = 0.001. Presence of deceleration zones and low voltage areas were more frequent in the PVC group; 20 (69%) vs. 0 (0%), p < 0.0001 and 21 (72%) vs. 0 (0%), p < 0.0001. The wavefront propagation speed was significantly lower in patients with PVCs than in the control group, 0.35 (0.27-0.40) vs. 0.63 (0.56-0.66) m/s, p < 0.0001. Patients with low voltage areas had longer activation duration 60 (52-67) vs. 36 (32-40) ms, p < 0.0001, more deceleration zones, 20 (95%) vs. 0 (0%), p < 0.0001, and lower wavefront propagation speed, 0.30 (0.26-0.36) vs. 0.54 (0.36-0.66) m/s, p = 0.002, than patients without low voltage areas.

CONCLUSION

Right ventricular outflow tract endocardial activation duration was longer, propagation speed was lower and deceleration zones were more frequent in patients with PVCs than in controls and were associated with the presence of low voltage areas.

Novel strategy of remote magnetic navigation-guided ablation for ventricular arrhythmias from right ventricle outflow tract

The optimized strategy to further increase the success rate of ablation for ventricular arrhythmias (VAs) from the right ventricular outflow tract (RVOT) is challenging. Recent studies have shown that the pulmonary sinus cusp (PSC) region may be the origin of certain RVOT VAs. We evaluated the efficacy of preferential ablation below the pulmonary valve (PV) and alternated radiofrequency delivery in the PSC using remote magnetic navigation (RMN). Sixty-five (65) consecutive patients experiencing VAs with RVOT-like appearance were included in this study. Mapping and ablation were preferentially performed below the PV. Ablation in the PSC would only be attempted when intensified ablation below the PV could not eliminate VAs. Finally, if ablation in the RVOT region failed, the aortic sinus cusp (ASC) would be mapped. Sixty-one (61) of 65 (93.8%) patients achieved procedural success. Except 7 cases of which the VAs were ablated in the ASC, the rest 54 VAs were thought to be originate from the RVOT region. Fifty (50) of 54 VAs were successfully ablated below the PV, and in the presence of a local special signal in the bipolar electrogram a more aggressive ablation was required. Subsequent ablation in the PSC with assistance of the RMN system achieved success in the remaining 4 patients. No complications occurred in this study. Our strategy of using RMN-guided ablation below the PV for VAs of RVOT origin was proved to be effective. PSC mapping and ablation using a magnetic catheter may provide the optimal strategy for treating these types of arrhythmias.

Successful ablation of premature ventricular contractions exclusively guided by epicardial and endocardial non-invasive mapping (ECGI) and confirmed by substrate mapping

Ablation of premature ventricular contractions (PVCs), relies mostly on a detailed activation mapping. This can be impossible to achieve in case of paucity or even absence of PVCs during the procedure. Pacemapping as an alternative has many limitations. We present a case of a patient with very frequent symptomatic PVCs, that on the day of the procedure had total absence of PVCs. We performed successful ablation based exclusively on electrocardiographic imaging confirmed by substrate mapping.

Idiopathic Premature Ventricular Contractions From the Outflow Tract Display an Underlying Substrate That Can Be Unmasked by a Type 2 Brugada Electrocardiographic Pattern at High Right Precordial Leads

Background: Patients with premature ventricular contractions (PVCs) from the right ventricular outflow tract (RVOT) and apparently normal hearts, can have ST elevation similar to type 2 or type 3 Brugada pattern in the electrocardiographic (ECG) performed at a higher position. Cardiac magnetic resonance (CMR), has shown conflicting data regarding existence of structural abnormalities in patients with idiopathic PVCs from the RVOT. Objective: Our aim was to evaluate the prevalence of low voltage areas (LVAs) in the RVOT of patients with PVCS from the outflow tract, and in a control group. Secondly, assess for the presence of a non-invasive ECG marker. Methods: A 56 consecutive patients, 45 with frequent PVCs (>10000/24 h) LBBB, vertical axis, negative in aVL and 11 subjects without PVCs. Arrhythmogenic right ventricular cardiomyopathy was ruled out in all patients. An ECG was performed with V1-V2 at the level of the second intercostal space and the presence of ST-segment elevation with a Type 2 or 3 Brugada pattern (Type 2 BrP) was assessed. Bipolar voltage map of the RVOT was performed in sinus rhythm (0.5-1.5 mV color display). Areas with electrograms <1.5 mV represented the LVA. The area adjacent to the pulmonary valve usually displays voltage between 0.5 and 1.5 mV and is classified as transitional-voltage zone. Presence of LVAs outside this transitional-voltage zone were estimated. We compared two groups with and without ST-segment elevation and tested for the association between ECG pattern and LVAs. Results: None of the patients in the control group had ST-segment elevation or LVAs. In the PVC group, no patient had type 1 Brugada pattern, 29 patients (64%) had type 2 or 3 ST-segment elevation (Type 2 BrP), and 28 (62%) had LVAs outside the transitional-voltage zone. LVAs were more frequent in patients with Type 2 BrP; 93% versus 4%, p < 0.0001. The ECG pattern was associated with the presence of LVAs, OR (95% CI): 202.50 (16.92-2423), p < 0.0001. Conclusion: Low voltage areas were frequently present in the RVOT of patients with idiopathic PVCs. They were absent in controls and can be unmasked by the presence of Type 2 BrP in high right precordial leads.

Electrocardiographic imaging (ECGI): What is the minimal number of leads needed to obtain a good spatial resolution?

AIMS

Assess the minimal number of ECGI leads needed to obtain a good spatial resolution.

METHODS

We enrolled 20 patients that underwent ablation of premature ventricular or atrial contractions using Carto and ECGI with AMYCARD. We evaluated the agreement regarding the site of origin of the arrhythmia between the ECGI and Carto, the area and diameter of the earliest activation site obtained with the ECGI (EASa and EASd). Based on previous studies with pacemapping, we considered a good spatial resolution of the ECGI when the EASd measured on the isopotential map was less than 18 mm. In presence of agreement the ECGI was reprocessed: a) with half the number of electrode bands (8 leads per electrode band) and b) with 6 electrode bands.

RESULTS

The initial map was obtained with 23 (22-23) electrode bands per patient, corresponding to 143 (130-170) leads. Agreement rate was 85%, the median EASa and EASd were: 0.7 (0.5-1.3) cm² and 9 (8-13) mm. With half the number of electrode bands including 73 (60-79) leads, agreement rate was 80%, the EASa and EASd were: 2.1 (1.5-6.2) cm² and 16 (14 -28) mm. With only six electrode bands using 38 (30-42) leads, agreement rate was 55%, EASa and EASd were: 4.0 (3.3-5.0) cm² and 23 (21-25) mm. The number of leads was a predictor of agreement with a good spatial resolution, OR (95% CI) of 1.138 (1.050-1.234), p = .002. According to the ROC curve, the minimal number of leads was 74 (AUC 0.981; 95% CI: 0.949-1.00, p < .0001).

CONCLUSION

Reducing the number of leads was associated with a lower agreement rate and a significant reduction of spatial resolution. However, the number of leads needed to achieve a good spatial resolution was less than the maximal available.

Contact feedback improves 1-year outcomes of remote magnetic navigation-guided ischemic ventricular tachycardia ablation

INTRODUCTION

Remote magnetic navigation (RMN)-guided catheter ablation (CA) is a feasible treatment option for patients presenting with ischemic ventricular tachycardia (VT). Catheter-tissue contact feedback, enhances lesion formation and may consequently improve CA outcomes. Until recently, contact feedback was unavailable for RMN-guided CA. The novel e-Contact Module (ECM) was developed to continuously monitor and ensure catheter-tissue contact during RMN-guided CA.

OBJECTIVE

The present study aims to evaluate the effect of ECM implementation on acute and long-term outcomes in RMN-guided ischemic VT ablation.

METHOD

This retrospective, two-center study included consecutive ischemic VT patients undergoing RMN-guided CA from 2010 to 2017. Baseline clinical data, procedural data, including radiation times, and acute success rates were compared between CA procedures performed with ECM (ECM+) and without ECM (ECM-). One-year VT-free survival was analyzed using Cox-proportional hazards models, adjusting for potential confounders: age, left ventricular function, VT inducibility at baseline and substrate based ablation strategy.

RESULTS

The current study included 145 patients (ECM+ N = 25, ECM- N = 120). Significantly lower fluoroscopy times were observed in the ECM+ group (9.5 (IQR 5.3-13.5) versus 12.5 min (IQR 8.0-18.0), P = 0.025). Non-inducibility of the clinical VT at the end of procedure was observed in 92% ECM+ versus 72% ECM- patients (P = 0.19). ECM guidance was associated with significantly lower VT-recurrence rates during 1-year follow-up (16% ECM+ versus 40% ECM-; multivariable HR 0.29, 95%-CI 0.10-0.69, P = 0.021, reference group: ECM-).

CONCLUSION

Contact feedback by the ECM further decreases fluoroscopy exposure and improves VT-free survival in RMN-guided ischemic VT ablation.

Robotic navigation shows superior improvement in efficiency for atrial fibrillation ablation

Background

Because of the expanding atrial fibrillation (AF) burden, AF catheter ablation (CA) techniques have to become more efficient. Efficient AF CA procedures are characterized by successful pulmonary vein isolation (PVI) within reasonable procedure time. Currently there are many PVI techniques available and all show substantial improvements over time. However, the magnitude of improvement in procedural efficiency has not yet been compared between different techniques. The aim of this study was to compare efficiency improvement between manually (MAN) guided, cryoballoon (CB) and remote magnetic navigation (RMN) guided PVI.

Methods

A total of 221 patients were included in this retrospective study. Procedural parameters of 115 patients treated with first-generation PVI techniques (MAN-1, CB-1, RMN-1) performed in 2010, were compared to 106 patients who were treated with the latest, second generation techniques (MAN-2, CB-2, RMN-2). Efficiency was characterized by the following parameters: total ablation time, total procedure time, first pass isolation (FPI) (i.e. successful isolation after the first pulmonary vein (PV) encirclement) and touch-up rates.

Results

Every technique showed significant improvement of procedure times from the first to the second generation (P<0.001). In-between second generation techniques, the procedure times were comparable. The greatest magnitude of procedure time improvement was observed within the RMN groups (∆-180min), which was significantly greater compared to CB (∆-48 min, P<0.001) and MAN (∆-98min, P=0.011) groups. The highest FPI rates were observed in RMN-2 (78% and 74%; left and right PVs respectively), which was significantly higher compared to other techniques (MAN-2: 24% and 24%; CB-2: 50% and 48%; P<0.001).

Conclusions

The highest magnitude of efficiency improvement was detected in RMN guided PVI.

Atrioventricular node reentrant tachycardia: Remote magnetic navigation ablation versus manual ablation - impact on operator fluoroscopy time

INTRODUCTION AND AIMS

Remote magnetic navigation systems have demonstrated benefits in the ablation of difficult substrates. Their role in the ablation of atrioventricular nodal reentrant tachycardia (AVNRT), however, has only been studied in small patient series. The aim of this study was to compare the results of AVNRT ablation using magnetic navigation, in a center where every procedure is performed with this system, with manual ablation.

METHODS

We selected 139 consecutive patients undergoing AVNRT ablation with magnetic navigation by a single operator between January 2009 and June 2016 and compared them to a group of 101 consecutive patients undergoing manual ablation in the same period by the same operator in another hospital. The methodology was the same in both groups. Success rates, complications, procedure time, radiofrequency time, total and operator fluoroscopy time, and recurrence rates were compared.

RESULTS

There were no differences in success and complication rates. Procedure and total fluoroscopy times were not significantly different, but operator fluoroscopy time was significantly shorter with the magnetic navigation system (2.4±1.5 min vs. 7.2±4 min; p<0.001). The recurrence rate was higher in the manual group, although without statistical significance.

CONCLUSIONS

The ablation of AVNRT with magnetic navigation is feasible using the same methodology as for manual ablation. Success and complication rates were similar. Operator fluoroscopy time was significantly less with the magnetic navigation system.

Feasibility of a novel mapping system combined with remote magnetic navigation for catheter ablation of premature ventricular contractions

BACKGROUND

Remote magnetic navigation (RMN) is often used in combination with a 3-dimensional mapping system to perform catheter ablations. This study aim to investigate the feasibility and effectiveness of a novel 3D-mapping system, EnSite Precision, combined with RMN for catheter ablation of premature ventricular contractions (PVCs), and compared it to the procedures performed by CARTO3 with RMN.

METHODS

Forty-three consecutive PVC patients were either ablated with the guidance of EnSite Precision (n = 22) or CARTO (n = 21) navigated by RMN. Procedure-related details, acute and long-term success were assessed.

RESULTS

Patient characteristics between both the groups were similar (age: 47.1 ± 19.8 vs 47.1 ± 12.7, female: 63.6% vs 57.1%). No significant difference was found in the procedure time (99.5 ± 30.4 vs 92.9 ± 24.8 min, P = 0.436), mapping time (18.6 ± 12.8 vs 15.5 ± 10.2 min, P = 0.390), radiofrequency ablation time (333.4 ± 267.0 vs 469.3 ± 343.1 s, P = 0.154), fluoroscopy time (4.0 ± 1.9 vs 3.8 ± 2.0 min, P = 0.635), and X-ray dose (1.8 ± 1.4 vs 2.0 ± 1.2 Gycm2, P = 0.649) between the two groups. No significant procedural complication occurred in either group. In addition, there was no significant differences regarding the acute success rate (90.9% vs 90.5%, P = 0.961) and long-term success rate (86.4% vs 81.0%, P = 0.631) after 16.2 ± 6.2 months of follow-up between the two groups.

CONCLUSIONS

RMN combined with EnSite Precision mapping system is effective and safe for catheter ablation of PVCs.

Premature ventricular contractions of the right ventricular outflow tract: Upward displacement of the ECG unmasks ST elevation in V1 associated with the presence of low voltage areas

INTRODUCTION AND AIMS

Frequent premature ventricular contractions (PVCs) originating from the right ventricular outflow tract (RVOT) are usually considered a benign entity and the ECG is typically normal. The aim of this study was to assess whether upward displacement of the ECG to the second intercostal space (ICS) would reveal any abnormal pattern.

METHODS

A total of 18 consecutive patients with apparently normal hearts were studied, mean age 44±16 years, 12 women, who underwent catheter ablation of the RVOT due to frequent PVCs. A 12-lead ECG was performed in the standard position and repeated in a higher position, at the level of the second ICS. Three-dimensional bipolar electroanatomical voltage mapping (EVM) was performed in all patients and low voltage areas (LVAs) were defined as areas with amplitude <1.5 mV.

RESULTS

The ECG in the second ICS was normal in eleven patients but in seven (39%) it revealed a pattern of ST-segment elevation in V1. EVM revealed the presence of LVAs in six patients (33%) which included the earliest activation site (EAS) in five. The ST elevation was associated with the presence of LVAs (p<0.0001) and with the LVAs at the EAS (p=0.002).

CONCLUSION

In this group of patients with apparently normal hearts and with frequent PVCs of the RVOT, upward displacement of the ECG revealed the presence of ST elevation in more than one third of patients, and the ST elevation was associated with the presence of LVAs in the RVOT.

Isolated diastolic potentials as predictors of success in ablation of right ventricular outflow tract idiopathic premature ventricular contractions

Background and aims

Discrete potentials, low voltage and fragmented electrograms, have been previously reported at ablation site, in patients with premature ventricular contractions (PVCs) originating in the right ventricular outflow tract (RVOT). The aim of this study was to review the electrograms at ablation site and assess the presence of diastolic potentials and their association with success.

Methods

We retrospectively reviewed the electrograms obtained at the radiofrequency (RF) delivery sites of 48 patients subjected to ablation of RVOT frequent PVCs. We assessed the duration and amplitude of local electrogram, local activation time, and presence of diastolic potentials and fragmented electrograms.

Results

We reviewed 134 electrograms, median 2 (1–4) per patient. Success was achieved in 40 patients (83%). At successful sites the local activation time was earlier– 54 (-35 to -77) ms vs -26 (-12 to -35) ms, p<0.0001; the local electrogram had lower amplitude 1 (0.45–1.15) vs 1.5 (0.5–2.1) mV, p = 0.006, and longer duration 106 (80–154) vs 74 (60–90) ms, p<0.0001. Diastolic potentials and fragmented electrograms were more frequently present, respectively 76% vs 9%, p <0.0001 and 54% vs 11%, p<0.0001. In univariable analysis these variables were all associated with success. In multivariable analysis only the presence of diastolic potentials [OR 15.5 (95% CI: 3.92–61.2; p<0.0001)], and the value of local activation time [OR 1.11 (95% CI: 1.049–1.172 p<0.0001)], were significantly associated with success.

Conclusion

In this group of patients the presence of diastolic potentials at the ablation site was associated with success.

Remote magnetic navigation facilitates the ablations of frequent ventricular premature complexes originating from the outflow tract and the valve annulus as compared to manual control navigation

OBJECTIVE

The purpose of this study was to assess the role of remote magnetic navigation (RMN) in the ablation of ventricular premature complexes (VPCs) arising from outflow tracts (OT) and valve annuli by comparing to manual control navigation (MCN).

METHODS

A total of 152 patients with frequent VPCs were prospectively enrolled. 64 (42%) patients underwent ablation guided by RMN. Acute success rate was defined as the complete elimination and non-inducibility of clinical VPCs during the procedure.

RESULTS

Overall, acute success rate of RMN group was not different from MCN group (87.5% vs 84.1%, p = 0.56). Compared to MCN group, the fluoroscopic time of OT-VPCs ablation in the RMN group was significantly reduced by 67% (2.9 ± 2.3 min vs 8.9 ± 9.7 min, p = 0.006), and the ablation applications in successful cases were significantly reduced (11 ± 7 vs 15 ± 11, p = 0.018). Compared to MCN, RMN significantly decreased ablation applications (15 ± 9 vs 23 ± 9, p = 0.013) in the acute success rates of ablating VPCs of valve annulus, and has a trend of a higher success rate for VPCs arising from tricuspid annulus (10/11 vs 7/12, p = 0.193). No complications occurred in the RMN group. Three cases of cardiac tamponade and one case of transient atrioventricular block occurred in the MCN group (p = 0.22). After a mean follow up of 16.2 months, 2/56 and 3/74 patients had a recurrence of VPCs in the RMN group and MCN group respectively (p = 0.75).

CONCLUSIONS

When compared to MCN, RMN-guided ablation for VPCs was just as effective and safe, with the added benefit of reduced fluoroscopic time and fewer ablation applications.

Remote magnetic navigation vs. manual navigation for ablation of ventricular tachycardia: a meta-analysis

BACKGROUND

The purpose of this study was to prospectively evaluate the efficacy and safety of remote magnetic navigation (RMN) in comparison with manual catheter navigation (MCN) in performing ventricular tachycardia ablation.

METHODS

An electronic search was performed using PubMed (1948-2013) and EMBASE (1974-2013) studies comparing RMN with MCN which were published prior to 31 December 2013. Outcomes of interest were as follows: acute success, recurrence rate, complications, total procedure and fluoroscopic times. Standard mean difference (SMD) and its 95 % confidence interval (CI) were used for continuous outcomes; odds ratios (OR) were reported for dichotomous variables.

RESULTS

Four non-randomised studies, including a total of 328 patients, were identified. RMN was deployed in 191 patients. Acute success and long-term freedom from arrhythmias were not significantly different between the RMN and control groups (OR 1.845, 95 % CI 0.731-4.659, p = 0.195 and OR 0.676, 95 % CI 0.383-1.194, p = 0.177, respectively). RMN was associated with less peri-procedural complications (OR 0.279, 95 % CI 0.092-0.843, p = 0.024). Shorter procedural and fluoroscopy times were achieved (95 % CI -0.487 to -0.035, p = 0.024 and 95 % CI -1.467 to -0.984, p<0.001, respectively).

CONCLUSION

The acute and long-term success rates for VT ablation are equal between RMN and MCN, whereas the RMN-guided procedure can be performed with a lower complication rate and less procedural and fluoroscopic times. More prospective randomised trials will be needed to better evaluate the superior role of RMN for catheter ablation of ventricular tachycardia.

Safety and Clinical Outcome of Catheter Ablation of Ventricular Arrhythmias Using Contact Force Sensing: Consecutive Case Series

BACKGROUND

Poor catheter-to-myocardial contact can lead to ineffective ablation lesions and suboptimal outcome. Contact force (CF) sensing catheters in ventricular tachyarrhythmia (VT) ablations have not been studied for their long-term efficacy.

PURPOSE

The aim of this study was to compare CF ablation to manual ablation (MAN) and remote magnetic navigation (RMN) ablation for safety and efficacy in acute and long-term outcome.

METHODS

A total of 239 consecutive patients who underwent VT ablation with the use of MAN, CF, or RMN catheters were included in this single-center cohort study from January 2007 until March 2014. The primary endpoints were procedural success, acute major complications, and VT recurrences at follow-up. The median follow-up period was 25 months.

RESULTS

Acute success was achieved in 182 out of 239 procedures (76%). Acute success in manual ablation, CF ablation and RMN ablation was 71%, 71%, and 86%, respectively (P = 0.03). Major complications occurred in 3.3% and there were less major complications (P = 0.04) in the RMN group. After an initial successful procedure, 66 of 182 patients (36%) had a recurrence during follow-up. This was not significantly different between groups. Using an intention-to-treat analysis, 124 patients (52%) had a recurrence. The recurrence rate was lowest in the RMN group.

CONCLUSION

The use of CF sensing catheters did not improve procedural outcome or safety profile in comparison to non-CF sensing ablation in this observational study of ventricular arrhythmia ablations.

Remote magnetic navigation for ablation of typical atrial flutter: Long-term results

INTRODUCTION AND AIM

Remote magnetic navigation has proved to be effective in the ablation of most supraventricular and ventricular arrhythmias. Initial studies reported worse results with this system compared to conventional ablation for atrial flutter. The aim of this study was to assess the acute and long-term success of atrial flutter ablation with remote magnetic navigation and to retrospectively compare the results obtained with an 8-mm tip catheter versus an irrigated catheter.

METHODS

We studied 38 consecutive patients, mean age 61 ± 15 years, 28 male, who underwent ablation of typical atrial flutter with the Niobe II remote magnetic navigation system (Stereotaxis). Ablation was performed with an 8-mm tip catheter in 17 patients and with an irrigated-tip catheter in 21 patients. Acute success was defined as the presence of bidirectional isthmus block, and long-term success as absence of symptoms and atrial flutter during Holter monitoring.

RESULTS

Bidirectional isthmus block was achieved in 37 patients (97%), and the success rate was similar in both groups. Total procedure time was not significantly different between the groups but fluoroscopy time was shorter in the irrigated tip group (13.4 ± 3.7 min vs. 6 ± 4.4 min; p<0.01). The number of applications and total radiofrequency time did not differ. There were no complications. During a follow-up of 32 ± 19 months there were two relapses, one in each group.

CONCLUSIONS

The Niobe II remote control system for ablation of typical atrial flutter is safe and effective in both the short and long term. The 8-mm and irrigated-tip catheters showed similar safety and efficacy.