Prediction of atrial fibrillation using the recurrence complex network of body surface potential mapping signals.

OBJECTIVE: Atrial fibrillation (AF) is the most common type of persistent arrhythmia. Early diagnosis and intervention of AF is essential to avert the further fatality. The technique of noninvasive electrical mapping, especially the body surface potential mapping (BSPM), has a more practical application in the study of predicting AF, when compared with the invasive electrical mapping methods such as the epicardial mapping and interventional catheter mapping. However, the prediction of AF with noninvasive signals has been inadequately studied. Thus, the aim of this paper was to analyze the properties of atrial dynamic system based on the noninvasive BSPM signals (BSPMs), using the recurrence complex network, and consequently to evaluate its role in predicting the recurrence of AF in clinical aspect. METHOD: Twelve patients with persistent AF were included in this study. Their preoperative and postoperative BSPMs were recorded. Initially, the preoperative BSPMs were transformed into the recurrence complex network to characterize the complexity property of the atria. Subsequently, the parameters of recurrence ratio (REC), determinism (DET), entropy of the diagonal structure distribution (ENTR), and laminarity (LAM) were calculated. Furthermore, the difference in the parameters in the four regions of the body and the difference obtained from the dominant frequency (DF) method were compared. Finally, the results obtained for the atrial dynamic system complexity from a 12-lead electrocardiogram (ECG) from the BSPMs were discussed. RESULTS: Our study revealed that the patients whose REC is greater than an average threshold, and with a lower LAM presented a much higher possibility of AF recurrence, after the AF surgery. CONCLUSIONS: The recurrence complex network is a useful and convenient way to evaluate the nonlinear properties of the BSPMs in patients with AF. It has good immunity to the lead position and has a potential role in the understanding of predicting the recurrence of AF.

First data on cardiac mapping and outcome of pulmonary vein isolation using a novel ablation catheter with tip mini electrodes.

AIMS: Pulmonary vein isolation (PVI) is a standard treatment of atrial fibrillation (AF). AF recurrence after PVI occurs in a substantial number of cases. A novel ablation catheter equipped with mini-electrodes (ME) may facilitate PVI. Our study evaluated outcome after PVI with the ME catheter compared to a standard catheter. METHODS: Patients undergoing PVI with the ME catheter were compared to a control group ablated with a standard contact force sensing catheter. Freedom of AF after 12 months was the study endpoint. Additionally, low voltage areas (LVA) <0.5 mV were identified with a circular mapping catheter (CMC) and the ablation catheter in each group. LVA were compared between the maps obtained with the CMC and the ME or standard catheter, respectively. RESULTS: A total of 110 patients underwent PVI with ME catheter (n = 59) or the standard catheter (n = 51). Procedure duration (117.4 ±â€¯43 vs. 103.1 ±â€¯32.8 min, p = 0.15), radiation dose (1135.6 ±â€¯1125.7 vs. 1078.8 ±â€¯951.4 µGy/m2, p = 0.91), incidence of complications and 12-month success rate (64.4 vs 72.5%, p = 0.36) were not significantly different between the groups. LVA were significantly smaller when obtained with the standard catheter compared to the CMC (14 ±â€¯13 vs. 58.5 ±â€¯22.1 cm2, p < 0.001), while no such difference was seen for mapping with the ME compared to the CMC (37 ±â€¯30.3 vs. 33.4 ±â€¯39 cm2, p = 0.4). CONCLUSION: Clinical outcomes are comparable between ME catheter and a standard contact force sensing catheter. Furthermore, better LVA detection points to improved mapping capabilities of the ME catheter.

Multicentre safety of adding Focal Impulse and Rotor Modulation (FIRM) to conventional ablation for atrial fibrillation.

AIMS: Focal Impulse and Rotor Modulation (FIRM) uses 64-electrode basket catheters to identify atrial fibrillation (AF)-sustaining sites for ablation, with promising results in many studies. Accordingly, new basket designs are being tested by several groups. We set out to determine the procedural safety of adding basket mapping and map-guided ablation to conventional pulmonary vein isolation (PVI). METHODS AND RESULTS: We collected 30 day procedural safety data in five US centres for consecutive patients undergoing FIRM plus PVI (FIRM-PVI) compared with contemporaneous controls undergoing PVI without FIRM. A total of 625 cases were included in this analysis: 325 FIRM-PVI and 300 PVI-controls. FIRM-PVI patients were more likely than PVI-controls to be male (83% vs. 66%, P < 0.001) and have long-standing persistent AF (26% vs. 13%, P < 0.001) reflecting patients referred for FIRM. Total ablation time was greater for FIRM-PVI (62 ± 22 min) vs. PVI-controls (52 ± 18 min, P = 0.03). The complication rate for FIRM-PVI procedures (4.3%) was similar to controls (4.0%, P = 1) for both major and minor complications; no deaths were reported. The rate of complications potentially attributable to the basket catheter was small and did not differ between basket types (Constellation 2.8% vs. FIRMap 1.8%, P = 0.7) or between cases in which basket catheters were and were not used (P = 0.5). Complication rates did not differ between centres (P = 0.6). CONCLUSIONS: Procedural complications from the use of the basket catheters for AF mapping are low, and thus procedural safety appears similar between FIRM-PVI and PVI-controls in a large multicentre cohort. Future studies are required to determine the optimal approach to maximize the efficacy of FIRM-guided ablation.

Fluoroless Catheter Ablation of Cardiac Arrhythmias: A 5-Year Experience.

BACKGROUND: Catheter ablations have been traditionally performed with the use of fluoroscopic guidance, which exposes the patient and staff to the inherent risks of radiation. We have developed techniques to eliminate the use of fluoroscopy during cardiac ablations and have been performing completely fluoroless catheter ablations on our patients for over 5 years. METHODS: We present a retrospective analysis of the safety, efficacy, and feasibility data from 500 consecutive patients who underwent nonfluoroscopic catheter ablation, targeting a total of 639 arrhythmias, including atrioventricular reciprocating tachycardia (AVRT), atrioventricular nodal reentrant tachycardia (AVNRT), atrial tachycardia (AT), atrial fibrillation (AF), premature ventricular contractions (PVCs), and ventricular tachycardia (VT). We perform fluoroless ablations using intracardiac electrograms, electroanatomic mapping, and for most cases intracardiac echocardiography. Our experience includes exclusively endocardial cardiac ablations. RESULTS: The mean follow-up was 20.5 months. Recurrence rate for AVRT was 6.5%, for AVNRT 2.5%, for macro-reentrant AT 6.4%, for focal AT 5.4%, for AF 22.6%, for PVC 6.7%, and for VT 21.4%. Major complications occurred in five patients (1.0%); minor complications occurred in three patients (0.6%). No deaths occurred. Fluoroscopy was used in one instance, for 0.3 minutes, to confirm venous access. CONCLUSIONS: Completely fluoroless catheter ablations may be routinely performed for all endocardial ablations without compromising safety, efficacy, or procedural duration.

Left Atrial Substrate Modification Targeting Low-Voltage Areas for Catheter Ablation of Atrial Fibrillation: A Systematic Review and Meta-Analysis.

BACKGROUND: This meta-analysis aims to assess the impact of a voltage-guided substrate modification by targeting low-voltage area (LVA) in addition to pulmonary vein isolation (PVI) in patients undergoing catheter ablation for atrial fibrillation (AF). METHODS: MEDLINE/PubMed, Cochrane Library, and references reporting AF ablation and "voltage* OR substrate* OR fibrosis OR fibrotic area*" were screened and studies included if matching inclusion and exclusion criteria. RESULTS: Six studies were included. Patients enrolled were 885 (517 in the study group and 368 in the control group). Median age was 60 years; 92% had nonparoxysmal AF. At a mean follow-up of 17 months, 70% of patients in the study group vs. 43% in the control group were free from AF/atrial tachycardia (AT) recurrences (odds ratio [OR] = 3.41, 95% confidence interval [CI] 2.22-5.24). LVA ablation in addition to PVI was more effective than PVI alone and PVI + conventional wide empirical ablation (70% vs. 43%, OR = 3.41, 95% CI 2.22-5.24), without increasing the adverse event rate (2.5% vs. 6%, OR = 0.43, 95% CI 0.15-1.26). Compared to PVI + conventional wide empirical ablation, LVA ablation reduced the occurrence of postablation AT (14% vs. 46%, OR = 0.16, 95% CI 0.07-0.37), procedure time (176 min vs. 220 min, OR = 0.36, 95% CI 0.24-0.56), fluoroscopy time (25 min vs. 31 min, OR = 0.22, 95% CI 0.12-0.39), and radiofrequency time (55 min vs. 90 min, OR = 0.49, 95% CI 0.27-0.90). CONCLUSIONS: A voltage-guided substrate modification by targeting LVA in addition to PVI is more effective, safer, and holds a lower proarrhythmic potential than conventional ablation approaches. Further randomized studies are necessary to confirm these findings.

Comparison of remote magnetic navigation ablation and manual ablation of idiopathic ventricular arrhythmia after failed manual ablation.

PURPOSE: Catheter ablation for idiopathic ventricular arrhythmia (VA) is effective and safe, but efficacy is frequently limited due to an epicardial origin and difficult anatomy. The remote magnetic navigation (RMN) catheter has a flexible catheter design allowing access to difficult anatomy. We describe the efficacy of the RMN for ablation of idiopathic VA after failed manual ablation. METHODS: Among 235 patients with idiopathic VA referred for catheter ablation, we identified 51 patients who were referred for repeat ablation after a failed manual ablation. We analyzed the clinical characteristics, including the successful ablation site and findings at electrophysiology study, in repeat procedures conducted using RMN as compared with manual ablation. Among these patients, 22 (43 %) underwent repeat ablation with the RMN and 29 (57 %) underwent repeat ablation with a manual ablation. RESULTS: Overall, successful ablation rate was significantly higher using RMN as compared with manual ablation (91 vs. 69 %, P = 0.02). Fluoroscopy time in the RMN was 17 ± 12 min as compared with 43 ± 18 min in the manual ablation (P = 0.009). Successful ablation rate in the posterior right ventricular outflow tract (RVOT) plus posterior-tricuspid annulus was higher with RMN as compared with manual ablation (92 vs. 50 %, P = 0.03). Neither groups exhibited any major complications. CONCLUSIONS: The RMN is more effective in selected patients with recurrent idiopathic VA after failed manual ablation and is associated with less fluoroscopy time. The RMN catheters have a flexible design enabling them to access otherwise difficult anatomy including the posterior tricuspid annulus and posterior RVOT.

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

PURPOSE: To compare the efficacy and accuracy of rotational angiography with three-dimensional reconstruction (3DATG) image merged with electro-anatomical mapping (EAM) vs. CT-EAM. METHODS: A prospective, randomized, parallel, two-center study conducted in 36 patients (25 men, age 65 ± 10 years) undergoing AF ablation (33 % paroxysmal, 67 % persistent) guided by 3DATG (group 1) vs. CT (group 2) image fusion with EAM. 3DATG was performed on the Philips Allura Xper FD 10 system. Procedural characteristics including time, radiation exposure, outcome, and navigation accuracy were compared between two groups. RESULTS: There was no significant difference between the groups in total procedure duration or time spent for various procedural steps. Minor differences in procedural characteristics were present between two centers. Segmentation and fusion time for 3DATG or CT-EAM was short and similar between both centers. Accuracy of navigation guided by either method was high and did not depend on left atrial size. Maintenance of sinus rhythm between the two groups was no different up to 24 months of follow-up. CONCLUSION: This study did not find superiority of 3DATG-EAM image merge to guide AF ablation when compared to CT-EAM fusion. Both merging techniques result in similar navigation accuracy.

Getting to zero: impact of electroanatomical mapping on fluoroscopy use in pediatric catheter ablation.

PURPOSE: Over the past several years, alternative imaging techniques including electroanatomic mapping systems such as CARTO®3 (C3) have been developed to improve anatomic resolution and potentially limit radiation exposure in electrophysiology (EP) procedures. We retrospectively examined the effect of the introduction of C3 on patient radiation exposure during EP studies and ablation procedures at a children's hospital. METHODS: All patients that underwent EP and ablation procedures between January 2012 and August 2015 were included; demographic information, fluoroscopy time (FT), total radiation dose (RAD), and dose-area product (DAP) were collected. Patients were stratified by time period (before vs. after C3 introduction) in three groups: (1) normal heart, (2) congenital heart disease (CHD), and (3) those requiring trans-septal (TS) access. The normal heart group was further separated by arrhythmia diagnosis (accessory pathway (AP), AV nodal reentry tachycardia (AVNRT), atrial, or ventricular arrhythmia). Mean values were compared using a single sample t test, as well as analysis of covariance to control for age, weight, and arrhythmia diagnosis. RESULTS: Mean FT decreased after introduction of C3 in patients in all three patient groups (p < 0.01). When separated by arrhythmia diagnosis, FT decreased in the AP and AVNRT groups (p < 0.0001). After controlling for age, weight, and arrhythmia diagnosis, there was a statistically significant decrease in FT in all three groups and in both RAD and DAP in the normal heart group. Zero fluoroscopy was achieved in 50/159 (31 %) and ≤1 min of FT in 71/159 (45 %) of cases. CONCLUSIONS: We have shown a significant decrease in multiple measures of radiation after introduction of C3. Continued refinements are needed to further decrease radiation utilization and achieve the goal of zero fluoroscopy.

Catheter ablation of atrial fibrillation in patients with concomitant sinus bradycardia-Insights from the German Ablation Registry.

AIMS: This investigation addresses procedural characteristics of catheter ablation in patients with atrial fibrillation (AF) and sinus bradycardia. METHODS: From the prospective, multi-center German Ablation Registry 1073 patients with sinus rhythm at the time of AF ablation were divided into two groups according to heart rate at start of procedure (A, <60 beats per minute (bpm), n=197; B, 60-99bpm, n=876). RESULTS: Acute procedural success was high (≥98%) and similar between groups. Procedure duration and energy application time were increased in group A (180min vs. 155min and 2561s vs. 1879s, respectively). Major complications were more frequent in group A (2.2% vs. 0.5%), and a greater proportion of these patients was discharged under antiarrhythmic medication (64% vs. 52%). CONCLUSION: Catheter ablation of AF with concomitant sinus bradycardia is associated with high procedural efficacy, longer procedure- and energy application durations, and a slightly elevated complication rate.

Electroanatomic mapping systems (CARTO/EnSite NavX) vs. conventional mapping for ablation procedures in a training program.

BACKGROUND: Three-dimensional electroanatomic mapping (EAM) systems reduce radiation exposure when radio frequency catheter ablation (RFCA) procedures are performed by well-trained senior operators. Given the steep learning curve associated with complex RFCA, trainees and their mentors must rely on multiple imaging modalities to maximize safety and success, which might increase procedure and fluoroscopy times. The objective of the present study is to determine if 3-D EAM (CARTO and ESI-NavX) improves procedural outcomes (fluoroscopy time, radio frequency time, procedure duration, complication, and success rates) during CA procedures as compared to fluoroscopically guided conventional mapping alone in an academic teaching hospital. METHODS: We analyzed a total of 1070 consecutive RFCA procedures over an 8-year period for fluoroscopic time stratified by ablation target and mapping system. Multivariate logistic regression and adjusted odds ratios were calculated for each variable. RESULTS: No statistically significant differences in acute success rates were noted between conventional and 3-D mapping cases [CARTO (p = 0.68) or ESI-NavX (p = 0.20)]. Moreover, complication rates were also not significantly different between CARTO (p = 0.23) and ESI-NavX (p = 0.53) when compared to conventional mapping. Procedure, radio frequency, and fluoroscopy times were significantly longer with CARTO and ESI-NavX versus conventional mapping [fluoroscopy time: CARTO, 28.3 min; ESI, 28.5 min; and conventional, 24.3 min; p < 0.001)]. CONCLUSIONS: The use of 3-D EAM systems during teaching cases significantly increases radiation exposure when compared with conventional mapping. These findings suggest a need to develop alternative training strategies that enhance confidence and safety during catheter manipulation and allow for reduced fluoroscopy and procedure times during RFCA.

Efficacy and safety of zero-fluoroscopy ablation for supraventricular tachycardias. Use of optional contact force measurement for zero-fluoroscopy ablation in a clinical routine setting.

BACKGROUND: Conventional catheter ablation of cardiac arrhythmias is associated with radiation risks for patients and laboratory personnel. Widespread use of zero-fluoroscopic catheter ablation in clinical routine is limited by safety concerns. This study investigated the feasibility of zero-fluoroscopy catheter ablation using a three-dimensional mapping system and optional catheter contact force technology for an all-comers collective. PATIENTS AND METHODS: The study comprised 184 patients; 91 patients, including 29 pediatric patients, underwent a zero-fluoroscopic electrophysiology (EP) study using the EnSite NavX system with real-time visualization of all electrodes. These patients were matched to a control group, which was treated using fluoroscopy in the same period. Inclusion criteria were documented supraventricular tachycardia or a history of symptomatic paroxysmal supraventricular tachycardia. Transseptal access, if necessary, was achieved under transesophageal echocardiographic guidance for ablation of left-sided arrhythmias. Radiofrequency (using optional contact force measurement) or a cryotechnique was used for ablation. RESULTS: We observed no major acute complications. There were no significant differences between the two groups in the follow-up period. CONCLUSION: Zero-fluoroscopic catheter ablation is generally feasible in right-sided cardiac arrhythmias. Safety concerns regarding left atrial substrates or children can be overcome with optional real-time contact force measurement.

Impact of nonfluoroscopic MediGuide™ tracking system on radiation exposure in radiofrequency ablation procedures (LESS-RADS registry)-an initial experience.

BACKGROUND: Radiation exposure in the electrophysiology (EP) lab is a major concern to most electrophysiologists. A new technology, MediGuide™ nonfluoroscopic catheter tracking system, has been used for the first time in the USA recently. We intended to evaluate the efficacy of this novel catheter tracking system in reducing radiation exposure. METHODS: We performed a prospective observational study by comparing the radiation exposure with MediGuide™ system to that of conventional mapping systems. The first 45 EP procedures performed with the MediGuide™ system were compared to 45 matched patients undergoing similar procedures during the same time frame using conventional mapping systems (CARTO and NavX) and fluoroscopy. We collected and compared baseline characteristics, procedural variables including fluoroscopic exposure between both groups. RESULTS: Forty-five patients underwent EP procedures using the MediGuide™ technology. They were matched with an equal number of patients with conventional mapping systems. Of the 45 patients included in the study, 33 underwent right atrial flutter ablations, 5 underwent atrioventricular nodal reentrant tachycardia ablations, 4 underwent ablation of Wolf-Parkinson-White syndrome, and 3 underwent EP studies with no ablation. There were no differences in mean age, gender distribution, and body mass index between the groups. Procedure duration in the MediGuide™ group was significantly lower than the duration in the conventional group (103 vs. 142 min, p = 0.03). The fluoroscopic time was significantly less during the procedures performed with the MediGuide™ technology when compared to the control group (8 vs. 21 min, p < 0.001). No major complications occurred during the procedures in either group. CONCLUSION: MediGuide™, a new nonfluoroscopic catheter tracking system, is associated with more than a 50 % reduction in fluoroscopic time when compared to conventional mapping systems.

Long-term outcomes of adjunctive complex fractionated electrogram ablation to pulmonary vein isolation as treatment for non-paroxysmal atrial fibrillation.

PURPOSE: The adjunctive ablation of areas of complex fractionated electrogram (CFE) to pulmonary vein isolation (PVI) is an emerging strategy for patients with non-paroxysmal atrial fibrillation (AF). We studied the long-term outcomes of this approach. METHODS: Sixty-six patients (mean age 58 ± 9, 86.4 % male) with non-paroxysmal AF underwent ablation procedures consisting of PVI plus extensive CFE ablation. Post-ablation atrial tachycardia (AT) was also targeted if presented. All patients were followed up regularly on an ambulatory basis by means of ECG and Holter recordings. RESULTS: After a mean follow-up period of 40 ± 14 months and 1.7 ± 0.7 procedures, 38 patients (57.6 %) were free of arrhythmias, 15 (22.7 %) displayed clinical improvement and 13 (19.7 %) suffered recurrences of persistent AF/AT. Females displayed poorer long-term outcomes than males (arrhythmia-free 22.2 vs. 63.2 %, p < 0.05). Multivariate analysis demonstrated that long duration of uninterrupted AF prior to the procedure was an additional predictor of long-term failure (odds ratio 1.49, p < 0.01). ROC analysis (area under curve 0.80; p < 0.001) estimated 3.5 years as the optimal cut-off point for predicting long-term failure (sensitivity 85 %, specificity 74 %). The cumulative data showed a significantly higher percentage of arrhythmia-free patients when the duration of AF had been ≤ 2 years (69.7 %) and ≤ 4 years (68.9 %) than when it was > 4 years (33.3 %; p < 0.01). CONCLUSIONS: PVI + CFE ablation in non-paroxysmal AF appears to provide a reasonable proportion of arrhythmia-free patients during long-term follow-up. Poorer long-term results can be expected among female patients and those with an uninterrupted AF duration of > 4 years.

Utility of mapping signals to improve precision of atrioventricular node ablation.

BACKGROUND: Atrioventricular node (AVN) ablation is effective for rate control in atrial fibrillation. This may require multiple radiofrequency applications to achieve complete atrioventricular block (CAB). In this retrospective study, we tested the hypothesis that mapping the AVN utilizing electrograms (EGMs) on both proximal and distal bipoles of the mapping catheter may improve the likelihood of CAB. METHODS: Lesion characteristics and EGM components on the proximal and distal bipoles of the ablation catheter in first-time AVN ablation procedures were analyzed. Outcomes of each lesion, including presence of CAB, acute recurrence of AVN conduction, new-onset right bundle branch block (RBBB), and junctional escape rhythm, were analyzed. Multivariate binary logistic regression analysis was performed to identify EGM characteristics that independently predicted the outcomes of interest. Lesions with these EGM characteristics were then identified and their outcomes compared with the whole cohort. RESULTS: A total of 441 ablation lesions were analyzed. EGM characteristics that independently predicted outcomes were the presence of His and atrial EGMs on the distal bipole and the absence of ventricular EGM on the proximal bipole. Among the 25 lesions with all these characteristics, 18 (72%) resulted in CAB compared to the overall cohort rate of 38% (P = 0.001). There was no new-onset RBBB. The likelihood of acute recurrent AVN conduction and junctional escape rhythm were similar. CONCLUSION: Combining proximal and distal bipole EGM characteristics of the ablation catheter can improve the accuracy of AVN localization during AVN ablation and avoid right bundle branch injury.

Catheter ablation of atrial fibrillation guided by a 3D electroanatomical mapping system: a 2-year follow-up study from the Italian Registry On NavX Atrial Fibrillation ablation procedures (IRON-AF).

AIMS: Clinical trials have established that atrial fibrillation (AF) catheter ablation improves symptoms in appropriately selected patients. Confirmation of these results by long-term prospective observational studies is needed. This registry was created to describe the experience of 16 Italian centers with a large cohort of AF patients treated with catheter ablation guided by the NavX 3D mapping system. METHODS: From November 2006 to May 2008, 545 consecutive patients (age 60.4 ± 9.8, 67 % male) with paroxysmal (44 %), persistent (43 %), and long-standing persistent (13 %) AF referred for catheter ablation guided by the NavX system, were included in this registry. For this paper, follow-up was censored at 24 months; however, patients are being followed in the ongoing registry. RESULTS: Before the ablation, 80 % of patients failed to respond to at least one antiarrhythmic drug aimed at rhythm control. Pulmonary vein (PV) isolation guided by a circular mapping catheter was performed in 70 % of patients whereas non potential-guided PV encircling was performed in 30 % of patients. In 67 % of patients, additional left atrial (LA) substrate modification was performed. Image integration was performed in 9.2 % of patients. Considering a 3-month blanking period, after a single-ablation procedure, the patients had 1- and 2-year freedom from AF recurrence of 67.4 and 57.0 % (36.1 % off antiarrhythmic drugs), respectively. Cox regression analysis showed that AF recurrences during blanking (HR 2.1), and previous AF ablation (HR 3.3) were independent predictors of AF recurrences. Major procedure-related complications occurred in 53 patients (9.7 %). In 35 patients (6.7 %), a repeat procedure was performed at a median of 5 months after the initial procedure. CONCLUSIONS: This prospective, multicenter clinical experience provides significant insights into current ablation care of patients with AF. Despite favorable outcomes, real-world complication rates appear higher than previously recognized.

Cryoablation of AVNRT when sustained tachycardia cannot be induced.

BACKGROUND: Inducibility of sustained tachycardia is preferred prior to cryoablation for atrioventricular nodal reentrant tachycardia (AVNRT). METHOD: The Pediatric Electrophysiology Database of a single institution was retrospectively reviewed for patients with clinical sustained (≥ 30 seconds of symptoms) AVNRT documented by noninvasive means who underwent cryoablation for AVNRT to determine if intermediate-term success with cryoablation for AVNRT can be achieved without inducibility of sustained AVNRT during electrophysiology study (EPS). RESULTS: There were no differences between patients with sustained (≥ 30 seconds of tachycardia) AVNRT (N = 67) and patients with nonsustained (ns, ≥ 3 beats and <30 seconds of tachycardia) AVNRT at EPS (N = 16). Acute success was achieved without PR prolongation in all patients. Although duration of follow-up was shorter for the sustained group than the nonsustained group (2.7 ± 1.6 years vs 3.8 ± 1.4 years, P = 0.008), recurrence rate was similar (6% vs 6.3%, P = 0.6). In patients with only nonsustained AVNRT at EPS, supportive findings for procedural effectiveness seen: (1) Dual atrioventricular node physiology (DAVNP) was eliminated in 14/14, (2) the fast pathway effective refractory period (FPERP) decreased after ablation in 10/11, (3) sustained slow pathway conduction was eliminated in 8/8 including both patients without discrete DAVNP prior to ablation, and (4) FPERP increased during lesion formation in 10/10. CONCLUSION: Intermediate-term success can be achieved with cryoablation of ns AVNRT. Attention should be paid to supportive indicators of damage to slow pathway.

Lessons from dissociated pulmonary vein potentials: entry block implies exit block.

AIMS: Prior reports using pacing manoeuvres, demonstrated an up to 42% prevalence of residual pulmonary vein to left atrium (PV-LA) exit conduction after apparent LA-PV entry block. We aimed to determine in a two-centre study the prevalence of residual PV-LA exit conduction in the presence of unambiguously proven entry block and without pacing manoeuvres. METHODS AND RESULTS: Of 378 patients, 132 (35%) exhibited spontaneous pulmonary vein (PV) potentials following circumferential PV isolation guided by three-dimensional mapping and a circular mapping catheter. Pulmonary vein automaticity was regarded as unambiguous proof of LA-PV entry block. We determined the prevalence of spontaneous exit conduction of the spontaneous PV potentials toward the LA. Pulmonary vein automaticity was observed in 171 PVs: 61 right superior PV, 33 right inferior PV, 47 left superior PV, and 30 left inferior PV. Cycle length of the PV automaticity was >1000 ms in all cases. Spontaneous PV-LA exit conduction was observed in one of 171 PVs (0.6%). In a subset of 69 PVs, pacing from within the PV invariably confirmed PVLA exit block. CONCLUSION: Unidirectional block at the LA-PV junction is unusual (0.6%). This observation is supportive of LA-PV entry block as a sufficient electrophysiological endpoint for PV isolation.

Image integration increases efficacy of paroxysmal atrial fibrillation catheter ablation: results from the CartoMerge Italian Registry.

AIMS: The aim of this study was to investigate whether circumferential pulmonary vein (PV) isolation guided by image integration improves the procedural and clinical outcomes of atrial fibrillation (AF) ablation in comparison with segmental PV isolation and circumferential PV isolation guided by three-dimensional (3D) electroanatomical mapping alone. METHODS AND RESULTS: Procedural and clinical outcomes of 573 patients who underwent their first catheter ablation for paroxysmal AF between January 2005 and April 2007 were collected from 12 centres. We evaluated three techniques: segmental ostial PV isolation (SOCA group, 240 patients), circumferential PV isolation guided by electroanatomical mapping (CARTO group, 107 patients), and circumferential PV isolation guided by electroanatomical mapping integrated with magnetic resonance/computed tomographic images of the left atrium (MERGE group, 226 patients). Procedure duration proved to be shorter in MERGE group patients than in CARTO group patients (P < 0.04), but longer than in SOCA group patients (P < 0.0001). During follow-up, atrial tachyarrhythmias relapsed more frequently in SOCA group patients (44.6%) and CARTO group patients (41.7%) than in MERGE group patients (22.6%; P < 0.0001). CONCLUSION: In patients with paroxysmal AF, circumferential PV isolation guided by image integration significantly improves clinical outcome in comparison with both circumferential PV isolation guided by 3D mapping alone and with segmental electrophysiologically guided PV isolation.

Generalized training subset selection for statistical estimation of epicardial activation maps from intravenous catheter measurements.

Catheter-based electrophysiological studies of the epicardium are limited to regions near the coronary vessels or require transthoracic access. We have developed a statistical approach by which to estimate high-resolution maps of epicardial activation from very low-resolution multi-electrode venous catheter measurements. This technique uses a linear estimation model that derives a relationship between venous catheter measurements and unmeasured epicardial sites from a set of previously recorded, high-resolution epicardial activation-time maps used as a training data set based on the spatial covariance of the measurement sites. We performed 14 dog experiments with various interventions to create an epicardial activation-time map database. This database included a total of 592 epicardial activation maps which were recorded using a sock array placed on the ventricles of dog hearts. We present five approaches, which examined sequential addition and removal of maps to select a generalized training set for the estimation technique. The selection consisted of choosing a subset of epicardial ectopic activation-time maps from the database of beats which resulted in estimation accuracy levels better than or at least similar to using all the maps in database. Our aim was to minimize the redundancy in the database and to be able to guide the eventual procedures required to obtain training data from open-chest surgery patients. The results from this study illustrated this redundancy and suggested that by including an optimal subset (around 100 maps) of the full database the estimation technique was able to perform as well as and even in some cases better than including all the maps in the database. The results also suggest that such an approach is feasible for providing accurate reconstruction of complete epicardial activation-time maps in a clinical setting and with fewer maps we can obtain similar reconstruction accuracy levels.