Novel noncontact charge density map in the setting of post-atrial fibrillation atrial tachycardias: first experience with the Acutus SuperMap Algorithm

Purpose

The purpose of this study was to evaluate the safety and feasibility of the new high-resolution mapping algorithm SuperMap (Acutus Medical, CA, USA) in identifying and guiding ablation in the setting of regular atrial tachycardias following index atrial fibrillation (AF) ablation.

Methods

Seven consecutive patients who underwent a radiofrequency catheter ablation guided by the novel noncontact charge density (CD) SuperMap for atrial tachycardia were prospectively enrolled in our study.

Results

Arrhythmogenic substrate was identified in all seven patients. Mean number of EGM per map was 5859.7 ±?4348.5 points. Three patients (43%) exhibited focal tachycardia mechanisms in the left atrium, alternating from anteroseptal right superior pulmonary vein (RSPV), posterior in proximity of left inferior pulmonary vein (LIPV), and interarial septum in proximity of fossa ovalis, respectively. Four patients exhibited macroreentrant mechanism. In 3 of these patients, SuperMap detected mitral isthmus-dependent flutters with tachycardia cycle lengths of 240, 270 and 420 ms, respectively. In one patient, the mechanism was a macroreentrant tachycardia with the critical isthmus located between the crista terminalis and atriotomy. The mean ablation time (min) was 18.2?±?12.5 and the mean procedural duration time was 56.4?±?12.1 min. No minor or major complications occurred.

Conclusion

The novel high-resolution mapping algorithm SuperMap proved to be safe, fast, and feasible in identifying and guiding ablation in the setting of regular atrial tachycardias following index AF ablation.

     

A multi-purpose spiral high-density mapping catheter: initial clinical experience in complex atrial arrhythmias

Purpose

There is an increasing need for catheter ablation procedures to treat complex atrial tachycardias (AT) and atrial fibrillation (AF), often requiring detailed endocardial mapping. The sequential point-to-point contact mapping of complex arrhythmias is time-consuming and may not always be feasible. We assessed the utility of a novel spiral duo-decapolar high-density (HD) mapping catheter to delineate complex arrhythmia substrates for ablation.

Methods

The patients underwent HD mapping using a spiral catheter (AFocusII) and the EnSite NavX system, during catheter ablation procedures, to treat atrial arrhythmias.

Results

In 26 patients, a total of 32 atrial arrhythmias were mapped and ablated, comprising of five focal AT, eight macroreentrant AT, 11 persistent AF and eight paroxysmal AF. The HD catheter was used to acquire endocardial surface geometries in all cases and to map the pulmonary veins in patients undergoing AF ablation. In persistent AF, HD catheter mapping permitted the creation of highly detailed complex fractionated electrogram maps (left atrium 449?±?128 points in 7.2?±?2.6 min; right atrium 411?±?113 points in 6.7?±?1.6 min). In AT, activation mapping was performed with the acquisition of 305?±?158 timing points in 7.3?±?2.6 min, guiding successful ablation in all cases. During the follow-up of 7.0?±?2.6 months, all AT patients remained free of significant arrhythmia.

Conclusions

High-density contact mapping with a novel spiral multipolar catheter allows rapid assessment of focal and macroreentrant AT, and complex fractionated electrical activity in the atria. It has further multi-functional capabilities as a pulmonary vein mapping catheter and for accurate geometry creation when used with a 3D mapping system.     

Validation of computed tomography image integration into the EnSite NavX mapping system to perform catheter ablation of atrial fibrillation

Introduction: The complex anatomy of the left atrium (LA) makes location of ablation catheters difficult using fluoroscopy alone, and therefore 3D mapping systems are now routinely used. We describe the integration of a CT image into the EnSite NavX System with Fusion and its validation in patients undergoing atrial fibrillation (AF) or left atrial tachycardia (AT) catheter ablation. Methods and Results: Twenty‐three patients (61 ± 9.2 years, 16 male) with paroxysmal (14) and persistent (8) AF and persistent (1) AT underwent ablation using CT image integration into the EnSite NavX mapping system with the EnSite Fusion Dynamic Registration software module. In all cases, segmentation of the CT data was accomplished using the EnSite Verismo segmentation tool, although repeat segmentation attempts were required in seven cases. The CT was registered with the NavX‐created geometry using an average of 24 user‐defined fiducial pairs (range 9 to 48). The average distance from NavX‐measured lesion positions to the CT surface was 3.2 ± 0.9 mm (median 2.4 mm). A large, automated, retrospective test using registrations with random subsets of each patient's fiducial pairs showed this average distance decreasing as the number of fiducial pairs increased, although the improvement ceased to be significant beyond 15 pairs. In confirmation, those studies which had used 16 or more pairs had a smaller average lesion‐to‐surface distance (2.9 ± 0.7 mm) than those using 15 or fewer (4.3 ± 0.8 mm, P < 0.02). Finally, for the 13 patients who underwent left atrial circumferential ablation (LACA), there was no significant difference between the circumference computed using NavX‐measured positions and CT surface positions for either the left pulmonary veins (178 ± 64 vs. 177 ± 60 mm; P = 0.81) or the right pulmonary veins (218 ± 86 vs. 207 ± 81 mm; P = 0.08). Conclusion: CT image integration into the EnSite NavX Fusion system was successful in all patients undergoing catheter ablation. A learning curve exists for the Verismo segmentation tool; but once the 3D model was created, the registration process was easily accomplished, with a registration error that is comparable with registration errors using other mapping systems with CT image integration. All patients went on to have subsequent successful ablation procedures. Where LACA was performed (13 patients), only four patients required segmental ostial lesions to achieve electrical isolation.     

Initial experience with robotic navigation for catheter ablation of paroxysmal and persistent atrial fibrillation

Background and PurposeRemote robotic navigation (RRN) technology has been developed to facilitate catheter ablation of symptomatic atrial fibrillation (AF). Here, we assess procedural parameters of AF ablation obtained during initial use of RRN compared with a control group treated with a manual ablation approach.MethodsConsecutive patients with symptomatic paroxysmal or persistent AF were subjected to radiofrequency catheter ablation with RRN (Sensei X [Hansen Medical, Mountain View, CA]; n = 25; mean age, 60 ± 2.3 years) or using the standard manual technique (n = 61; mean age, 62 ± 1.4 years). A circumferential pulmonary vein isolation approach guided by 3-dimensional electroanatomical mapping was followed.ResultsRemote robotic navigation was associated with reduction of overall fluoroscopy time by 26%. In a case-control subgroup analysis comparing 25 patients with similar clinical characteristics from each group, mean fluoroscopy time was reduced by 22%. Acute isolation of pulmonary veins was achieved in 97% (RRN) and 96% (conventional ablation), respectively. Ablation times and frequency of adverse events were not significantly different among study groups.ConclusionsThe early use of RRN resulted in a significant reduction of overall fluoroscopy time and was equally effective and safe compared with manual catheter ablation.     

心房颤动经导管射频消融的止痛治疗

目的研究小剂量咪唑安定联合芬太尼在心房颤动(简称房颤)经导管射频消融术中的止痛疗效及安全性。方法对50例房颤患者在CARTO指导下行环肺静脉电隔离和/或左房线性消融。消融前静脉给予1μg/kg芬太尼和0.4mg/kg咪唑安定,术中以小剂量(1μg.kg-1.h-1)芬太尼静脉维持,消融剂量1～3μg.kg.-1.h-1,消融剂量以患者无疼痛或仅有轻微疼痛掌握,特别疼痛处加用咪唑安定1mg。结果50例共隔离肺静脉204根,17例患者加做左房线性消融,9例典型心房扑动患者加做右房峡部消融,即刻电隔离成功率98.0%。手术时间262±21min,透视时间38±7min,芬太尼剂量245±32μg,咪唑安定剂量3.1±1.1mg,术中患者仅有轻微疼痛。结论小剂量咪唑安定联合芬太尼在房颤经导管射频消融术中止痛治疗安全有效。     

Myocardium of the Superior Vena Cava,Coronary Sinus,Vein of Marshall,and the Pulmonary Vein Ostia: Gross Anatomic Studies in 620 Hearts

Anatomy of Myocardial Extensions in Thoracic Veins. Introduction: Radiofrequency ablation for atrial fibrillation (AF) frequently involves energy delivery at the ostia of the thoracic veins. Detailed evaluation of the myocardium extending into the caval veins, vein of Marshall, as well as at the pulmonary vein ostia has not been completely evaluated. Methods and Results: Post‐mortem assessment of 620 formalin‐fixed hearts (mean age 60 ± 23 years, 44% female) was performed. The hearts were examined for integrity of venous structures and their atrial connections. Systematic gross anatomic evaluation including measurements on myocardial extensions in these veins was performed. Macroscopic myocardial extensions into pulmonary veins were noted in 99% of specimens evaluated and were circumferentially symmetric (99.6%). Myocardial extensions into the superior vena cava (SVC) occurred in 78% with the majority being circumferentially asymmetric (61%). Occasionally, myocardium extended into the azygos vein (6%). There were no myocardial extensions in the inferior vena cava (IVC). In some cases, the right atrial pectinate muscle extended into the coronary sinus (7%). The vein of Marshall was consistently located anterior to the left‐sided pulmonary veins and posterior to the left atrial appendage, overlying the left atrial endocardial ridge. Conclusions: Myocardial extensions into the pulmonary veins are usually circumferential at the ostia validating the necessity for wide area rather than segmental ablation to isolate these veins during AF ablation. Myocardial extensions into the SVC are common and less likely to be circumferential, whereas extensions into the IVC are not present. The left atrial ridge is a reliable endocardial target for radiofrequency ablation of the vein of Marshall. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1304‐1309, December 2012)     

Elimination of focal atrial fibrillation with a single radiofrequency ablation: use of a basket catheter in a pulmonary vein for computerized activation sequence mapping

A focal source for atrial fibrillation (AF) may be found in the first few centimeters of the pulmonary veins. Radiofrequency (RF) ablation may be directed at this source using activation mapping, but if the responsible atrial extrasystoles are infrequent or difficult to map, elimination of the source may require complete electrical isolation of the vein with multiple RF lesions. A new three-dimensional mapping system using a 64-pole basket catheter has been developed recently. We report the use of this system for ablation of focal AF in two patients. Mapping identified foci in the left and right superior pulmonary veins. Each focus was eliminated with a single RF ablation.     

Substrate and procedural predictors of outcomes after catheter ablation for atrial fibrillation in patients with hypertrophic cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) is often accompanied by atrial fibrillation (AF) due to diastolic dysfunction, elevated left atrial pressure, and enlargement. Although catheter ablation for drug‐refractory AF is an effective treatment, the efficacy in HCM remains to be established. Methods: Thirty‐three consecutive patients (25 male, age 51 ± 11 years) with HCM underwent pulmonary vein (PV) isolation (n = 8) or wide area circumferential ablation with additional linear ablation (n = 25) for drug‐refractory AF. Twelve‐lead and 24‐hour ambulating ECGs, echocardiograms, event monitor strips, and SF 36 quality of life (QOL) surveys were obtained before ablation and for routine follow‐up. Results: Twenty‐one (64%) patients had paroxysmal AF and 12 (36%) had persistent/permanent AF for 6.2 ± 5.2 years. The average ejection fraction was 0.63 ± 0.12. The average left atrial volume index was 70 ± 24 mL/m 2 . Over a follow‐up of 1.5 ± 1.2 years, 1‐year survival with AF elimination was 62%(Confidence Interval [CI]: 66‐84) and with AF control was 75%(CI: 66‐84). AF control was less likely in patients with a persistent/chronic AF, larger left atrial volumes, and more advanced diastolic disease. Additional linear ablation may improve outcomes in patient with severe left atrial enlargement and more advanced diastolic dysfunction. Two patients had a periprocedureal TIA, one PV stenosis, and one died after mitral valve replacement from prosthetic valve thrombosis. QOL scores improved from baseline at 3 and 12 months. Conclusion: Outcomes after AF ablation in patients with HCM are favorable. Diastolic dysfunction, left atrial enlargement, and AF subtype influence outcomes. Future studies of rhythm management approaches in HCM patients are required to clarify the optimal clinical approach.     

Reversal of pulmonary vein remodeling after catheter ablation of atrial fibrillation

Background Pulmonary veins (PV) and the atria undergo electrical and structural remodeling in atrial fibrillation (AF). This study aimed to determine PV and left atrial (LA) reverse remodeling after catheter ablation for AF assessed by chest computed tomography (CT). Methods PV electrophysiologic studies and catheter ablation were performed in 63 patients (68% male; mean ± SD age: 56 ± 10 years) with symptomatic AF (49% paroxysmal, 51% persistent). Chest CT was performed before and 3 months after catheter ablation. Results At baseline, patients with persistent AF had a greater LA volume (91 ± 29 cm³ vs. 66 ± 27 cm3; P = 0.003) and mean PV ostial area (241 ± 43 mm² vs. 212 ± 47 mm²; P = 0.03) than patients with paroxysmal AF. There was no significant correlation between the effective refractory period and the area of the left superior PV ostium. At 3 months of follow-up after ablation, 48 patients (76%) were AF free on or off antiar?rhythmic drugs. There was a significant reduction in LA volume (77 ± 31 cm³ to 70 ± 28 cm³; P < 0.001) and mean PV ostial area (224 ± 48 mm² to 182 ± 43 mm²; P < 0.001). Patients with persistent AF had more reduction in LA volume (11.8 ± 12.8 cm³ vs. 4.0 ± 11.2 cm³; P = 0.04) and PV ostial area (62 mm² vs. 34 mm²; P = 0.04) than those who have paroxysmal AF. The reduction of the averaged PV ostial area was significantly correlated with the reduction of LA volume (r = 0.38, P = 0.03). Conclusions Catheter ablation of AF improves structural remodeling of PV ostia and left atrium. This finding is more apparent in patients with persistent AF treated by catheter ablation.     

非接触式球囊标测系统指导阵发性心房颤动个体化消融

目的探讨应用非接触式球囊三维标测系统(EnSite Array)指导下心房颤动(简称房颤)个体化射频消融的临床效果。方法18例阵发性房颤患者,应用EnSite Array三维标测房颤优势电传导部位指导个体化消融,并结合大头电极心房内描记到或虚拟电位显示为碎裂电位区进行消融,消融终点为房颤终止转窦性心律或消融线形成双向阻滞。重复术前电刺激或用异丙上腺素静脉滴注后不能诱发或诱发<30s的房颤。结果首次消融的即时成功率为94.4%(17/18),消融中1例出现心包压塞。15例行左右上肺静脉之间靠顶部心房电学改良消融,11例加左上肺静脉与左心耳之间等部位消融,6例加消融左或/和右房峡部或冠状窦口等部位消融。随访15.3±11.3个月,14例术后不服用抗心律失常药物均无房颤发生,3例房颤复发,1例出现心房扑动发作,中期成功率77.8%(14/18)。结论EnSite Array指导下实时根据房颤优势传导区个体化射频消融,消融靶点灵活、针对性强,消融创伤小,中期效果良好。     

Stepwise linear approach to catheter ablation of atrial fibrillation

BACKGROUND: This study attempted to convert atrial fibrillation (AF) to sinus rhythm using a stepwise linear catheter ablation approach. METHODS: One hundred and ninety-six patients (43 with persistent AF) were enrolled in the study. A multiple electrode array was used for anatomical navigation and activation mapping. Continuously incremental stimulation was used to induce AF if spontaneous AF was not present. Stepwise linear ablation was applied until AF was converted to sinus rhythm or atypical atrial flutter (AAFL) or atrial tachycardia (AT). The stepwise approach initially utilized a figure-7 lesion line between the right and left superior pulmonary vein on the roof of the left atrium and then extended along the ridge between the left appendage and the left pulmonary veins until the mitral valve annulus, as the primary lesions. If AF still persisted, high-frequency potentials in the inferior left atrium, coronary sinus, or right atrium were targeted. Noninducibility of AF was used as the end point. RESULTS: AF was converted to sinus rhythm in 81.6% of patients (90.8% of paroxysmal and 51.1% of persistent AF, P<.01). The remainders of patients were converted to AAFL or AT. AF was terminated after ablation in right atrium in 7 patients. During an 18.2+/-7.3 month follow-up, 88.3% of patients were free of atrial tachyarrhythmias without medication, 9.7% of patients had refractory AAFL/AT, and only 2.1% of patients had paroxysmal AF. CONCLUSION: Stepwise linear ablation is effective in converting AF to sinus rhythm and the figure-7 lesion line should be the basic lesion. Right atrium ablation is necessary in some patients.     

Long-term results of catheter ablation for atrial fibrillation in 866 patients

PurposeThis study presents eight-year experience with ablation techniques, recurrent arrhythmias, and long-term outcomes in patients undergoing catheter ablation for atrial fibrillation (AF).MethodsCatheter ablation of AF was performed in 866 consecutive patients in a total of 1272 ablation procedures. Ablation strategy and procedure endpoints were left at the operator's discretion. Total study population and groups of paroxysmal (n=508/59%), persistent (n=102/12%), and long-standing persistent AF (n=256/29%) were evaluated.ResultsPulmonary vein isolation alone or with cavo-tricuspid isthmus ablation was accomplished in 36% of the patients. It was significantly more often used in paroxysmal AF than in persistent or long-standing persistent AF (both p<0.001). More extensive ablation prevailed in persistent AF types. Ablation was repeated in 307 (35%) patients. Patients with long-standing persistent AF underwent significantly more repeat procedures than patients with paroxysmal AF (p<0.001) or persistent AF (p=0.001). Recurrent AF dominated before the first repeat ablation in 68% cases, while recurrent atrial tachycardia (AT) prevailed before the second (73%), and third (93%) repeat ablation. Patients with long-standing persistent AF presented with recurrent AT in 50% of the cases already before the first repeat ablation. At the end of 49±26 month follow-up, 83% of the patients remained in stable sinus rhythm (SR); 70% of the patients without antiarrhythmic drugs. SR maintenance was insignificantly superior in long-standing persistent AF group (91%) compared to paroxysmal AF (82%) and persistent AF patients (68%).ConclusionPatients with persistent AF types underwent more extensive initial ablation. Patients with long-standing persistent AF experienced best long-term outcome likely as a consequence of higher number of repeat ablation procedures.     

NT-proANP levels in peripheral and cardiac circulation

Background

Recent studies have reported an association between N-terminal atrial natriuretic peptide (NT-proANP) and the progression of atrial fibrillation (AF). However, NT-proANP levels in peripheral and cardiac circulation in AF patients and in non-AF individuals need to be defined. The aims of the current study are (1) to analyze NT-proANP levels in peripheral and cardiac circulation in AF patients and (2) to compare NT-proANP levels in individuals with and without AF.

Methods

We recruited AF patients who were undergoing their first AF catheter ablation and non-AF individuals. Blood plasma samples taken from the femoral vein and the left atrium (LA) were collected before AF ablation in the AF patients and from the cubital vein in the non-AF controls. Low voltage areas (LVAs) were determined using high-density maps during catheter ablation and defined as?<?0.5 mV.

Results

The study included 189 AF patients (64?±?10 years, 59% male, 61% persistent AF, 30% LVAs) and 26 non-AF individuals (58?±?10 years, 50% male). Patients with AF were significantly older and had larger LA (p?<?0.05). Compared to non-AF controls, peripheral and cardiac NT-proANP levels were significantly higher in AF patients without and with LVAs (median 5.4, 10.5, 14.8 ng/ml, respectively, p?<?0.001). In multivariable analysis, NT-proANP (OR 1.238, 95% CI 1.007–1.521, p?=?0.043) remained significantly different between non-AF individuals and AF patients. In AF, NT-proANP levels were significantly higher in the cardiac blood samples than in the peripheral blood (median 13.0 versus 11.4 ng/ml, p?=?0.003). The ability to predict LVAs was modest when using cardiac NT-proANP (AUC 0.661) and peripheral NT-proANP (AUC 0.635), without statistical difference (p?=?0.937).

Conclusions

NT-proANP levels are higher in individuals with AF than in controls and are more pronounced in progressed AF. Elevated cardiac and peripheral NT-proANP levels similarly predict LVAs.

     

Noncontact mapping-guided catheter ablation of atrial fibrillation associated with left atrial ectopy

We report the use of a novel noncontact mapping system used to perform left atrial mapping and to guide radiofrequency ablation in two patients, each with atrial fibrillation (AF) triggered by left atrial ectopy. A noncontact multielectrode probe and ablation catheter were advanced into the left atrium through a transseptal puncture or a patent foramen ovale. Isopotential mapping delineated the focal origin at the ostium of the right lower pulmonary vein in one patient and close to the ostium of the left upper pulmonary vein in the other patient. The ablation catheter was guided to the target sites using a locator signal. The foci were ablated successfully in both patients. No recurrences of AF were observed during follow-up at 4 and 6 months, respectively.     

Regional endocardial left atrial voltage and electrogram fractionation in patients with atrial fibrillation

Introduction: Heterogeneities in electrophysiological properties may contribute to the development of atrial fibrillation, and regional disparities in endocardial voltage in the left atrium have been related to arrhythmogenic mechanisms. This study aimed at investigating endocardial voltage in different regions of the left atrium in patients with atrial fibrillation (AF). Methods and Results: Thirty‐six patients (aged 56 ± 7 years, 10 female) scheduled for circumferential ablation for paroxysmal AF were studied. Voltage measurements were performed during AF and with constant right ventricular pacing in the anterior, posterior, superior and inferior walls outside the antrum of the left (LPV), and right (RPV) pulmonary veins, by means of electroanatomical mapping. There was a high agreement among measurements performed in the endocardium of the posterior atrial wall (ICC > 0.70), and moderate agreement among measurements performed in the superior and inferior walls (0.50 < ICC< 0.70), outside both PV antra. The posterior left atrial wall demonstrated significantly higher voltages both outside the LPV antrum (1.29 ± 1.36 mV) and the RPV antrum (1.20 ± 0.63 mV) compared to the inferior, anterior and superior walls (0.47 ± 0.49, 0.68 ± 0.69, and 0.61 ± 0.83 mV outside the LPV antrum, and 0.39 ± 0.23, 0.65 ± 0.49, and 0.49 ± 0.24 mV outside the RPV antrum, respectively). Fractionated electrograms were mainly identified at the posterior left atrial wall, outside the right PV antrum. Conclusion: During AF, the posterior wall displays significantly higher voltage and electrogram fractionation compared with other parts of the left atrial endocardium outside the antra of both pulmonary veins in patients with paroxysmal AF.     

右侧神经丛消融对阵发心房颤动伴窦性心动过缓心率的影响

目的:探讨环肺静脉消融的基础上,进一步进行右侧神经丛消融以观察消融对心率的影响。方法:12例心动过缓伴心房颤动的患者,其中男性9例,女性3例,平均年龄(60.58±9.25)岁,在完成环肺静脉隔离的基础上,进行解剖指导下右侧神经丛的消融。结果:12例均完成四个肺静脉隔离及上腔静脉去神经消融,消融上腔静脉过程中,心率由(72.92±5.30)次/min增加到(84.58±5.63)次/min,术后平均随访(18±8)个月,心房颤动成功率50%。心率由术前(56.67±4.87)次/min,增加到术后1w(68.92±6.20)次/min,术后6个月(65.75±4.09)次/min。心率变异性(SDNN)由术前(132.83±16.7)ms减少为术后1w(87.67±19.21)ms,术后6个月(109.75±18.65)ms。结论:在环肺静脉消融的基础上,进行解剖指导下的上腔静脉消融可以进一步提高心率,达到去迷走神经支配的目的。     

Long‐Term Outcome of Catheter Ablation in Patients with Atrial Fibrillation Originating from Nonpulmonary Vein Ectopy

Long‐Term Outcome of NPV AF Ablation . Introduction: Data regarding the long‐term outcome of catheter ablation in patients with nonpulmonary vein (NPV) ectopy initiating atrial fibrillation (AF) are limited. We aimed to evaluate the long‐term result of patients with AF who had NPV triggers and underwent catheter ablation. Methods and Results: The study included 660 consecutive patients (age 54 ± 11 years old, 477 males) who had undergone catheter ablation for AF. Group 1 consisted of 132 patients with AF initiating from the NPV, and group 2 consisted of 528 patients with AF initiating from pulmonary vein (PV) triggers only. Patients from Group 1 were younger than those from Group 2 (51 ± 12 years old vs 54 ± 11 years old, P = 0.001) and were more likely to be females (34.4% vs 25.8%, P = 0.049). The incidences of nonparoxysmal AF (36.4% vs 16.3%, P < 0.001) and right atrial (RA) enlargement (31.3% vs 19%, P = 0.004) were higher, and the biatrial substrates were worse in Group 1 than those in Group 2 (left atrial voltage 1.5 ± 0.7 mV vs 1.9 ± 0.7 mV, P < 0.001, RA voltage 1.6 ± 0.5 mV vs 1.8 ± 0.6 mV, P = 0.014). During a follow‐up period of 46 ± 23 months, there was a higher AF recurrence rate in Group 1 than in Group 2 (57.6% vs 38.8%, P < 0.001). The independent predictors of AF recurrence were NPV trigger (P < 0.001, HR 2, 95% CI 1.4–2.85), nonparoxysmal AF (P = 0.021, HR 1.55, 95% CI 1.07–2.24), larger left atrial diameter (P = 0.002, HR 1.04, 95% CI 1.02–1.07) and worse left atrial substrate (P = 0.028, HR 1.3, 95% CI 1.03–1.64). Conclusion: Compared to AF originating from the PV alone, AF originating from the NPV ectopy showed a worse outcome. (J Cardiovasc Electrophysiol, Vol. 24, pp. 250‐258, March 2013)     

Pulmonary vein isolation using second-generation single-shot devices: not all the same?

Introduction

Single-shot devices have been developed to simplify pulmonary vein isolation (PVI). Randomized studies of the second-generation cryoballoon (CB 2nd) demonstrated excellent results. There are limited data comparing results of circular pulmonary vein ablation catheter (PVAC) with conventional RF ablation or CB for PVI.

Objective

Using a sequential registry cohort and a prospective randomized study, we aimed to compare the acute and long-term results of CB 2nd and PVAC Gold.

Methods

In the registry, consecutive patients with paroxysmal atrial fibrillation (AF) undergoing their first PVI were included. The preferred method used was PVAC Gold in 2014 and CB 2nd in 2015. Subsequently, a randomized study (PVAC vs. CB 2nd) was performed. Ablation success was measured as freedom of AF or atrial tachycardias (AT) off antiarrhythmic drugs.

Results

In the registry cohort, PVAC Gold was used in 60 patients and CB 2nd in 56 patients (age 66?±?11 years, 52% male, LAD 43?±?6). In the randomized study, 20 patients were treated with PVAC Gold and 22 with CB 2nd (age 67?±?9; 43% men, LAD 40?±?7 mm). During a mean follow up of 13.2?±?3.6 months, success was 54% in PVAC Gold patients and 81% in CB 2nd cases (p?=?0.001). In the randomized study 12 months success was 50% versus 86%, p?<?0.05. Complications occurred rare in both groups.

Conclusions

Our registry data and the randomized study both suggest superiority of PVI using CB 2nd as compared with PVI using PVAC Gold.

     

The Relationship Between Electrogram Cycle Length and Dominant Frequency in Patients with Persistent Atrial Fibrillation

Introduction: Sites of complex fractionated atrial electrograms (CFAE) with a short mean cycle length (MCL) and sites with a high dominant frequency (DF) have been advocated as targets for ablation in patients with persistent atrial fibrillation (AF). However, there are little data on the relationship between theses 2 markers. This study assessed the relationship between the DF and electrogram MCL after pulmonary vein (PV) isolation in patients with persistent AF. Methods and Results: A total of 44 patients with persistent AF were studied. Four‐second bipolar electrograms were obtained with a multielectrode mapping catheter at regions throughout the left atrium after isolation of the pulmonary veins, with analysis of the MCL and DF at each site. The DF was defined as the largest frequency peak within a 2.5‐ to 16‐Hz spectral profile generated with fast Fourier transformation of the electrogram. A total of 9,262 electrograms from the 44 patients were analyzed. The average MCL and DF post‐PV isolation were 135 ± 24 ms and 6.1 ± 0.6 Hz, respectively. There was a statistically significant but weak correlation between the MCL and DF (r = 0.21, P < 0.001). Additionally, analysis of this relationship within each patient did not demonstrate a strong correlation (range of r values per patient =?0.18 to 0.47). Conclusions: There is a poor correlation between the electrogram MCL and DF in patients with persistent AF. Ablation strategies targeting DF and those targeting CFAE are therefore unlikely to direct ablation toward similar left atrial sites. Comparative studies are necessary to determine the effectiveness of each strategy in guiding catheter ablation of persistent AF.     

Pulmonary vein paced activation sequence mapping: comparison with activation sequences during onset of focal atrial fibrillation

INTRODUCTION: Atrial fibrillation (AF) may originate from a single focus, with the vast majority observed within the pulmonary veins. To facilitate mapping, we hypothesized that there would be a characteristic right atrial endocardial activation sequence pattern associated with pacing and spontaneous focal activity from each of the four pulmonary veins. METHODS AND RESULTS: In 10 patients with focal AF, a standardized set of catheters was positioned in the right atrium. These included a 20-pole catheter along the crista terminalis, a decapolar catheter in the coronary sinus (CS), and a His-bundle electrode. Pacing (700 and 300 msec) was performed with a mapping catheter from each of the four pulmonary veins. Activation sequence maps were created by measurement of activation times to each of the recording bipoles with the proximal CS bipole as the arbitrary reference point. Similar maps were constructed for the activation sequence of the pulmonary vein ectopic that initiated AF. There was a characteristic right atrial activation map created by pacing each pulmonary vein that corresponded closely with the map from the same pulmonary vein during initiation of focal AF. The pulmonary vein of origin could be distinguished on the basis of this characteristic pattern and some stereotypic observations. CS activation occurred proximal to distal for right pulmonary veins and distal to proximal for left pulmonary veins. Significant differences in activation timing between the CS and crista terminalis differentiated upper from lower pulmonary veins. CONCLUSION: There is a characteristic right atrial activation map for activity arising from each of the four pulmonary veins that corresponded closely with the map from the same pulmonary vein during initiation of focal AF. These findings may facilitate mapping and ablation of focal AF.