Electrical Isolation Of Pulmonary Veins Research Articles

Impact of body mass index on atrial fibrillation ablation using cryoballoon: procedural data and clinical outcomes

Abstract Background The impact of body mass index (BMI) on atrial fibrillation (AF) ablation using cryoballoon (CB) has been seldom reported. Purpose To evaluate the impact of BMI on procedural data as well as the clinical efficacy and safety character of using CB. Methods Symptomatic AF patients (paroxysmal / persistent AF) with BMI ≥25 who underwent CB based pulmonary vein isolation (PVI) were enrolled. CB PVI was performed using the second generation CB (CB 2, 28mm), with 4min based freeze protocol and bonus freeze delivery in case of time-to-isolation (TTI) >75 sec. All procedures were performed under conscious sedation. Procedural endpoint was electrical pulmonary vein isolation. Clinical success was defined as no recurrence of AF/atrial tachycardia (AT). Results Data from 600 consecutive patients were collected. Three groups defined: BMI 25–29 (Group 1, G1 n=337); BMI 30–34 (Group 2, G2 n=149); BMI ≥35 (Group 3, G3 n=114). Patients in Group 3 were younger (G1: 67±11 y; G2: 68±10y G3 62±11y; p<0,001) and presented bigger LA (G1 39,5±4,9 mm; G2: 41,6±5,5; G3 42,4±5,1; p<0,001). Most of the patients presented with PAF (G1: 59,3% G2: 57,7% G3: 54,4%). Among 2342 Targeted PVs, 2332 (99,6%) were isolated using solely the CB (G2: one procedure was abolished due to failed aortic puncture during transseptal access; G3: one PVI was not completed due to PNP; 6 touch up RF ablation in G1 and 2 in G3). Procedure time (G1:58,45 min; G2: 60,44 min; G3 63,19 min) and fluoroscopy time (G1: 9,3 min; G2: 9,5 G3: 10,6 min) were comparable among the groups. PN Injury was the main recorded complication: 20/600 (2,6%) patients with a transient PN palsy (PNP) and 6/600 (1%) with a persistent PNP. No sedation related complication was recorded. Follow up survival curve analysis after one year revealed a favorable follow up in G1 (78,4%) and G2 (82,5%) compared to G3 (66,5%) (G1 Vs G3 p: 0,002 G2 vs G3 p=0,008, G1 vs G2 p=0,47). The influence of BMI on the follow up was confirmed in the subgroup of patients with paroxysmal AF but not in patients presenting persistent AF. Conclusions Cryoballoon ablation in obese patients is feasible and associated with a relatively low complication rate. BMI plays a role in predicting recurrences especially in patients presenting with paroxysmal AF. Funding Acknowledgement Type of funding source: None

Pulmonary Vein Isolation With Single Pulse Irreversible Electroporation: A First in Human Study in 10 Patients With Atrial Fibrillation.

Irreversible electroporation (IRE) is a promising new nonthermal ablation technology for pulmonary vein (PV) isolation in patients with atrial fibrillation. Experimental data suggest that IRE ablation produces large enough lesions without the risk of PV stenosis, artery, nerve, or esophageal damage. This study aimed to investigate the feasibility and safety of single pulse IRE PV isolation in patients with atrial fibrillation. Ten patients with symptomatic paroxysmal or persistent atrial fibrillation underwent single pulse IRE PV isolation under general anesthesia. Three-dimensional reconstruction and electroanatomical voltage mapping (EnSite Precision, Abbott) of left atrium and PVs were performed using a conventional circular mapping catheter. PV isolation was performed by delivering nonarcing, nonbarotraumatic 6 ms, 200 J direct current IRE applications via a custom nondeflectable 14-polar circular IRE ablation catheter with a variable hoop diameter (16-27 mm). A deflectable sheath (Agilis, Abbott) was used to maneuver the ablation catheter. A minimum of 2 IRE applications with slightly different catheter positions were delivered per vein to achieve circular tissue contact, even if PV potentials were abolished after the first application. Bidirectional PV isolation was confirmed with the circular mapping catheter and a post ablation voltage map. After a 30-minute waiting period, adenosine testing (30 mg) was used to reveal dormant PV conduction. All 40 PVs could be successfully isolated with a mean of 2.4±0.4 IRE applications per PV. Mean delivered peak voltage and peak current were 2154±59 V and 33.9±1.6 A, respectively. No PV reconnections occurred during the waiting period and adenosine testing. No periprocedural complications were observed. In the 10 patients of this first-in-human study, acute bidirectional electrical PV isolation could be achieved safely by single pulse IRE ablation.

Procedural outcomes and learning curve of cardiac arrhythmias catheter ablation using remote magnetic navigation: Experience from a large-scale single-center study.

BackgroundRemote magnetic navigation (RMN)‐guided ablation has become an inspiring method of catheter ablation for tachyarrhythmias.HypothesisData from a large‐scale single center may provide further insight into the safety of and the learning curve for RMN‐guided ablation.MethodsA total of 1003 catheter ablation procedures using RMN for conditions including supraventricular ventricular tachycardia, atrial tachyarrhythmias, and premature ventricular contraction/ventricular tachycardia (PVC/VT) were retrospectively analyzed from an ablation registry. Procedural outcomes, including procedure time, mapping time, X‐ray time, and RF time, were assessed. The complications were classified into two categories: major and minor. A subanalysis was used to illustrate the learning curve of RMN‐guided ablation by assessing procedure time and total X‐ray time of 502 atrial fibrillation (AF) ablation procedures.ResultsAmong these procedures, 556 (55.4%) were AF and 290 (28.9%) were PVC/VT. Electrical pulmonary vein isolation was achieved in 99.0% of AF procedures, and acute success reached 90.3% in PVC/VT procedures. The overall complication rate was 0.5%. In the subanalysis of AF procedures, the overall procedure time and X‐ray time of procedures were short (125.9 ± 54.6 and 5.3 ± 3.9 minutes, respectively) and proceeded to decrease from the initial 30 procedures to about 300 procedures, where the learning curve reached plateau, demonstrating maximum procedure efficiency.ConclusionsRMN‐guided ablation is safe, as verified by very low overall complication rate and reduced X‐ray time. In our study, even the first AF procedures had a relatively low procedure time and total X‐ray time, and procedure efficiency improved during the learning curve.

PCV20 RADIOFREQUENCY CATHETER ABLATION VERSUS THE 2ND-GENERATION CRYOBALLOON FOR THE TREATMENT OF PAROXYSMAL ATRIAL FIBRILLATION IN CHINA: A COST- EFFECTIVENESS ANALYSIS

Both the contact-force catheter (Thermocool SmartTouch®) and the 2nd-generation cryoballoon (the 2nd-CB) have become a revolutionary enhancement on the previous technology, for the better contact-force sensitivity or the broader segmental electrical isolation of pulmonary veins. The aim of this study was to evaluate the cost effectiveness of radiofrequency catheter ablation (RFCA )using contact-force catheter (Thermocool SmartTouch®) versus the 2nd-CBA in PAF patients from third-party payer's perspective in China.

P978Core to block: a new ablation strategy for treating persistent atrial fibrillation

Abstract Background Ablation strategy targeting the core of atrial fibrillation (AF) rotors alone can lead to both stabilisation and destabilisation of rotational activity. Non-contact dipole density mapping system is designed to rapidly identify dynamic regional atrial activation patterns of interest (API) during AF. Purpose To assess the feasibility of an ablation strategy consisted of pulmonary vein isolation + targeting the core of APIs followed by linear ablation to the nearest non-conducting boundary to treat persistent AF. Methods The ablation strategy includes: 1. Antral pulmonary vein electrical isolation (APVI); 2. APIs (focal, localised rotational and localised irregular activation; Figure1) detection by dipole density mapping; 3. API core ablation followed by linear ablation to the nearest non-conduction barrier (APVI/mitral valve); 4. repeat step 2 and 3 in LA (RA, if necessary) until sinus rhythm is achieved. Results Consecutive 40 persistent AF patients (mean 62±12 years, 29 males, AF duration 10±4 months, LA diameter 42±9 mm) were included from 2 centres. An average of 2.0±0.7 APIs per patient were targeted post-APVI. Acute AF termination by ablation was achieved in 27/40 (68%) patients. The mean ablation time of APVI and “Core to block” was 33±12 mins and 31±22 mins, respectively. No major complication occurred. During a mean follow-up of 12±5 months, 32/40 patients (80%) maintained sinus rhythm. Conclusion APVI + “Core to block” guided by the dipole density mapping is feasible for treating persistent AF. A larger randomised study is needed to test the effectiveness of this ablation strategy. Acknowledgement/Funding None

Acute enhancement of necrotic radio-frequency ablation lesions in left atrium and pulmonary vein ostia in swine model with non-contrast-enhanced T1 -weighted MRI.

To evaluate non-contrast-enhanced MRI of acute radio-frequency ablation (RFA) lesions in the left atrium (LA) and pulmonary vein (PV) ostia. The goal is to provide a method for discrimination between necrotic (permanent) lesions and reversible injury, which is associated with recurrence after treatment of atrial fibrillation. Fifteen normal swine underwent RFA around the right-superior PV ostia. Electrical pulmonary vein isolation (PVI) was verified by electro-anatomic mapping (EAM) and pacing. MRI was carried out using a 3D respiratory-gated T1 -weighted long inversion time (TWILITE) sequence without contrast agent. Key settings were: inversion time 700 ms, triggering over 2 cardiac cycles, pixel size 1.1 mm3 . Contrast-enhanced imaging and T2 -weighted imaging were carried out for comparison. Six animals were sacrificed on ablation day for TTC-stained gross pathology, 9 animals were sacrificed after 2-3 mo after repeat EAM and MRI. Image intensity ratio (IIR) was used to measure lesion enhancement, and gross pathology was used to validate image enhancement patterns and compare lesion widths. RFA lesions exhibited unambiguous enhancement in acute TWILITE imaging (IIR = 2.34 ± 0.49 at 1.5T), and the enhancement patterns corresponded well with gross pathology. Lesion widths in MRI correlated well with gross pathology (R2 = 0.84), with slight underestimation by 0.9 ± 0.5 mm. Lesion enhancement subsided chronically. TWILITE imaging allowed acute detection of permanent RFA lesions in swine LA and PV ostia, without the need for contrast agent. Lesion enhancement pattern showed good correspondence to gross pathology and was well visualized by volume rendering. This method may provide valuable intra- or post-procedural assessment of RFA treatment.

Predictors of sustained isolation of pulmonary vein ostia with cryoballoon ablation using a second-generation cryoballoon Arctic Front Advance

Aim. To determine the electrophysiological and biophysical predictors of sustained isolation of pulmonary vein (PV) ostia, affecting the immediate and longterm results of interventional treatment of atrial fibrillation (AF) using cryoballoon ablation (CBA) with the second-generation cryoballoon Arctic Front Advance. Material and methods. The analysis included 143 PV in 37 patients with a paro-xysmal/persistent form of AF, which, after the primary CBA with the use of the second-generation cryoballoon, carried out additional interventions due to recurrence of AF and/or combined arrhythmia. During the primary CBA, the registration of biophysical and electrophysiological parameters of the procedure was performed. During the ablation in the right PV from the diagnostic electrode installed in the superior vena cava, the ipsilateral phrenic nerve was stimulated (2000 ms, 25 mA). When the phrenic nerve response to stimulation was decreased/disappeared, ablation ceased instantly. At the end of the procedure, isolation control of the PV was performed. A repeat/additional procedure was performed for the recurrence of AF and/or documented combined arrhythmia no earlier than 3 months after the initial ablation. The stability of the LV isolation was assessed using a circular mapping technique. According to the results of mapping, drugs were divided into 2 groups: isolated and with recurrent activity. Results. The frequency of sustained isolation of PV was 67,8%. Recurrent spike activity was recorded in 46 PV (32,2%). Higher frequency of registration of electrical isolation of PV in real time (68% vs 50%, p=0,001), stability of occlusion with a cryoballoon (85,5% vs 69,5%, p=0,024), low values of the minimum cryoballoon temperatures reached (49,2±6,3 vs 44,0±4,9, p<0,0001) and less need for additional applications (8,3% vs 34,7%, p<0,0001) were registered in the group of chronic isolation of PV. Multi-factor analysis of these parameters confirmed the predictor role of the minimum cryoballoon temperature. According to the ROC analysis, the threshold minimum temperature was 45,5° C with a sensitivity of 68% and a specificity of 60,9%. Conclusion. Cryoballoon isolation of PV ostia is an effective and safe method for achieving chronic isolation of PV. The minimum cryoballoon temperature with a threshold value of <-45,5° C is an independent predictor of long-term isolation of PV.

Feasibility and safety of cryoballoon ablation for atrial fibrillation in patients with congenital heart disease

BACKGROUNDThe prevalence of atrial fibrillation (AF) is on the rise in the aging population with congenital heart disease (CHD). A few case series have described the feasibility and early outcomes associated with radiofrequency catheter ablation of AF centered on electrically isolating pulmonary veins (PV) in patients with CHD. In contrast, cryoballoon ablation has not previously been studied in this patient population despite its theoretical advantages, which include a favorable safety profile and shorter procedural time.AIMTo assess the safety and feasibility of cryoballoon ablation for AF in an initial cohort of patients with CHD.METHODSThe study population consisted of consecutive patients with CHD and cryoballoon ablation for AF at the Montreal Heart Institute between December 2012 and June 2017. Procedural complications, acute success, and 1-year freedom from recurrent AF after a single procedure with or without antiarrhythmic drugs were assessed. Procedures were performed under conscious sedation. Left atrial access was obtained via a single transseptal puncture or through an existing atrial septal defect (ASD). Cryoballoon occlusion was assessed by distal injection of 50% diluted contrast into the pulmonary vein. At least one 240-second cryothermal application was performed upon obtaining complete pulmonary vein occlusion. Following ablation, patients were routinely followed at outpatient visits at 1, 3, 6, and 12 mo, and then annually.RESULTSTen patients, median age 57.9 (interquartile range 48.2-61.7) years, 60% female, met inclusion criteria and were followed for 2.8 (interquartile range 1.4-4.5) years. Two had moderately complex CHD (sinus venosus ASD with partial anomalous pulmonary venous return; aortic coarctation with a persistent left superior vena cava), with the remainder having simple defects. AF was paroxysmal in 8 (80.0%) and persistent in 2 (20.0%) patients. The pulmonary vein anatomy was normal in 6 (60.0%) patients. Four had left common PV (n = 3) and/or 3 right PV (n = 2). Electrical pulmonary vein isolation (PVI) was acutely successful in all. One patient had transient phrenic nerve palsy that recovered during the intervention. No major complication occurred. One year after a single ablation procedure, 6 (60%) patients remained free from AF. One patient with recurrent AF had recovered pulmonary vein conduction and underwent a second PVI procedure. A second patient had ablation of an extra-pulmonary vein trigger for AF.CONCLUSIONCryoballoon ablation for AF is feasible and safe in patients with simple and moderate forms of CHD, with an excellent acute success rate and modest 1-year freedom from recurrent AF.

Effect of acupuncture at Neiguan point combined with amiodarone therapy on early recurrence after pulmonary vein electrical isolation in patients with persistent atrial fibrillation.

Early atrial fibrillation (AF) recurrences are common and have been shown to predict AF recurrences late after AF ablation during follow-up. Neiguan point acupuncture has been recognized to be therapeutic in treating AF in clinical practice. Eighty-five patients were enrolled in succession due to persistent AF. All patients were randomized divided into control group and acupuncture group. In the control group (n = 45), amiodarone was orally taken from the first day after pulmonary vein isolation (PVI). In the acupuncture group (n = 40), patients were treated with Neiguan point acupuncture for 7 days and amiodarone was prescribed as same as the control group after PVI. The levels of inflammatory factors were analyzed before operation, 1 week after the operation and 3 months later. After 3 months, the acupuncture group had a lower rate of early recurrences than the control group (5/40 [12.5%] vs 15/45 [33.3%], P = 0.039). The inflammatory factors level in the two groups were significantly increased after ablation. However, compared with the control group, the levels of TNF-α, IL-6, CRP, TGF-β1, MMP2 in the acupuncture group significantly lower (P < 0.05). In a multivariate analysis, acupuncture was an independent factor associated with a lower rate of early recurrences during the blanking period (odds ratio, 0.17; 95% confidence interval, 0.05-0.63; P = 0.008). Neiguan point acupuncture combined with amiodarone is superior to amiodarone alone in reducing early recurrences of patients with persistent AF after PVI. The efficacy of Neiguan acupuncture therapy on the early recurrence is associated with the decreased inflammation factors.

BLOCKING IT OUT: APPROACH TO TESTING FOR EXIT BLOCK IN TACHYCARDIA

Complete bi-directional electrical isolation of pulmonary veins (PV) is the cornerstone of catheter ablation (CA) therapy for atrial fibrillation (AF). Bi-directional block is confirmed by left atrial (LA) non-capture during pacing from PV and vice versa, and requires careful assessment of PV to LA

Electroporation and its Relevance for Cardiac Catheter Ablation.

Irreversible electroporation can be used as a nonthermal energy source to ablate tissue. Cardiac catheter ablation byirreversible electroporation may be a safe and effective alternative for thermal ablation techniques such as radiofrequency or cryoablation. Total applied current, not delivered power (watts), energy (joules), or voltage, is the parameter that most directly relates to the local voltage gradient that causes electroporation. Electroporation can beachieved with various modalities: direct current, alternating current, pulsed direct current, or any combination of these. Experimental cardiac and noncardiac studies have demonstrated tissue specificity with survival of arteries and nerves inlarge lesions. In addition, porcine data suggest that application inside a pulmonary vein does not lead to pulmonary vein stenosis and that the esophagus is remarkably insensitive to electroporation. Therefore, irreversible electroporation is a very promising technique for cardiac catheter ablation and especially for electrical pulmonary veinisolation.

Atrial fibrillation ablation using cryoballoon technology: Recent advances and practical techniques.

Atrial fibrillation (AF) affects 1-2% of the population, and its prevalence is estimated to double in the next 50 years as the population ages. AF results in impaired patients' life quality, deteriorated cardiac function, and even increased mortality. Antiarrhythmic drugs frequently fail to restore sinus rhythm. Catheter ablation is a valuable treatment approach for AF, even as a first-line therapy strategy in selected patients. Effective electrical pulmonary vein isolation (PVI) is the cornerstone of all AF ablation strategies. Use of radiofrequency (RF) catheter in combination of a three-dimensional electroanatomical mapping system is the most established ablation approach. However, catheter ablation of AF is challenging even sometimes for experienced operators. To facilitate catheter ablation of AF without compromising the durability of the pulmonary vein isolation, "single shot" ablation devices have been developed; of them, cryoballoon ablation, is by far the most widely investigated. In this report, we review the current knowledge of AF and discuss the recent evidence in catheter ablation of AF, particularly cryoballoon ablation. Moreover, we review relevant data from the literature as well as our own experience and summarize the key procedural practical techniques in PVI using cryoballoon technology, aiming to shorten the learning curve of the ablation technique and to contribute further to reduction of the disease burden.

Dosing of the second-generation cryoballoon using acute time-to-pulmonary vein isolation as an indicator of durable ablation in a canine model.

Rigid time-based dosing protocol(s) currently used in the clinic for cryoballoon ablation of atrial fibrillation may be inadequate to guide the circumferential and transmural cryothermal energy transfer across the pulmonary vein (PV) and may result in injury to collateral tissues or electrical gaps between the PV and left atrium (LA). A physiologic endpoint (e.g., acute time-to-PV isolation a.k.a. time-to-effect; TTE) may be effective in the determination of a transmural lesion formation and may allow for individualized ablation dosing across each PV. Thirty PVs from 15 dogs were randomized into five dosing protocols, including (1) TTE + 60s, (2) TTE + 90s, (3) TTE + 120s, (4) TTE + 150s, and (5) 2 × 180s. Ablations were conducted with a 23-mm second-generation cryoballoon, and TTE was assessed during a freeze by pacing from an inner balloon-lumen circular diagnostic catheter to a quadripolar diagnostic catheter in the coronary sinus. After ablation, animals were survived for 30 to 34days, and repeat electrophysiology assessment of PV isolation was conducted after which animals were euthanized for gross anatomy and histological examination. At study termination, efficacy endpoint evaluations were based on maintenance of PV electrical isolation, gross anatomy assessment of PV lesions, and histological examination of PVs. Five efficacy endpoint failures were noted, including the following: 1 PV in the TTE + 90 sec group; 2 PVs in the TTE + 120 sec group; 1 PV in the TTE + 150s group; and 1 PV in the 2 × 180s group. Regarding safety, one phrenic nerve injury was observed in the 2 × 180s cohort. No other complications were observed. In a canine model, effective PV isolation could be found even in the shortest duration dosing cohort (TTE + 60s). One complication (phrenic nerve injury) was observed in the longest duration dosing group (2 × 180s). Further studies will be required to correlate these results to a 28-mm cryoballoon (more commonly used in the cryoablation of a human LA); however, to date, this is the first reporting of a successful cryoablation using TTE + 60s dosing (approximately 90s total duration of freezing).

Impact of Pulmonary Vein Anatomy on Long-term Outcome of Cryoballoon Ablation for Atrial Fibrillation

Variant pulmonary vein anatomy (PVA) has been reported to influence the recurrence of atrial fibrillation (AF) after radiofrequency ablation. However, the effects of PVA on AF in patients undergoing cryoballoon ablation (CBA) remain unknown. The present study aimed to examine the impact of PVA on the long-term outcome of CBA for AF. A total of 78 patients (mean age 60.7±10.9 years, 64.1% males) with symptomatic and drug-refractory paroxysmal AF were enrolled in the study. Left atrium (LA) and PVA acquired at computed tomography angiography (CTA) were reconstructed with CARTO® 3 SYSTEM. Patients were routinely evaluated by 24-hour Holter monitoring following CBA. Cox regression was used to detect the predictors of AF recurrence after CBA. The results showed abnormal PVA in 30 patients (38.5%) and 18 patients (23.1%) had left common PV (LCPV). Electrical pulmonary vein isolation was achieved in all patients. After a mean follow-up of 689.5±103.8 days, it was found that patients with abnormal PVA had similar AF recurrence rate to those with normal PVA (26.7% vs. 25.0%, P=0.54), and there was no significant difference in AF recurrence rate between LCPV patients and non-LCPV patients (33.7% vs. 23.3%, P=0.29). Cox regression analysis showed that AF duration (72.9±9.0 vs. 42.3±43.2 months, HR 1.001; 95%CI 1.003-1.014; P<0.001) and cryo-applications of right-side PVs (3.0±1.6 vs. 4.7±1.7, HR 0.661; 95% CI 0.473-0.925; P=0.016) were independent predictors of freedom from AF, but PVA was not identified as a predictor of long-term success. In conclusion, the variant PVA cannot significantly influence the long-term outcome of AF patients undergoing CBA; longer AF duration and less cryo-applications of right-side PVs are associated with higher AF recurrent rate.

Individualized ablation strategy guided by live simultaneous global mapping to treat persistent atrial fibrillation.

Atrial fibrillation (AF) is the most common clinical arrhythmia encountered. Catheter ablation has become the first-line therapy for symptomatic drug-refractory paroxysmal and persistent AF. Although pulmonary vein electrical isolation is still the cornerstone of the ablation strategy, the clinical outcome particularly in treating persistent AF is suboptimal. Significant efforts have been applied with live global chamber mapping of AF aimed to identify patient-specific drivers and/or maintainers located outside of the pulmonary veins to further improve the outcome of catheter ablation. Within this review, we present an overview of contemporary global chamber AF mapping technologies and characteristics, with a particular focus on global, noncontact, dipole density mapping illustrated with a clinical case of persistent AF ablation using this novel methodology.

Congenital Absence of Left Atrial Appendage Diagnosed by Multimodality Imaging

A 70-years-old male with a history of hypertension and drug resistant paroxysmal atrial fibrillation (AF) presented to our hospital for catheter ablation to his symptomatic AF. He had no prior surgical or percutaneous procedure to close or exclude the left atrial appendage (LAA). A transesophageal echocardiography (TEE) was performed to rule out intra-cardiac thrombus prior to the ablation procedure. Although the TEE imaging at multiple acquisition angles was obtained, the LAA could not be visualized and an absence of the LAA was suspected. An absence of the LAA was confirmed using cardiac computed tomography (CT), which included 3D reconstruction. Additionally, the LAA was not visualized with left atrium (LA) angiography. During the ablation procedure, 3D voltage mapping in LA was created and no low voltage area or abnormal potential was recorded around the usual root location of the LAA. Successful electrical pulmonary vein isolation was achieved with no major complications. After six months of follow-up, the patient remained in sinus rhythm without any antiarrhythmic drugs and showed no related clinical symptoms. He stopped his anticoagulation therapy due to lack of evidence of AF recurrence and an absence of LAA. Multimodality imaging allowed us to identify the congenital absence of LAA.

Predictors of a Persistent Status of Pulmonary Vein Electrical Isolation by a Cryoballoon Application for Drug-Refractory Atrial Fibrillation.

Pulmonary vein isolation (PVI) using a cryoballoon (CB) is utilized for treating atrial fibrillation. This study aimed to assess the effect of the procedural characteristics of CB-based PVI (CB-PVI) on late PV reconnections.Methods and Results:A total of 389 consecutive patients underwent the CB-PVI as their index procedure; 45 consecutive patients underwent re-do procedures (184±87 days after the index CB-PVI). A total of 146 of 178 PVs (82%) remained isolated. The occlusion grade was evaluated in 171 PVs. Complete PV occlusion by the CB (grade 4) was obtained in 122 of 171 PVs (71%) during the index CB-PVI and the PVI status was maintained in 111 PVs (91%). Among the remaining 49 CB-PVIs without complete PV occlusion (grades 1-3), 20 PVs (41%) had late PV reconnections despite successful PVI during the index CB-PVI. A "pull-down maneuver" was performed in 20 PVs because of leakage of blood at the inferior aspect of the PVs, and all those PVs with a successful pull-down maneuver maintained their PVI status. A multivariate analysis demonstrated that the presence of complete PV occlusion was the only independent predictor for persistence of PVI. The occlusion grade was a reliable predictor of the long-term durability of PVI.

5-Year Outcome of Pulmonary Vein Isolation by Loss of Pace Capture on the Ablation Line Versus Electrical Circumferential Pulmonary Vein Isolation

This study sought to compare long-term arrhythmia-free survival between electrical circumferential pulmonary vein isolation (PVI) and PVI with the endpoint of unexcitability along the ablation line. PVI is the standard ablation strategy of paroxysmal atrial fibrillation, although arrhythmia recurrence in long-term follow-up (FU) is high. The endpoint of unexcitability along the ablation line results in decreased arrhythmia recurrence compared to electrical PVI in 1-year FU. Seventy-four consecutive patients (age 62.5 ± 10.6 years; 70.3% male) with de novo paroxysmal atrial fibrillation who were initially included in our randomized trial and underwent catheter ablation at our institution were analyzed. Patients who were randomized to either a conventional group (PVI, guided by circumferential catheter signals) or a pace-guided group (PG, anatomical ablation line encircling, ablation until loss of pace capture at 10 V, 2-ms pulse width on the ablation line) underwent long-term FU. The primary endpoint was recurrence of any atrial fibrillation or atrial tachycardia after a blanking period of 3 months. Sixty-nine patients completed a mean FU period of 5.14 ± 0.98 years. Arrhythmia-free survival without antiarrhythmic drug therapy was significantly higher in the PG group (71.05% vs. 25.81%, p= 0.002). Furthermore, multiple procedure success (1.29 ± 0.61 procedures in PG vs. 1.97 ± 1.06 procedures in conventional group, p< 0.001) was higher in the PG group compared to the conventional group (89.47% vs. 58.06%, p= 0.005). The endpoint of unexcitability along the PVI line improves success rates, resulting in a significant reduction of exposure to invasive procedures in 5-year FU.

Correlates of Arrhythmia Recurrence After Hybrid Epi- and Endocardial Radiofrequency Ablation for Persistent Atrial Fibrillation.

Long-term efficacy of catheter-based treatment of persistent atrial fibrillation is unsatisfactory. Minimally invasive surgical ablation techniques have been developed recently, but their efficacy has never been systematically tested. Seventy patients (median age, 63.5 years) with persistent atrial fibrillation underwent epicardial thoracoscopic radiofrequency pulmonary vein isolation, linear ablation, Marshal ligament disruption, and exclusion of the left atrial appendage. The procedure was followed by electroanatomic mapping and ablation (EAM) 2 to 3 months later. Only 76% of patients were in normal sinus rhythm at the beginning of EAM. All 4 pulmonary veins and the left atrium posterior wall were found isolated in 69% and 23% of patients, respectively. Arrhythmia-free survival off antiarrhythmic drugs 12 months after EAM was 77%. Using previously ineffective antiarrhythmic drugs and reablation procedures, arrhythmia free-survival increased to 97% during follow-up (mean, 936±432 days; range, 346-1509 days). The majority of arrhythmia recurrences occurred during the first 12 months after EAM. In a multivariable-adjusted estimates, left atrium volume >165 mL, absent normal sinus rhythm at admission for EAM, and inducibility of any sustained tachyarrhythmia at the end of EAM procedure were identified as independent correlates of atrial fibrillation recurrence. Our report demonstrated that the majority of patients after epicardial ablation, using bipolar radiofrequency instruments, required endocardial catheter ablation to complete the linear ablation lesions and a significant proportion of patients required spot-ablations to complete electric pulmonary vein isolation. Noninducibility of any arrhythmia after a staged hybrid procedure seemed to be the strongest correlate of long-term arrhythmia-free survival. URL: www.ablace.cz. Unique identifier: cz-060520121617.

Targeting ablation strategies and electro-anatomical systems for different atrial fibrillation patterns.

Catheter ablation (CA) is an established and widespread treatment option for drug refractory atrial fibrillation (AF). CA has undergone considerable improvements during the last years and several ablation strategies have been proposed for different AF patterns. The main cornerstone is the electrical isolation of pulmonary veins (PVs) especially among patients with paroxysmal AF. This can be achieved mainly with the use of radiofrequency or cryo-energy. However ablation strategy remains uncertain in patients with persistent AF. Several mapping systems have been developed in order to acquire electrical and anatomical information of the left and right atrium. For patients with persistent atrial fibrillation new systems are able to identify potential AF triggers arising out of the PVs, but the role of ablation of this triggers is still not clear. Although several improvements have been performed in CA of AF, the main cornerstone of treatment remains the electrical isolation of PVs. This approach provides good clinical results at long-term follow-up in patients with paroxysmal AF. However, the ablation strategy apart from electrical isolation of PV in patients with persistent AF is still not well defined. Further improvement of mapping systems could provide more information about alternative ablation strategies.