Drug-resistant Atrial Fibrillation Research Articles

OP-282 Role of Type I Procollagen C-Terminal to Predict Recurrence after Cryoablation in Lone AF Patients

Atrial fibrillation (AF) ablation via pulmonary vein isolation (PVI) has become an important therapeutic strategy especially in drug-resistant paroxysmal AF patients. However, there was significant amount of patients with recurrence. Although type-I procollagen C-terminal (Pcoll-1-C) is involved in atrial remodelling, it is unknown whether plasma Pcoll-1-C level before PVI can be used as a predictive factor for AF recurrence. The goal of this study was to clarify whether the plasma Pcoll-1-C level, before PVI, can be used as a predictive factor for AF recurrence after PVI.

Incidences of esophageal injury during esophageal temperature monitoring: a comparative study of a multi-thermocouple temperature probe and a deflectable temperature probe in atrial fibrillation ablation

The study aim was to compare the incidence of esophageal injuries between different temperature probes in the monitoring of esophageal temperature during atrial fibrillation (AF) ablation. One hundred patients with drug-resistant AF were prospectively and randomly assigned into two groups according to the esophageal temperature probe used: the multi-thermocouple probe group (n = 50) and the deflectable temperature probe group (n = 50). Extensive pulmonary vein (PV) isolation was performed with a 3.5-mm open irrigated tip ablation catheter by using a radiofrequency (RF) power of 25-30 W. In both groups, the esophageal temperature thermocouple was placed on the area of the esophagus adjacent to the ablation site. When the esophageal temperature reached 42 °C, the RF energy delivery was stopped. Esophageal endoscopy was performed 1 day after the catheter ablation. No differences existed between the two groups in terms of clinical background and various parameters related to the catheter ablation, including RF delivery time and number of RF deliveries at an esophageal temperature of >42 °C. Esophageal lesions, such as esophagitis and esophageal ulcers, occurred in 10/50 (20 %) and 15/50 (30 %) patients in the multi-thermocouple and deflectable temperature probe groups, respectively (P = 0.25). Most lesions were mild to moderate injuries, and all were cured using conservative treatment. The incidence of esophageal injury was almost equal between the multi-thermocouple temperature probe and the deflectable temperature probe during esophageal temperature monitoring. Most of the esophageal lesions that developed during esophageal temperature monitoring were mild to moderate and reversible.

Complex Left Atrial Appendage Morphology and Left Atrial Appendage Thrombus Formation in Patients With Atrial Fibrillation

In patients with atrial fibrillation (AF), most thrombus forms in the left atrial appendage (LAA). However, the relation of LAA morphology with LAA thrombus is unknown. We prospectively enrolled 633 consecutive patients who were candidates for catheter ablation for symptomatic drug-resistant AF. Transesophageal echocardiography (TEE) was performed to assess LAA thrombus. LAA structure was assessed by 3-dimensional TEE. LAA orifice area, depth, volume, and number of lobes were measured on reconstructed 3-dimensional images. Clinical characteristics and echocardiographic measures were compared to determine variables predicting LAA thrombus. Excluded were 69 (10.9%) patients who met the exclusion criteria. Finally, this study comprised 564 patients, of whom LAA thrombus was observed in 36 (6.4%) patients. Multivariate analysis revealed CHADS2 (Congestive heart failure, Hypertension Age>75, Diabetes mellitus and prior Stroke or transient ischemic attack) score (P=0.002), left ventricular ejection fraction (P=0.01), degree of spontaneous echo contrast (P=0.02), left atrial volume (P=0.02), and number of LAA lobes (P<0.001) to be independently associated with thrombus formation. Most patients with LAA thrombus (32/34, 94.4%) had ≥3 LAA lobes, whereas LAA thrombus was observed in only 2 (0.7%) of 296 patients with 1 or 2 lobes. LAA volume significantly decreased in patients maintaining sinus rhythm after catheter ablation (P=0.0009). Number of LAA lobes did not change in any patient. Complex LAA morphology characterized by an increased number of LAA lobes was associated with the presence of LAA thrombus independently of clinical risk and blood stasis. This study suggests that LAA morphology might be a congenital risk factor for LAA thrombus formation in patients with AF.

Connective Tissue Growth Factor: A Predictor of Recurrence after Catheter Ablation in Patients with Nonparoxysmal Atrial Fibrillation

Although catheter ablation can effectively eliminate atrial fibrillation (AF), the progression of atrial remodeling increases the risk of recurrence. We, therefore, examined the possibility of determining the postablation prognosis of patients with AF using biomarkers of atrial structural remodeling and serum connective tissue growth factor (CTGF) level, and measured its changes after catheter ablation. Subjects were 400 consecutive patients (308 with paroxysmal AF and 92 with nonparoxysmal AF [persistent and long-standing persistent AF]) who underwent catheter ablation for drug-resistant AF. Serum CTGF levels were measured before and 2 months after ablation. During the follow-up period of 20.5 ± 6.9 (8-30) months, 61 patients (66%) with nonparoxysmal AF and 95 patients (31%) with paroxysmal AF had recurrence after catheter ablation. Recurrence was associated with higher "baseline CTGF level" in patients with nonparoxysmal AF (936.5 ± 93.1 ng/mL vs 746.3 ± 56.9 ng/mL, P = 0.007) instead of patients with paroxysmal AF (851.6 ± 97.6 ng/mL vs 807.6 ± 99.1 ng/mL, P = 0.921). In nonparoxysmal AF, the recurrence subgroup also had larger left atrial diameter (LAD; 47.1 ± 5.2 mm vs 39.5 ± 4.3 mm, P = 0.035) compared with the nonrecurrence subgroup, and "baseline serum CTGF" and LAD were shown to be independent predictors for postablation recurrence by a Cox proportional hazards model. However, the 2-month postablation elevations of CTGF in patients with recurrence were not significantly different from that in patients without recurrence in nonparoxysmal AF. Our finding indicates that "baseline serum CTGF level" is an independent predictor for recurrence in patients with nonparoxysmal AF following catheter ablation. Two-month postablation elevation in CTGF has no association with recurrence.

Oesophageal cooling with ice water does not reduce the incidence of oesophageal lesions complicating catheter ablation of atrial fibrillation: randomized controlled study

Atrial fibrillation (AF) ablation can result in oesophageal injuries that lead to atrio-oesophageal fistulae, a life-threatening complication. This study aimed to evaluate whether oesophageal cooling could prevent oesophageal lesions complicating AF ablation. We randomly assigned 100 patients with drug-resistant AF to an oesophageal cooling group or a control group. In the oesophageal cooling group, we injected 5 mL of ice water into the oesophagus prior to radiofrequency (RF) energy delivery adjacent to the oesophagus. If the oesophageal temperature reached 42°C, the RF energy delivery was stopped, and the ice water injection was repeated. In the control group, oesophageal cooling was not applied. Oesophageal endoscopy was performed 1 day after the catheter ablation, and lesions were qualitatively assessed as mild, moderate, or severe. The numbers of ablation sites with an oesophageal temperature of >42°C were 1.7 ± 1.4 and 2.6 ± 1.7 in the oesophageal cooling group and the control group, respectively (P = 0.04), and the maximal oesophageal temperature at those sites was 43.0 ± 0.6 and 44.7 ± 0.9°C (P < 0.0001). Oesophageal lesions occurred almost equally between the oesophageal cooling group [10 of 50 patients (20%)] and the control group [11 of 50 patients (22%)]. However, the severity of the oesophageal lesions was slightly milder in the oesophageal cooling group (three moderate, seven mild) than in the control group (three severe, one moderate, seven mild). Oesophageal cooling may alleviate the severity of oesophageal lesions but does not reduce the incidence of this complication under the specific protocol evaluated here.

A Rare Complication of Cryoballoon: Gastroparesis

Despite higher frequency of complications secondary to collateral nerve damage after radiofrequency catheter ablation of atrial fibrillation (AF), in the cryoballoon technique gastroparesis has not been clearly revealed yet. We presented a patient who developed severe gastroparesis during cryoballoon ablation. A -64 -year-old female patient underwent pulmonary vein isolation (PVI) of drug resistant symptomatic paroxysmal AF with cryoballoon. PVI was achieved in 3 pulmonary veins with cryoballoon using standard tecnique. During isolation of the right inferior pulmonary vein, the patient complained of stomach ache, bloating, and nausea. At the beginning, these complaints were thought to be related to gastric irritation due to heparin bolus, and the procedure was continued. Proton pump inhibitor was administered through intravenous route. However her complaints continued with increasing severity. Fluoroscopy revealed that stomach was completely full of air which indicates an episode of acute pyloric spasm or gastroparesis (Figure 1). Then nasogastric tube was placed, and IV metochlopramide was administered. At the end of 24 hours, her complaints regressed completely. Then her nasogastric tube was removed, and oral intake was initiated. She has been still asymptomatic after 6 months follow-up. The diagnosis of gastroparesis confirmed with gastric emptying scintigraphy. Although this procedural complication which can cause serious symptoms is not seen so frequently, it should be kept in mind in patients with similar complaints, and it should be considered in the management of the patients with similar complaints. We presented this case to emphasize the above mentioned important points.

Pulmonary vein isolation in patients with Brugada syndrome and atrial fibrillation: a 2-year follow-up

Pharmacological treatment of atrial fibrillation (AF) in the setting of Brugada syndrome (BS) might be challenging as many antiarrhythmic drugs (AADs) with sodium channel blocking properties might expose the patients to the development of ventricular arrhythmias. Moreover, patients with BS and implantable cardioverter-defibrillator (ICD) might experience inappropriate shocks because of AF with rapid ventricular response. The role of pulmonary vein isolation (PVI) in patients with BS and recurrent episodes of AF has not been established yet. In this study, we analysed the outcome of PVI using radiofrequency energy or cryoballoon (CB) ablation at 2 years follow-up. Consecutive patients with BS having undergone PVI for drug-resistant paroxysmal AF were eligible for this study. Nine patients (three males; mean age: 52 ± 26 years) were included. Six patients (67%) had an ICD implanted of whom three had inappropriate shocks because of rapid AF. At a mean 22.1 ± 6.4 months follow-up, six patients (67%) were free of AF without AADs. None of the three patients who had experienced inappropriate ICD interventions for AF had further ICD shocks after ablation. In our study PVI can be an effective and safe procedure to treat patients with BS and recurrent episodes of paroxysmal AF.

Updated National Multicenter Registry on Procedural Safety of Catheter Ablation for Atrial Fibrillation

Despite catheter ablation (CA) becoming an accepted treatment option for symptomatic, drug-resistant atrial fibrillation (AF), safety of this procedure continues to be cause for concern. Aim of the present multicenter registry was to assess the incidence of early CA complications and detect their predictors in a contemporary, unselected AF population From January 1, 2011 to December 31, 2011, data from 2,323 consecutive patients who underwent CA (median age 60 [52-67]; 72.3% male) for AF in 29 Italian centers were collected. All major complications occurring to the patient from admission to 30th postprocedural day were recorded. No procedure-related death was observed. Major complications occurred in 94 patients (4.0%): 50 patients (2.2%) suffered vascular access complications; 12 patients (0.5%) developed cardiac tamponade; 14 patients (0.6%) presented with pericarditis; 5 patients (0.2%) had transient ischemic attack; 4 patients had stroke; 3 patients (0.1%) had phrenic nerve paralysis; 3 patients (0.1%) had hemothorax. Other isolated but serious adverse events were documented in 3 patients (0.1%). Female gender (OR 2.643; 95% CI 1.686-4.143; P < 0.0001) and longer procedural duration (OR 2.195; 95% CI 1.388-3.473; P < 0.001) independently predicted a higher risk of complications. Major complications occurred in 4.0% of the CA procedures for AF, with vascular access complications being the most frequent events.

Clinical Characteristics and Management of Periesophageal Vagal Nerve Injury Complicating Left Atrial Ablation of Atrial Fibrillation: Lessons from Eleven Cases

This study aimed to elucidate the clinical characteristics and management of periesophageal vagal nerve injury complicating the ablation of atrial fibrillation (AF). A total of 3,695 patients with drug-resistant AF underwent extensive pulmonary vein isolation at our institution. Either a nonirrigated or an irrigated ablation catheter was employed, with radiofrequency power of 25-40 W. Esophageal temperature was monitored in 3,538 patients: when the esophageal temperature reached 42°C radiofrequency delivery was stopped. A total of 11 patients (60 ± 11 years, 10 males) were diagnosed as having a periesophageal vagal nerve injury after the AF ablation. Symptoms included nausea, vomiting, bloating, constipation, and gastric pain, which occurred within 72 hours after the procedure. Gastrointestinal fluoroscopy and/or endoscopy revealed gastric hypomotility (10 patients) and pyloric spasm (1 patient). Intravenous erythromycin (3 mg/kg every 8 hours) was effective in relieving symptoms in 5 patients, and the patient with pyloric spasm underwent esophagojejunal anstomosis. Eight patients almost fully recovered within 40 days; however, 3 patients suffered from severe symptoms for 3-12 months. This complication occurred in 4 of the 157 patients (2.5%) who did not have esophageal temperature monitoring, and 7 of the 3,538 (0.2%) who did (P = 0.0007). The 3 patients with persistent severe symptoms received no esophageal temperature monitoring. The clinical course and severity of the periesophageal vagal nerve injury varied, but most patients finally recovered with conservative treatment. Radiofrequency delivery under esophageal temperature monitoring might reduce both the incidence and the severity of this complication.

Abstract 9688: Association of Common Variations on Chromosome 4q25 and Left Atrial Volume in Patients with Atrial Fibrillation

Objectives: To examine the association between single nucleotide polymorphisms (SNPs) near PITX2 and left atrial size in patients with atrial fibrillation (AF). Background: Recent studies have shown that several genetic variants near the PITX2 locus on chromosome 4q25 are associated with AF. However, the mechanism that mediates this association remains unclear. Basic murine studies suggest that reduced PITX2 expression is associated with left atrial dilatation. Methods: We prospectively enrolled 96 patients (mean age 60 ± 10 yrs, 72 % male) with drug resistant AF (57% paroxysmal, 38% persistent and 5% longstanding persistent) who underwent catheter ablation. Following DNA extraction from blood obtained pre-operatively, SNPs rs10033464 and rs2200733 were genotyped using the Sequenom MassARRAY. Left atrial volume (LAV) was determined using 3-dimensional imaging (CT or MRI prior to first ablation) by investigators blinded to genotype results. Results: The minor allele frequency at SNPs rs10033464 and rs2200733 were 0.14 and 0.25, respectively. Using multivariate linear regression, the minor allele at rs10033464 (co-dominant model) was independently associated with larger LAV (P = 0.037) after adjustment for age, gender, BMI, type of AF, left ventricular ejection fraction, and history of hypertension. However, no association was found between rs2200733 variant alleles and LAV (P = 0.82). Conclusion: SNP rs10033464 near the PITX2 locus on 4q25 is significantly associated with LAV. Left atrial dilatation may mediate the association of common variants at 4q25 with AF.

Abstract 18612: Intravenous Infusion of Ultrashort-acting Beta-blocker, Landiolol, for Prevention of Immediate Recurrence of Atrial Fibrillation after Catheter Ablation

BACKGROUND: Immediate recurrence of atrial fibrillation (AF) after catheter ablation (CA) troubles with patients. We investigated whether intraveneous infusion of landiolol, an ultrashort-acting beta-blocker, could inhibit immediate AF recurrence after CA by randomized controlled trial. METHOD: atients with drug-resistant AF treated by CA were assigned to receive either landiolol or placebo after the procedure. In the landiolol group, landiolol was infused ntraveneously at speed of 1 μg/kg/min and continued for 3 days after the CA. The primary end point was occurrence/non-occurrence of AF, defined as supra-ventricular arrhythmia more than 5 min, up to 3-day after CA. Logistic regression analysis was performed to investigate risk factor. RESULT: 31 and 24 patients were assigned to landiolol group and placebo group, respectively. There were no significant difference between both groups in systolic blood pressure (SBP) before CA, diastolic blood pressure (DBP) before CA and changes from pre-CA to post-CA of SBP and DBP. AF recurrence occurred in 5 patients (10%) in landiolol group versus 11 patients (45%) in the placebo group (P=0.016, Figure). Multivariable analysis revealed that landiolol infusion significantly reduced the risk of transient AF recurrence after procedure (Hazard ratio: 0.208, 95% confidence interval of hazard ratio: 0.048-0.897, P=0.035). CONCLUSIONS: Short-term landiolol infusion successfully decreased immediate AF recurrence after CA without changing SBP and DBP. Administration of landiolol may become a new strategy to facilitate management after CA.

Study Design of the Man and Machine Trial: A Prospective International Controlled Noninferiority Trial Comparing Manual with Robotic Catheter Ablation for Treatment of Atrial Fibrillation

Pulmonary vein isolation (PVI) has become the cornerstone procedure for the treatment of symptomatic drug-resistant atrial fibrillation (AF). At the present time, circumferential PVI (CPVI) using irrigated radiofrequency (RF) is the mostly used ablation technique. However, for CPVI, precise catheter navigation and excellent catheter stability is crucial thereby requiring experienced operators. Robotic navigation systems have been introduced to facilitate catheter navigation and to improve catheter stability, therefore potentially increasing procedural success and making CPVI accessible to less experienced operators. To date, no prospective randomized trial has evaluated the efficacy and safety of CPVI using RNS compared to manually performed ablation. In this prospective international multicenter noninferiority trial, 258 patients with either paroxysmal or short-standing persistent AF will be randomized for comparison of PVI using either manual or robotic ablation. In all patients, CPVI will be performed using irrigated RF ablation in combination with a 3D mapping system. The primary endpoint of the trial is the absence of AF or atrial tachycardia without antiarrhythmic drug therapy during 12-month follow-up. Secondary endpoints will be evaluation of periprocedural complications and procedural data such as procedure time, fluoroscopy time, as well as the incidence of esophageal injury assessed by endoscopy within 48 hours after the procedure. The "Man and Machine Trial" is the first prospective international randomized controlled multicenter noninferiority trial to compare manually performed CPVI with robotically navigated CPVI, evaluating both the safety and efficacy of the 2 techniques during a 12-month follow-up period.

Association of Atrial Myocardial Fibrosis with a Common Matrix Metalloproteinase-2 Promoter Polymorphism

Background Atrial fibrillation (AF), the most common cardiac arrhythmia, is associated with the common –1306C/T matrix metalloproteinase-2 single nucleotide polymorphism (MMP2 SNP), which reduces the synthesis of matrix metalloproteinase-2 enzyme. Understanding the factors that mediate this association may improve current preventive and therapeutic strategies for AF. Methods To test the hypothesis that MMP2 SNP is associated with atrial fibrosis, the study was designed as a single center, observational, cross-sectional study. One hundred consecutive patients with symptomatic drug-resistant AF who underwent catheter ablation between September 2009 and February 2011 were enrolled. The endocardial bipolar electrogram voltage was measured point by point in the left atrium as panel data clustered by patient and compared with the result of genetic testing for MMP2 SNP. Results MMP2 SNP was present in at least 1 copy in 43% of patients, the minor allele frequency was 0.27, and genotype frequencies were in Hardy-Weinberg equilibrium (Χ2 = 2.34, P = .126). The overall mean atrial voltage for the 4878 measures in 87 patients was 0.89 ± 1.10 mV. MMP2 SNP was significantly associated with reduced bipolar voltage in codominant (–0.11 mV per T copy, P = .003) and dominant (–0.18 mV if CT or TT, P Conclusions We report a strong association between a common MMP2 promoter polymorphism and atrial scar fibrosis. Impaired tissue remodeling may mediate the previously reported association between the –1306C/T MMP2 polymorphism and AF.

Current Hot Potatoes in Atrial Fibrillation Ablation

Atrial fibrillation (AF) ablation has evolved to the treatment of choice for patients with drug-resistant and symptomatic AF. Pulmonary vein isolation at the ostial or antral level usually is sufficient for treatment of true paroxysmal AF. For persistent AF ablation, drivers and perpetuators outside of the pulmonary veins are responsible for AF maintenance and have to be targeted to achieve satisfying arrhythmia-free success rate. Both complex fractionated atrial electrogram (CFAE) ablation and linear ablation are added to pulmonary vein isolation for persistent AF ablation. Nevertheless, ablation failure and necessity of repeat ablations are still frequent, especially after persistent AF ablation. Pulmonary vein reconduction is the main reason for arrhythmia recurrence after paroxysmal and to a lesser extent after persistent AF ablation. Failure of persistent AF ablation mostly is a consequence of inadequate trigger ablation, substrate modification or incompletely ablated or reconducting linear lesions. In this review we will discuss these points responsible for AF recurrence after ablation and review current possibilities on how to overcome these limitations.

Atrial Fibrillation and the Role of LAA in Pathophysiology and Clinical Outcomes?

Left atrial appendage (LAA) is a source of thromboembolism especially in patients with non valvular atrial fibrillation (AF). It is reasonable to accept LAA as a distinct part of left atrium (LA) with unique anatomical and physiological properties. Advances in imaging modalities increased the knowledge about anatomical and physiological characteristics of LAA. It is important to prevent the AF patients from systemic thromboembolic events, and new pharmacological and non pharmacological management approaches demonstrate encouraging results. Also pulmonary vein isolation which has been accepted as a curative and useful treatment option for the treatment of drug resistant AF has been helpful in understanding the electrophysiological properties of LAA. Accumulating data revealed that LAA continues to be the one of the most important structure of heart during AF because of its distinctive anatomical, mechanical, and electrophysiological properties.

Radiofrequency hot balloon catheter ablation for the treatment of atrial fibrillation: A 3-center study in Japan

BackgroundThe safety and efficacy of radiofrequency hot balloon catheter (Toray-Satake balloon [TSB]) ablation for the treatment of atrial fibrillation (AF) was evaluated in a 3-center pilot study. MethodsThirty patients (24 men; age, 61±8 years) with drug-resistant AF (paroxysmal, n=24; persistent, n=6) were evaluated in this study. The pulmonary veins (PVs) and PV antrum were isolated using the TSB under general anesthesia (n=12) or deep sedation (n=18). ResultsComplete PV isolation was achieved in 110 (92%) of 120 PVs, and decreased PV potentials were observed in the right superior PV in 4 patients (13%), left superior PV in 4 patients (13%), and left inferior PV in 2 patients (7%). The mean total procedure time was 104±27min. The mean total fluoroscopic and total application times were 32±14min and 12±2min, respectively. After a single session, 22 (73%) and 20 (67%) of the 30 patients were free from AF after 6 and 11.4±2.2 months of follow-up, respectively. There were no device-related severe complications such as stroke, esophageal fistula, symptomatic PV stenosis, phrenic nerve palsy, or pyloric spasm. ConclusionTSB catheter ablation might be a promising approach for the treatment of drug-resistant AF.

Presence of left atrial anomalies and normal variant pulmonary venous anatomy is unrelated to adverse outcome following radiofrequency catheter ablation therapy in patients with drug resistant atrial fibrillation

Purpose: The prevalence of left atrial (LA) anomalies and normal variant pulmonary venous anatomy (NVPVA) was suspected to be increased in patients with atrial fibrillation (AF). The objectives were 1. To determine the frequency of these entities in patients with drug resistant AF and 2. To assess if their presence correlates with adverse outcome following radiofrequency catheter ablation (RFCA).

Interim Results of the 5-Box Thoracoscopic Maze Procedure

In accordance with the Cox-Maze paradigm, successful treatment of atrial fibrillation (AF) requires (1) complete posterior left atrial isolation, (2) elimination of corridors for perimitral reentry, (3) elimination of cardiac venous (superior vena cava and coronary sinus) arrhythmogenic foci, (4) complete autonomic denervation, and (5) occlusion or removal of the left atrial appendage. Using a totally thoracoscopic approach, isolation of all left atrial arrhythmogenic substrate is achieved through the creation of 5 discrete but contiguous compartments, thereby enabling unambiguous verification with bidirectional block. Since no previous closed-chest procedure incorporates all these end points, an update on patient outcomes is reported. One hundred seventy-nine consecutive patients with antiarrhythmic drug-resistant AF (3 paroxysmal, 5 persistent, 171 longstanding persistent cases), known preoperatively for 5.7 (range 0.5 to 25) years, underwent the 5-box thoracoscopic Maze procedure. Only 1 patient suffered a serious procedural complication (sternotomy for pulmonary artery injury). Postoperative rhythm surveillance consisted of 1 week of continuous ambulatory monitoring at 3, 6, 13, and 24 months. Failure was defined as any tachyarrhythmia exceeding 30 seconds beyond the 3-month anniversary. Freedom from AF was observed in 137 of 142 patients at 3 months, 115 of 119 patients at 6 months, 75 of 78 patients at 13 months, and 24 of 25 patients at 24 months. Two patients remain in sinus rhythm on low-dose antiarrhythmia therapy. Warfarin is discontinued only after the first monitoring session confirms rhythm stability. Replication of the left atrial Cox-Maze lesion set through a totally thoracoscopic approach isolates virtually all arrhythmogenic substrate. Meticulous verification of compartment integrity allows for outcomes equivalent to the Cox-Maze benchmark.

Electrical Isolation of the Superior Vena Cava Using Upstream Phrenic Pacing to Avoid Phrenic Nerve Injury

Phrenic nerve (PN) injury is a potential complication that can occur during superior vena cava (SVC) isolation to cure atrial fibrillation (AF). Avoiding radiofrequency (RF) energy delivery is the safer alternative but may result in failed isolation. High-output PN pacing above the ablation site (upstream PN pacing) to confirm whether the PN is intact is a promising technique to avoid PN injury. This study was conducted to elucidate the safety of delivering RF energy at the site of capture of the right PN using upstream high-output pacing during electrical SVC isolation. SVC isolation was conducted in 41 drug-resistant AF patients. When high-output pacing (25 mA) from the distal tip of the ablation catheter captured the PN at the right atrial-SVC junction, upstream PN pacing (cycle length: 1000-1500 ms) was applied during RF delivery. The application of RF energy was stopped upon the failure or weakness of diaphragmatic twitching. The feasibility of SVC isolation using upstream PN pacing was investigated. In all 41 patients, SVC isolation was successfully achieved. RF energy was delivered at the PN capture site in 26 patients (154 ± 138 second, 18 ± 5 W), and upstream PN pacing was successfully applied in all of the patients. Out of 46 SVC isolations, including five repeated sessions, PN injury occurred in one patient, who recovered spontaneously within 2 weeks. Upstream PN pacing may be effective for the safe completion of SVC isolation and to reduce the severity of PN injury.

The intrinsic autonomic nervous system in atrial fibrillation: a review.

The procedure of catheter ablation for the treatment of drug resistant atrial fibrillation (AF) has evolved but still relies on lesion sets intended to isolate areas of focal firing, mainly the myocardial sleeves of the pulmonary veins (PVs), from the rest of the atria. However the success rates for this procedure have varied inversely with the type of AF. At best success rates have been 20 to 30% below that of other catheter ablation procedures for Wolff-Parkinson-White syndrome, atrioventricular junctional re-entrant tachycardia and atrial flutter. Basic and clinical evidence has emerged suggesting a critical role of the ganglionated plexi (GP) at the PV-atrial junctions in the initiation and maintenance of the focal form of AF. At present the highest success rates have been obtained with the combination of PV isolation and GP ablation both as catheter ablation or minimally invasive surgical procedures. Various lines of evidence from earlier and more recent reports provide that both neurally based and myocardially based forms of AF can separately dominate or coexist within the context of atrial remodeling. Future studies are focusing on non-pharmacological, non-ablative approaches for the prevention and treatment of AF in order to avoid the substantive complications of both these regimens.