Percutaneous Catheter Ablation Research Articles

Successful percutaneous epicardial catheter ablation of ventricular tachycardia arising from the crux of the heart in a patient with prior coronary artery bypass grafting

A 63-year-old man with a history of remote inferior myocardial infarction and coronary artery bypass grafting (CABG) underwent catheter ablation of ventricular tachycardia (VT). Epicardial catheter ablation of the VT was successful at the crux of the heart despite limited mapping within the pericardial space due to pericardial adhesion. Percutaneous subxiphoidal pericardial approach is usually impossible in patients with a history of open heart surgery due to pericardial adhesions. This report suggested that epicardial VT arising from the crux of the heart could be successfully treated by catheter ablation via subxiphoidal pericardial approach despite pericardial adhesions complicated by prior CABG.

Outcomes of Catheter Ablation of Ventricular Tachycardia in the Setting of Structural Heart Disease.

Sustained ventricular tachycardias are common in the setting of structural heart disease, either due to prior myocardial infarction or a variety of non-ischemic etiologies, including idiopathic dilated cardiomyopathy, hypertrophic cardiomyopathy, and arrhythmogenic right ventricular cardiomyopathy. Over the past two decades, percutaneous catheter ablation has evolved dramatically and has become an effective tool for the control of ventricular arrhythmias. Single and multicenter observational studies as well as several prospective randomized trials have begun to investigate long-term outcomes after catheter ablation procedures. These studies encompass a wide range of mapping and ablation techniques, including conventional activation mapping/entrainment criteria, substrate modification guided by pacemapping, late potential and abnormal electrogram ablation, scar de-channeling, and core isolation. While large-scale, multicenter prospective randomized clinical trials are somewhat limited, the published data demonstrate favorable outcomes with respect to a reduction in overall ventricular tachycardia (VT) burden, reduction of implantable cardioverter defibrillator (ICD) shocks, and discontinuation of anti-arrhythmic medications across varying disease subtypes and convincingly support the use of catheter ablation as the standard of care for many patients with VT in the setting of structural heart disease.

Atrial flutter after surgical maze: incidence, diagnosis, and management.

The prevalence of atrial fibrillation is increasing and surgical ablation is becoming more common, both as a stand-alone procedure and when performed concomitantly with other cardiac surgery. Although surgical ablation is effective, with it unique challenges arise, including iatrogenic macroreentrant tachycardias that are often highly symptomatic and difficult to manage conservatively. Postsurgical ablation, localization of the arrhythmic circuit is difficult to determine using surface ECG alone because of alterations in the atrial myocardium, and multiple different pathways are often present. Most, however, localize to the left atrium, and percutaneous catheter ablation is emerging as an effective treatment modality. Patients with complex postoperative arrhythmias should be referred to a dedicated atrial fibrillation center when possible and symptomatic arrhythmias mapped and ablated. Knowledge of the previously performed surgical lesion set is of vital importance in understanding the mechanism of the arrhythmia and increasing procedural success rates. http://links.lww.com/HCO/A31.

Pharmacological Tests in Atrial Fibrillation Ablation.

The invasive management of atrial fibrillation (AF) has been considerably changed by the identification of major sites of AF initiation and/or maintenance within the pulmonary vein antra. Percutaneous catheter ablation of these targets has become the standard of care for sustained maintenance of sinus rhythm. Long-term failure of ablation is related to an inability to create a durable transmural lesion or to identify all of the non-pulmonary vein arrhythmia triggers. Pharmacological challenges during catheter ablation have been suggested to improve outcomes in both paroxysmal and persistent AF. Herein we review the mechanism and evidence for the use of pharmacological adjuncts during the catheter ablation of AF.

Role of alternative interventional procedures when endo- and epicardial catheter ablation attempts for ventricular arrhythmias fail.

Ventricular tachycardia (VT) refractory to antiarrhythmic drugs and standard percutaneous catheter ablation techniques portends a poor prognosis. We characterized the reasons for ablation failure and describe alternative interventional procedures in this high-risk group. Sixty-seven patients with VT refractory to 4±2 antiarrhythmic drugs and 2±1 previous endocardial/epicardial catheter ablation attempts underwent transcoronary ethanol ablation, surgical epicardial window (Epi-window), or surgical cryoablation (OR-Cryo; age, 62±11 years; VT storm in 52%). Failure of endo/epicardial ablation attempts was because of VT of intramural origin (35 patients), nonendocardial origin with prohibitive epicardial access because of pericardial adhesions (16), and anatomic barriers to ablation (8). In 8 patients, VT was of nonendocardial origin with a coexisting condition also requiring cardiac surgery. Transcoronary ethanol ablation alone was attempted in 37 patients, OR-Cryo alone in 21 patients, and a combination of transcoronary ethanol ablation and OR-Cryo (5 patients), or transcoronary ethanol ablation and Epi-window (4 patients), in the remainder. Overall, alternative interventional procedures abolished ≥1 inducible VT and terminated storm in 69% and 74% of patients, respectively, although 25% of patients had at least 1 complication. By 6 months post procedures, there was a significant reduction in defibrillator shocks (from a median of 8 per month to 1; P<0.001) and antiarrhythmic drug requirement although 55% of patients had at least 1 VT recurrence, and mortality was 17%. A collaborative strategy of alternative interventional procedures offers the possibility of achieving arrhythmia control in high-risk patients with VT that is otherwise uncontrollable with antiarrhythmic drugs and standard percutaneous catheter ablation techniques.

Gastroparesis as a Complication of Atrial Fibrillation Ablation

Percutaneous catheter ablation is a safe and effective treatment for symptomatic drug-resistant atrial fibrillation (AF). Gastroparesis is a little known complication of AF ablation. We aimed to evaluate the frequency of gastroparesis in the patients who underwent catheter ablation for AF by cryoballoon (CB) or radiofrequency (RF) and to define risk factors for gastroparesis. In all, 104 patients were treated with pulmonary vein (PV) isolation with 2 different technologies: CB in 58 patients (group 1) and open-irrigated tip RF catheter in 46 patients (group 2). Gastroparesis was seen in 7 cases (6 cases in group 1 and 1 case in group 2, respectively). The complaints related with gastroparesis began during the procedure in 4 of 6 patients of group 1. The other 3 patients admitted to our outpatient clinic with similar complaints within 72 to 96 hours after the procedure. For gastroparesis cases of group 1, mean minimal CB temperature on inferior PVs was lower and left atrium diameter was smaller. Management was conservative, and the patients have no residual symptoms at 6-month follow-up. The only patient still demonstrating residual symptoms during follow-up was in group 2. Although, clinically manifest gastroparesis is quite common with CB ablation, the process is generally reversible. However, damage may not be as reversible with RF ablation. In conclusion, during cryoablation, lower temperatures on inferior PVs and small left atrium size may be associated with increased risk of gastroparesis, and fluoroscopic guidance may be useful to avoid this complication.

Ventricular tachycardia ablation: a comprehensive review for anesthesiologists.

Percutaneous catheter ablation is being increasingly performed in patients with recurrent ventricular tachycardia (VT) unresponsive to medical treatment. Optimal management of patients requires careful consideration of the severity of the underlying cardiac disease, the anesthetic drug interactions, and the procedural technique during VT mapping and ablation. The goal is to choose an anesthetic technique that has the least effect on arrhythmogenicity, allowing reproducibility of the VT in the electrophysiology laboratory. Anesthetics can alter action potential and ventricular depolarization directly through their effects on ion channels and gap junctions, as well as indirectly via their effects on the autonomic nervous system. Furthermore, maintaining hemodynamic stability and monitoring for adequate end-organ perfusion are additional challenges. In this review, we provide a comprehensive update on the currently performed VT ablation procedures and their anesthetic considerations.

Acute Gastric Dysfunction After Catheter Ablation of Atrial Fibrillation

Gastroparesis is a chronic disorder characterized by slow gastric emptying in the absence of mechanical obstruction. Rarely, acute cases of gastroparesis can present as an extracardiac complication caused by vagus nerve injury following radiofrequency ablation for the treatment of refractory atrial fibrillation. This presentation is rare and may present a challenge for management since only a few cases have been described in the literature. We report a case of acute delayed gastric empting as a consequence of percutaneous catheter ablation of atrial fibrillation, which improved after symptomatic treatment with prokinetic agents. J Med Cases. 2015;6(4):143-145 doi: http://dx.doi.org/10.14740/jmc2050w

Selecting the Appropriate Ablation Strategy: the Role of Endocardial and/or Epicardial Access.

Percutaneous catheter ablation has emerged as an effective treatment modality for the management of ventricular tachycardia. Despite years of progress in this field, the role of epicardial mapping and ablation needs to be further refined. In this review, we discuss the relationship between the type of underlying heart disease and the location of the arrythmogenic substrate as it pertains to a procedural approach. We describe the contribution of preprocedural and intraprocedural diagnostic tools for the localisation of the arrhythmogenic substrate, with a special emphasis on cardiac MRI and electrophysiological mapping. In our opinion, the preferred approach to target ventricular tachycardia should depend on the patient's underlying heart disease and the location of scar tissue, which can be best visualised using cardiac MRI.

Reduction of radiation exposure in catheter ablation of atrial fibrillation: Lesson learned

Over the last decades, the concern for the radiation injury hazard to the patients and the professional staff has increased in the medical community. Since there is no magnitude of radiation exposure that is known to be completely safe, the use of ionizing radiation during medical diagnostic or interventional procedures should be as low as reasonably achievable (ALARA principle). Nevertheless, in cardiovascular medicine, radiation exposure for coronary percutaneous interventions or catheter ablation of cardiac arrhythmias may be high: for ablation of a complex arrhythmia, such as atrial fibrillation, the mean dose can be > 15 mSv and in some cases > 50 mSv. In interventional electrophysiology, although fluoroscopy has been widely used since the beginning to navigate catheters in the heart and the vessels and to monitor their position, the procedure is not based on fluoroscopic imaging. Therefore, non-fluoroscopic three-dimensional systems can be used to navigate electrophysiology catheters in the heart with no or minimal use of fluoroscopy. Although zero-fluoroscopy procedures are feasible in limited series, there may be difficulties in using no fluoroscopy on a routine basis. Currently, a significant reduction in radiation exposure towards near zero-fluoroscopy procedures seems a simpler task to achieve, especially in ablation of complex arrhythmias, such as atrial fibrillation. The data reported in the literature suggest the following three considerations. First, the use of the non-fluoroscopic systems is associated with a consistent reduction in radiation exposure in multiple centers: the more sophisticated and reliable this technology is, the higher the reduction in radiation exposure. Second, the use of these systems does not automatically lead to reduction of radiation exposure, but an optimized workflow should be developed and adopted for a safe non-fluoroscopic navigation of catheters. Third, at any level of expertise, there is a specific learning curve for the operators in the non-fluoroscopic manipulation of catheters; however, the learning curve is shorter for more experienced operators compared to less experienced operators.

Acute Gastric Dysfunction After Catheter Ablation of Atrial Fibrillation: Presidential Poster

Introduction: Gastroparesis is a chronic disorder characterized by slow gastric emptying in the absence of mechanical obstruction. Rarely, acute cases of gastroparesis can present as an extracardiac complication caused by vagus nerve injury following radiofrequency ablation for the treatment of refractory atrial fibrillation. Here, we report a case of acute delayed gastric empting as a consequence of percutaneous catheter ablation of atrial fibrillation. Case Report: A 47-year-old female underwent catheter ablation for drug refractory atrial fibrillation. No complications were detected during procedure and the patient was discharged after 24 hours. Seven days later, the patient was seen in the emergency department with symptoms of worsening fullness and abdominal distention. On admission, the patient denied any nausea, vomiting, and/or abdominal pain. Abdominal exam showed a non-tender but distended abdomen, bowel sounds were markedly decreased, and positive succussion splash during auscultation. The hematological profile, blood sugar, electrolytes, renal function, and LFTs were otherwise unremarkable. A CT of the abdomen showed severe distention of the gastric lumen containing heterogeneous congested material. However, there was not evidence of luminal obstruction, as contrast material was observed in the mid ileum. A scintigraphic 4-hour gastric emptying test (GET) was performed. Thirty-two percent of the meal was retained at the end of 4 hours (Normal <10% retention at the end of 4 hours). Diagnosis of gastroparesis was made, a nasogastric tube was inserted, and the patient was started on metoclopramide HCL 20 mg IV every 8 hours. On the following day, the patient became less symptomatic with a significant reduction in abdominal distention. On the third day, metoclopramide was switched to 10 mg PO before meals and she was able to tolerate a liquid diet. The patient made an excellent recovery and was discharged with a taper (4 weeks) course of metoclopramide. The patient did not complain of any gastrointestinal symptoms during the follow-up 2 weeks after hospital discharge. Discussion: Catheter ablation has improved the treatment paradigm of atrial fibrillation, but it may be associated with significant gastrointestinal complications. The onset of symptoms varies, and can occur immediately post-procedure and up to 4 days later. Management is no different to that of other causes of acute gastric emptying delay, and it usually entails a combination of strategies. As electrophysiologists continue to use this procedure in the management of atrial fibrillation, such cases will continue to arise. It is our intent to make gastroenterologists aware of this rare complication, to facilitate early initial diagnosis and management.

The prevalence and risk factors for atrioesophageal fistula after percutaneous radiofrequency catheter ablation for atrial fibrillation: the Canadian experience

Atrioesophageal fistula (AEF) is an infrequent complication of radiofrequency (RF) ablation for atrial fibrillation (AF). The aim of this study was to determine the prevalence and operator-dependent factors associated with AEF using a nationwide survey of electrophysiologists (EP). Thirty-eight EPs performing AF ablation between 2008 and 2012 were invited to complete a web-based questionnaire assessing the prevalence and factors associated with AEF. Responses were obtained from 25 EPs (68%) accounting for 7,016 AF ablations. Five cases of proven AEF (0.07%) were reported. Operators who reported AEF [AEF (+)] more often used general anesthesia (GA) [90% AEF (+) vs. 44% AEF (-), p = 0.046]. AEF (+) operators were also more likely to be users of the non-brushing technique in the posterior wall of the LA [5 (100%) AEF (+) vs. 5 (25%) AEF (-), p = 0.005]. The combined usage of GA and non-brushing technique during LA posterior wall ablation had a strong association with AEF (+) operators [4 (80%) AEF (+) vs. 2 (10%) AEF (-), p = 0.002]. There was a trend towards higher maximal RF energy setting in the posterior wall [47.4 + 7.6 AEF (+) vs. 40.2 + 8 AEF (-), p = 0.09]. Other procedure parameters were similar. The reported prevalence of AEF among Canadian AF ablators is 0.07%. AEF was associated with high mortality. The use of GA and non-brushing movements during posterior wall ablation were two factors associated with AEF.

Identification of left atrial fibrosis with a late-enhancement MR sequence (LE-MR): preliminary results

This study was done to identify left atrial fibrosis in a group of consecutive patients with atrial fibrillation (AF) candidate for percutaneous radiofrequency catheter ablation (RFCA) by using a late-enhancement magnetic resonance (LE-MR) sequence, and to validate the technique by comparison with electroanatomical mapping (EAM). We enrolled 37 patients (29 males; mean age, 61 years) candidate for percutaneous RFCA of AF, who were studied with LE-MR and EAM. To identify left AF we used a three-dimensional LE sequence with cardiac gating and respiratory navigator. The EAM study involved the acquisition of 200 points in the left atrium (LA). The LA was divided into seven segments (pulmonary vein antra, floor, anterior wall, posterior wall-roof). Two blinded radiologists assessed the presence of fibrosis (area of hyperintense signal), reaching a consensus in discordant cases. Inter-observer variability was also evaluated to estimate the reproducibility of the method. We analysed the anatomical agreement between the results obtained with LE-MR imaging and EAM. Five patients were excluded because of to poor image quality. As for the other 32 patients, inter-observer agreement was good [Cohen's kappa κ = 0.72 with 95 % confidence interval (CI) of 0.55, 0.89]. In the classification of LA segments affected by fibrosis, LE-MR had a sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of 66 % (95 % CI 53.7 %, 77.2 %); 87 % (95 % CI 80.9 %, 91.9 %); 69 % (95 % CI 56.5 %, 80.1 %); 85.5 % (95 % CI 79.1 %, 90.6 %) and 81 % (95 % CU 75.1 %, 85.7 %). Despite the small size of the sample studied, the LE-MR sequence proved more useful for excluding the presence of AF than for confirming its existence. Identification of AF prior to RFCA is paramount to select those patients who are truly amenable to the ablation procedure, which is expensive and not entirely free of risks.

Catheter ablation of atrial fibrillation: an update from the most important trials

The treatment of atrial fibrillation has greatly changed over the past decade. Following the pivotal observation by Haissaguerre et al. who showed the relevance of ectopic beats in the initiation of atrial fibrillation, percutaneous catheter ablation of atrial fibrillation has evolved as the most effective therapeutic option for the treatment of paroxysmal atrial fibrillation. The aim of this review is to analyze the role of catheter ablation in the management of atrial fibrillation on the basis of the most important trials published so far. A brief mention to complications and strategies for their early detection is also made.

Gastroparesis: an under-recognized complication after atrial fibrillation catheter ablation procedure

Purpose: Percutaneous catheter ablation (CA) is a well-established treatment for symptomatic atrial fibrillation (AF). Major complications occur in up to 6% of procedures, being mostly cardiovascular events. Among extracardiac complications, only a few cases of gastroparesis have been reported. We present two cases of gastroparesis after CA. Methods: Patients with AF undergoing CA with radiofrecuency (RF) or cryoablation therapy (CrT) were consecutively included. CrT was performed in those patients with normal anatomy of pulmonary veins (PV) and paroxysmal AF, and the rest of the patients underwent RF CA. Results: From May 2011 to December 2012 a total of 106 procedures were performed (80 RF and 26 CrT procedures). Mean age was 63,6years, 63% were male. AF was persistent in 48% of cases. The incidence of gastroparesis was 1.88% (2/106). Patients complained of shortness of breath, dysphagia, early satiety and epigastric discomfort within 72-96 hours after CA. RF standard CA was performed in both cases (a 3.5-mm irrigated catheter with up to 35 W in a temperature-controlled, power limited mode). CT scan excluded atrio-esophageal fistula and showed a marked gastric dilatation and remnants of food (figure). A gastric emptying study was diagnostic of gastroparesis. Management was conservative with pro-kinetic therapy, proton pump inhibitors and ceasing oral intake during the first 3 days. At 6 months follow-up patients have no residual symptoms. ![Figure][1] X-ray and CTscan images Conclusions: Gastroparesis is a poorly defined and often under-recognized extracardiac complication caused by vagus nerve injury after CA. Delayed presentation and subtle symptoms can mask this complication. A prompt diagnosis and treatment are necessary in order to avoid significant patient morbidity [1]: pending:yes

Catheter Ablation for Persistent Atrial Fibrillation in a Patient With Previous Repair of Total Anomalous Pulmonary Venous Connection

25-year-old male with a history of repaired total anomalous pulmonary venous (PV) connection and persistent atrial fibrillation (AF) refractory to antiarrhythmic medication was referred for percutaneous catheter ablation. At 10 weeks of age, he underwent surgical repair for total anomalous PV connection to the coronary sinus (cardiac variant) involving deroofing of the coronary sinus and closure of the atrial septal defect. At 19 years of age, he developed symptoms of breathlessness and palpitations and was found to be in persistent AF. He underwent a cardioversion and maintained sinus rhythm for 3 months before undergoing a second cardioversion for recurrent symptomatic persistent AF. He maintained sinus rhythm for 18 months on sotalol 120 mg BID before representing with increased breathlessness on exertion. Exercise echocardiography demonstrated an increase in pulmonary arterial pressures from 34 at rest to 60 mm Hg at peak exercise together with the initiation of AF. In view of this, he underwent a cardiac MRI, which demonstrated all 4 PVs draining into a dilated PV confluence (unroofed coronary sinus), which was connected to the left atrium by a small orifice measuring 13 by 15 mm. This was associated with restricted and turbulent flow between the 2 chambers, thought to be responsible for the significant dilatation of the PV confluence, and may have provided the substrate for the initiation and maintenance of AF. He remained in AF and was rate controlled with β-blockers. At 23 years of age, he underwent an operation to relieve the obstruction between the 2 chambers. Access to the right atrium was made through the original incision from the superior to the inferior vena cava and to the left atrium through the interatrial septum. The connection between the PV confluence and left atrium was confirmed to be 15 mm in both directions. The coronary sinus was cut back further to enlarge the opening between the 2 chambers. Although initial plans were for a MAZE procedure, the surgeon felt the anatomy was difficult and was complicated further by extensive adhesions and, therefore, this was not undertaken. After his operation, the patient was commenced on amiodarone, cardioverted, and maintained sinus rhythm for 1 year before developing symptomatic persistent AF when he was referred for catheter ablation. Under general anesthesia, a single transseptal puncture facilitated access to the left atrium but only limited access to the circumference of the PV confluence could be achieved because of difficulty in catheter manipulation. A circumfer ential mapping catheter confirmed the presence of rapid atrial activity within the venous confluence (Figure); however, electric isolation could not be achieved. Therefore, he was commenced on amiodarone, and a further procedure was planned after a preprocedural computed tomographic scan for integration with Carto 3 (CARTO-MERGE, Biosense Webster). The computed tomography image demonstrated all 4 PVs draining into the dilated venous confluence, which was connected to a

New Technologies and Hybrid Surgery for Atrial Fibrillation

The Cox maze III and Cox maze IV procedures are surgical solutions for the treatment of symptomatic stand-alone atrial fibrillation. Despite their proven efficacy, these procedures have not gained widespread acceptance because of the invasiveness, complexity, and technical difficulty. Endocardial pulmonary vein isolation is the cornerstone of percutaneous catheter ablation for atrial fibrillation. It is currently accepted as an invasive therapy, if rhythm control has failed using antiarrhythmic drugs or electrical cardioversions. Pulmonary vein isolation is reported to be effective in 60%–85% of patients with paroxysmal atrial fibrillation and in 30%–50% of patients with persistent atrial fibrillation. A second or third ablation is often necessary to achieve these results, and complications may occur in up to 6% of patients.Surgical treatment of atrial fibrillation has seen important improvements in the last decade. New technologies have simplified creation of transmural lesions on the beating heart through a less-invasive, thoracoscopic procedure. This allows for pulmonary vein isolation, isolation of the posterior wall, and left atrial appendage exclusion—usually combined with ganglionic plexi evaluation and destruction. Nonetheless, it is still uncertain whether these procedures are effective in restoring permanent sinus rhythm since transmurality of a lesion set cannot be guaranteed with current ablation catheters on the beating heart.In an attempt to limit the shortcomings of an endo- or an epicardial technique, a hybrid approach has recently been introduced. This approach is based on a close collaboration between the surgeon and the electrophysiologist, employing a patient-tailored procedure which is adapted to the origin of the patient’s atrial fibrillation and takes into consideration triggers and substrate. Using a mono- or bilateral energy source, a thoracoscopic epicardial approach is combined with a percutaneous endocardial ablation in a single-step or in a sequential-step procedure.This article provides our experience and an overview of the current knowledge in the hybrid treatment of stand-alone atrial fibrillation.

Catheter Ablation for Supraventricular Tachycardias: Contemporary Issues

The treatment of cardiac arrhythmias has evolved significantly over the last 30 years. Understanding of arrhythmia mechanisms has led to pharmacologic therapies, surgical interventions and the widely used percutaneous catheter ablation techniques. The focus of this review is centered on the current catheter ablation therapies available for supraventricular tachycardia. We will discuss current management strategies including challenges when considering catheter ablation therapy for management of supraventricular tachycardias: atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia utilizing an accessory pathway, atrial tachycardia and atrial flutter. Selected contemporary issues related to supraventricular tachycardia physiology, ablation approaches and ablation outcomes and complications will be discussed. Future goals for electrophysiologists are to continue to improve procedural safety and efficiency, while maintaining the impressive success rates that have been achieved.

Ten-year trends in the use of catheter ablation for treatment of atrial fibrillation vs. the use of coronary intervention for the treatment of ischaemic heart disease in Australia

Percutaneous coronary intervention (PCI) and catheter ablation are well-accepted therapeutic interventions for treatment of coronary artery disease and atrial fibrillation (AF), respectively. We sought to examine temporal trends in the provision of these services over the past decade in Australia. A retrospective review of the numbers of PCIs and AF ablations from 2000/01 to 2009/10 was performed on data from three sources: the Australian Institute of Health, Welfare and Aging (AIHW), Medicare Australia database (MA), and local records at a high volume tertiary referral centre (RMH) for AF ablation. Linear regression models were fitted comparing trends in population-adjusted procedural numbers over the 10-year period. There was a 5% per year population-adjusted increment in PCIs over 10 years from both the AIHW and MA sources, respectively (P < 0.001). This was similar to the growth rate of all cardiovascular procedures (AIHW: 5.1 vs. 3.8%/year, P = 0.27). Atrial fibrillation ablations showed a 30.9, 23.2, and 39.8% per year population-adjusted increment over 10 years from the AIHW, MA, and RMH sources respectively (P < 0.001 for all). Growth of AF ablations was significantly higher than PCIs (P < 0.001 for AIHW and MA sources) and all cardiovascular procedures (AIHW: 30.9 vs. 3.8%/year, P < 0.001). The provision of catheter-based AF ablation services in Australia has increased exponentially over the past decade. Its annual growth rate exceeded that of PCIs and all cardiovascular procedures. Given the increasing epidemic of AF, these data have critical implications for public health policy assessing the adequacy of infrastructure, training, and funding for AF ablation services.

40. Worldwide experience with the Arctic Front cardiac CryoAblation System for treatment of atrial fibrillation

Introduction: Pulmonary vein (PV) isolation by percutaneous catheter ablation is a cornerstone for treatment of atrial fibrillation (AF). The 2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation made a Class 1 recommendation for catheter ablation for symptomatic paroxysmal AF refractory or intolerant to at least one Class 1 or 3 antiarrhythmic medication. The Arctic Front Cardiac CryoAblation System, a minimally invasive device that enables intravascular deployment of a cryoballoon to the left atrium, creates circumferentially transmural lesions at the PV antrum, blocking ectopic conduction to the LA from PV triggers that initiate AF. The device has been used to treat over 37,000 cases worldwide. A recent randomized, controlled clinical trial, the Sustained Treatment of Paroxysmal Atrial Fibrillation study (STOP AF), evaluated safety and efficacy of cryoablation (CRYO) in comparison with anti-arrhythmic drug therapy (AAD) for drug- refractory recurrent, symptomatic paroxysmal atrial fibrillation. Acute procedural success was achieved in 98.2% (160/163) of patients randomized to cryoablation. At 12 months, 69.9% of CRYO patients demonstrated treatment success compared to 7.3% of AAD patients. The overall rate of serious adverse events in the trial was 12.3% for the CRYO arm in comparison to 14.6 for AAD ( p = 0.69). Methods: To further explore worldwide experience with the device and cryoablation procedure, a literature search was conducted for all data published from June 14, 2005 to November 16, 2012. Only articles that contained both safety and clinical outcomes results for Arctic Front or the next generation Arctic Front Advance System were included. Results: 44 studies reporting on rates of acute PVI and chronic efficacy (3–21 months) from 2722 patients in 15 countries were identified. With the addition of STOP AF ( n = 163 CRYO) and an FDA approved continued access protocol (CAP, n = 78), data from 2963 patients were analyzed. Fourteen of these studies, representing data from 13 countries, reported outcomes on 1293 patients at 12 months or longer. Twelve were nonrandomized, prospective observational studies and one was a randomized trial. In these studies, rates of acute PVI ranged from 100 to 67% while chronic efficacy for paroxysmal AF was 88–59%. The overall complication rate was low (6.1%) among all 44 studies, with 1 stroke, 2 TIA, 6 transient esophageal ulcerations, 3 delayed gastric emptying/gastroparesis and 7 pericardial effusions being the most serious adverse events in 2722 patients. As in the CAP, phrenic nerve palsy was the main complication reported in the literature, with an incidence of 4.66% compared to 11.2% in STOP AF and 3.7% in the CAP. Conclusions: Multiple studies, including data on over 1300 patients with at least one year followup duration, support the effectiveness and safety of the Arctic Front device and appear to be consistent with STOP AF results. Two ongoing, multi-center, nonrandomized postmarket studies sponsored by Medtronic continue to evaluate long term clinical outcomes of drug-refractory paroxysmal AF patients treated with the Arctic Front or the next generation Arctic Front Advance.