Left Atrial Radiofrequency Ablation Research Articles

A modified method of left atrial radiofrequency ablation for atrial fibrillation in a patient undergoing mitral valve replacement under warm blood cardioplegia

A modified method of left atrial radiofrequency ablation for atrial fibrillation in a patient undergoing mitral valve replacement under warm blood cardioplegia

Improved 1-year outcomes after active cooling during left atrial radiofrequency ablation

BackgroundActive esophageal cooling during pulmonary vein isolation (PVI) with radiofrequency (RF) ablation for the treatment of atrial fibrillation (AF) is increasingly being utilized to reduce esophageal injury and atrioesophageal fistula formation. Randomized controlled data also show trends towards increased freedom from AF when using active cooling. This study aimed to compare 1-year arrhythmia recurrence rates between patients treated with luminal esophageal temperature (LET) monitoring versus active esophageal cooling during left atrial ablation.MethodData from two healthcare systems (including 3 hospitals and 4 electrophysiologists) were reviewed for patient rhythm status at 1-year follow-up after receiving PVI for the treatment of AF. Results were compared between patients receiving active esophageal cooling (ensoETM, Attune Medical, Chicago, IL) and those treated with traditional LET monitoring using Kaplan–Meier estimates.ResultsA total of 513 patients were reviewed; 253 received LET monitoring using either single or multi-sensor temperature probes; and 260 received active cooling. The mean age was 66.8 (SD ± 10) years, and 36.8% were female. Arrhythmias were 60.1% paroxysmal AF, 34.3% persistent AF, and 5.6% long-standing persistent AF, with no significant difference between groups. At 1-year follow-up, KM estimates for freedom from AF were 58.2% for LET-monitored patients and 72.2% for actively cooled patients, for an absolute increase in freedom from AF of 14% with active esophageal cooling (p = .03). Adjustment for the confounders of patient age, gender, type of AF, and operator with an inverse probability of treatment weighted Cox proportional hazards model yielded a hazard ratio of 0.6 for the effect of cooling on AF recurrence (p = 0.045).ConclusionsIn this first study to date of the association between esophageal protection strategy and long-term efficacy of left atrial RF ablation, a clinically and statistically significant improvement in freedom from atrial arrhythmia at 1 year was found in patients treated with active esophageal cooling when compared to patients who received LET monitoring. More rigorous prospective studies or randomized studies are required to validate the findings of the current study.

Abstract 11738: Epicardial Connections as an Etiology in Recalcitrant Tachyarrhythmias After Left Atrial Ablations in Patients With Persistent Atrial Fibrillation

Introduction: Left atrial radio frequency ablation(RFA) for persistent atrial fibrillation(AF) and left atrial tachycardias(LAT) are often challenging due to the presence of epicardial connections(EC). Hypothesis: Mapping and subsequent ablation of epicardial connections using high density(HD) mapping and activation patterns leads to successful termination of persistent AF and LAT. Methods: We studied 40 patients who were found to have epicardial connections as determined by HD mapping, missing isochrones and activation patterns. All patients underwent antral ablation for pulmonary vein isolation (PVI). LAT were remapped using Advisor HD Grid catheter. Results: At baseline, the mean age and BMI was 74±6.4 and 33.5±5.8 respectively. Out of 40 patients with EC, 21 were associated with the Vein of Marshall (Figure 1), 4 were associated with Septo-pulmonary bundles(figure 2), 6 were associated with the Bachman Bundle(Figure 3) and 9 were associated with Septo-atrial bundles. Acutely, endocardial ablation opposite to the epicardial connection sites achieved success with PVI, Posterior Wall Isolation(PWI) and termination of LAT. Conclusions: EC significantly contributes to the failure of PVI, PWI and the reorganization of LAT. Rigorous mapping of the connecting bundles using HD mapping helps target the ablation sites for successful outcomes.

Abstract 11726: Atrial Arrythmia Recurrence in Patients After Left Atrial Ablation is Associated With Epicardial Connections and Directly Correlated to Reduced Left Ventricular Ejection Fraction

Introduction: Heart Failure with Reduced Ejection Fraction has a positive association with atrial arrhythmia incidence and recurrence. However, this has not been studied in atrial fibrillation (AF) and atrial tachycardia (AT) patients who underwent left atrial radiofrequency ablation(RFA) and were subsequently found to have epicardial connections(EC). Hypothesis: Heart Failure with Reduced Ejection Fraction was associated with an increased recurrence of atrial tachyarrythmias in patients with epicardial connections. Methods: We studied 40 consecutive patients with persistent atrial arrhythmias who underwent RFA for AF and AT at our center. Epicardial connections were determined by high density mapping, missing isochrones and activation patterns. Clinical, echocardiographic and activation mapping pattern characteristics were collected. Results: Forty patients were found to have EC (Table 1). The association of EC and echocardiographic parameters were assessed. Reduced Left Ventricular Ejection Fraction was associated with an increased recurrence of atrial tachyarrhythmias in patients due to epicardial connections((HR:1.25(1.05-1.48)) (Table 2). Conclusions: Reduced Left Ventricular Ejection Fraction is positively correlated with atrial tachyarrythmia recurrence in patients due to epicardial connections.

Pericarditis following left atrial ablation.

We aimed to evaluate the incidence of acute pericarditis following cardioneuroablation (CNA) and to compare this with patients undergoing left atrial (LA) radiofrequency ablation for atrial fibrillation (AF). This is a single-center prospective study. During the study period, CNA for vasovagal syncope was performed in 42 patients, pulmonary vein isolation (PVI) for paroxysmal AF in 46 patients, and posterior wall isolation (PWI) in addition to PVI for persistent AF in 22 patients. Pericarditis was reported by 18 (16.4%) patients overall: 1 (2.4%) patient in CNA group, 8 (17.4%) patients in PVI group, and 9 (40.9%) patients in PWI (p < .001). On univariable logistic regression analysis, CNA was associated with a lower risk of pericarditis (odds ratio 0.11, 95% confidence interval [CI] 0.01-0.97), while ablation of PWI plus PVI was associated with a higher risk of pericarditis compared with PVI (odds ratio 3.29, 95% CI 1.05-10.3). This study shows that pericarditis is extremely uncommon following CNA and is significantly less frequent than following AF ablation. This difference is likely related to the much lower amount of LA ablation necessary in this group.

Proactive Esophageal Cooling Protects Against Thermal Insults During High-Power Short-Duration Radiofrequency Ablation

Background: Atrioesophageal fistula (AEF) is a severe complication of left atrial radiofrequency (RF) ablation for the treatment of atrial fibrillation. Proactive cooling with a novel cooling device has been shown to significantly reduce thermal injury, with no AEFs yet encountered after thousands of treatments worldwide. Computer modeling suggested that lethal temperatures could be avoided with moderate-power and moderate-duration RF ablation. We aimed to evaluate the effects of proactive cooling during high-power short-duration (HPSD) ablation, and compare the computed results to clinical data and recently published experimental data. Methods: A computer model accounting for the left atrium and esophagus including the active cooling device was created. We used both the Arrhenius equation and 50oC isotherm to estimate the esophageal thermal damage during 50 W, 10 second and 90 W, 4 second RF ablations. Results: Under control conditions, temperatures across the esophageal wall exceeded the lethal isotherm, in agreement with recent experimental data. With proactive esophageal cooling in place, temperatures in the esophageal tissue were significantly reduced, with the resulting fraction of esophageal damage reduced by 74% under 50 W and 10 seconds of ablation, and by 82% under 90 W and 4 seconds of ablation. Esophageal damage was restricted to the epi-esophageal region, sparing the remainder of the esophageal tissue, including the mucosal surface. Conclusions: Proactive esophageal cooling significantly reduced temperatures and the resulting fraction of damage in the esophagus during HPSD ablation. These findings offer a mechanistic rationale explaining the absence of AEF encountered to date using proactive esophageal cooling.

Contact-force recovery predicts the absence of cardiac perforation during steam pops.

Cardiac perforation (CP) is an uncommon but clinically important complication of radiofrequency ablation (RFA). We previously showed that contact-force recovery after a steam pop predicts the absence of CP in an open-chest animal model after pericardial dissection. We attempted to determine whether this also applies when pericardium is present. In 5 open-chest sheep, left atrial RFA was performed under direct observation with a 7.5F ThermoCool SmartTouch force-sensing catheter (Biosense Webster Inc., Irvine, CA, USA). The catheter's contact force was measured every 50ms during RFA. After each steam pop, the presence (+) or absence (-) of CP was noted, as well as whether pericardium was present over the ablation site. Contact-force signals were analyzed to detect contact-force recovery. Perforation rates were compared between sites with or without pericardium. Ninety-six steam pops occurred: 77 with pericardium and 19 without. For the pericardial steam pops, contact-force recovery occurred in 31/60 CP- events (52%) and 1/17 CP+ events (6%; P = 0.0006). For nonpericardial steam pops, contact-force recovery occurred in 4/9 CP- events (44%) and 1/10 CP+ events (P = 0.14). The rate of CP was 22% with pericardium and 52% without (P = 0.02). Pericardial tissue charred extensively during steam pop induction, even in the absence of CP. Contact-force recovery predicts the absence of CP during RFA independently of whether the pericardium is present. The presence of the pericardium may decrease the likelihood of perforation, perhaps by acting as a thermal sink. Additional studies are needed to correlate these results with clinical experience.

231Local impedance-guided ablation and ultra-high density mapping provide improved ablation metrics vs conventional or contact force-guided ablation for cavotricuspid isthmus dependent atrial flutter

Abstract INTRODUCTION. Radiofrequency ablation (RFA) of cavotricuspid isthmus dependent atrial flutter (CTI-AFL) can be performed with fluoroscopy (Fluo) or 3-dimensional (3D) electroanatomic mapping and contact force (CF) catheters. Local impedance (LI) is an alternative but no comparisons have yet been made. METHODS. An observational study comparing Fluo, CF- and LI-guided RFA for CTI-AFL. In the LI group, if CTI block was not obtained after initial ablation, ultra-high density mapping (UHDm) was used to identify breakthrough sites. Contact was determined using patient specific LI; RF delivered until 20 ohm LI drop seen, or LI drop plateaued &amp;gt;2 secs. In the CF group 10-40g force was used. Power was limited to 40-50W in all groups. Total RFA time, time from RFA start to CTI block, no. of lesions required to achieve block, acute success, complications and re-ablation during follow-up were analysed using ANOVA. RESULTS. Data presented for 24 patients (7 Fluo, 7 CF, 10 LI). Mean RFA time: 6.6, 5.9, 3.2 min respectively (p = 0.0478). Statistically significant differences also seen with LI vs Fluo (p = 0.0451) and LI vs CF (p = 0.0313). Time from first RFA to block: 25.5, 19.8, 14.2 min (p = 0.5688); number of lesions to achieve block: 8.5, 10.3, 8 (p = 0.3909). 100% success and no complications in all groups. 0% need for re-ablation (16.3 ± 7, 12.6 ± 8, 6.5 ± 4.4 months follow-up). DISCUSSION. This data illustrates that UHDm and LI-guidance significantly reduces the amount of CTI RFA, by 52% and 47% vs Fluo and CF respectively (p = sig, fig. 1). A reduction from first RFA to block is also seen (43% and 37%; p = ns, fig. 2). Given no difference in the no. of lesions, LI-guided RFA during lesion formation shortens the duration of each lesion. Many patients require further RFA (+/- mapping) if they do not achieve block following the initial ablation line, resulting in longer procedures. Several patients without block in the LI group underwent repeat UHDm, which quickly identified CTI or epicardial-endocardial breakthrough (fig. 3 &amp; 4), allowing rapid targeting for re-ablation. In the fluo group, these procedures would often be significantly prolonged, meaning extensive RFA and radiation exposure. Fig. 1 shows smaller error bars with LI compared to the others, resulting in more predictable total ablation times; this could potentially benefit procedure scheduling (more procedures per unit time). We could not directly compare overall procedure time as many in the CF group had CTI RFA combined with left atrial RFA. Multiple LI cases were performed fluo-free with only magnetic tracking. This may allow case scheduling without a radiographer, with potential cost savings. CONCLUSION. LI-guided CTI-AFL RFA is safe and effective and has shown favourable ablation metrics compared to Fluo or CF-RFA. LI-RFA with UHDm more quickly and accurately identifies breakthrough and with fluoro-free technique could possibly reduce procedure time and cost. A larger study is planned to provide more insight. Abstract Figures

P1037Relationship between left atrium low voltage areas and atrial fibrillation radiofrequency ablation success-rate: preliminary results of the SMOP study

Abstract Background radio frequency catheter ablation (CA) is an effective therapy for atrial fibrillation (AF). Some authors have described a potential relationship between the presence of areas of fibrosis in the left atrium (LA) and the success of CA, nevertheless there is a lack of multicenter studies in this field. Objective the aim of our study was to assess the relationship between the of presence of low voltage areas of the LA detected during subtrate mapping at the time of the procedure and recurrences of AF after CA. Methods we analyzed 214 patients of the SMOP-AF (Substrate Mapping as Outcome Predictor in Atrial Fibrillation Ablation), a prospective multi-centric study enrolling patients with both paroxysmal and persistent AF undergoing a first radio-frequency CA procedure. High-density mapping was performed in sinus rhythm using the CARTO system before performing pulmonary vein isolation. Areas with less than 0,5 mV on mapping were defined as low voltage zone (LVZ), while between 0,5 mV and 1,5 mV intermediate voltage zone (IVZ). IVZ and LVZ were expressed as a percentage of the LA surface. Comparisons were made by Pearson correlation, cross-tables and Chi-square test or Student T test. Results the mean age of the enrolled population was 59±9 years, left ventricular ejection fraction was 59±9%, 86.4% of the pts had tested at least one anti-arrhythmic drug. Persistent atrial fibrillation was present in 10.3% of patients. The rate of documented AF recurrence at 3 months was 15,3% (n=29). There was a statistical significant correlation between the presence of IVZ and the rate of recurrences at 3 months (r=0.16, p value 0.03). Patients with IVZ greater than 4% of the left atrium surface showed a higher risk of recurrences (19.5% vs. 8,7%, p value 0.04). No statistical difference was observed in other procedural variables (number of lesions, contact force, force-time integral) among patients with or without recurrences. Conclusion Our study showed a relationship between CA short-term success rate and the presence of areas of intermediate voltage zone detected with high-density substrate mapping at the time of the procedure. The presence of areas of intermediate voltage zone greater than 4% of the LA determines a 2.5 folds increased risk of short-term recurrence. Our data needs to be confirmed in a longer follow-up.

Сравнение эффективности хирургического лечения персистирующей фибрилляции предсердий с помощью биатриальной и левопредсердной радиочастотной аблации у пациентов при протезировании митрального клапана

Сравнение эффективности хирургического лечения персистирующей фибрилляции предсердий с помощью биатриальной и левопредсердной радиочастотной аблации у пациентов при протезировании митрального клапана

Safety of Uninterrupted Periprocedural Edoxaban Versus Phenprocoumon for Patients Who Underwent Left Atrial Catheter Ablation Procedures

Data about the safety of edoxaban in patients who underwent left atrial (LA) radiofrequency (RF) ablation procedures are lacking. This study sought to compare the safety of uninterrupted edoxaban with uninterrupted phenprocoumon administration during LA RF ablation for atrial fibrillation and atrial tachycardia. In total, 231 patients (mean age 64 ± 11years, male 71%) who underwent LA RF ablation under continuous oral anticoagulation (OAC) with edoxaban or phenprocoumon were included in the study. Patients on uninterrupted edoxaban (60 mg or 30 mg/day for at least 4 weeks) were matched for gender, age and type of arrhythmia with 2 patients on uninterrupted phenprocoumon (international normalized ratio 2 to 3). We identified 77 consecutive patients on edoxaban and n = 154 patients on phenprocoumon. Heparin was administered periprocedurally to achieve an activated clotting time of 280 to 300 seconds. No protamine was administered periprocedurally. The primary end point was a composite of bleeding, thromboembolic events, and death. The primary end point was met in 9 patients in the edoxaban group and in 22 patients in the phenprocoumon group (p = 0.69). No patient in either group died or had a thromboembolic complication. No major bleeding complication was observed in the edoxaban group, whereas one was found in 1 patient in the phenprocoumon group (p ≥0.99). Minor bleeding complications occurred in 9 patients (12%) in the edoxaban group and in 21 patients (14%) in the phenprocoumon group (p = 0.84). Uninterrupted OAC with edoxaban appeared to be as safe as uninterrupted OAC with phenprocoumon in patients who underwent LA RF ablation procedures.

Severe Debilitating Esophageal Dysphagia: A Rare Complication of Cardiac Radiofrequency Ablation

Introduction: Left atrial radiofrequency ablation (LA-RFA) is a successful and relatively safe treatment for atrial fibrillation (AF). Major complications have been reported at a rate of 2-6%, but associated esophageal injury has been rarely reported. Clinical and endoscopic presentation is variable, and prompt management is critical to avoid poor outcomes. We present a unique case of severe esophageal dysphagia caused by LA-RFA. Case Report: A 67-year-old man presented with acute onset of dysphagia to solids 5 days following coronary artery bypass surgery (CABG) and LA-RFA for AF. He had associated chest discomfort, weight loss of 45 pounds in 5 months and impaired quality of life. He had no previous history of dysphagia or other gastrointestinal conditions. Initial barium swallow and upper endoscopy (EGD) showed inflammation and narrowing of the distal esophageal lumen. Pathology was non-diagnostic. Elsewhere, the patient had received empiric therapy with proton pump inhibitor and fluconazole for 3 weeks to treat candida esophagitis without improvement. Re-evaluation with EGD at our hospital showed severe esophageal stenosis measuring 14cm in length (6mm inner diameter), severe mucosal inflammation and white exudate. Pathology showed necroinflammatory material with granulation tissue. Fungal stain and viral testing were negative. Endoscopic dilation or stenting of this stricture were not attempted due to disease extent and risk of complications. Subsequently, he underwent chest imaging and thoracic surgery consultation followed by successful minimally invasive esophagectomy for ischemic necrosis of the esophagus. Discussion: While LA-RFA is generally safe, esophageal complications have extremely high morbidity and mortality depending on the depth of tissue injury. This unique case of a 14cm esophageal stricture was due to thermal injury from LA-RFA, leading to debilitating dysphagia and malnutrition. The esophagus is vulnerable to thermal injury due to its anatomical location. Understanding the variable clinical presentations and endoscopic findings, in addition to the nature of deep tissue injury is crucial in the management of such cases. Serial chest imaging and early referral to cardiothoracic surgery prevent progression into devastating consequences, like atrio-esophageal fistula (up to 93%). This patient's challenging clinical course exemplifies the need for a high index of suspicion and increased awareness of this elusive diagnosis.Figure 1

Effects of atrial fibrillation radiofrequency ablation on operativerisk of coronary artery bypass grafting

Objective To investigate the effect of concominant atrial fibrillation rediofrequency ablation(RFA) on operative risk of coronary artery bypass grafting(CABG). Methods From January 2006 to July 2015, 15 cases patients with CABG and RFA and 1 442 patients with CABG in the Cardiac Surgery Department of Anzhen Hospital of Beijing Affiliated to Capital Medical University were selected.These patients were matched with propensity score matching methods by 1 to 3, 15 cases patients in CABG+ RFA group, and 45 cases patients in CABG group.All procedures were performed under general anesthsia and off-pump cardiopulmonary bypass.Patients in CABG+ RFA group underwent concomitant left atrial radiofrequency ablation during CABG, while in CABG group only underwent coronary artery bypass grafting. Results There were no significant difference in perioperative mortality(0 vs. 4.4(2/45), P=1.00), stroke(0 vs. 0, P=1.00), reoperation for bleeding(6.7%(1/15) vs. 4.4%(2/15), P=1.00), renal failure(0 vs. 0, P=1.00), intra-aortic balloon pump(0 vs. 0, P=1.00), mechanical ventilation time(13.0(6, 42) h vs. 11.8(7, 35) h, P=0.64), intensive care unit time(17.5(10, 47) h vs. 15.0(9, 37) h, P=0.70), hospital stay after operation(7.5(6, 23) d vs. 9.0(6, 30) d, P=0.55), implantation of permanent pacemaker(0 vs. 0, P=1.00) and readmission 30 days after operation(0 vs. 0, P=1.00) between the two groups. Conclusion Radiofrequency catheter ablation of atrial fibrillation in patients undergoing coronary artery bypass grafting does not increase the risk of perioperative death and other adverse events, and have good safety. Key words: Atrial fibrillation; Radiofrequency; Coronary artery bypass grafting

The Mid-Term Results of Patients who Underwent Radiofrequency Atrial Fibrillation Ablation Together with Mitral Valve Surgery.

ObjetiveSaline-irrigated radiofrequency ablation, which has been widely used for surgical treatment of atrial fibrillation in recent years, is 80-90% successful in achieving sinus rhythm. In our study, our surgical experience and mid-term results in patients who underwent mitral valve surgery and left atrial radiofrequency ablation were analyzed.MethodsForty patients (15 males, 25 females; mean age 52.05±9.9 years; range 32-74) underwent surgery for atrial fibrillation associated with mitral valvular disease. All patients manifested atrial fibrillation, which started at least six months before the surgical intervention. The majority of patients (36 patients, 90%) were in NYHA class III; 34 (85%) patients had rheumatic heart disease. In addition to mitral valve surgery and radiofrequency ablation, coronary artery bypass, DeVega tricuspid annuloplasty, left ventricular aneurysm repair, and left atrial thrombus excision were performed. Following discharge from the hospital, patients' follow-up was performed as outpatient clinic examinations and the average follow-up period of patients was 18±3 months.ResultsWhile the incidence of sinus rhythm was 85.3% on the first postoperative day, it was 80% during discharge and 71% in the 1st year follow-up examination.ConclusionRadiofrequency ablation is an effective method when it is performed by appropriate surgical technique. Its rate for returning to sinus rhythm is as high as the rate of conventional surgical procedure.

Abstract 19004: Contact Force Recovery Predicts Absence of Cardiac Perforation During Steam Pop Formation

Introduction: Cardiac perforations (CP) are an uncommon complication of radiofrequency ablation (RFA) that has profound clinical importance. We previously published results showing that the presence of contact force recovery after a steam pop occurs can be used to predict the absence of perforation in the absence of pericardium. Now, we aimed to determine if this relationship exists with the pericardium present, validate our results from the previous study, and determine the effects pericardium has on RFA. Methods: A 7.5F Thermocool Smarttouch force-sensing catheter (Biosense Webster Inc., Diamond Bar, CA) was used to perform left atrial RFA under direct observation in five open-chest sheep. The catheter’s contact force was measured every 50 ms during RFA. After each steam pop, the presence (+) or absence (-) of CP was noted as well as if pericardium was present or not over the ablation site. The contact force signals were then analyzed to determine if contact force recovery was present. In addition, the rate of perforation in the presence or absence of pericardium was also compared. Results: A total of 86 steam pops occurred (Table 1); 62 with pericardium and 24 without pericardium. For the pericardial data, contact force recovery was seen in 16 of the 49 CP- cases (33%) and 0 of the 13 CP+ cases (0%), p = 0.03. For the nonpericardial data, contact force recovery was seen in 6 of the 14 CP- cases (43%) and 0 of the 10 CP+ cases (0%), p = 0.02. The rate of cardiac perforation was 21% with pericardium and 42% without, p = 0.05. Pericardial tissue showed extensive charring during steam pops, even in the absence of CP. Conclusions: Contact-force recovery predicts the absence of CP during RFA independent of the presence or absence of the pericardium, confirming prior work. Our results suggest the pericardium decreases the likelihood of perforation, perhaps by acting as a thermal sink. Further studies are needed to correlate these results with clinical experiences.

Comparison of biatrial and left atrial radiofrequency ablation in patients with heart valves diseases

We analysed results of left atrial and biatrial anatomic scheme of radiofrequency (RF) ablation of the atria in patients with valvular heart. From 2007 to 2011, RF ablation procedure performed 283 patients with atrial fibrillation and heart valve disease. Patients were divided into two groups - group I performed a complete circuit biatrial procedure (procedure maze IV) - 131 patients, in group II only ablation of the left atrium -152 patients. Most of the patients had long-term persistent AF. The main problem of early postoperative period is dysfunction of pacemaker complex, which observed in 64.9% and 50.7% patients for group I and II, respectively (p = 0.031). Permanent dysfunction of pacemaker complex required implantation of permanent pacemaker (9.2% and 4.6% of cases for group I and II, respectively, p = 0,023). Predictors of dysfunction of the pacemaker complex were biatrial execution method and duration of AF. Freedom from AF and AT during 36 months after surgery was 80.4% for patients in group I and 78.5% for patients in group II, with no statistically significant difference (log-rank test, p = 0.621). Atrial transport function has not revealed that the active fraction of the right atrium was 29.8% higher than in group II in the early postoperative phase and by 17.9% in the long term, with no difference between groups for the left atrium has been received.

Cardiac Troponin Assessment Following Atrial Fibrillation Ablation: Implications for Chest Pain Evaluation

Background: The range of elevation of troponin I (tI) that is within expected limits from left atrial radiofrequency ablation for atrial fibrillation (AF) is not well described, though such information may be of clinical value.

Comparison of Safety of Left Atrial Catheter Ablation Procedures for Atrial Arrhythmias Under Continuous Anticoagulation With Apixaban Versus Phenprocoumon

Apixaban is increasingly used for stroke prevention in patients with atrial fibrillation. Data about the safety of left atrial radiofrequency ablation procedures under continuous apixaban therapy are lacking. We performed a matched-cohort study of patients undergoing left atrium ablation procedures for atrial fibrillation or left atrial flutter. For each patient on apixaban, 2 patients on phenprocoumon were matched by age, gender, and type of arrhythmia. The primary safety end point was a composite of bleeding, thromboembolic events, and death. We identified 105 consecutive patients (35 women; mean age 63years) on apixaban and matched 210 phenprocoumon patients (70 women, mean age 64years). The primary end point was met in 11 patients of the apixaban group and 26 patients of the phenprocoumon group (10.5% vs 12.3%, p= 0.71). Major bleeding complications occurred in 1 patient of the apixaban group and 1 patient of the phenprocoumon group (1% vs 0.5%, p >0.99). Minor bleeding complications were observed in 10 patients of the apixaban group and 25 patients of the phenprocoumon group (9.5% vs 11.9%, p= 0.61). No patient in either group experienced a thromboembolic event and no patient died. In patients on apixaban, no clinical variable was predictive for bleeding complications. Left atrial ablation procedures under continuous oral anticoagulation with apixaban are feasible and as safe as under continuous oral anticoagulation with phenprocoumon.

Contact-force recovery can predict cardiac perforation during radiofrequency ablation.

During radiofrequency ablation (RFA), the ability to know whether a steam pop has led to cardiac perforation (CP) would be of profound clinical significance. We aimed to determine whether catheter contact-force characteristics can predict whether a steam pop during RFA causes CP. We used a 7.5F Thermocool® Smarttouch™ force-sensing catheter (Biosense Webster Inc., Diamond Bar, CA, USA) to perform open-chest left atrial RFA under direct visualization in four sheep. We measured the contact force and its direction every 50 ms during RFA. At each steam pop, we noted whether CP occurred. We then analyzed the contact-force signals to determine whether specific features predicted the presence (+) or absence (-) of CP. A total of 24 steam pops occurred; 10 were CP+ and 14 were CP-. At the time of CP+ and CP- events, the contact force was 50 ± 25 and 40 ± 15 g, respectively (P = 0.146). All steam-pop events were associated with a rapid drop-off in contact force, but 10 of the 14 CP- events showed an immediate contact-force rebound, whereas none of the CP+ events did. This rebound presumably occurred as the catheter tip resumed contact with the left atrial wall. The average contact-force rebound equaled 80-100% of the contact-force drop-off. The ability to measure catheter contact force during RFA is a valuable asset, as contact-force recovery may be used to predict CP. Further studies are warranted to validate our findings in the clinical setting.

OP-023 Left Atrial Radiofrequency Ablation During Mitral Valve Surgery Improve Functional Capacity and the Clinical Outcome

Aims of this study were to report sinus rhythm restoration and to determinate functional capacity and clinical outcome at follow-up after concomitant left atrial radiofrequency ablation (RFA) during mitral valve surgery. Between December 2008 and December 2011, 83 patients with AF underwent mitral valve surgery at our institution. Forty-five (54%) patients (Group A) received concomitant left atrium RFA and 38 (46%) patients did not (Group NA). All patients were evaluated 18±8,6 months after surgery. In each group clinical evaluation, cardiopulmonary exercise testing, two-dimensional echocardiography, 24 ECG Holter monitoring, and BNP level were compared during follow-up. Group A showed a significant improvement in SR rates at 6 and 18 months compared to group NA (29/45 versus 6/38 and 36/45 versus 5/38; p<0,01 respectively). Freedom from AF at follow-up and functional analysis are reported in the picture. Concomitant left atrium RFA during mitral valve surgery significantly increases SR restoration and patient exercise capacity at follow-up. Our findings suggest that the use oh left atrial RFA during mitral valve surgery is justified.