Patients Undergoing Radiofrequency Catheter Ablation Research Articles

Acute Cardiac MRI Assessment of Radiofrequency Ablation Lesions for Pediatric Ventricular Arrhythmia: Feasibility and Clinical Correlation.

Arrhythmia ablation with current techniques is not universally successful. Inadequate ablation lesion formation may be responsible for some arrhythmia recurrences. Periprocedural visualization of ablation lesions may identify inadequate lesions and gaps to guide further ablation and reduce risk of arrhythmia recurrence. This feasibility study assessed acute postprocedure ablation lesions by MRI, and correlated these findings with clinical outcomes. Ten pediatric patients who underwent ventricular tachycardia ablation were transferred immediately postablation to a 1.5T MRI scanner and late gadolinium enhancement (LGE) imaging was performed to characterize ablation lesions. Immediate and mid-term arrhythmia recurrences were assessed. Patient characteristics include median age 14 years (1-18 years), median weight 52 kg (11-81 kg), normal cardiac anatomy (n = 6), d-transposition of great arteries post arterial switch repair (n = 2), anomalous coronary artery origin post repair (n = 1), and cardiac rhabdomyoma (n = 1). All patients underwent radiofrequency catheter ablation of ventricular arrhythmia with acute procedural success. LGE was identified at the reported ablation site in 9/10 patients, all arrhythmia-free at median 7 months follow-up. LGE was not visible in 1 patient who had recurrence of frequent premature ventricular contractions within 2 hours, confirmed on Holter at 1 and 21 months post procedure. Ventricular ablation lesion visibility by MRI in the acute post procedure setting is feasible. Lesions identifiable with MRI may correlate with clinical outcomes. Acute MRI identification of gaps or inadequate lesions may provide the unique temporal opportunity for additional ablation therapy to decrease arrhythmia recurrence.

Electrocardiogram: his bundle potentials can be recorded noninvasively beat by beat on surface electrocardiogram

BackgroundThe micro waveform of His bundle potential can’t be recorded beat-to-beat on surface electrocardiogram yet. We have found that the micro-wavelets before QRS complex may be related to atrioventricular conduction system potentials. This study is to explore the possibility of His bundle potential can be noninvasively recorded on surface electrocardiogram.MethodsWe randomized 65 patients undergoing radiofrequency catheter ablation of paroxysmal superventricular tachycardia (exclude overt Wolff-Parkinson-White syndrome) to receive “conventional electrocardiogram” and “new electrocardiogram” before the procedure. His bundle electrogram was collected during the procedure. Comparative analysis of PAs (PA interval recorded on surface electrocardiogram), AHs (AH interval recorded on surface electrocardiogram) and HVs (HV interval recorded on surface electrocardiogram) interval recorded on surface “new electrocardiogram” and PA, AH, HV interval recorded on His bundle electrogram was investigated.ResultsThere was no difference (P > 0.05) between groups in HVs interval (49.63 ± 6.19 ms) and HV interval (49.35 ± 6.49 ms). Results of correlational analysis found that HVS interval was significantly positively associated with HV interval (r = 0.929; P < 0.01).ConclusionsHis bundle potentials can be noninvasively recorded on surface electrocardiogram. Noninvasive His bundle potential tracing might represent a new method for locating the site of atrioventricular block and identifying the origin of a wide QRS complex.

Interventional treatment in patients with myocarditis: Pro and Contra

Ventricular tachyarrhythmias (VTs) are often encountered in patients with inflammatory heart diseases. VT can become lifethreatening in patients with myocarditis, and the management may vary in different types of myocarditis. Purpose of the study is to describe VT characteristics in patients with verified myocarditis, and to evaluate the efficacy and safety of VT management, when tailored to the type of myocarditis. Study population comprised: 56 patients with morphologically verified myocarditis; 18 patients with primary cardiomyopathy (control group). All patients underwent full clinical evaluation, endomyocardial biopsy (including immunohistochemical analysis). Forty (54 %) patients underwent radiofrequency catheter ablation of VT. An implantable cardioverter-defibrillator (ICD) was inserted in 17 patients. There was no statistically significant difference between myocarditis and primary cardiomyopathy groups by demographic and echocardiographic data. In myocarditis group, nonsustained VT and/or frequent premature ventricular beats were seen in 59 % of patients; sustained VT in 12,5 % subjects, 1 patient had a history of ventricular fibrillation. VT ablation was associated with a significant decrease in VT recurrence (p=0,0009) during the follow-up period. Active myocarditis was associated with a higher VT recurrence rate (67 % in active vs. 19 % in borderline myocarditis). Among patients with ICD implantation, only one subject (with active myocarditis at admission) had life-threatening ventricular arrhythmia. In this selected group of patients with verified myocarditis and clinically significant VTs, catheter ablation seems at least partly effective. Patients with borderline myocarditis and symptomatic VTs may benefit from ablation. Therefore, morphological diagnostic of myocarditis can be a key point in choice of treatment.

Catheter ablation for ventricular tachycardia following surgical treatment of pulmonary stenosis with intact ventricular septum.

This study was aimed to report the characteristics and treatment of ventricular tachycardia (VT) following surgical treatment of pulmonary stenosis with intact ventricular septum. Five patients underwent radiofrequency catheter ablation for sustained monomorphic left bundle branch block (LBBB) type VT who previously underwent surgical treatment of pulmonary stenosis. Except stimulation, voltage and activation mapping was performed using three-dimensional (3D) electro-anatomic mapping and ablation was applied accordingly. Four VTs were induced during EP study. Two VTs were focal and the earliest activity was targeted in the right ventricular apex (RVA). The other two VTs were reentrant and the critical isthmus located in the mid-lateral wall and anterior wall of right ventricle, respectively. Ablation abolished all inducible VTs in four patients. In the patient whose VT was non-inducible, radiofrequency (RF) energy was delivered to the RVA where pacing mapping matched the clinical VT. One focal VT recurred 60 months after the initial RF ablation. Repeat mapping and ablation was performed and no VT recurred over a 24-month period. The mechanism of VT following surgical treatment of pulmonary stenosis can be either focal or reentrant. Ablation of this subgroup of VT is feasible.

Prediction of Sinus Node Dysfunction in Patients with Paroxysmal Atrial Fibrillation and Sinus Pause

Background and Objectives: Sinus pause association of paroxysmal atrial fibrillation (PAP) is generally considered a sinus node dysfunction (SND) known as tachycardia-bradycardia syndrome (TBS). Cure of tachyarrhythmias in some patients with prolonged pauses on termination of tachyarrhythmia resulted in an improvement in sinus node function and/or a return to normal ranges thus avoiding the need for permanent pacing. The purpose of this study was to investigate the electrophysiological and clinical characteristics as well as their sinus node function in patients with prolonged pauses and PAP. Methods and Results: Of 1266 PAP patients undergoing radiofrequency catheter ablation (RFCA), 122 patients with pauses (>2 s) were studied. The mean maximum symptomatic prolonged pause on termination of tachycardias was 2.67 ± 1.4 s (2.0–12.6 s). SND developed in 32 patients. There was no difference between the patients with and without SND in terms of the age and sex. Patients were divided into two groups based on the intracardiac electrophysiology study after the RFCA procedure. Eleven patients (8 men, 3 women; age 30–72 years, mean 48.2 ± 9.3 years) were placed in a normal sinus node function (NSF) group, and 17 patients (12 men, 5 women; age 37–75 years, mean 62.2 ± 7.5 years) were in an SND group. There was no significant difference in gender, left atrial dimension, left ventricular ejection fraction, blood pressure, or the longest pause between the two groups. RFCA was successful in 28 patients. Electrophysiological data show that corrected sinus node recovery time (CSNRT) was 409 ± 152 ms in NSF group patients and 558 ± 178 ms in SND group before the ablation procedure (P 2 cycle lengths in 12 patients. In the multivariate analysis, prolonged pauses on termination of tachyarrhythmia, frequency of pauses, and mean heart rate after ablation were independent predictors of SND. Conclusions: (1) Catheter ablation of atrial fibrillation (AF) is effective in treating paroxysmal AF-related TBS; (2) in some patients, there is progressive improvement of sinus node function after elimination of AF, an indication that these sinus pauses may be a manifestation of tachycardia-mediated remodeling of the sinus node, and that permanent pacemaker implantation is unnecessary; (3) among the extrinsic and intrinsic causes of SND, intrinsic causes are seldom reversible and some causes of extrinsic SND may be reversible; and (4) prolonged pauses on termination of PAF, frequency of pauses (>2.0 s), and mean heart rate after ablation were independent predictive factors of SND.

Effect of remote ischemic preconditioning on myocardial injury and inflammatory response induced by ablation for atrial fibrillation: A randomized controlled trial

BackgroundRemote ischemic preconditioning (RIPC) has been suggested to reduce postoperative release of cardiac and inflammatory markers in patients undergoing cardiac surgery. This study aimed to evaluate the effect of RIPC on nonischemic myocardial damage and inflammatory response in patients undergoing radiofrequency catheter ablation for paroxysmal atrial fibrillation (AF). MethodsSeventy-two patients with drug-refractory paroxysmal AF undergoing radiofrequency catheter ablation were randomized into RIPC or control groups. RIPC (intermittent arm ischemia through four cycles of 5-min inflation and 5-min deflation of a blood-pressure cuff) was performed once daily on 2 consecutive days before the ablation and immediately before ablation. Cardiac troponin-I (cTnI), high-sensitive C-reactive protein (hs-CRP), and interleukin (IL)-6 levels were measured before RIPC/sham RIPC, after the ablation, and 24 and 72h later. The early recurrence of atrial fibrillation (ERAF) in the two groups was observed over the subsequent 3months. ResultsRadiofrequency ablation resulted in a significant rise in cTnI, hs-CRP, and IL-6 in both groups, which persisted for 72h. The RIPC group showed a lower increase in cTnI (P<0.001), hs-CRP (P=0.003), and IL-6 (P=0.008) than the control and tended to have a lower risk of ERAF (hazard ratio [HR]=0.77, 95% confidence interval [CI]: 0.32–1.88). ConclusionsThese results show that RIPC before ablation for paroxysmal AF significantly reduces the increase in cTnI, hs-CRP, and IL-6 associated with the procedure and results in a lower risk of ERAF. These findings suggest that RIPC could provide cardioprotection against nonischemic myocardial damage.

16-04: Association between biomarkers of fibrotic turnover, PR interval and electro-anatomical substrate in AF patients undergoing radiofrequency catheter ablation

16-04: Association between biomarkers of fibrotic turnover, PR interval and electro-anatomical substrate in AF patients undergoing radiofrequency catheter ablation

216-31: Clinical, Electrocardiographic, and Electrophysiologic Characteristics of the Patients with Focal Atrial Tachycardia

Purpose: Although smaller studies have described the P-wave morphology from different anatomic locations, a detailed algorithm characterizing the likely location of a tachycardia associated with a P-wave of unknown origin has been lacking. The purpose of this study was: 1) to perform a detailed analysis of the P-wave morphology in focal atrial tachycardia (FAT) and construct an algorithm for identification of the anatomic site of origin, 2) to evaluate clinical and electrophysiological characteristics of FAT. Methods: In this retrospective study, 146 patients undergoing radiofrequency catheter ablation for right and left FATs were included. Clinical, electrocardiographic, and electrophysiologic, characteristics were reported. Summary of results: One hundred forty-six consecutive patients with FAT were considered for inclusion in the study (56% female, mean age: 46 ± 15 years, age range: 15–86 years). The distribution of AT was right atrial in 78% and left atrial in 22%. The most common site for right-sided ATs was crista terminalis and pulmonary vein was the preferred origin for left ATs. A female predominance (60%) was seen in right-sided AT and a male predominance (60%) was observed in left-sided tachycardias (p = 0.04). Lead V1 was the most helpful lead in distinguishing right from left tachycardias. Atrial electrogram-P wave interval at successful ablation site was significantly longer in left-sided ATs (45 ± 7 vs. 41 ± 7 ms, p = 0.006). Conclusions: This study shows a significant gender differences in right and left ATs. Leads V1 and I were the most useful leads to localize the FAT. Proposed P-wave algorithm could determine the likely origin of tachycardia in 95% of the patients.

Is transesophageal echocardiogram mandatory in patients undergoing ablation of atrial fibrillation with uninterrupted novel oral anticoagulants? Results from a prospective multicenter registry

Transesophageal echocardiography (TEE) is recommended in patients undergoing atrial fibrillation (AF) ablation, but use of this strategy is variable. To evaluate whether TEE is necessary before AF ablation in patients treated with novel oral anticoagulants (NOACs). We performed a prospective multicenter registry of AF patients undergoing radiofrequency catheter ablation on uninterrupted NOACs (apixaban and rivaroxaban). All patients were on NOACs for at least 4 weeks before ablation. Heparin bolus was administered to all patients before transseptal catheterization to maintain a target activated clotting time above 300 seconds. A subset of 86 patients underwent brain diffuse magnetic resonance imaging (dMRI) to detect silent cerebral ischemia (SCI). A total of 970 patients (514 [53%] apixaban patients and 456 [47%] rivaroxaban patients) were enrolled for this study. The mean age was 69.5 ± 9.0 years, with 824 patients (85%) having nonparoxysmal AF, and 636 patients (65.6%) were male. The average CHA2DS2-VASc score was 3.01 ± 1.3 and CHADS2 score was ≥2 in 609 patients (62.8%). Intracardiac echocardiogram ruled out left atrial appendage thrombus in all patients whose left atrial appendage was visualized (692, 71%), and detected "smoke" in 407 patients (42%). SCI at postprocedure dMRI was detected in 2.3% (2/86). One thromboembolic event (transient ischemic attack) (0.10%) with positive dMRI occurred in a patient on uninterrupted rivaroxaban with longstanding persistent AF. Our study illustrates that performing AF ablation while on uninterrupted apixaban and rivaroxaban without TEE is feasible and safe. This finding has important clinical and economic relevance.

Novel electrophysiological characteristics of atrioventricular nodal continuous conduction curves in atrioventricular nodal re-entrant tachycardia with concomitant cavotricuspid isthmus-dependent atrial flutter.

The detailed electrophysiological characteristics of patients with both atrioventricular nodal re-entrant tachycardia (AVNRT) and atrial flutter (AFL) have not been clarified. This study investigated the related electrophysiological differences in a large series of patients undergoing radiofrequency catheter ablation of AVNRT. A total of 1063 clinically documented AVNRT patients underwent catheter ablation were enrolled. Before the slow pathway (SP) ablation, 61 patients (5.7%) had inducible sustained cavotricuspid isthmus (CTI)-dependent AFL (Group 1), and the others (94.3%) without inducible sustained CTI-dependent AFL were defined as Group 2. The electrophysiological characteristics of these two groups and effect of the SP ablation on the inducibility of AFL were assessed. In Group 1, 36 patients (59%) had inducible/sustained AFL after the ablation of AVNRT and required a CTI ablation. The Group 1 patients had more AVNRT with continuous atrioventricular (AV) node function curves (P < 0.001, odds ratio = 7.55 [3.70-16.7], multivariate regression), and a younger age (P = 0.02, odds ratio = 1.02 [1.003-1.03], multivariate regression) than Group 2. The other characteristics were comparable between the two groups. The long-term follow-up (64.9 ± 34.9 months) revealed that the recurrence of AFL/atrial fibrillation was similar between the two groups (P > 0.05). Atrioventricular nodal re-entrant tachycardia patients with concomitant CTI-dependent AFL had more continuous AV node function curves. Forty-one per cent of these patients had non-inducible AFL after the SP ablation, indicating a slow conduction isthmus in the triangle of Koch area.

Abstract 13988: Novel Quantitative Assessment of Whole Blood Thrombogenicity in Patients Treated With Anticoagulants Undergoing Radiofrequency Catheter Ablation for Atrial Fibrillation

Introduction: Non-vitamin K antagonist oral anticoagulants (NOACs) are equivalent to warfarin in preventing thromboembolism in patients with atrial fibrillation (AF). Recently, Total Thrombus-formation Analysis System (T-TAS) was developed as an easy-to-use system for quantitative analysis of thrombus formation using microchips with thrombogenic surfaces (collagen, PL chip; collagen plus tissue factor, AR chip). Hypothesis: We evaluated the efficacy and safety of NOACs using the T-TAS in AF patients undergoing radiofrequency catheter ablation (RFCA). Methods: After exclusion of 19 from 121 consecutive patients undergoing RFCA for AF, the remaining 102 patients were divided into two groups; AF patients treated with warfarin (n=28), and NOACs (n=74). Blood samples obtained on the day (anticoagulant-free point), 3 days and 1 month after RFCA were used in T-TAS to compute the thrombus formation area under the curve (AUC) (PL24-AUC10, AUC for PL chip; AR10-AUC30, for AR chip). Results and Conclusion: The AR10-AUC30 and PL24-AUC10 levels were identical between the warfarin and NOACs groups on the day of RFCA (1708.5±162.1 vs 1757.5±138.0 in AR10-AUC30, p=0.13 and 389.1±95.5 vs 391.7±76.0 in PL24-AUC10, p=0.94, respectively). AR10-AUC30, but not PL24-AUC10 levels, was significantly lower in warfarin and NOACs groups at 3 days and 1 month after RFCA. Multiple logistic regression analysis identified AR10-AUC30 levels on the day of RFCA as a significant predictor of bleeding events in the period of three months after RFCA [odds ratio (OR) 20.6; 95% confidence interval (95%CI): 2.46 to 172.6; p=0.005]. Receiver-operating characteristic analysis showed that AR10-AUC30 levels on the day of RFCA significantly predicted bleeding events [AUC 0.849 (95%CI: 0.719-0.979; p&lt;0.001)]. The cut-off levels of AR10-AUC30 were 1647.6 for identification of bleeding events within three months after RFCA. These results suggested that AR10-AUC30 level determined by T-TAS is a potentially useful marker for assessment of the efficacy and safety of anti-coagulant therapy including warfarin and NOACs, in AF patients undergoing RFCA.

Abstract 11574: Ventricular Arrhythmia Ablation Lesions in Children and Adolescents: Acute Magnetic Resonance Imaging With Outcome Correlation

Introduction: Catheter ablation for arrhythmias is not always 100% effective when using current techniques. Failure of ablation may be secondary to inadequate lesion development. Peri-procedural visualization of ablation lesions may identify inadequate lesions or gaps to guide further ablation and reduce risk of arrhythmia recurrence. Methods: This pilot feasibility study assessed acute post-procedure ablation lesions by MRI, and correlated these findings with clinical outcomes. Six patients who underwent ventricular tachycardia ablation were transferred immediately post-ablation to a 1.5T MRI scanner for imaging. Late gadolinium enhancement (LGE) imaging was performed using a novel motion-corrected, phase sensitive inversion recovery sequence while free breathing. Immediate and short term arrhythmia recurrences were assessed. Results: Patient characteristics include median age 14.5 yrs (11 - 17 yrs), median weight 59 kg (43 - 81kg), normal cardiac anatomy (n = 4), anomalous coronary artery post repair (n = 1), and cardiac rhabdomyomas (n = 1). All patients underwent radiofrequency catheter ablation of ventricular arrhythmia with acute procedural success. LGE was identified at the reported ablation site in 5/6 patients, and not seen in 1 patient. The 5 patients with identifiable lesions were arrhythmia- and symptom-free at follow-up, ranging 1-6 months. The 1 patient in whom a lesion could not be identified had recurrence of frequent premature ventricular contractions within 2 hours post-procedure, confirmed on Holter monitoring 1 month later. Conclusions: Ventricular ablation lesion visibility by MRI in the acute post-procedure setting is feasible, and lesions identifiable with MRI may correlate with clinical outcomes. MRI identification of gaps or inadequate lesions may provide the unique temporal opportunity for additional ablation therapy to decrease arrhythmia recurrence.

Abstract 14355: Sinus Rhythm Prior to Catheter Ablation Positively Impacts Ablation Outcome in Non-Paroxysmal Atrial Fibrillation Patients

Background: Catheter ablation of non-paroxysmal atrial fibrillation (NPAF) is associated with longer procedure times and lower long-term success rates than that of paroxysmal AF. We tested the hypothesis that NPAF patients entering the EP laboratory (lab) with sinus rhythm (SR) have shorter procedure time and better ablation-outcome than those with AF as the entry-rhythm. Methods: Total of 804 consecutive NPAF patients undergoing radiofrequency catheter ablation at our center were included in this prospective analysis. Based on the presenting rhythm in the EP lab, patients were classified into two groups; patients on SR (group 1, n=236, age 63±10 years, male 71%, LVEF 55.2±8.4, LA size 4.5±0.9 cm), patients in AF (group 2, n=568, age 64±10 years, male 69%, LVEF 54.4±11.4, LA size 4.6±0.6 cm). All patients were followed up for 38±6 months for arrhythmia recurrence by event recorder, ECG and Holter monitoring. Results: The baseline characteristics were not different between the groups. When comparing the procedural parameters between the groups, patients presenting with SR required significantly shorter radiofrequency time (64.1±30.7 min vs. 82.3±29.4 min in AF group, p&lt;0.0001) and procedure times (143.9±91.2 min vs. 162.3±62.2 min in AF group, p=0.019). At the end of follow-up, significantly higher recurrence rate was noted in those presenting with AF compared to patients on SR at the procedure; 264 of 568 (47%) vs. 80 of 236 (34%) respectively, log-rank p=0.002 (unadjusted hazard ratio 1.55 [1.17 - 2.05]) (figure). After adjusting for AF type, age, gender, LA size, and LVEF in multivariable Cox model, patients presenting with AF at procedure were twice more likely to fail compared to those on SR (hazard ratio 1.91 (95% CI 1.19 to 4.15), p=0.001). Conclusion: Sinus rhythm prior to catheter ablation for non-paroxysmal AF decreases the duration of ablation and increases the long-term efficacy of the procedure. Figure: Kaplan-Meier curve showing recurrence by study groups

Adenosine-guided pulmonary vein isolation for the treatment of paroxysmal atrial fibrillation: an international, multicentre, randomised superiority trial

Catheter ablation is increasingly used to manage atrial fibrillation, but arrhythmia recurrences are common. Adenosine might identify pulmonary veins at risk of reconnection by unmasking dormant conduction, and thereby guide additional ablation to improve arrhythmia-free survival. We assessed whether adenosine-guided pulmonary vein isolation could prevent arrhythmia recurrence in patients undergoing radiofrequency catheter ablation for paroxysmal atrial fibrillation. We did this randomised trial at 18 hospitals in Australia, Europe, and North America. We enrolled patients aged older than 18 years who had had at least three symptomatic atrial fibrillation episodes in the past 6 months, and for whom treatment with an antiarrhythmic drug failed. After pulmonary vein isolation, intravenous adenosine was administered. If dormant conduction was present, patients were randomly assigned (1:1) to additional adenosine-guided ablation to abolish dormant conduction or to no further ablation. If no dormant conduction was revealed, randomly selected patients were included in a registry. Patients were masked to treatment allocation and outcomes were assessed by a masked adjudicating committee. Patients were followed up for 1 year. The primary outcome was time to symptomatic atrial tachyarrhythmia after a single procedure in the intention-to-treat population. The trial is registered with ClinicalTrials.gov, number NCT01058980. Adenosine unmasked dormant pulmonary vein conduction in 284 (53%) of 534 patients. 102 (69·4%) of 147 patients with additional adenosine-guided ablation were free from symptomatic atrial tachyarrhythmia compared with 58 (42·3%) of 137 patients with no further ablation, corresponding to an absolute risk reduction of 27·1% (95% CI 15·9-38·2; p<0·0001) and a hazard ratio of 0·44 (95% CI 0·31-0·64; p<0·0001). Of 115 patients without dormant pulmonary vein conduction, 64 (55·7%) remained free from symptomatic atrial tachyarrhythmia (p=0·0191 vs dormant conduction with no further ablation). Occurrences of serious adverse events were similar in each group. One death (massive stroke) was deemed probably related to ablation in a patient included in the registry. Adenosine testing to identify and target dormant pulmonary vein conduction during catheter ablation of atrial fibrillation is a safe and highly effective strategy to improve arrhythmia-free survival in patients with paroxysmal atrial fibrillation. This approach should be considered for incorporation into routine clinical practice. Canadian Institutes of Health Research, St Jude Medical, Biosense-Webster, and M Lachapelle (Montreal Heart Institute Foundation).

Efficacy and Safety of Non-Vitamin K Antagonist Oral Anticoagulants versus Vitamin K Antagonist Oral Anticoagulants in Patients Undergoing Radiofrequency Catheter Ablation of Atrial Fibrillation: A Meta-Analysis.

BackgroundUse of the non-vitamin K antagonist oral anticoagulants (NOACs) is endorsed by current guidelines for stroke prevention in patients with atrial fibrillation (AF). However efficacy and safety of NOACs in patients undergoing catheter ablation (RFCA) of AF has not been well established yet.ObjectivesTo perform a meta-analysis of all studies comparing NOACs and vitamin K antagonist oral anticoagulants (VKAs) in patients undergoing RFCA.Data SourcesStudies were searched for in PubMed and Google Scholar databases.Study Eligibility CriteriaStudies were considered eligible if: they evaluated the clinical impact of NOACs versus VKAs; they specifically analyzed the use of anticoagulants during periprocedural phase of RFCA; they reported clinical outcome data.Study Appraisal and Synthesis Methods25 studies were selected, including 9881 cases. The summary measure used was the risk ratio (RR) with 95% confidence interval (CI). The random-effects or the fixed effect model were used to synthesize results from the selected studies.ResultsThere was no significant difference in thromboembolic complications (RR 1.39; p=0.13). Bleeding complications were significantly lower in the NOACs-treated arm as compared to VKAs (RR=0.67, p<0.001). Interestingly, a larger number of thromboembolic events was found in the VKAs-treated arm in those studies where VKAs had been interrupted during the periprocedural phase (RR=0.68; p=ns). In this same subgroup a significantly higher incidence of both minor (RR=0.54; p=0.002) and major bleeding (RR=0.41; p=0.01) events was recorded. Conversely, the incidence of thromboembolic events in the VKAs-treated arm was significantly lower in those studies with uninterrupted periprocedural anticoagulation treatment (RR=1.89; p=0.02).LimitationsAs with every meta-analysis, no patients-level data were available.Conclusions and ImplicationsThe use of NOACs in patients undergoing RFCA is safe, given the lower incidence of bleedings observed with NOACs. On the other side, periprocedural interruption of VKAs and bridging with heparin is associated with a higher bleeding rate with no significant benefit on onset of thromboembolic events.

Feasibility and safety of uninterrupted periprocedural apixaban administration in patients undergoing radiofrequency catheter ablation for atrial fibrillation: Results from a multicenter study.

Periprocedural anticoagulation management with uninterrupted warfarin and a "therapeutic" international normalized ratio is the best approach for reducing both thromboembolic and bleeding complications in the setting of catheter ablation for atrial fibrillation (AF). The purpose of this study was to evaluate the safety and feasibility of uninterrupted apixaban in this setting. This was a prospective multicenter registry of AF patients undergoing radiofrequency catheter ablation at 4 institutions in United States and Europe with uninterrupted apixaban. These patients were compared with an equal number of patients, matched for age, gender, and type of AF, undergoing AF ablation on uninterrupted warfarin.The apixaban group was comprised of consecutive patients who had taken their last dose of apixaban the morning of the procedure. A subset of 29 patients in the apixaban group underwent diffusion magnetic resonance imaging (dMRI) to detect silent cerebral ischemia. A total of 400 patients (200 patients in each group) were included in the study. The average age was 65.9 ± 9.9 years, 286 (71.5%) were male, and 334 (83.5%) had nonparoxysmal AF. There were no statistical differences with regard to major complications (1% vs 0.5%, P = 1), minor complications (3.5% vs 2.5%, P = .56), or total bleeding complications (4.5% vs 3%, P = .43) between the apixaban and warfarin groups. There were no symptomatic thromboembolic complications. All dMRIs were negative for "new" silent cerebral ischemia in the apixaban group. Uninterrupted apixaban administration in patients undergoing AF ablation seems to be feasibleand effective in preventing clinical and silent thromboembolic events without increasing the risk of major bleeding.

Acute hemodynamic decompensation during catheter ablation of scar-related ventricular tachycardia: incidence, predictors, and impact on mortality.

The occurrence of periprocedural acute hemodynamic decompensation (AHD) in patients undergoing radiofrequency catheter ablation of scar-related ventricular tachycardia (VT) has not been previously investigated. We identified univariate predictors of periprocedural AHD in 193 consecutive patients undergoing radiofrequency catheter ablation of scar-related VT. AHD was defined as persistent hypotension despite vasopressors and requiring mechanical support or procedure discontinuation. AHD occurred in 22 (11%) patients. Compared with the rest of the population, patients with AHD were older (68.5±10.7 versus 61.6±15.0 years; P=0.037); had a higher prevalence of diabetes mellitus (36% versus 18%; P=0.045), ischemic cardiomyopathy (86% versus 52%; P=0.002), chronic obstructive pulmonary disease (41% versus 13%; P=0.001), and VT storm (77% versus 43%; P=0.002); had more severe heart failure (New York Heart Association class III/IV: 55% versus 15%, P<0.001; left ventricular ejection fraction: 26±10% versus 36±16%, P=0.003); and more often received periprocedural general anesthesia (59% versus 29%; P=0.004). At 21±7 months follow-up, the mortality rate was higher in the AHD group compared with the rest of the population (50% versus 11%, log-rank P<0.001). AHD occurs in 11% of patients undergoing radiofrequency catheter ablation of scar-related VT and is associated with increased risk of mortality over follow-up. AHD may be predicted by clinical factors, including advanced age, ischemic cardiomyopathy, more severe heart failure status (New York Heart Association class III/IV, lower ejection fraction), associated comorbidities (diabetes mellitus and chronic obstructive pulmonary disease), presentation with VT storm, and use of general anesthesia.

Abstract 17710: Phrenic Nerve Injury Despite High-Output Pacing in Patients Undergoing Radiofrequency Catheter Ablation of Atrial Fibrillation

Introduction: High-output pacing has been advocated as a strategy to avoid injury to the phrenic nerve (PN) during antral pulmonary vein (PV) isolation. We assessed the hypothesis that pacing does not prevent PN injury in patients undergoing radiofrequency (RF) ablation of atrial fibrillation (AF). Methods: The medical records of 198 consecutive patients (age=63±12 years, 129 men, ejection fraction=57±10%, LA=44±6mm, paroxysmal=49%) undergoing their first ablation procedure for AF were reviewed. All patients underwent antral PV isolation using a 3D mapping system (CARTO XP or CARTO 3) and a 3.5 mm irrigated-tip ablation catheter (maximum power, 25 W). Prior to RF energy delivery, high-output pacing (20 mA @ 10 ms, maximum output) was performed to asses for PN capture. Sites that afforded PN capture were avoided and RF energy was delivered at adjacent sites without PN capture. The 3-D maps were reviewed to identify the prevalence and sites of PN capture. Results: High-output pacing along the anterior right antrum resulted in PN capture in 35 patients (18%). The most common site with a positive response was the crux between the upper and lower PVs (60%), followed by the right superior PV (43%), and the right inferior PV (20%). Of the patients with PN capture, 49% had only one site of capture, 20% with two sites, and 31% had 3 or more sites. All PVs were isolated at the end of the procedure. Two patients (1%) developed PN injury (symptom onset on the day after the procedure), which was confirmed on radiography. In neither case was there evidence of PN capture during the procedure. Symptoms resolved in both patients within 3 months, with normalization of radiographic findings. Conclusions: High-output pacing along the anterior right PV antrum yields PN capture in roughly one-fifth of the patients undergoing PV isolation. Despite a negative response to pacing and alteration of the lesion set, PN injury may occur. The reason for this discordance is unknown, but may include the possibility that the capture threshold of the PN exceeds the maximum output of the stimulator, or that RF energy may injure the pericardiophrenic artery, which accompanies the PN. Avoiding high-power or long-duration lesions and high contact force in this region may minimize the risk of PN injury.

Abstract 18881: New Oral Anticoagulants for Periprocedural Management of Anticoagulation in Patients Undergoing Radiofrequency Catheter Ablation for Atrial Fibrillation: a Meta-analysis

Introduction: Thromboembolic events are the most feared complication of radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). The traditional periprocedural anticoagulation approach is discontinuation of vitamin K antagonist and bridging with heparin. Newly procedures are done under therapeutic INR 2-3. Recent studies used periprocedural new direct oral anticoagulants (NOACs). Hypothesis: We evaluated the available evidence on the efficacy and safety of NOACs for periprocedural anticoagulation during RFCA of AF. Methods: Pubmed, Embase and Cochrane Central were searched. Retrospective and prospective studies published as peer-reviewed full-size articles were included if they reported embolic events and major and minor bleeding. Results: Fifteen studies were identified (14 observational studies, 1 small randomized trial). A total of 7050 patients were included (NOACs group: 2887 ). A total of 37 thromboembolic complications occurred (0,5%) with 17 events in the NOAC group (0,6%) and 20 in the warfarin group (0,5%) (odds ratio 0.97, 95% confidence interval (CI) 0.48 to 1.99). Major bleeding were numerically higher in the warfarin group compared to the NOACs group. However, the difference did not reach statistical significance (odds ratio 0.69, CI 0.43 to 1.10). Subgroup analysis did not reveal any differences in event rates. Conclusions: Our review suggests that dabigatran etexilate and rivaroxaban are as effective and safe as warfarin for periprocedural anticoagulation in patients undergoing RFCA of AF. However, it has to be acknowledged that the current evidence is mainly based on observational studies.

24Acute and long-term outcomes for patients undergoing radiofrequency catheter ablation of scar-related ventricular tachycardia by robotic catheter navigation

Introduction: Robotically-guided ablation offers theoretical advantages with greater catheter stability that can improve lesion depth. We performed a non-randomised comparison of patients undergoing ventricular tachycardia (VT) ablation either manually or using the Hansen robotic system. Methods: Consecutive patients with infarct-related scar underwent VT ablation using the Hansen system to assess feasibility, and were compared with patients undergoing manual VT ablation during the study period. All cases underwent a transeptal endocardial approach, using CARTO™ and irrigated catheter ablation guided by activation and entrainment manoeuvres if VT was sustained and tolerated, or substrate modification. The 6 month pre-ablation Implantable Cardioverter Defibrillator (ICD) therapy (Anti-tachycardia pacing (ATP) + shocks) was compared with the post ablation burden represented as a 6 monthly rate of each patient's total therapy burden during follow up ((6/follow-up duration (mths)) x total therapies post ablation)). Results: 25pts had VT ablations for infarct related scar during the study period. 13 pts had robotically guided ablation and 12 pts had manual ablation. Patients in both the robotic and manual groups had significantly impaired left ventricular function (EF 27±14% vs. 32 + /-11% respectively; p=0.32). The previous coronary revascularisationapproach, use of cardiac resynchronisation and amiodarone were similar in both groups. However 31% (4/13) of patients undergoing robotic ablation had been referred due to a failed manual approach and persisting high therapy burden as compared to 8% (1/12) redo procedures in the manual group (p=0.37). This was reflected by a trend towards higher pre-ablation therapy burden in the robotic as compared to the manual group (mean 312±566 vs. 11±9, p=0.08; median 11 vs. 9.5, p=0.50). In each group, 1 patient presented with slow incessant VT below the device therapy zone, and 1 patient had their device implanted post ablation. Post-procedure, the clinical VT was non-inducible in 85% (11/13) of the robotic group and in 92% (11/12) of the manual group. There were no peri-procedural complications. Mean follow-up was 23.5 months. Long-term mortality rates were similar (31%, 4/13 vs. 25%, 3/12; p=1.0). Post ablation, the 6 monthly therapy burden fell in both the robotic (mean reduction=290±560, median 3, p=0.047 Wilcoxon signed rank test) and manual (mean reduction=5.3±19, median 6.5, p=0.03) group. The overall reduction in therapy across all patients was 93% in the robotic and by 48% in the manual group. Conclusions: In this feasibility study, robotic VT ablation had a similar safety profile to manual ablation and a trend towards greater therapy reduction in a sicker cohort of patients. Table comparing acute procedural outcomes, 6 month pre/post ablation ICD therapies, and mortality rates between the robotic and manual groups. †Students t-test. §Fisher's exact test. ‖ Wilcoxon signed rank test. ![Graphic][1] [1]: /embed/inline-graphic-1.gif