Radiofrequency Catheter Ablation Procedures Research Articles

Impact of epicardial fat on the duration of radiofrequency energy delivery during catheter ablation of atrial fibrillation

AimsThis study aimed to determine the impact of the volume of epicardial fat on the duration of radiofrequency (RF) energy delivery during the procedure of ablation of atrial fibrillation (AF). MethodsThe volume of epicardial fat was measured from spiral computerized tomography scan. The primary endpoint was the duration of RF delivery for pulmonary vein isolation (PVI), and the overall total duration of RF application. Secondary endpoint was conversion of AF to sinus rhythm or organisation of the arrhythmia after PVI. ResultsFrom March 2015 to May 2018, 222 patients (45.5% with persistent AF) underwent a first RF catheter ablation procedure for AF. The total duration of RF delivery, and the duration of RF delivery specifically for PVI were significantly associated with higher total volume of epicardial fat (p = 0.0002; p = 0.009 respectively), periatrial (p = 0.003; p = 0.045) and periventricular epicardial fat (p = 0.001; p = 0.012). In multivariate analysis, total epicardial fat volume was not significantly associated with total RF delivery duration (p = 0.743). For patients with arrhythmia at the time of the procedure, patients who achieved conversion or organisation of their arrhythmia after PVI had similar levels of total epicardial fat to those whose arrhythmia persisted (65 ± 35.2 vs 74.5 ± 31.2 ml; p = 0.192). ConclusionWe observed a significant relation between total, periatrial, and periventricular epicardial fat, and the duration of RF delivery during ablation of AF. This relation was not significant by multivariate analysis meaning that epicardial fat may be a marker, but not an independent factor, of ablation complexity.

P1020Persistent AF patients with limited areas of low voltage have a similar benefit from pulmonary vein isolation as compared to paroxysmal AF patients: insight from the SMOP study

Abstract Background Pulmonary vein isolation (PVI) performed with radio-frequency catheter ablation (CA) is an effective therapy for atrial fibrillation (AF). However previous data have suggested that PVI is less effective in persistent (PER) vs. paroxysmal (PAR) AF. Atrial fibrosis and scar, indeed, are an important substrate involved in persistent AF, and some author correlate them to an increased rate of recurrences after CA. For this reason several adjunctive ablation strategies have been suggested for invasive treatment in PER AF pts. However, there is a lack of evidence on their effectivness in current literature. Objective the aim of our study was to assess the rate of AF recurrences in PAR and PER AF patients after a first pulmonary vein isolation (IVP) procedure, and their relationship with low voltage areas of the left atrium assessed by means of high density mapping performed before CA. Methods we analyzed 214 patients of the SMOP-AF study (Substrate Mapping as Outcome Predictor in Atrial Fibrillation Ablation), a prospective multi-centric registry enrolling patients with both PAR and PER AF undergoing a first radio-frequency CA procedure aimed to obtain permanent PVI . High-density mapping was performed in sinus rhythm using the CARTO system before PVI. Areas with less than 0,5 mV on mapping were defined as low voltage zone (LVZ); LVZ was indexed on the atrial area. Comparisons were made by cross-tables and Chi-square test or Student T test. Results Patients with PER AF (n = 44, 21%) were older (63 ± 9 vs 58 ± 10 yrs, p = 0.01), but notably with no difference in LVEF and atrial dimensions as compared to pts with PAR AF. In addition no statistical difference was observed in procedural variables, except for a greater LVZ area on atrial mapping (8 ± 18 % vs. 5 ± 15 %, p = 0.04) and a longer p wave duration (115 ± 21 msec vs. 103 ± 18 msec, p = 0.01) in pts with PER AF. The incidence of recurrence in the overall population was 15.3% at 3 months and 13.7% from 3 to 12 months: there was no statistical difference in success-rate between PER and PAR pts (respectively 79,5% vs 86% p value = 0.315 in blanking period and 85,3% vs 86,5% p value = 0.8 at 3-12 months follow-up). No statistical difference was observed for ablation variables (number of lesion, contact force, force time integral) in pts with vs. without recurrences. Conclusion Our study showed that pulmonary vein isolation alone seems to be as effective in paroxismal and persistent AF patients with low degree of left atrial fibrosis. Our data call into question the idea that PVI alone is not effective in PER AF. High density mapping of the LA could help to identify a subset of PER AF patients with a limited extension of low voltage areas (i.e around 10% of the overall LA surface) that could benefit from PVI without adjunctive ablation strategies. Our data needs to be confirmed in a longer follow-up.

Zero-fluoroscopy approach for ablation of supraventricular tachycardia using the Ensite NavX system: a multicenter experience

BackgroundThree-dimensional electroanatomic mapping systems have demonstrated a significant reduction in radiation exposure during radiofrequency catheter ablation procedures. We aimed to investigate the safety, feasibility and efficacy of a completely zero-fluoroscopy approach for catheter ablation of supraventricular tachycardia using the Ensite NavX navigation system compared with a conventional fluoroscopy approach.MethodsA multicenter prospective non-randomized registry study was performed in seven centers from January 2013 to February 2018. Consecutive patients referred for catheter ablation of supraventricular tachycardia were assigned either to a completely zero-fluoroscopic approach (ZF) or conventional fluoroscopy approach (CF) according to the operator’s preference. Patients with atrial tachycardia were excluded.ResultsTotally, 1020 patients were enrolled in ZF group; 2040 patients ablated by CF approach were selected for controls. There was no significant difference between the zero-fluoroscopy group and conventional fluoroscopy group as to procedure time (60.3 ± 20.3 vs. 59.7 ± 22.6 min, P = 0.90), immediate success rate of procedure (98.8% vs. 99.2%, P = 0.22), arrhythmia recurrence (0.4% vs. 0.5%, P = 0.85), total success rate of procedure (98.4% vs. 98.8%, P = 0.39) or complications (1.1% vs. 1.5%, P = 0.41). Compared with the conventional fluoroscopy approach, the zero-fluoroscopy approach provided similar outcomes without compromising the safety or efficacy of the procedure.ConclusionThe completely zero-fluoroscopy approach demonstrated safety and efficacy comparable to a conventional fluoroscopy approach for catheter ablation of supraventricular tachycardia, and mitigated radiation exposure to both patients and operators.Trial registrationclinicaltrials.gov Identifier: NCT03042078; first registered February 3, 2017; retrospectively registered.

Laryngeal mask versus facemask in the respiratory management during catheter ablation

BackgroundThe purpose of this study is to investigate if a laryngeal mask could improve respiratory condition during radiofrequency catheter ablation (RFCA).MethodsTwenty-four consecutive patients who underwent RFCA for atrial fibrillation were divided into two groups (Facemask group; n = 10, Laryngeal mask group; n = 14). All patients were completely sedated under intravenous anesthesia and fitted with artificial respirators during the RFCA. The capnography waveforms and their differential coefficients were analyzed to evaluate the changes of end-tidal CO2 (ETCO2) values, respiratory intervals, expiratory durations, and inspiratory durations.ResultsDuring the RFCA, ETCO2 values of the laryngeal mask group were higher than those of the facemask group (36.0 vs. 29.2 mmHg, p = 0.005). The respiratory interval was significantly longer in the laryngeal mask group than those in the facemask group (4.28 s vs.5.25 s, p < 0.001). In both expiratory and inspiratory phases, the mean of the maximum and minimum values of CO2 was significantly higher when using a laryngeal mask than when using a facemask. The inspiratory-expiratory ratio of the laryngeal mask group was significantly larger than that of the facemask group (1.59 vs. 1.27, p < 0.001). The total procedure duration, fluoroscopic duration and the ablation energy were significantly lower in the laryngeal mask group than in the facemask group. The ETCO2 value is the most influential parameter on the fluoroscopic duration during the RFCA procedure (β = − 0.477, p = 0.029).ConclusionsThe use of a laryngeal mask could stabilize respiration during intravenous anesthesia, which could improve the efficiency of RFCA.

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.

P1010Electrophysiological characteristics of paroxysmal tachycardia in children with short PQ interval

Abstract Introduction It is well known that children with short PQ interval can have different types paroxysmal tachycardia (PT). Combination of short PQ interval with PT is called Lown-Ganong-Levine (LGL) syndrome. We have hypothesized that in children with short PQ interval electrophysiological types of PT do not correlate with shortening of PQ interval. Purpose The aim of the study was to assess the PT types based on results of the electrophysiological studies and radiofrequencycatheter ablation (RFA), and to estimate the AV conduction parameters and their dynamic changes before and after the procedure. Materials and methods of research: 55 children with supraventricular tachycardia (SVT) and short PQ interval were examined. The examination included:ECG, 24-hour Holter monitor, transesophageal pacing study (TEPS), intracardiac electrophysiological study (EPS). 22 children underwent RFA procedure. During the period of the study 55 children had 111 TEPS and 28 EPS studies. Results 21 (38,2%) children had orthodromic AV reentrant tachycardia with accessory pathway (AVRT), 27 (49,1%) had typical (slow-fast) AV nodal reentrant tachycardia (AVNRT), 2 (3,6%) had atypical AVNRT, 1 (1,8%) had combination of typical and atypical AVNRT, 1 (1,8%) had atrial ectopic tachycardia combined with atypical AVNRT, 4 (7,3%) had spontaneous atrial fibrillation or atrial flutter, 3 (5,4%) had combination with typical AVNRT and 1 child (1,8%) had AVRT. PQ interval measured 107,2 ms (83–120ms). 22 (40%) children underwent RFA-13 children with typical AVNRT, 9 with AVRT. In children with AVNRT tachycardia cycle length was 229–425 ms (309,8±67,6ms). Primary RFA was effective in 10 (76,9%) children. The AVNRT recurrence was found in 3 (13,6%) cases after 7,2±4,3 month from the time of procedure. After slow pathway ablation PQ interval length didn't change (107,1±9,1ms compared to 108,2±7,1ms; p=0,2). No change occurred with the maximal rate of 1:1 conduction through AV node (187,8±14,8 imp/min compared to187±12,5 imp/min; p=0,2). Effective refractory period of AV node (AVNERP) increased by a small amount (288,9±14ms, compared to 266±42,7ms; p=0,06). 9 (40,9%) children underwent RFA of the accessory pathway (AP). In all of the cases there were concealed AP with the left-sided localization. AVRT cycle length was 259–382 ms (304,2±41,2ms). After RFA of concealed AP maximal rate of 1:1 conduction through AV node increased by a small amount (220±26,4 imp/min compared to 191,2±23,6 imp/min) and AVNERP decreased (256,7±25,2ms compared to 268,6±38,9ms; p=0,09).After RFA of AP PQ interval length didn't change (110±5,9ms compared to 110±5ms; p=0,1). Conclusion In children with short PQ interval PT was associated with dual physiology of AV connection or with concealed AP. After the successful RFA in children with AVNRT and AVRT there was no PQ interval normalization, which remained short in all examinations. Thus, short PQ- interval is a co-existing phenomenon in children with AVNRT and AVRT.

Catheter ablation of electrical storm in patients with arrhythmogenic right ventricular cardiomyopathy

Therapeutic strategies for electrical storm (ES) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) are not well defined. The purpose of this study was to report the acute and long-term results of ventricular tachycardia (VT) radiofrequency catheter ablation (RFCA) as a treatment of ES in patients with ARVC. This multicenter study retrospectively enrolled 23 consecutive patients with ARVC (mean age 43.6 ± 16.7 years; all men) who underwent 24 RFCA procedures for ES between 2003 and2015. Thirteen patients (57%) had a previous VT RFCA procedure; 14 (61%) had right ventricular dysfunction and 7 (30%) left ventricular ejection fraction ≤ 50%. The clinical VT was inducible in 19 procedures (79%). Epicardial ablation was performed in 4 procedures (17%). The median number of targeted VTs was 1 (range 1-6). Complete acute success (no VT inducible) was achieved in 11 procedures (46%) and partial acute success (clinical VT nor inducible) in 11 (46%). After a median follow-up of 3.9 years (range 1 month-10 years), ES recurred in 2 patients and end-stage heart failure developed in 4 (17%), leading to 1 death and 3 heart transplantations. At 1-year follow-up, the probability of freedom from VT recurrence was 75% and did not significantly predict long-term survival. At the last evaluation, 8 patients (35%) were free of non-β-blocker antiarrhythmic drugs as compared with 1 (4%) at baseline (P = .02). Catheter ablation was efficient to prevent ES recurrence in patients with ARVC. However, these patients were at high risk of evolution toward ARVC-related heart failure that was not associated with VT recurrence.

Characteristics of ventricular tachycardia and long-term treatment outcome in patients with dilated cardiomyopathy complicated by lamin A/C gene mutations

BackgroundDilated cardiomyopathy caused by lamin A/C gene (LMNA) mutation is complicated with atrioventricular (AV) conduction disturbances, malignant ventricular arrhythmias, and progressive severe heart failure. Radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) has been reported to be challenging due to the high recurrence rate in patients with LMNA-related cardiomyopathy. However, electrophysiological and histopathological characteristics of VT substrate remain to be fully elucidated. Methods and resultsWe experienced 6 familial patients with LMNA-related cardiomyopathy in 3 pedigrees (6 males, 43.7±4.5 [SD] years). All patients had first VT attack at 50±6.6 [SD] years of age, and 4 underwent RFCA for incessant VT. Their electrocardiograms during VT showed similar QRS morphologies, characterized by an inferior axis, SR pattern in aVR, and QS pattern in aVL, suggesting the origin of the basal anterior ventricle. Indeed, the VTs had multiple exits around the basal anterior ventricular septum in all RFCA cases. Although we performed multiple RFCA procedures including epicardial ablation and surgical cryoablation, all cases experienced VT recurrences in 4.5±6.4 [SD] months after last procedure. All patients developed end-stage heart failure with frequent VT events, and died at 59.5±3.6 years of age (severe heart failure in 5 and lung disease in 1). In three autopsy cases with RFCA, fibrofatty degeneration was noted in the AV node. In addition, in the deep basal ventricular septum, inhomogenous fibrotic degenerated tissue was noted beyond the reach of RF lesions. ConclusionsThese results demonstrate that patients with LMNA-related cardiomyopathy are characterized by VTs refractory to RFCA probably because of the deep intramural focus at the basal ventricular septum, resulting in poor prognosis with progressive severe heart failure despite all available optimized therapies. Thus, we should consider heart transplantation in their early 50s when several VT events begin to occur.

Cost-reduction strategy for isoproterenol use in radiofrequency catheter ablation procedures.

A cost-reduction strategy for isoproterenol use in radiofrequency catheter ablation procedures was evaluated. A medication-use evaluation at a 454-bed tertiary medical center revealed that the cardiac catheterization laboratory was the highest user of isoproterenol. Isoproterenol was removed from all AcuDose-Rx machines Omnicell, Mountain View, CA, and compounding was performed by pharmacy personnel. It was initially provided to the cardiac catheterization laboratory as an 8-µg/mL concentration in 20-mL 0.9% sodium chloride injection syringes with a 24-hour beyond-use date. This resulted in an initial cost savings but with an unacceptably high rate of wastage. Isoproterenol was then compounded as a 4-µg/mL concentration in 30 mL 5% dextrose in water syringes with a 9-day beyond-use date after a thorough literature search supported longer stability with this admixture. After 12 months of our current process, isoproterenol use during radio frequency catheter ablations (RFCAs) in the cardiac catheterization laboratory was reduced by 85%, decreasing the number of ampules used from 11.15 to 1.66 per week. A pharmacy-initiated process to mitigate an extraordinary increase in isoproterenol acquisition cost resulted in a reduction in usage in a tertiary care community hospital. Isoproterenol usage was reduced 85% after two different interventions were implemented, which is estimated to save $1,839 per procedure.

Radiofrequency catheter ablation of premature ventricular contractions from near the His-bundle.

ObjectiveThis study aimed to investigate the effects of radiofrequency catheter ablation (RFCA) and clinical and electrophysiological characteristics in symptomatic patients with premature ventricular contractions (PVCs) from near the His‐bundle (His‐PVCs).MethodsThe patient characteristics, prevalence of complications with any life style related disease (ALSRD) including hypertension, dyslipidemia, or diabetes mellitus, and/or cardiovascular disease (CVD) including coronary artery disease, cerebrovascular disease, renal dysfunction, or cardiomyopathy, clinical status, frequency of PVCs evaluated by 24hour Holter monitoring, echocardiography including the left ventricular diastolic dysfunction (LVDD) parameters, and electrophysiological findings were evaluated in 14 consecutive symptomatic patients with His‐PVCs.ResultsThe prevalence of males, being elderly and/or slightly obese, current and/or history of smoking, ALSRD or CVD related complications, and LVDD probably resulting from ALSRD and/or CVD complications were higher in patients with His‐PVCs. RFCA of His‐PVCs steadily decreased the PVC frequency and improved the systolic function, LV dilation, and clinical status, but not the LVDD. There was a significant relationship between the accordance rate of the QRS polarity between sinus rhythm and His‐PVCs and the distance between the successful ablation site and His‐bundle.ConclusionThe analysis of the QRS duration and accordance rate of the QRS polarity between sinus rhythm and His‐PVCs before the RFCA may help to determine the distance between the origin of the PVCs and His‐bundle. Further, the appropriate ablation catheter may be selected during the RFCA procedure. Finally, RFCA may be one of the most effective, feasible, and safest therapies for symptomatic patients with His‐PVCs.

Sympathetic responses induced by radiofrequency catheter ablation of atrial fibrillation.

Radiofrequency catheter ablation (RFCA) is a frequently performed procedure in patients with atrial fibrillation. Prior studies have shown that the RFCA may directly stimulate vagal afferents during the procedure, whereas the vagal tone assessed by heart rate variability (HRV) is lowered weeks after the RFCA procedure. The effects of RFCA performed in the left atrium on sympathetic nerve activity have not been assessed. In the present study, we hypothesized that RFCA would lower muscle sympathetic nerve activity (MSNA) during ablation and would raise MSNA 1 day postablation. A total of 18 patients were studied. In protocol 1 ( n = 10), electrocardiogram, blood pressure, and MSNA in the peroneal nerve were recorded through the RFCA procedure performed in the electrophysiology laboratory. In protocol 2, eight patients were studied before the procedure and 1 day postablation. RFCA led to a decrease in MSNA immediately after the procedure (25.4 ± 3.2 to 17.2 ± 3.8 bursts/min, P < 0.05). Cardiac parasympathetic activity was determined using indexes of HRV and increased during the procedure. One day postablation, MSNA was above baseline values (21.3 ± 3.7 to 35.7 ± 2.6 bursts/min, P < 0.05). HRV indexes of cardiac parasympathetic activity fell, and the HRV index of sympathovagal balance was not significantly altered. The results show that RFCA raised cardiac parasympathetic activity and decreased MSNA during the procedure. One day postablation, MSNA rose and cardiac parasympathetic activity fell. In addition, RFCA evokes differentiated sympathetic responses directed to the heart and skeletal muscles. NEW & NOTEWORTHY The effects of radiofrequency catheter ablation performed in the left atrium on muscle sympathetic nerve activity (MSNA) have not been assessed. The results of this study show that radiofrequency catheter ablation raised cardiac parasympathetic activity and decreased MSNA during the procedure. One day postablation, MSNA rose and cardiac parasympathetic activity fell. We speculate that the partial autonomic afferent denervation induces these effects on autonomic activity.

Radiofrequency catheter ablation prior to percutaneous coronary intervention in patients with atrial fibrillation coexisting with stable coronary artery disease: a single-center pilot study.

Atrial fibrillation (AF) frequently coexists with cardiovascular disease (CAD) in a clinical setting. However, the optimum therapy for AF patients who have concomitant CAD is unclear. We retrospectively examined the efficacy and safety of radiofrequency catheter ablation (RFCA) prior to percutaneous coronary intervention (PCI) in patients with AF who had concomitant stable CAD. Between January 2014 and December 2015, a total 264 patients (179 men; mean age, 65.5 ± 10.1years) who were referred to undergo a first RFCA procedure were reviewed in this study. Of the 264 patients, 41 (15.5%) had stable CAD detected by multi-detector computed tomography before RFCA. Thirty-seven patients who had AF with stable CAD were divided into two treatment arms: (1) RFCA prior to PCI (n = 13) and (2) PCI prior to RFCA (n = 24) [four patients excluded because of left main coronary artery disease (LMCA) or triple vessel disease (TVD)]. The median follow-up was 14 (IQR 8-19) months. There was no significant difference in AF recurrence rate after the procedure between the RFCA first group and PCI first group (P = 0.515). No symptomatic cardiovascular events occurred the during follow-up period. The PCI first group had a significantly longer duration of triple therapy (188.5 ± 167days vs 5.6 ± 24.5days, P = 0.01) and all of the four bleeding events occurred during triple therapy (P = 0.01). The results of this single-center pilot study suggested that prior RFCA in patients with AF coexisting with CAD could have fewer serious bleeding events than prior PCI.

Techniques for reducing air bubble intrusion into the left atrium during radiofrequency catheter and cryoballoon ablation procedures: An ex vivo study with a high-resolution camera

Air embolisms are serious complications during catheter ablation procedures. The aims of the present study were to determine when air bubbles enter the left atrium (LA) during catheter ablation procedures and to identify techniques that reduce air bubble intrusion. An exvivo study was performed to monitor air bubbles using a silicone heart model and a high-resolution camera. In total, 280 radiofrequency catheter and cryoballoon ablation processes were tested. Small and large air bubbles were often observed during catheter ablation processes. Many small air bubbles arose during sheath flushing at fast speeds (15 mL/2 s) (median bubble number [quartiles]: 35 [20-53] for SL0, 35 [23-44] for Agilis, and 98 [91-100] for FlexCath) and during initial cryoballoon inflation/freezing/deflation (34 [22-47]). Large (≥1.5 mm) air bubbles were observed during Lasso catheter insertion (1 [0-1]), cryoballoon insertion (2[1-2]), and initial inflation/freezing/deflation (1 [1-3]). Massive air bubbles were observed during Optima catheter insertion into the sheath using an inserter (10 [2-15]). Sheath flushing at slow speeds (15 mL/5 s) significantly reduced the number of air bubbles. Before cryoballoon insertion, temporary balloon inflation and air bubble removal from the inflated surface were most effective in reducing air bubble intrusions. Optima catheter insertion without an inserter significantly reduced large air bubble intrusion. Air bubbles entered the LA at specific times. Techniques such as sheath flushing at slow speeds, temporary cryoballoon inflation before insertion, inserting the Optima catheter without an inserter, and avoidance of negative pressure in the LA could reduce air bubble intrusion.

Clinical Utility of Intravenous Nifekalant Injection during Radiofrequency catheter Ablation for Persistent Atrial Fibrillation.

Radiofrequency catheter ablation (RFCA) for persistent atrial fibrillation (AF) is still challenging even in RFCA-era for AF. The aim of this study was to assess the clinical utility of nifekalant, a pure potassium channel blocker,during RFCA for persistent AF. We retrospectively enrolled 157 consecutive persistentAF patientsundergoing first RFCA procedure withcomplex fractionated atrial electrogram (CFAE)ablation after pulmonary veins isolation and compared outcomes between patientswith (NFK group: N=79) and without (No-NFK group: N=78)additional CFAE ablation using intravenous nifekalant (0.3mg/kg). Primary endpoint was 24-month atrial arrhythmia-free survival post ablation.The prevalence of AF terminationwas significantly higher in NFK group than No-NFK group (64.6% versus 7.7%, P<0.001). Arrhythmia-free survival, however, was not significantly different between 2 groups (61.5% versus 54.1%, P=0.63).There was no significant difference between 2 groups in the prevalence of recurrent atrial tachycardia(25.0% versus 23.5%, P=0.89). Arrhythmia-free survivalin patients with AF termination during procedure was significantly higher thanthose without (73.0% versus 41.0%, P=0.002; adjusted hazard ratio 0.48, 95% confidence interval 0.17-0.84, P=0.02) amongNFK group,but not amongNo-NFK group (66.7% versus 53.2%, P=0.53). Intravenous nifekalant injection during additional CFAE ablation did not improve sinus maintenancerate after RFCA procedure for AF, but AF termination by nifekalant injection could be a clinical predictor of better success rates after procedure.

Electrocardiographic left ventricular hypertrophy predicts recurrence of atrial arrhythmias after catheter ablation of paroxysmal atrial fibrillation.

Left ventricular hypertrophy (LVH) is an independent predictor of new-onset atrial fibrillation. Whether LVH can predict the recurrence of arrhythmia after radiofrequency catheter ablation (RFCA) in patients with paroxysmal atrial fibrillation (PAF) remains unclear. PAF patients with baseline-electrocardiographic LVH has a higher recurrence rate after RFCA procedure compared with those without LVH. A total of 436 patients with PAF undergoing first RFCA were consecutively enrolled and clustered into 2 groups based on electrocardiogram (ECG) findings: non-ECG LVH (218 patients) and ECG LVH (218 patients). LVH was characterized by the Romhilt-Estes point score system; the score ≥5points were defined as LVH. At 42 months' (interquartile range, 18.0-60.0 months) follow-up after RFCA, 151 (69.3%) patients in the non-ECG LVH group and 108 (49.5%) patients in the ECG LVH group maintained sinus rhythm without using antiarrhythmic drugs (P < 0.001). Patients with ECG LVH tended to experience a much higher prevalence of stroke and recurrence of atrial arrhythmia episodes compared with those without ECG LVH (log-rank P < 0.001). Multivariate analysis found the presence of ECG LVH and left atrial diameter to be independent risk factors for recurrence after adjusting for confounding factors. The presence of ECG LVH was a strong and independent predictor of recurrence in patients with PAF following RFCA.

Autonomic Responses during Atrial Fibrillation Ablation

Left atrial radiofrequency catheter ablation (RFCA) is a therapy for atrial fibrillation. RFCA may alter sensory input from left atrium and pulmonary veins. It is speculated that RFCA may alter autonomic afferents and alter indices of sympathetic function. Although prior studies have shown that RFCA may alter autonomic function, which was assessed with heart rate variability (HRV), the effects of left atrial RFCA on sympathetic nerve activity have not been assessed. In this study, we hypothesized that RFCA would raise muscle sympathetic nerve activity (MSNA) during and after the RFCA procedure. Total of 18 patients (16 M, 2 F, 57 ± 3 years, 181 ± 2 cm, 97 ± 5 kg) were studied. In Protocol 1 (n = 10), the ECG, BP and MSNA from the peroneal nerve were recorded through the RFCA procedure in the electrophysiology laboratory. In Protocol 2 (n = 8), ECG, BP and MSNA were recorded before (within one week) and one day after the RFCA in a research laboratory. In Protocol 1, MSNA was obtained prior (n = 9), during (n = 3) and just post (within 15 min, n = 7) the RFCA procedure. Compared to prior RFCA, MSNA decreased during (28.4 ± 3.7 to 16.0 ± 2.6 bursts/min, P &lt; 0.05) and just post (28.6 ± 3.1 to 16.5 ± 4.1 bursts/min, P &lt; 0.05) the RFCA. Cardiac sympathetic tone (HRV) also decreased (prior, during, post LF/HF: 0.64 ± 0.15, 0.49 ± 0.11, 0.16 ± 0.04, P &lt; 0.05, n = 10). Vagal tone (HRV indexes: RMSSD, SDSD, HF) increased during RFCA (all P &lt; 0.05, n = 10). In Protocol 2, MSNA increased one day after RFCA (21.3 ± 3.7 to 35.7 ± 2.6 bursts/min, P &lt; 0.05, n = 6), and blood pressure did not change. Vagal tone (HRV indexes) decreased (all P &lt; 0.05, n = 8), while LF/HF also tended (P = 0.09, n = 8) to decrease one day after RFCA. Despite body motions and electronic noise during the RFCA procedure, we successfully obtained MSNA recordings during the RFCA procedure. The MSNA data suggest that the sympathetic activity is suppressed, and the HRV indexes suggest that the vagal tone is activated during the procedure. We speculate that the radiofrequency energy stimulates the vagal afferents, which in turn induces the observed effects during the procedure. Our data suggest the RFCA induces autonomic denervation in the heart and induces decreases in vagal and cardiac sympathetic tone one day post procedure. The rise in the sympathetic output to muscle after the procedure may represent a compensatory response to maintain blood pressure.Support or Funding InformationSupported by American Heart Association Grant 15GRNT24480051 (Cui), Penn State Heart and Vascular Institute Penny A. Garban Endowment (Cui), National Institutes of Health Grants P01 HL096570 (Sinoway) and UL1 TR000127 (Sinoway).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Predictors of Acute Failure Ablation of Intra-atrial Re-entrant Tachycardia in Patients With Congenital Heart Disease: Cardiac Disease, Atypical Flutter, and Previous Atrial Fibrillation.

BackgroundIntra‐atrial re‐entrant tachycardia (IART) in patients with congenital heart disease (CHD) increases morbidity and mortality. Radiofrequency catheter ablation has evolved as the first‐line treatment. The aim of this study was to analyze the acute success and to identify predictors of failed IART radiofrequency catheter ablation in CHD.Methods and ResultsThe observational study included all consecutive patients with CHD who underwent a first ablation procedure for IART at a single center from January 2009 to December 2015 (94 patients, 39.4% female, age: 36.55±14.9 years). In the first procedure, 114 IART were ablated (acute success: 74.6%; 1.21±0.41 IART per patient) with an acute success of 74.5%. Cavotricuspid isthmus–related IART was the only arrhythmia in 51%; non–cavotricuspid isthmus–related IART was the only mechanism in 27.7% and 21.3% of the patients had both types of IART. Predictors of acute radiofrequency catheter ablation failure were as follows: nonrelated cavotricuspid isthmus IART (odds ratio 7.3; confidence interval [CI], 1.9–17.9; P=0.04), previous atrial fibrillation (odds ratio 6.1; CI, 1.3–18.4; P=0.02), transposition of great arteries (odds ratio, 4.9; CI, 1.4–17.2; P=0.01) and systemic ventricle dilation (odds ratio 4.8; CI, 1.1–21.7; P=0.04) with an area under the receiver operating characteristic curve of 0.83±0.056 (CI, 0.74–0.93, P=0.001). After a mean follow‐up longer than 3.5 years, 78.3% of the patients were in sinus rhythm (33.1% of the patients required more than 1 radiofrequency catheter ablation procedure).ConclusionsAlthough ablation in CHD is a challenging procedure, acute success of 75% can be achieved in moderate–highly complex CHD patients in a referral center. Predictors of failed ablation are IART different from cavotricuspid isthmus, previous atrial fibrillation, and markers of complex CHD (transposition of great arteries, systemic ventricle dilation).

Predictors of arrhythmia recurrence in patients with heart failure undergoing left atrial ablation for atrial fibrillation.

Atrial fibrillation (AF) ablation is increasingly used in patients with reduced left ventricular ejection fraction (LVEF). The aim of the present study was to evaluate the long-term results of a single radiofrequency catheter ablation procedure in heart failure (HF) patients with AF. We tested the hypothesis that left atrial ablation is an effective therapeutic modality in patients with heart failure. Our study included HF patients with LVEF <50% who underwent catheter ablation for AF at our department between January 2010 and March 2017. All patients underwent our institution's protocol for follow-up post-ablation. The study enrolled a total of 38 patients (mean age, 54.1 ± 12.2 years; 28 [73.7%] males; mean LVEF, 38.2% ± 6.3%). After a mean follow-up period of 38.2 months (range, 5-92 months), 28 patients (73.7%) were free from arrhythmia recurrence. In multivariate analysis, early arrhythmia recurrence (P = 0.03) and amiodarone antiarrhythmic drug administration (P = 0.003) remained independent predictors of arrhythmia recurrence. The main findings of this study are that (1) a single radiofrequency catheter ablation procedure is an effective and safe modality for AF in patients with concomitant HF; (2) after a mean 3.3 years of follow-up, 73.7% of HF patients remained in sinus rhythm; and (3) early arrhythmia recurrence was a significant predictor of arrhythmia recurrence after the blanking period.

Clinical Characteristics and Efficacy of Radiofrequency Catheter Ablation in the Treatment of Elderly Patients with Atrial Fibrillation

ObjectiveThis study aims to investigate the clinical characteristics and therapeutic effect of radiofrequency catheter ablation (RFCA) in elderly patients with atrial fibrillation (AF). Materials and MethodsThis retrospective study included 668 patients with AF who underwent RFCA in our hospital from June 2010 to June 2015. Patients were divided into 2 groups according to age: group E (≥60 years old, n = 308) and group N (<60 years old, n = 360). Ablation endpoints included the following 3 points: (1) all preset ablation lines were completed; (2) all pulmonary veins were electrically isolated; and (3) negative evoked results were achieved. The success of follow-up was defined as patients who did not have an atrial arrhythmia attack for at least 3 months without the administration of antiarrhythmia drugs. ResultsClinical characteristics of elderly patients with AF: the proportion accounted for by female patients with AF, patients with hypertension, and patients with a CHADS2 score ≥2 points was significantly higher than that in group N (P < 0.001). RFCA procedure and safety: differences in the success rate of the first operation and severe complications were not statistically significant (P > 0.05). Postoperative follow-up: the follow-up period was between 6 and 12 months after operation. Differences in the proportion of patients with repeated ablation and total success rate were not statistically significant (P > 0.05). ConclusionsAlthough elderly patients with AF had more clinical complications, no differences in the success rate of RFCA and postoperative complications between the 2 groups were found. RFCA is a safe and effective treatment for elderly patients with AF.

Metabolic benefits of rivaroxaban in non-valvular atrial fibrillation patients after radiofrequency catheter ablation.

Rivaroxaban is a new oral anticoagulant for stroke prevention in patients with non-valvular atrial fibrillation (NVAF), which has less drug-food interaction than warfarin. We conducted this prospective randomized study to evaluate the metabolic benefits as well as the safety and efficacy with rivaroxaban versus warfarin in patients with NVAF following radiofrequency catheter ablation (RFCA). From April to July 2014, 60 patients with NVAF undergoing RFCA were prospectively enrolled in our study. Following RFCA, all patients were randomly assigned to receive rivaroxaban (Group R, n=30) or warfarin (Group W, n=30). Metabolic indices including serum total protein, albumin, globulin, and high-density lipoprotein (HDL) as well as bleeding, stroke, and systemic thromboembolism events were evaluated and compared during follow-up after 15, 30, 60, and 90 d of RFCA procedure. Serum total protein, albumin, globulin, and HDL levels were all significantly elevated at each follow-up stage in Group R when compared to the baseline (P<0.05 respectively). In Group W, the metabolic indices decreased at first and then had an increasing trend. There were no deaths or thromboembolic complications in each group. The prevalence of total bleeding complications was similar between Group R and Group W (11/30, 36.7% vs. 10/30, 33.3%, P=0.79). Patients with NVAF receiving rivaroxaban after RFCA procedures appear to benefit from a metabolic perspective compared with warfarin, providing practical clinical reference for the choice of the anticoagulant. Rivaroxaban seems to be as safe and effective in preventing thromboembolic events as warfarin for these patients.