Efficacy Of Radiofrequency Catheter Ablation Research Articles

Radiofrequency catheter ablation using QDOT MICRO: single-center experience in treating outflow tract premature ventricular complexes

Abstract Aims This study sought to examine the efficacy of radiofrequency catheter ablation (RFCA) for premature ventricular complexes (PVCs) originating from the outflow tracts. The investigation utilized the QDOT MICRO™ (QDOT) catheter, known for enabling a temperature-controlled ablation strategy. Methods and results The study began in November 2022 at a single center. All patients (n=100, 57% male, mean age 49±18) were prospectively and consecutively enrolled and underwent PVCs ablation with QDOT-MICRO™ catheter. The procedural and efficacy data of the study population were compared with those of a control group composed of a cohort of 100 propensity score-matched patients who underwent the same procedure with the ThermoCool® SmartTouch® Catheter using the Ablation Index strategy. Acute procedural success was defined as the elimination of the targeted PVCs at the termination of the procedure. Clinical success was defined as at least an 80% decrease in PVCs burden. Follow-up visits with 24- to 48-h Holter monitoring were performed at baseline and 1, 3, and every 3 months thereafter. Both patients with follow-up <6 months and non-outflow tracts PVCs were excluded. In the study cohort, the average PVCs burden was 21,13% (IQR: 12,50, 24,44) and the RVOT PVCs were 58% (n=58). The mean procedure and fluoroscopy times were 113±103 and 18±15, respectively, and significantly differ between both groups (p=0.02 and p<0.001, respectively). Signals detected by the microelectrodes at the effective site of ablation differed significantly from those recorded by the standard bipolar electrodes (p<0.001). No major complication occurred during the procedures, and there was no procedure-related mortality. The freedom from PVCs recurrences was 86% in the QDOT group and 84% in the STSF group.Freedom from PVCs recurrences at a mean follow-up of 11.5±1.6 months did not significantly differ between both groups (86% vs 84%, respectively; p=0.65). Conclusion This study suggests that RFCA using the QDOT MICRO™ catheter is not only effective but also comparable to the standard approach for treating outflow tract PVCs. Moreover, the study highlights shorter fluoroscopy and procedure times, reinforcing the catheter's efficiency and safety. The use of microelectrodes proved beneficial in enhancing precision in RF delivery.

Progress in Echocardiography for Evaluating the Efficacy of Radiofrequency Catheter Ablation in Patients with Premature Ventricular Complexes

Progress in Echocardiography for Evaluating the Efficacy of Radiofrequency Catheter Ablation in Patients with Premature Ventricular Complexes

Efficacy of Radiofrequency Catheter Ablation versus Antiarrhythmic Drugs in Treating High Burden Premature Ventricular Contractions in Children with Structurally Normal Heart

Abstract Background Scarce literature on whether antiarrhythmic drugs (AADs) or radiofrequency catheter ablation (RFCA) is more efficacious when treating idiopathic high burden premature ventricular contractions (PVCs) in children with many questions remain unanswered in this age group. Objectives To compare the efficacy of RFCA versus AADs on high burden idiopathic PVCs in children. Methods A total of 60 eligible child ≤18 years with High burden PVCs (≥10% of total beats per day) that were treated by either AADs (group A) or RFCA (group B). Both Baseline and followup clinical symptoms were collected, Physical examination, repeat standard ECG, standard or 12-lead Holter recording, and echocardiography were performed. Results Among RFCA (n = 30) and AADs (n = 30) groups, treatment success was 80.0% and 20.0% respectively, while AADs medications cessation was 73.3% and 26.7% respectively, the differences were statistically significant. Conclusion RFCA appears to be more efficacious than AADs in PVC reduction and consequently AADs medications cessation postablation. Performing RFCA in children with classical mapping and navigation was a safe and highly effective therapeutic option. Abbreviations AADs: antiarrhythmic drugs; BBB: bundle branch block; CCB: calcium channel blocker; ECG: electrocardiogram; LVEDD: left ventricular end-diastolic dimension; LVEF: left ventricular ejection fraction; LVESD: left ventricular end-systolic dimension; LVOT: left ventricular outflow tract; NSVT: non sustained ventricular tachycardia; PVC: premature ventricular contraction; RFCA: radiofrequency catheter ablation; RV: right ventricular/ventricle; RVOT: right ventricular outflow tract

Radiofrequency catheter ablation for paroxysmal supraventricular tachycardia in children: Insights on its safety and efficacy from a lower middle-income country.

OBJECTIVE: Radiofrequency catheter ablation (RFCA) is a safe and effective treatment for paroxysmal supraventricular tachycardia in adults. However, data on its use in children, particularly from low- and middle-income countries, are limited. This study aimed to evaluate the safety and efficacy of RFCA in children with paroxysmal supraventricular tachycardia from Vietnam. METHODS: A prospective study was conducted from January 2009 to July 2016 at the University Medical Center, Ho Chi Minh City, Vietnam. Ninety-five children diagnosed with paroxysmal supraventricular tachycardia were enrolled; 90 patients underwent cardiac electrophysiology and RFCA. The patients were followed up for 3-12 months, with a mean follow-up period of 7.5 ± 2.3 months. RESULTS: The average age of the patients was 10.5 ± 3 years, with the youngest patient being 4 years old; 46.3% of the patients were female and 53.7% were male. The patients' average weight was 35.2 ± 9.6 kg. Atrioventricular reentrant tachycardia accounted for 72.6% of the cases and atrioventricular nodal reentrant tachycardia for 27.4% of the cases; no patients had atrial tachycardia. The success rate of RFCA was 98.9% (89/90 patients). During the 12-month follow-up, 5.6% of the patients experienced recurrence but were successfully treated with a second ablation. No severe complications were reported during the procedure and follow-up. CONCLUSIONS: This study found RFCA to be a safe and effective treatment for paroxysmal supraventricular tachycardia in children. It demonstrated a high success rate and low recurrence and complication rates for RFCA in children, thereby highlighting the potential advantages of the procedure as a treatment option.

Electrocardiogram Parameters That Affect the Success Rate of Radiofrequency Ablation in Patients with Outflow Tract Ventricular Premature Complexes.

Objectives The objectives of this study are to assess the efficacy of radiofrequency catheter ablation (RFCA) in patients with outflow tract (OT) ventricular premature complexes (VPCs) and to explore the electrocardiographic (ECG) features of initially successful procedures. Methods Based on the outcome of ablation, 154 consecutive patients with OT-VPCs who underwent RFCA from January 2017 to December 2019 were divided into two groups. The rate of successful procedures and the ECG features were analyzed and compared between the two groups. Results The highest success rate was found in patients with VPCs from the right ventricular outflow tract (RVOT), and the lowest success rate was evident among patients with complexes from both the RVOT and the left ventricular OT (LVOT). The patients with successful procedures (136) reflected a lower pseudo delta wave ratio (16.2% vs. 44.4%, P < 0.01), a smaller R-wave amplitude in lead V1 (V1) (0.23 ± 0.24 mV vs. 0.35 ± 0.44 mV, P < 0.05), shorter intrinsicoid deflection time in lead V2 (V2) (44.00 ± 18.33 ms vs. 57.41 ± 20.67 ms, P < 0.01), a shorter RS duration in V2 (93.67 ± 21.33 ms vs. 106.93 ± 18.76 ms, P < 0.01), and smaller R/S-waveratios in V2. Furthermore, multivariate analysis demonstrated that RS duration in V2 was above 109.17 ms and R/S ratio in V2 was above 0.28, forecasting a failed procedure. Conclusions The ECG predictors of failed ablation were characterized by RS duration and R/S ratio in V2.

Contact force guided radiofrequency current application at developing myocardium

Catheter contact is akey determinantfor lesion size in radiofrequency catheter ablation (RFA). Monitoring of contact force (CF) during RFA has been shown to improve efficacy of RFA in experimental settings as well as in adult patients. Coronary artery narrowing after RFA has been described in experimental settings as well as in children and adults and may be dependent from catheter contact. The value of CF monitoring concerning these issues has not been systematically studied yet. Value of high versus low CF during RFA in piglets was studied to assess lesion size and potential coronary artery involvement mimicking RFA in small children. RFA with continuous CF monitoring was performed in 24 piglets (median weight 18.5 kg) using a 7 F TactiCath Quartzradiofrequency (RF) ablation catheter (Abbott). A total of 7 lesions were induced in each animal applying low (10-20 g) or high (40-60 g) CF. RF energy was delivered with a target temperature of 65°C at 30 W for 30 s. Coronary angiography was performed prior and immediately after RF application. Animals were assigned to repeat coronary angiography followed by heart removal after 48 h (n = 12) or 6 months (n = 12). Lesions with surrounding myocardium were excised, fixated, and stained. Lesion volumes were measured by microscopic planimetry. A total of 148 RF lesions were identified in the explanted hearts. Only in the subset of lesions at the AV annulus 6 month after ablation, lesion size and number of lesions exhibiting transmural extension were higher in the high CF group compared to low CF. In all other locations CF had no impact on lesion size and mural extension after 48 h as well as after 6 months. Additional parameters such as lesion size index and force time integral were also not related to lesion size. Coronary artery damage was present in two animals after 48 h and in one after 6 months and was not related to CF. In our experimental setting, lesion size in piglets was not related to catheter CF. Transmural extension of the RF lesions involving the layers of the coronary arteries was frequently noted irrespective of CF. Coronary artery narrowing was present in 3/24 animals and was not related to CF. In infants and toddlers, low CF (10-20 g) may be of adequate effect. Impact of CF monitoring during conventional RF ablation in children requires further investigation.

Radiofrequency Lesion Quality Markers: Current State of Knowledge

The long-term efficacy of radiofrequency catheter ablation is highly dependent on the location and size of the lesions delivered via the ablation catheter. This is particularly the case for radiofrequency ablation for atrial fibrillation, where contiguous, transmural lesions are required for durable pulmonary vein isolation. Therefore, reliable lesion quality markers that accurately relate to lesion size in the context of 3D mapping have been sought to improve the reliability of conduction block. Force–time integral, Ablation Index and Lesion Size Index are metrics currently used in clinical practice. Several studies have shown better clinical outcomes using these indices compared with using contact force alone or no marker at all. A theoretical limitation of these composite lesion indices is that they rely on input values such as contact force, application duration and power. A recent technology assessessing local tissue impedance (an output measure) has shown promising results. Temperature, another output measure, is not routinely used due to the significant impact of catheter irrigation on readings, but two recent catheter technologies have sought to overcome this obstacle. This paper provides an update on the current knowledge on these lesion quality markers.

Long term prognosis in patients with pulmonary hypertension undergoing catheter ablation for supraventricular tachycardia

Various forms of supraventricular tachycardia (SVT) occur in patients with severe pulmonary hypertension (PH). Despite the high efficacy of radiofrequency catheter ablation (RFCA) for SVT, insufficient data exist regarding patients with PH. Thirty SVTs in 23 PH patients (age 47 [35–60] years; mean pulmonary artery pressure 44 [32–50] mmHg) were analyzed. Procedural success rate, short- and long-term clinical outcomes, were evaluated during a median follow-up of 5.1 years. Single-procedure success rate was 83%; 94% (17/18) in typical atrial flutter, 73% (8/11) in atrial tachycardia (AT), and 100% (1/1) in atrioventricular nodal reentrant tachycardia. Antiarrhythmic drugs, serum brain natriuretic peptide levels and number of hospitalizations significantly decreased after RFCA than that before (p = 0.002, 0.04, and 0.002, respectively). Four patients had several procedures. After last RFCA, 12 patients had SVT and 8 patients died. Kaplan–Meier curves showed that patients with SVT after the last RFCA had a lower survival rate compared to those without (p = 0.0297). Multivariate analysis identified any SVT after the last RFCA as significant risk factor of mortality (hazard ratio: 9.31; p = 0.016). RFCA for SVT in patients with PH is feasible and effective in the short-term, but SVT is common during long-term follow-up and associated with lower survival.

Clinical Safety and Efficacy of Ablation for Atrial Fibrillation Patients With a History of Stroke.

Objectives: To evaluate the clinical safety and efficacy of radiofrequency catheter ablation for atrial fibrillation patients with a history of stroke.Methods and Results: A total of 116 symptomatic, drug-refractory AF patients with a history of stroke, and 1:2 matched patients without a history of stroke were enrolled. Of these, 28 cases occurred stroke within 3 months (Group 1), 88 cases with stroke history longer than 3 months (Group 2), and 232 cases without stroke (Group 3). PVI was performed in all patients, extended to ablation of linear lesions ablation. The periprocedural stroke rates and other procedure-related in-hospital complications did not differ significantly among the three groups. The maintenance rate of SR after the procedure showed no significant difference (p = 0.333), 52.7, 66.4, and 70.7% in Group 1, 2, and 3, respectively. Furthermore, the comparison between a history of stroke and those without it were also shown no significant difference (p = 0.351).Conclusions: Radiofrequency ablation for AF patients occurred stroke, even within 3 months is safe and effective, without higher periprocedural complication rate and recurrence rate.

A deep learning model to predict recurrence of atrial fibrillation after pulmonary vein isolation

Background and ObjectivesThe efficacy of radiofrequency catheter ablation (RFCA) in atrial fibrillation (AF) is well established. The standard approach to RFCA in AF is pulmonary vein isolation (PVI). However, a large proportion of patients experiences recurrence of atrial tachyarrhythmia. The purpose of this study is to find out whether the AI model can assess AF recurrence in patients who underwent PVI.Materials and methodsThis study was a retrospective cohort study that enrolled consecutive patients who underwent catheter ablation for symptomatic, drug-refractory AF and PVI. We developed an AI algorithm to predict recurrence of AF after PVI using patient demographics and three-dimensional (3D) reconstructed left atrium (LA) images.ResultsWe included 527 consecutive patients in the study. The overall mean LA diameter was 42.0 ± 6.8 mm, and the mean LA volume calculated using 3D reconstructed images was 151.1 ± 46.7 ml. During the follow-up period, atrial tachyarrhythmia recurred in 158 patients. The area under the curve (AUC) of the AI model based on a convolutional neural network (including 3D reconstruction images) was 0.61 (95% confidence interval [CI] 0.53–0.74) using the test dataset. The total test accuracy was 66.3% (57.0–75.6), and the sensitivity was 53.3% (34.8–71.9). The specificity was 73.2% (51.8–75.0), and the F1 score was 52.5% 34.5–66.7).ConclusionIn this study, we developed an AI algorithm to predict recurrence of AF after catheter ablation of PVI using individual reconstructed LA images. This AI model was unable to predict recurrence of AF overwhelmingly; therefore, further large-scale study is needed.

Clinical characteristics and radiofrequency ablation of focal atrial tachycardia in 125 children

Objective: To investigate the clinical characteristics of focal atrial tachycardia (FAT) and the efficacy of radiofrequency catheter ablation (RFCA) in pediatric FAT. Methods: A total of 125 children with FAT who were treated with RFCA in the First Hospital of Tsinghua University from January 2010 to July 2018 were involved in the study. The clinical characteristics, origin of FAT, success rate of RFCA and recurrence rate and complications post RFCA were retrospectively analyzed, and the efficacy and X-ray radiation were compared between two-dimensional (2D) and 3D mapping system by t test or Chi-square analysis. Results: Among the 125 children, 57 were males and 68 females, age of (7.6±3.5) years old and body weight of (27.7±13.3) kg; and 62 (49.6%) had paroxysmal FAT, and 63 (50.4%) incessant FAT. Twenty-seven patients (21.6%) presented with tachycardia-induced cardiomyopathy (TIC), and 22 of whom (81.5%) were secondary to the incessant FATs. Most of the FATs originated from atrial auricle (46/125, 36.8%). Ablation was successful in 111 children (88.8%), and the recurrence rate was 25.2% (28/111). No complications were identified in the whole group. The efficacy and safety of 3D mapping system (87 cases) was better than that of the 2D mapping system (38 cases), according to the lower recurrence rate ((19.0% (15/79) vs. 40.6% (13/32), χ2 = 3.849, P=0.049), shorter X-ray exposure time ((4.9±2.3) vs. (12.5±5.7) min, t=7.942, P<0.01) and lower radiation doses ((5.3±3.3) vs. (10.9±3.7) mGy, t=8.038, P<0.01). Conclusions: FAT in children is mainly originated from atrial auricle, and incessant FAT is prone to progress to tachycardia-induced cardiomyopathy. RFCA is safe and effective for drug-resistant or drug-intolerant FAT in children, and 3D mapping system should be preferred.

Late gadolinium enhancement location and transcatheter ablation efficacy in a large cohort of patients affected by myocarditis with arrhythmic manifestation

Abstract Introduction Myocarditis is a complex inflammatory disease, usually secondary to viral infections or immune system dysregulation, with extremely heterogeneous clinical manifestations. Among them, potentially life-threatening ventricular arrhythmias (VA) may present at any stage of the disease as an expression of myocardial electrical instability. Purpose Our aim was to evaluate the efficacy of radiofrequency catheter ablation (RFCA) of VA in our large cohort of myocarditis, trying to understand the predictors of RFCA success. Methods and results 144 patients (61 men; age 43 [29–54] years) with history of myocarditis with arrhythmic presentation (118 biopsy-proven, 82%) composed our population. At presentation, 26% of patients suffered of ventricular tachycardia (VT) while in 17% cardiac arrest occurred: overall 49 patients (35%) were implanted with an ICD. The median left ventricular ejection fraction (LVEF) was 58% (48–61%). An intensive non-invasive and invasive work-up was performed: 104 patients underwent cardiac magnetic resonance (CMR) that showed late gadolinium enhancement (LGE) in 67 of them (63%). In 37 patients LGE was found in the anteroseptal portion of the left ventricle: this pattern showed association with major arrhythmic relapse (VT and ventricular fibrillation) during follow up (Fig. 1; OR 4.0, CI 95% 1.14–14.1, p=0.03). 95 patients underwent endocardial RFCA, using contact electroanatomic mapping. Interestingly, in patients with anteroseptal LGE RCFA didn't affect significantly the arrhythmic relapse (OR 5, CI 95% 0.9–33, p=0.06). Otherwise RFCA prevent arrhythmic relapse in patients that showed LGE in ventricular portion other than the anteroseptal one (OR 0.027, IC 95% 0.002–0.40, p&amp;lt;0.01). During a median follow-up of 735 days (418–2168) 6 deaths occurred: logistic regression on all-cause death showed LVEF and VT at presentation as the only independent predictors for mortality (p=0.01). Conclusions In myocarditis patients with VA, LGE pattern predicts arrhythmic relapse during follow-up. RFCA success rate is strictly linked to scar location, being significantly higher in patients with non-anteroseptal LGE. Figure 1 Funding Acknowledgement Type of funding source: None

Clinical efficacy and safety of radiofrequency catheter ablation for atrial fibrillation in patients aged ≥80 years

To evaluate the clinical safety and efficacy of radiofrequency catheter ablation for atrial fibrillation (AF) in patients aged ≥80 years. A total of 333 AF patients aged ≥60 years were enrolled, who underwent contact force-guided radiofrequency catheter ablation with uninterrupted anticoagulation. All patients were followed-up for at least 12 months. Success was defined by the absence of episodes of AF/atrial tachycardia lasting more than 30 seconds after a 3-month blanking period, without antiarrhythmic drugs. Compared to patients aged 60-79 years (Group 2, n=244), patients aged ≥80 years (Group 1, n=89) were presented with higher rate of diabetes (36.0%vs 22.1%, P=.011), lower body mass index (23.4 ± 3.1vs 24.9 ± 3.4kg/m2 , P=.001), lower creatinine clearance (56.9 ± 16.5vs 83.3 ± 24.5mL/min, P<.001), higher CHA2 DS2 -VASc score (4.3 ± 1.3vs 3.3 ± 1.4, P<.001), and HAS-BLED score (2.2 ± 0.8vs 1.8 ± 0.8, P<.001). Wide antral pulmonary vein isolation was achieved in all patients, and there was no significant difference in procedure time, ablation time, fluoroscopy time, and complications rate between two age groups (P>.05). After a mean follow-up of 24.4 ± 9.6 months, the overall success rate was 78.2% in Group 1 and 78.9% in Group 2 (P=.622). Radiofrequency ablation with contact force sensing catheters for AF is safe and effective in selected patients aged ≥80 years.

Radio frequency catheter ablation of arrhythmias with low dose X-ray guided by three-dimensional mapping system in 14 children

Objective: To assess the feasibility and efficacy of radiofrequency catheter ablation (RFCA) of arrhythmias with low dose X-ray in children guided by three-dimensional mapping system. Methods: Fourteen children with tachyarrhythmia who were transferred to Tianjin Medical University General Hospital after being hospitalized in Tianjin Children's Hospital and underwent RFCA from April 2017 to May 2018 were included.The results of intraoperative electrophysiological examination, intraoperative X-ray dosage,the immediate success rateand complications of RFCA,and the recurrence during the follow-up for at least 6 months were recorded. Results: Among the 14 children, 11 cases were diagnosed with supraventricular tachycardia.Five cases had atrioventricular reentrant tachycardia (AVRT) which included two cases with left accessory pathway and three cases with right accessory pathway, and four cases had atrioventricular nodular reentrant tachycardia (AVNRT), one case had atrial flutter (AFL), one case had both AFL and AVNRT. One case had focal atrial tachycardia, one case had ventricular tachycardia, and one case had premature ventricular contraction. Eleven cases underwent RFCA with zero radiation, and 3 cases underwent atrial septal puncture with low dose X-ray. The exposure amounts were 3.85, 3.23 and 4.67 mGy, respectively. No complications occurred except for one case with AVRT had atrioventricular block and recovered to normal in 25 days after operation.During the follow-up of 7 to 20 months, no arrhythmias had been found in 13 cases, and one case with AVRT and AFL recurred. Conclusion: Under the guidance of three-dimensional mapping system, RFCA of tachyarrhythmia with low dose X-ray in children is feasible.

Long-term outcomes of ablation for ventricular arrhythmias in mitral valve prolapse.

Prior studies reporting efficacy of radiofrequency catheter ablation for complex ventricular ectopy in mitral valve prolapse (MVP) are limited by selective inclusion of bileaflet MVP, papillary muscle only ablation, or short-term follow-up. We sought to evaluate the long-term incidence of hemodynamically significant ventricular tachycardia (VT) or fibrillation (VF) in patients with MVP after initial ablation. We studied consecutive patients with MVP undergoing ablation for complex ventricular ectopy between 2013 and 2017 at our institution. Of 580 patients with MVP, we included 15 (2.6%, 10 women; mean age 50 ± 14years, 53% bileaflet) with complex ventricular ectopy treated with initial ablation. Over a median follow-up of 3406 (1875-6551) days or 9years, 5 of 15 (33%) patients developed hemodynamically significant VT/VF after their initial ablation and underwent placement of an implantable cardioverter defibrillator (ICD). Three of 5 also underwent repeat ablations. Sustained VT was inducible prior to index ablation in all 5 who developed VT/VF, compared to none of the 10 patients who did not develop VT/VF after index ablation (p = 0.002). Complex ventricular ectopy at index ablation was multifocal in all 5 patients who underwent repeat intervention versus 4 of 10 patients (40%) who did not (p = 0.04). All 3 patients with subsequent VT/VF who underwent repeat ablation had a new clinically dominant focus of ventricular arrhythmia and 3 of the patients with ICD had appropriate VT/VF therapies. In the long term, a subset of MVP patients treated with ablation for ventricular arrhythmias, all with multifocal ectopy on initial EP study, develop hemodynamically significant VT/VF. Our findings suggest the progressive nature of ventricular arrhythmias in patients with MVP and multifocal ectopy.

Efficacy of radiofrequency catheter ablation for premature ventricular contractions in children.

This study evaluated the efficacy and safety of transcatheter radiofrequency ablation (RFCA) in treating ventricular premature contractions (PVCs) in children, summarized the countermeasures during intraoperative ventricular fibrillation (VF), and improved the safety of ventricular premature treatment. A retrospective analysis was conducted on 75 children with PVCs who received RFCA in the Second Affiliated Hospital of Wenzhou Medical University from January 2010 to April 2019. Data including age, sex, body weight, ejection fraction, left ventricular end diastolic diameter, burden and number of PVCs/24h, origin of PVCs, and its complications were collected. Paired t test was used to compare changes in cardiac function before and after surgery. Among the 75 cases treated with RFCA, 68 were successfully ablated, giving a success rate of 90.67%. After ablation, the left ventricular ejection fraction (LVEF) of the children was 69.13 ± 3.81%, which was significantly higher than that before surgery (69.13 ± 3.81% vs. 66.21 ± 3.22%, P= 0.012). One of the patients experienced VF during the operation, with no other complications. The initial locus of origin was the anterior septum of the right ventricular outflow tract, but VF occurred during the ablation process. Mean follow-up time was 39 ± 33 months, with two recurrent cases (2.94%). Performing RFCA in children is safe and effective, with a low recurrence rate and few complications. VF is not an indication to cease surgery; the key to eliminating complications is repositioning the catheter and finding a more accurate origin point.

Long-term outcomes of radiofrequency catheter ablation for atrial fibrillation in rheumatic heart disease patients with mild mitral stenosis.

To assess efficacy of radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) in rheumatic heart disease (RHD) patients with mild mitral stenosis (MS). This retrospective cohort study included 62 consecutive RHD patients with mild MS and AF and 124 AF patients without RHD with matched age, gender, AF types as control. Procedure endpoints were defined as circumferential pulmonary vein ablation (CPVA) for paroxysmal AF, CPVA plus bidirectional block of lines, and disappearance of complex fractionated atrial electrograms for non-paroxysmal patients in both groups. Cumulative success rate during the total follow-up (RHD, 23-140months; control, 24-140months) was lower in RHD group than control (32.3 vs. 56.5%, log-rank P = 0.006). In RHD patients, the success rate was higher in paroxysmal AF patients than non-paroxysmal AF patients during the mid-term follow-up (55.0 vs. 26.2%, log-rank P = 0.041), and was similar between the two AF types during the total follow-up (45.0 vs. 26.2%, log-rank P = 0.130). Patients without mitral regurgitation (MR) or with mild MR had a higher success rate than patients with moderate MR during the total follow-up in both groups (45.0 vs. 9.1%, log-rank P = 0.014 in RHD group; 64.5 vs. 43.8%, log-rank P = 0.001 in control group). The long-term outcome of RFCA for AF in RHD patients with mild MS was mediocre and worse than that for AF patients without RHD. The severity of MR was associated with RFCA outcome in both groups. In RHD patients with mild MS, a better prognosis of paroxysmal AF than non-paroxysmal AF was observed initially but turned similar over time.

3D electronic anatomy mapping guided radiofrequency catheter ablation in 95 children with atrioventricular nodal reentrant tachycardia

Objective: To investigate the clinical features and evaluate the efficacy of radiofrequency catheter ablation (RFCA) guided by 3D electronic-anatomy mapping system (CARTO3 System) in children with atrioventricular nodal reentrant tachycardia (AVNRT). Methods: This was a retrospective case-controlled study. Data were collected from 95 children with AVNRT who underwent RFCA using CARTO3 System in the first hospital of Tsinghua University from January 2014 to December 2017. The onset age, characteristic of electrophysiology and anatomy feature of Koch triangle were analyzed. The efficacy and safety of ablation and X-ray fluoroscopy were compared with control 135 children with AVNRT who underwent RFCA without using CARTO3 System. The t test or the chi-square test was used for group comparison. Linear regression equation was established for correlation analysis. Results: The onset age of the 95 children (male 55, female 40; the average age (8.0±3.6) years) with AVNRT was (0.2-17.0) years and 23(24.2%) children were less than 3 years old. Electrophysiologic study showed that 84.2% (80 cases) was AVNRT-slow fast (SF), 11.6% (11 cases) AVNRT-slowslow and 4.2%(4 cases) AVNRT-fast slow. The phenomena of atrio-Hisian(AH) jump occurred in 65.3% and the interval of AH jump was (73.0±10.6) ms. The height of Koch triangle (CSo-His) was (22.3±5.8) mm and related with the weight of children (Y=0.171X+ 16.660, r(2)=0.224, P<0.001).The distance between the successful ablation target and the lowest point of His zone (ABL-His) was (11.7±2.6) mm. And there was no relation with the body weight(Y=-0.005X + 11.650, r(2)=0.001, P=0.780) and CSo-His (Y=0.072X+9.914, r(2)=0.030, P=0.171). The acute success rate was 97.9% (93/95) and recurrent rate was 5.4% (5/93) during follow-up. No obvious complication was reported. Compared with control group, the fluoroscopy time ((3.3±2.5) vs. (10.7±5.8) min, t=13.190, P<0.05), radiation dose ((5.4±4.9) vs. (15.5±6.3) mGy, t=13.660, P<0.05), and dose area product (514±445) vs. (2 478±415) mGy·cm(2), t=33.850, P<0.05) were decreased significantly. Conclusions: AVNRT-SF was the most common type of AVNRT. AVNRT incidence in infant and toddlers is lower than that in elder children. CSo-His is correlated with the body weight. ABL-His is relatively fixed. There is no correlation between ABL-His and the body weight and also no correlation between ABL-His and CSo-His. RFCA of AVNRT in children using the CARTO3 system is safe, effective and minimizes X-ray fluoroscopy.

Cryoballoon antral pulmonary vein isolation vs contact force-sensing radiofrequency catheter ablation for pulmonary vein and posterior left atrial isolation in patients with persistent atrial fibrillation

The role of cryoballoon ablation (CBA) for antral pulmonary vein isolation (APVI) has not been well established in persistent atrial fibrillation (PerAF). Isolation of the left atrial posterior wall (BOX) after APVI has been suggested to improve the efficacy of radiofrequency catheter ablation (RFA) in PerAF. The purpose of this study was to compare characteristics and clinical outcomes of APVI by CBA vs APVI + BOX by contact force-guided RFA (CF-RFA) in patients with PerAF. APVI was performed in 167 consecutive patients with PerAF (mean age 64 ± 9 years; left atrial diameter 46 ± 6 mm) using CBA (n = 90) or CF-RFA (n = 77). After APVI, a roofline was created in 33 of 90 patients (37%) in the CBA group and BOX was performed in all 77 patients in the CF-RFA group. During 21 ± 10 months of follow-up after a single ablation procedure, 37 of 90 patients (41%) in the CBA group (APVI) and 39 of 77 (51%) in the CF-RFA group (APVI + BOX) remained in sinus rhythm without antiarrhythmic drugs (AADs) (P = .22). During repeat ablation, APVI + BOX using CF-RFA was performed in 20 of 90 patients (22%) and in 18 of 77 patients (23%) who initially underwent CBA or CF-RFA, respectively. At 19 ± 10 months after repeat ablation, sinus rhythm was maintained in 55 of 90 patients (61%) and 52 of 77 patients (68%) in the CBA and CF-RFA groups without AADs, respectively (P = .39). In PerAF, an initial approach of APVI by CBA or APVI+ BOX by CF-RFA has a similar efficacy of 40%-50% without AADs. After repeat ablation for APVI + BOX by CF-RFA in ∼25%, sinus rhythm is maintained in 60%-70% of patients without AADs.

Long-term outcome of radiofrequency catheter ablation for persistent atrial fibrillation.

Catheter ablation has been wildly used to treat atrial fibrillation (AF) and has achieved a better efficacy for paroxysmal AF (PAF) but not for persistent AF (PerAF). Furthermore, a few data on the efficacy and safety of catheter ablation for PerAF were reported. This study aimed to investigate long-term efficacy of radiofrequency catheter ablation (RFCA) for PerAF and explore predictors of late recurrence of atrial fibrillation (LRAF).A total of 92 consecutive patients with PerAF (64 males, aged 56.42 ± 11.24 years) were enrolled in this study and accepted circumferential pulmonary vein isolation (CPVI) alone or CPVI combined additional ablation.Maintenance rate of sinus rhythm (SR) was 40.2% after a single procedure with median follow-up of 15 months and 52.2% after mean 1.3 ± 0.6 procedures with median follow-up of 26 months. Long-term SR maintenance rate was no statistical difference between patients with CPVI alone and with CPVI combined additional ablation (48.6% vs 35.1%, log rank test, P = .152). Patients with AF duration < 24 months had a higher long-term SR maintenance rate than those with AF duration ≥ 24 months (55.6% vs 30.4%, log rank test, P = .022). AF duration (OR = 1.015, 95%CI 1.001–1.030, P = .015), and early recurrence of AF (ERAF) (OR = 10.654, 95%CI 3.853–29.460, P < .001) were predictors of LRAF after a single procedure.In conclusion, long-term maintenance SR rate was 52.2% in patients with PerAF after multiple procedures with a median over 2-year follow-up. Patients with AF duration < 24 months had better outcome. AF duration and ERAF were predictors of LRAF after a single procedure.