Ablation of Severe Drug‐Resistant Tachyarrhythmia During Pregnancy

Ablation of Tachyarrhythmia During Pregnancy. Aims: The goal of this study was to describe mapping and ablation of severe arrhythmias during pregnancy, with minimum or no X‐ray exposure. Treatment of tachyarrhythmia in pregnancy is a clinical problem. Pharmacotherapy entails a risk of adverse effects and is unsuccessful in some patients. Radiofrequency ablation has been performed rarely, because of fetal X‐ray exposure and potential maternal and fetus complications. Group and Method: Mapping and ablation was performed in 9 women (age 24–34 years) at 12–38th week of pregnancy. Three had permanent junctional reciprocating tachycardia, and 2 had incessant atrial tachycardia. Four of them had left ventricular ejection fraction ≤45%. One patient had atrioventricular nodal reciprocating tachycardia requiring cardioversion. Three patients had Wolff‐Parkinson‐White syndrome. Two of them had atrial fibrillation with ventricular rate 300 bpm and 1 had atrioventricular tachycardia 300 bpm. Fetal echocardiography was performed before and after the procedure. Results: Three women had an electroanatomic map and ablation done without X‐ray exposure. The mean fluoroscopy time in the whole group was 42 ± 37 seconds. The mean procedure time was 56 ± 18 minutes. After the procedure, all women and fetuses were in good condition. After a mean period of 43 ± 23 months follow up (FU), all patients were free of arrhythmia without complications related to ablation either in the mothers or children. Conclusion: Ablation can be performed safely with no or minimal radiation exposure during pregnancy. In the setting of malignant, drug‐resistant arrhythmia, ablation may be considered a therapeutic option in selected cases. (J Cardiovasc Electrophysiol, Vol. 21, pp. 877‐882, August 2010)     

Radiofrequency Ablation Strategies for Intramural Ventricular Arrhythmias

Catheter ablation is an established treatment strategy for ventricular arrhythmias. However, the presence of intramural substrate poses challenges with mapping and delivery of radiofrequency energy, limiting overall success of catheter ablation. Advances over the past decade have improved our understanding of intramural substrate and paved the way for innovative treatment approaches. Modifications in catheter ablation techniques and development of novel ablation technologies have led to improved clinical outcomes for patients with ventricular arrhythmias. In this review, we explore mapping techniques to identify intramural substrate and describe available radiofrequency energy delivery techniques that can improve overall success rates of catheter ablation.     

Pacemaker Implantation After Mitral Valve Surgery With Atrial Fibrillation Ablation

BackgroundThe incidence of permanent pacemaker (PPM) implantation is higher following mitral valve surgery (MVS) with ablation for atrial fibrillation (AF) compared with MVS alone.ObjectivesThis study identified risk factors and outcomes associated with PPM implantation in a randomized trial that evaluated ablation for AF in patients who underwent MVS.MethodsA total of 243 patients with AF and without previous PPM placement were randomly assigned to MVS alone (n = 117) or MVS + ablation (n = 126). Patients in the ablation group were further randomized to pulmonary vein isolation (PVI) (n = 62) or the biatrial maze procedure (n = 64). Using competing risk models, this study examined the association among PPM and baseline and operative risk factors, and the effect of PPM on time to discharge, readmissions, and 1-year mortality.ResultsThirty-five patients received a PPM within the first year (14.4%), 29 (83%) underwent implantation during the index hospitalization. The frequency of PPM implantation was 7.7% in patients randomized to MVS alone, 16.1% in MVS + PVI, and 25% in MVS + biatrial maze. The indications for PPM were similar among patients who underwent MVS with and without ablation. Ablation, multivalve surgery, and New York Heart Association functional (NYHA) functional class III/IV were independent risk factors for PPM implantation. Length of stay post-surgery was longer in patients who received PPMs, but it was not significant when adjusted for randomization assignment (MVS vs. ablation) and age (hazard ratio [HR]: 0.81; 95% confidence interval [CI]: 0.61 to 1.08; p = 0.14). PPM implantation did not increase 30-day readmission rate (HR: 1.43; 95% CI: 0.50 to 4.05; p = 0.50). The need for PPM was associated with a higher risk of 1-year mortality (HR: 3.21; 95% CI: 1.01 to 10.17; p = 0.05) after adjustment for randomization assignment, age, and NYHA functional class.ConclusionsAF ablation, multivalve surgery, and NYHA functional class III/IV were associated with an increased risk for permanent pacing. PPM implantation following MVS was associated with a significant increase in 1-year mortality. (Surgical Ablation Versus No Surgical Ablation for Patients With Atrial Fibrillation Undergoing Mitral Valve Surgery; NCT00903370)     

Catheter Ablation of Atrial Tachycardia Following Atrial Fibrillation Ablation

Atrial tachycardias represent the second front of atrial fibrillation (AF) ablation. They are frequently encountered during the index ablation for patients with persistent AF and are common following ablation of persistent AF, occurring in half of all patients who have had AF successfully terminated. An atrial tachycardia is rightly seen as a failure of AF ablation, as these tachycardias are poorly tolerated by patients. This article describes a simple, practical approach to diagnosis and ablation of these atrial tachycardias.     

Cooled Ablation

Research on cooled ablation has been evolving for the last 10 years. Findings and current applications are reviewed. A cooled ablation catheter is approved by the FDA for use in idiopathic ventricular tachycardia (VT) patients, based on data originally submitted by Cardiac Pathways, Inc. This technology has subsequently been used by the clinicians in atrial flutter cases, nonischemic VT, epicardial accessory pathways, and atrial fibrillation. The experience at Johns Hopkins suggests that cooled radiofrequency ablation has utility in a variety of situations and in some instances has come to be the ablation system of choice.     

Ablation of Atrial Fibrillation Utilizing Robotic Catheter Navigation in Comparison to Manual Navigation and Ablation: Single‐Center Experience

Background: Robotic catheter navigation and ablation either with magnetic catheter driving or with electromechanical guidance have emerged in the recent years for the treatment of atrial fibrillation. Objective: The aim of this study was to compare our center's experience of atrial fibrillation ablation using the Hansen Robotic Medical System with our current manual ablation technique in terms of acute and chronic success, as well as procedure time and radiation exposure to both the patient and the operator. Methods: A total of 390 consecutive patients with symptomatic and drug‐resistant atrial fibrillation (289 males, 62 ± 11 years) were prospectively enrolled in the study. All patients underwent the procedure either with conventional manual ablation (group 1, n = 197) or with the robotic navigation system (RNS) (group 2, n = 193). Results: The success rate for RNS was 85% (164 patients), while for manual ablation it was 81% (159 patients) (p = 0.264) at 14.1 ± 1.3 months with AADs previously ineffective. Fluoroscopy time was significantly lower for RNS (48.9 ± 24.6 minutes for RNS vs. 58.4 ± 20.1 minutes for manual ablation, P < 0.001). Mean fluoroscopy time was statistically reduced after 50 procedures (61.8 ± 23.2 minutes for first 50 cases vs. 44.5 ± 23.6 minutes for subsequent procedures, P < 0.0001). Conclusion: Robotic navigation and ablation of atrial fibrillation is safe and effective. Fluoroscopy time decreases with experience.     

消融指数指导下射频消融术治疗心房颤动的效果研究

背景既往射频消融术治疗心房颤动主要根据术者的临床经验进行操作,而量化消融评价指标的出现可以缩短手术时间,提高手术成功率,减少并发症的发生。目的研究消融指数(AI)指导下射频消融术治疗心房颤动的有效性及安全性,以期为AI指导下射频消融术治疗心房颤动提供临床依据。方法选取2018年10月-2019年5月于中国人民解放军白求恩国际和平医院心血管内科行射频消融术的心房颤动患者69例为研究对象。采用随机数字表法将患者分为试验组(41例,在AI指导下行射频消融术)和对照组(28例,在接触压力参数指导下行射频消融术)。比较两组一般资料、手术相关指标〔包括手术总时间、X线透视时间、肺静脉隔离(PVI)单圈隔离情况、电复律使用情况、手术相关并发症发生情况〕、近期(术后3个月)复发情况,并记录试验组术中实际使用的AI。结果试验组手术总时间、X线透视时间短于对照组(P<0.05);两组PVI单圈隔离率、电复律使用率、手术相关并发症发生率比较,差异无统计学意义(P>0.05)。两组近期复发率比较,差异无统计学意义(P>0.05)。试验组术中实际使用的AI,左心房后壁多为370,功率为30 W;环肺底部多为370,功率为30 W;左心房前壁多为420,功率为35 W;左心房顶部多为390~420,功率为30 W;脊部多为420,功率为30 W。结论AI指导下射频消融术治疗心房颤动缩短了手术总时间和X线透视时间,且不增加PVI单圈隔离率、电复律使用率、手术相关并发症发生率、近期复发率,有益于术者安全、高效地完成手术。     

Electrogram-Guided Radiofrequency Catheter Ablation of Atrial Tissue Comparison with Thermometry-Guide Ablation

Objectives: To characterize a new method for radiofrequency energy titration during ablation of atrial tissue based on reduction in electrogram amplitude. To compare this method with energy titration using electrode thermometry. Background: Complications associated with anatomy-based atrial endocardial radiofrequency ablation for suppression of atrial fibrillation may be due to flawed methods of energy titration. Methods: The effect of radiofrequency ablation on electrogram amplitude was characterized in a porcine model. A method for energy titration guided by electrogram amplitude reduction (electrogram-guided) was developed and validated prospectively. Focal (smooth and trabeculated endocardial areas) and linear (smooth endocardial areas) ablation was performed comparing energy titration guided by amplitude reduction with electrode thermometry. Results: Amplitude reduction during radiofrequency application was not necessarily equal among unipolar and bipolar electrograms in the ablation region; specific patterns of reduction could be discerned, based on factors such as catheter-endocardial orientation. A criterion of >90% reduction of unipolar and/or bipolar amplitude best predicted pathologic lesion success. Electrogram-guided focal and linear lesions in smooth areas were free of lesion complications such as endocardial charring, barotrauma, or damage to contiguous extraatrial structures. However, there was a significant incidence of insufficient lesion size, principally non-transmurality, probably due to undertitration of energy. Thermometry-guided focal and linear lesions in smooth areas were uniformly transmural but frequently evidenced complications, due to overtitration of energy. Electrogram-guided focal lesions in trabeculated areas could usually not be achieved, probably due to insufficient contact of the ablation electrode with adjacent pectinate muscles. Thermometry-guided focal lesions in trabeculated areas were smaller than electrogram-guided lesions and did not evidence complications. Conclusions: Electrogram-guided lesions in smooth endocardial areas were uncomplicated but had a significant incidence of non-transmurality. Thermometry-guided lesions were uniformly transmural but were frequently complicated.