Comparison of a Saline Irrigated Cooled-Tip Catheter to Large Electrode Catheters with Single and Multiple Temperature Sensors for Creation of Large Radiofrequency Lesions

Background: Several catheter technologies for creating large radiofrequency (RF) lesions are used in clinical practice, but direct comparisons of the pathological lesions created by these technologies are unavailable. The purpose of this study was to compare the safety and efficacy of lesions created by three different large lesion RF ablation technologies. Methods and Results: RF lesions were created in all four chambers of 15 mongrel dogs using 10 mm-tip multiple temperature sensor catheters, 10 mm tip single temperature sensor catheters, and 4 mm cooled-tip catheters. Pathological lesions were bisected, and measured after viability staining. A total of 242 (79 large-tip single sensor, 82 large-tip multiple sensor, and 81 cooled-tip) lesions were created. All atrial lesions were transmural but tended to have larger surface areas with the single thermistor large-tip catheter (73.4 ± 24.8 mm²) compared to either the multithermistor large-tip (60.9 ± 28.3 mm²) or the cooled-tip (61.9 ± 28.5 mm²) catheters (p = 0.07), especially those in the IVC-TA isthmus. Depths and volumes of ventricular lesions created by the multiple-thermistor catheter (5.0 ± 1.5 mm; 260 ± 168 mm³) were smaller than either the single thermistor (5.7 ± 1.5 mm; 428 ± 290 mm³) or cooled-tip (6.1 ± 1.8 mm; 403 ± 217 mm³) catheters (p < 0.05). The difference in the depth and volume of lesions made by large-tip single thermistor and cooled-tip catheters was not significant. Char formation occurred during 11% of ablation with the single thermistor catheter, 6% with multithermistor and 8% of cooled-tip catheter (p = NS). There were no complications of ablation. Conclusions: All three catheters reliably created full thickness atrial lesions. For ventricular lesions, depths and volumes were similar for 10 mm-tip single thermistor and cooled-tip catheters. The multithermistor catheter lesions were smaller due to more precise temperature regulated power control. Safety was similar in all 3 groups.     

Incidence of Pulmonary Vein Stenosis in Patients Submitted to Atrial Fibrillation Ablation: A Comparison of the Selective Segmental Ostial Ablation vs the Circumferential Pulmonary Veins Ablation

Introduction: Pulmonary vein (PV) stenosis is an important complication of the AF ablation and could be underestimated if their assessment is not systematically done. Selective Segmental Ostial Ablation (SSOA) and Circunferential Pulmonary Veins Ablation (CPVA) have demonstrated efficacy in atrial fibrillation (AF) treatment. In this study the real incidence of PV stenosis in patients (pts) submitted to both SSOA and CPVA was compared. Methods: Those pts with focal activity and normal left atrial size were submitted to SSOA, remaining pts were submitted to CPVA to treat refractory, symptomatic AF. Contrast enhanced magnetic resonance angiography (MRA) was routinely performed in all patients 4 months after the procedure. Results: A series of 73 consecutive patients (mean age of 51 ± 11 years; 75% male) were included. SSOA was performed in 32 patients, and the remaining 41 patients underwent to CPVA, obtaining similar efficacy rates (72% vs 76% arrythmia free probability at 12 months; log rank test p = NS). Six patients had a significant PV stenosis, all in SSOA group none in CPVA group (18.8% vs 0%; p = 0.005). All patients were asymptomatic and the stenosis was detected in routine MRA. No predictors of stenosis has been identified analysing patient procedure characteristics. Conclusion: PV stenosis is a potential complication of SSOA not seen in CPVA. The study confirms than MRA is useful for identifying patients with asymptomatic PV stenosis. Santiago Nava, A. Berruezo and A. Scalise were supported in part by a Grant from the Fundació Clínic per la Recerca Biomèdica.     

Initial description of radiofrequency catheter ablation as treatment for atrial flutter in Marfan’s syndrome: A case report and literature review

Marfan's syndrome is a common connective tissue disease with different musculoskeletal, ophthalmic and cardiac manifestations. Marfan's patients carry increased risk for cardiac arrhythmias. Only three cases of atrial flutter in Marfan's patients are described in the literature. We report a fourth case of a young Marfan's patient who presents with typical atrial flutter after motor vehicle accident. After electrical cardioversion, sinus rhythm was restored but he had recurrent atrial flutter on follow up. The patient then underwent electrophysiological study and successful radiofrequency catheter ablation of the flutter circuit. Since discharge, the patient has had no documented arrhythmias on follow up.     

Port-a-Cath perforation of the right atrium closed with an amplatzer ASD occluder.

Right atrial perforation can lead to tamponade and death. Closure devices are used for sealing of shunts in the heart. We describe an indwelling catheter that caused perforation of the right atrium and was treated with a percutaneous closure device.     

NASPE Plenary Lecture 2001. Catheter ablation: a personal perspective

Catheter ablation for control of cardiac arrhythmias was introduced 20 years ago. Since then, this technique has been applied successfully to virtually all cardiac rhythm disturbances. In this essay, some of the newer applications of ablative techniques for patients with AV nodal reentrant tachycardia, atrial flutter, and atrial fibrillation are emphasized. "AV nodal reentrant tachycardia" may involve a nodofascicular tract. A new classification of atrial flutter is proposed and various causes of atrial fibrillation are discussed.     

心悸患者窦性心律时静脉注射三磷酸腺苷对室上性心动过速的诊断作用

目的 探讨窦性心律时静脉注射三磷酸腺苷(adenosine triphosphate，ATP)对病因不明的心悸患者诊断房室结折返性心动过速(atrioventricular nodal reentrant tachycardia，AVNRT)和房室折返性心动过速(atrioventricular reentrant tachycarclia，AVRT)的价值。方法 97例疑为室上性心动过速(SVT)的心悸患者，其中心悸发作时无心电图记录者33例，有心电图记录但机制不明者64例。在窦性心律时静脉注射递增剂量ATP(5～40mg)，全部受试者均接受心内电生理检查。结果 95例完成了研究，其中ATP试验阳性67例(70．5％)，包括出现房室结双径路(atrioventricular node dual pathway，AVNDP)征象者44例(46．3％)、出现隐匿性旁路(concealed accessory pathway)征象者23例(24．2％)。ATP试验对AVNRT或AVRT的阳性预测值为94％，敏感性为86.3％，阴性预测值为64.3％，特异性为81．8％。结论 窦性心律时静脉注射ATP对心悸患者AVNRT和AVRT的阳性预测值高，是判明心悸病因的一个有价值的诊断方法。     

典型心房扑动导管射频消融终点评价

目的 :探讨峡部双向阻滞在射频导管消融 (RFCA)典型心房扑动 (AF)中的临床意义。方法 :将完成RFCA的 4 3例典型AF患者分为 3组 :①A组 ,12例 ,为静脉滴注 (静滴 )异丙肾上腺素 (1～ 5 μg/min)下不能诱发AF者 ;②B组 ,16例 ,为峡部发生双向传导阻滞者 ;③C组 ,15例 ,为在静滴异丙肾上腺素下 (1～ 5 μg/min)峡部双向传导阻滞者。对上述 3组患者进行常规的心内电生理检查及标测 ,下腔静脉至三尖瓣后叶或 (和 )三尖瓣隔叶至冠状窦口的欧氏嵴进行线性消融 ,以静滴异丙肾上腺素下不能诱发AF或峡部双向阻滞为消融终点。结果 :4 3例AF患者全部消融成功。A组中有 1例伴房室结折返性心动过速患者 ,进行房室结慢径改良后 ,AF不能被诱发。B组中有 1例并发房性心动过速及心房颤动患者 ,经过对AF线性消融后房性心动过速及心房颤动亦消失。随访 1～ 6 0个月 ,A组中有 4例复发 ,B组中有 2例复发 ,C组中无一例复发。结论 :下腔静脉、三尖瓣环和冠状窦口之间的峡部是典型AF折返环的一部分 ,RFCA治疗典型AF安全、可靠 ;静滴异丙肾上腺素下峡部双向传导阻滞作为典型AF的终点 ,可减少AF的复发     

Rhythm Versus Rate Control after Ablation and Pacing for Paroxysmal Atrial Fibrillation: Clinical Implications of the PAF 2 Trial

Four recent randomized controlled studies that compared rhythm control versus rate control therapy demonstrated that rate control therapy is an acceptable alternative to rhythm control therapy. The control of heart rate achievable with pharmacologic therapy is imperfect and, in many patients, difficult to obtain. Ablation and pacing therapy offers better control of heart rate than drug therapy.The aim of the PAF 2 trial was to evaluate the effect of antiarrhythmic drug therapy on long-term maintenance of normal sinus rhythm after ablation and pacing therapy and to evaluate the effect of maintenance of normal sinus rhythm on major clinical events, quality of life and cardiac performance and, therefore, to evaluate whether antiarrhythmic drug strategy yields any additional benefit to ablation and pacing therapy. In this multicenter randomized controlled trial, 68 patients with severely symptomatic paroxysmal atrial fibrillation were assigned, after successful atrioventricular junction ablation and pacing treatment, to antiarrhythmic drug therapy with amiodarone, propafenone, flecainide or sotalol and were compared with 69 patients assigned, after successful AV junction ablation and pacing treatment, to no antiarrhythmic drug therapy. Although patients in the antiarrhythmic drug arm had a reduction in the risk of developing chronic atrial fibrillation, there was no clinical benefit beyond that obtained with ablation and pacing alone. On the contrary, antiarrhythmic therapy was associated with more serious adverse clinical events, i.e. episodes of heart failure and hospitalization. This suggests that the control of ventricular rhythm by ablation and pacing has a greater beneficial effect on short-term clinical outcome than the preservation of atrial contraction. Therefore, the results of PAF2 study are consistent with the drug trials comparing rhythm and rate control.     

Atrial Fibrillation: What are the Targets for Intervention?

Atrial fibrillation (AF) is a difficult and growing problem in the population. While medical therapy controls symptoms in many patients, a proportion of individuals with this common arrhythmia cannot be optimally managed with drugs alone. However, truly curative therapy for AF has always been one of the holy grails of electrophysiology. The surgical maze procedure was the first to offer permanent maintenance of sinus rhythm in patients with AF but subjected the patient to open heart surgery; a catheter-based translation of the maze procedure served as proof of concept that a catheterization technique could be used to treat AF. Subsequent experience has narrowed the electrophysiologist's attention to ablation of triggers of AF, most often residing in the pulmonary veins, rather than requiring more extensive ablation lines to control the arrhythmia. The following discussion deals with the development and current status of techniques for catheter ablation of atrial fibrillation, focusing on determination of appropriate target sites for ablation.     

Large Tip Electrodes for Successful Elimination of Atrial Flutter Resistant to Conventional Catheter Ablation

The most widely accepted criterion for successful radiofrequency catheter (RFC) ablation of typical atrial flutter is the development of bi-directional isthmus block. In a subset of patients, conventional RFC ablation fails to achieve this endpoint because deeper and wider lesions are required. We investigated the efficacy of a long 8-mm tip catheter in these cases.One hundred and seventy-four consecutive patients (137 male; 61 ± 9 years) with recurrent typical atrial flutter underwent conventional RFC ablation first with a standard 4 mm tip catheter. In resistant cases (n = 52), ablation was continued using a large tip 8-mm catheter when the 4-mm tip catheter failed. Resistant atrial flutter was identified when 21 RFC pulses failed to reach the selected endpoint of bi-directional isthmus block or in cases of transient bi- directional block (at least 3 episodes).In 122 of the 174 patients (70%) conventional atrial flutter ablation was successfully performed with 13 ± 5 RFC applications. In the remaining 52 subjects (30%), the ablation procedure was completed using the large tip electrode catheter. In 30 of these 52 patients (58%), the catheter was changed because of persistent intra-atrial conduction after 21 RFC pulses and in 22 (42%) because of intermittent conduction block after 11 ± 5 applications. Using the large tip electrode catheter, the selected endpoint was achieved in all patients of both groups with 3 ± 2 RFC pulses (power output of 50–60 W, pulse duration of 60 sec). No post-procedure complications were observed. After 15 ± 5 months of follow-up, 16 patients (9%) had recurrence of atrial flutter. Five of the patients had been in the resistant group. In patients with atrial flutter resistant to conventional ablation therapy, the long tip (8-mm) catheter appears to be a safe and effective alternative to use of the conventional 4-mm tip catheter.