David Tschopp

Risk of Thromboembolic Events After Percutaneous Left Atrial Radiofrequency Ablation of Atrial Fibrillation

Background— In patients with atrial fibrillation (AF), the risk of thromboembolic events (TEs) is variable and is influenced by the presence and number of comorbid conditions. The effect of percutaneous left atrial radiofrequency ablation (LARFA) of AF on the risk of TEs is unclear. Methods and Results— LARFA was performed in 755 consecutive patients with paroxysmal (n=490) or chronic (n=265) AF. Four hundred eleven patients (56%) had ≥1 risk factor for stroke. All patients were anticoagulated with warfarin for ≥3 months after LARFA. A TE occurred in 7 patients (0.9%) within 2 weeks of LARFA. A late TE occurred 6 to 10 months after ablation in 2 patients (0.2%), 1 of whom still had AF, despite therapeutic anticoagulation in both. Among 522 patients who remained in sinus rhythm after LARFA, warfarin was discontinued in 79% of 256 patients without risk factors and in 68% of 266 patients with ≥1 risk factor. Patients older than 65 years or with a history of stroke were more likely to remain anticoagulated despite a successful outcome from LARFA. None of the patients in whom anticoagulation was discontinued had a TE during 25±8 months of follow-up. Conclusions— The risk of a TE after LARFA is 1.1%, with most events occurring within 2 weeks after the procedure. Discontinuation of anticoagulant therapy appears to be safe after successful LARFA, both in patients without risk factors for stroke and in patients with risk factors other than age >65 years and history of stroke. Sufficient safety data are as yet unavailable to support discontinuation of anticoagulation in patients older than 65 years or with a history of stroke.

A Tailored Approach to Catheter Ablation of Paroxysmal Atrial Fibrillation

Background— Because the genesis of atrial fibrillation (AF) is multifactorial and variable, an ablation strategy that involves pulmonary vein isolation and/or a particular set of ablation lines may not be equally effective or efficient in all patients with AF. A tailored strategy that targets initiators and drivers of AF is a possible alternative to a standardized lesion set. Methods and Results— Catheter ablation was performed in 153 consecutive patients (mean age, 56±11 years) with symptomatic paroxysmal AF with the use of an 8-mm tip radiofrequency ablation catheter. The esophagus was visualized with barium. The pulmonary veins and left atrium were mapped during spontaneous or induced AF. Arrhythmogenic pulmonary veins were isolated or encircled. If AF was still present or inducible, complex electrograms in the left atrium, coronary sinus, and superior vena cava were targeted for ablation. The end point of ablation was absence of frequent atrial ectopy and spontaneous AF during isoproterenol infusion and noninducibility of AF. Routine energy applications near the esophagus were avoided. During follow-up, left atrial flutter developed in 19% of patients and was still present in 10% at >12 weeks of follow-up. A repeat ablation procedure was performed in 18% of patients. During a mean follow-up of 11±4 months, 77% of patients were free from AF and/or atrial flutter without antiarrhythmic drug therapy. Pericardial tamponade or transient neurological events occurred in 2% of procedures. Conclusions— A tailored ablation strategy that only targets triggers and drivers of AF is feasible and eliminates paroxysmal AF in ≈80% of patients.

Characteristics of Cavotricuspid Isthmus–Dependent Atrial Flutter After Left Atrial Ablation of Atrial Fibrillation

Background— Patients who have previously undergone ablation of atrial fibrillation may experience cavotricuspid isthmus (CTI)-dependent atrial flutter during follow-up. The effects of left atrial (LA) ablation on the characteristics of CTI-dependent flutter have not been described. Methods and Results— Fifteen patients underwent ablation of CTI-dependent flutter late after LA ablation of AF. The ECG, biatrial activation patterns, and LA voltage maps during flutter were analyzed. Thirty age- and gender-matched patients who underwent ablation of CTI-dependent flutter without prior LA ablation served as control subjects. Among the patients with prior LA ablation, mapping revealed counterclockwise activation around the tricuspid annulus in 12 of 15 patients (80%) and clockwise activation in 3 of 15 patients (20%). The flutter waves in the inferior leads were upright in 9 of the 15 patients (60%) with prior LA ablation and in none of the control subjects (P<0.001). The upright flutter waves in the inferior leads in patients with counterclockwise flutter corresponded to craniocaudal activation of the right atrial free wall. LA activation contributed little to the genesis of the flutter waves in these patients because of a significant reduction in bipolar LA voltage (0.44±0.20 versus 1.54±0.19 mV in patients with biphasic/negative flutter waves; P<0.001). Conclusions— CTI-dependent flutter that occurs after LA ablation of atrial fibrillation often has atypical ECG characteristics because of altered LA activation. In patients presenting with atrial flutter after LA ablation, entrainment mapping should be performed at the CTI even if the ECG is uncharacteristic of CTI-dependent flutter.

Short and long-term outcomes of percutaneous left atrial appendage suture ligation: Results from a US multicenter evaluation

BACKGROUND Published studies of epicardial ligation of left atrial appendage (LAA) have reported discordant results. OBJECTIVE The purpose of this study was to delineate the safety and efficacy of LAA closure with the LARIAT device. METHODS This is a multicenter registry of 712 consecutive patients undergoing LAA ligation with LARIAT at 18 US hospitals. The primary end point was successful suture deployment, no leak by intraprocedural transesophageal echocardiography (TEE), and no major complication (death, stroke, cardiac perforation, and bleeding requiring transfusion) at discharge. A leak of 2-5 mm on follow-up TEE was the secondary end point. RESULTS LARIAT was successfully deployed in 682 patients (95.5%). A complete closure was achieved in 669 patients (98%), while 13 patients (1.8%) had a trace leak (<2 mm). There was 1 death related to the procedure. Ten patients (1.44%) had cardiac perforation necessitating open heart surgery, while another 14 (2.01%) did not need surgery. The risk of cardiac perforation decreased significantly after the introduction of a micropuncture (MP) needle for pericardial access. Delayed complications (pericarditis requiring >2 weeks of treatment with nonsteroidal anti-inflammatory drugs/colchicine and pericardial and pleural effusion after discharge) occurred in 34 (4.78%) patients, and the risk decreased significantly with the periprocedural use of colchicine. Follow-up TEE (n = 480) showed a leak of 2-5 mm in 6.5% and a thrombus in 2.5%. One patient had a leak of >5 mm. CONCLUSION LARIAT effectively closes the LAA and has acceptable procedural risks with the evolution of the use of the micropuncture needle for pericardial access and the use of colchicine for mitigating the postinflammatory response associated with LAA ligation and pericardial access.

Phased RF ablation in persistent atrial fibrillation.

BACKGROUND Persistent and long-standing persistent atrial fibrillation (AF) often requires extensive and/or repeat radiofrequency (RF) ablation procedures. OBJECTIVE The Tailored Treatment of Persistent Atrial Fibrillation (TTOP-AF) study assessed the effectiveness and safety of the phased RF system in a randomized controlled comparison of medical therapy against phased RF ablation for the management of persistent and long-standing persistent AF. METHODS Patients who had failed at least 1 antiarrhythmic drug (AAD) were randomized (2:1) to ablation management (AM) or medical management (MM). AM patients were allowed up to 2 ablations. Index and retreatment procedures consisted of pulmonary vein isolation and ablation of complex fractionated atrial electrograms. MM patients received AAD changes and/or cardioversion. The primary end points of the TTOP-AF study included chronic effectiveness and safety at 6 months and acute safety within 7 days of ablation. RESULTS At 6 months, a greater proportion of AM patients achieved effectiveness off AAD (77 of 138 [55.8%]) compared to MM patients (19 of 72 [26.4%]) (P < .0001). Acutely, 92.8% (128/138) of the procedures were successful while 12.3% (17/138) experienced a serious procedure and/or device-related adverse event. The predefined acute safety end point was not met. The proportion of patients with chronic safety events did not differ significantly between groups. CONCLUSIONS Catheter ablation of persistent/long-standing persistent AF with the phased RF ablation system is effective with greater reduction of AF compared with MM. More intense anticoagulation strategies, careful attention to catheter placement relative to the pulmonary vein ostia, and elimination of electrode interaction are expected to reduce the risk of stroke, pulmonary vein stenosis, and asymptomatic cerebral emboli.

Left atrial appendage ligation with the next generation LARIAT+ suture delivery device: Early clinical experience

BACKGROUND The purpose of the study was to determine the efficacy and safety of left atrial appendage (LAA) closure with a micropuncture pericardial access approach and the new LARIAT(+) suture delivery device. METHODS Seventy-two patients with atrial fibrillation were enrolled to undergo telescopic micropuncture pericardial access and percutaneous ligation of the LAA with the LARIAT(+) device. LAA closure was confirmed with transesophageal echocardiography (TEE) and contrast fluoroscopy immediately, then with TEE at 30days and 90days post-LAA ligation. Patients were monitored for 12months by an independent clinical research organization for adverse events, stroke, embolic events and death of any cause. RESULTS 72 patients were screened for the LARIAT(+) procedure. Fourteen patients were screened failures (7 patients due to unfavorable anatomy and 7 patients with LAA thrombus). Fifty-eight patients underwent successful LAA ligation. All 58 patients had complete acute closure of the LAA. At 1month 52 of 54 patients (96.3%) had LAA closure, while at 3months 48 of 52 patients (92.3%) had LAA closure. There were no leaks greater than 3mm at both 1 and 3months. There were no device or procedural related complications, and only 1 30day adverse event involving late pericardial effusion. There were no strokes, embolic events or deaths after 12months. CONCLUSIONS LAA closure with the micropuncture pericardial access approach and the LARIAT(+) device can be performed effectively with acceptably low periprocedural adverse events.

Surgical and Concomitant Epicardial-Endocardial (Hybrid) Ablation of Persistent and Long-Standing Persistent Atrial Fibrillation

Catheter ablation of atrial fibrillation (AF) has been shown to be effective for paroxysmal AF. However, for patients with persistent or longstanding persistent AF, the success rates for catheter ablation is low. The Cox-Maze procedure is the most effective non-pharmacological treatment of AF. However, due to the need for open-heart surgery and the morbidity associated with the surgical Cox-Maze procedure, minimally invasive and epicardial-endocardial (hybrid) ablation procedures have been developed. This article will review the main surgical and hybrid approaches used for the treatment of persistent and long-standing persistent AF.

EXPERIENCE OF PERCUTANEOUS LEFT ATRIAL APPENDAGE SUTURE LIGATION: RESULTS FROM A UNITED STATES MULTICENTER EVALUATION

The limited data regarding epicardial ligation of left atrial appendage (LAA) has discordant results regarding the safety. To delineate the safety and efficacy of LAA closure with the LARIAT device for LAA ligation. This is a retrospective, multicenter registry of 712 consecutive patients (mean

Effects of eliminating complex electrograms by radiofrequency catheter ablation on spectral characteristics of atrial fibrillation

SESSION 32: CATHETER ABLATION V: New Techniques and Approaches Friday, May 6, 2005 10:45 a.m.–12:15 p.m.