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Atrial Lesions (atrial + lesion)
Selected AbstractsProarrhythmia of Circumferential Left Atrial Lesions for Management of Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2006EMILE G. DAOUD M.D. Background: After circumferential ablation for atrial fibrillation, new onset left atrial flutter (LA Flr) may occur. This study assessed the relationship between induced and clinical episodes of LA Flr, the rate of spontaneous resolution of LA Flr, and the proarrhythmic effect of circumferential ablation. Methods and Results: A total 112 patients underwent circumferential LA ablation for atrial fibrillation. Immediately after completion of the ablation, LA Flr was induced in 43 of 112 (38%) patients, but was not targeted for ablation. During follow-up (14 ± 4 months), new onset LA Flr occurred in 28 of 112 (25%) patients; however, the presence of inducible LA Flr did not identify those patients with clinical LA Flr (P = 0.6). In comparison to episodes of atrial fibrillation occurring before circumferential ablation, LA Flr was associated with a faster ventricular rate (124 ± 19 beats/min vs 91 ± 16 beats/min, P < 0.001), and was more likely to be persistent requiring cardioversion (86% vs 32%, P = 0.01). By ,4 months postcircumferential ablation, clinical LA Flr resolved in 18 of 28 patients (64%). A second ablation procedure for LA Flr was performed in 9 of 10 patients. Of the 17 morphologies, 16 (94%) LA Flr circuits were successfully ablated. Conclusions: (1) LA Flrs that are induced immediately after circumferential ablation for atrial fibrillation do not identify those patients who require a second ablation procedure for clinical LA Flr; (2) Since the majority of clinical LA Flrs spontaneously resolve, ablation of LA Flr should be postponed several months; and (3) new onset LA Flr after ablation for atrial fibrillation is likely a manifestation of the proarrhythmic effect of ablation lines in the LA. [source] Percutaneous Catheter Ablation Procedures for the Treatment of Atrial FibrillationJOURNAL OF CARDIAC SURGERY, Issue 3 2004Anthony R. Magnano M.D. Given the success of the surgical Maze procedure, initial catheter-based approaches involved creation of linear atrial lesions. Success rates were low and utility was limited by a high complication rate and long procedural times. The recent discovery that AF is often initiated by atrial ectopic beats has resulted in therapies designed to target the ectopic sources, particularly those within the pulmonary veins. Experience and technological advances have improved the efficacy and safety of such procedures. This article will review catheter ablation procedures for the maintenance of sinus rhythm in patients with AF. (J Card Surg 2004;19:188-195) [source] Esophageal Luminal Temperature Measurement Underestimates Esophageal Tissue Temperature During Radiofrequency Ablation Within the Canine Left Atrium: Comparison Between 8 mm Tip and Open Irrigation CathetersJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2008JENNIFER E. CUMMINGS M.D. Introduction: Evaluation of luminal temperature during left atrial ablation is used clinically; however, luminal temperature does not necessarily reflect temperature within the esophageal wall and poses a risk of atrioesophageal fistula. This animal study evaluates luminal esophageal temperature and its relation to the temperature of the external esophageal tissue during left atrial lesions using the 8 mm solid tip and the open irrigated tip catheters (OIC). Methods and Results: A thermocouple was secured to the external surface of the esophagus at the level of the left atrium of the dogs. Luminal esophageal temperature was measured using a standard temperature probe. In four randomized dogs, lesions were placed using an 8 mm solid tip ablation catheter. In six randomized dogs, lesions were placed using the 3.5 mm OIC. The average peak esophageal tissue temperature when using the OIC was significantly higher than that of the 8 mm tip catheter (88.6°C ± 15.0°C vs. 62.3°C ± 12.5°C, P < 0.05). Both OIC and 8 mm tip catheter had significantly higher peak tissue temperatures than luminal temperatures (OIC: 88.6°C ± 15.0°C vs 39.7°C ± 0.82°C, P < 0.05) (8 mm: 62.3°C ± 12.5°C vs 39.0 ± 0.5°C, P < 0.05). Both catheters achieved peak temperatures faster in the tissue as compared to the lumen of the esophagus, although the tissue temperature peaked significantly faster for the OIC (OIC: 25 seconds vs 90 seconds, P < 0.05) (8 mm: 63 seconds vs 105 seconds, P < 0.05). Conclusion: Despite the significant difference in actual tissue temperatures, no significant difference was observed in luminal temperatures between the OIC and 8 mm tip catheter. [source] Atrial Linear Lesions: Feasibility Using CryoablationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2006KLAUS KETTERING Background: Long linear lesions are created in the left atrium to modify the atrial substrate, thereby curing atrial fibrillation. The creation of long linear left atrial lesions using radiofrequency (RF) ablation is time consuming and difficult. Furthermore, it might result in significant complications. Cryoablation might overcome some of the disadvantages of RF ablation. Therefore, the aim of our study was to assess whether the creation of a long linear lesion is possible using cryotherapy. Methods: A right atrial septal linear lesion was created in six pigs (median weight: 50 kg; range: 40,60 kg). The ablation procedure was performed with a 7-F Freezor cryocatheter. The nonfluoroscopic mapping system LocaLisa was used as a navigation tool. At each point, freezing was maintained at the lowest attainable temperature (,75°C) for 4 minutes. The CARTO system was used for the evaluation of the linear lesions. Furthermore, all animals were sacrificed immediately after the ablation procedure and a postmortem examination of the lesions was performed. Additionally, an analysis of the amplitudes of the intracardiac electrograms registered via the ablation catheter was performed before and after the ablation procedure. Results: A right atrial septal linear lesion could be created successfully in all six pigs. For the performance of this ablation line, a median number of 16 cryoapplications (range, 11,26) was necessary. The amplitudes of the intracardiac electrograms registered via the ablation catheter decreased significantly after ablation. The CARTO bipolar voltage map revealed very low potentials along the ablation line and showed a sharply demarcated ablation area at the septum in all pigs. Further analysis of the CARTO map revealed an incomplete conduction block in all cases. Most of the pigs had a small gap close to the fossa ovalis. The postmortem examination of 2,3,5-triphenyl-tetrazolium chloride-stained specimens showed sharply demarcated lesions without any ulcerations. There were no major complications during the procedure. Conclusions: The creation of long linear lesions using cryoablation is feasible and safe. Lesion characteristics are different and more favorable than those created by RF. However, the aim of creating a transmural lesion and a complete conduction block remains an unsolved problem even with current cryoablation techniques. Nevertheless, growing experience and technical improvements might overcome some of the current limitations of this new technique. [source] | ||||||||||