Electro - Mapping And Spectral Analysis Of Atrial Fibrillation Maintenance

Section Ⅰ:Identification of the Crucial Substrate of Persistent Atrial Fibrillation by Isochronal Spectral AnalysisBackground The long-term outcome of radiofrequency catheter ablation in persistent atrial fibrillation (AF) patients remains unsatisfactory. Further studies to clarify the mechanism of persistent AF is important to guide ablation. The purpose of this study was to characterize the spatial and temporal distribution of atrial activation of persistent AF by isochronal spectral analysis, and to identify the crucial substrate maintaining AF.Methods From January2008to December2010,66consecutive patients with drug-refractory persistent AF underwent pure linear ablation using AF termination as the desired procedural endpoint were enrolled. Left atrial activations of persistent AF were recorded in the noncontact mapping system. Digital data with geometry and electrograms information at2048locations were acquired and processed into the Matlab system for spectral analysis. Regions with high-frequency activities and rotors were identified for each case. The dynamic electrophysiological variations and location of effective targets were routine recorded and evaluated. Comparisons were made between the locations of the effective targets and the high-frequency activation regions.Results A total of284high-frequency activation regions were detected in66patients.59(89.4%) patients showed high-frequency activation in the roof of left atrium,36(75.0%) in the ridge between left superior pulmonary vein and left atrial appendage and53(80.3%) patients in the inter-atrial septum. There were169(80.1%) effective ablation episodes were located within the high-frequency activation regions. Non-stationary rotors were found in34(51.5%) patients.Conclusions The high-frequency activations of persistent AF were located in the roof, ridge and septum of left atrium.80.1%effective ablation episodes were located within the high-frequency activation regions. Non-stationary rotors were found in34(51.5%) patients. Section Ⅱ:Noncontact Mapping and Ablation of Recurrent Atrial Tachyarrhythmias Post Circumferential Pulmonary Vein IsolationBackground This study attempted to assess the mechanism and effectiveness of catheter ablation of the recurrent atrial fibrillation (AF)/atypical atrial flutter (AAFL) using noncontact mapping after circumferential pulmonary vein isolation (CPVI).Methods The study consisted of32patients developing AF/AAFL after CPVI procedure. Left atrial (LA) activation during AF/AAFL was mapped using noncontact mapping. Radiofrequency energy was delivered to the critical substrate of AF/AAFL defined by noncontact mapping.Results Forty-eight episodes of recurrent atrial arrhythmia were mapped,3of which was the typical right atrial flutter,14was AF, while31AAFL. The AF substrate was located at LA roof in10patients, at the ridge between left superior pulmonary vein (LSPV) and LA appendage (LAA) in4. A macro-reentrant mechanism was confirmed in the31AAFL. The critical isthmus of the reentrant circuit of AAFL was located at the LSPV-LAA ridge gaps (n=20), LA roof (n=7) and mitral isthmus (n=4). For the persistent AF before index CPVI procedure, the critical substrate of recurrent AF/AAFL was mainly located at LA roof (7/10,70%); while in paroxysmal AF at LSPV-LAA ridge (13/22,59.1%) and LA roof (6/22,27.3%). Ablation eliminated tachyarrrhythmias in28patients, and27/32(84.4%) of patients were free of AF/AAFL recurrence during the follow-up of26±13(6-70) months.Conclusion Majority of recurrent AF/AAFL after CPVI is macro-reentrant mechanism and related to LSPV-LAA ridge gap and LA roof, and most of which could be eliminated by ablation. Section Ⅲ:Long-Term Follow Up of Pure Linear Ablation on Persistent Atrial Fibrillation without Circumferential Pulmonary Vein IsolationBackground The long-term outcome of radiofrequency catheter ablation in persistent atrial fibrillation (AF) patients remains controversial due to different procedural strategies. This study aimed to present clinical outcome of a pure linear ablation approach without circumferential pulmonary vein isolation (CPVI) over an extended (>5years) follow-up period.Methods From January2005to December2009,120consecutive patients (94men; age,53.6±10.3years) with drug-refractory persistent AF underwent stepwise linear ablation using AF termination as the desired procedural endpoint were enrolled. Patients were prospectively randomized to ablation using an8-mm tip (n=61) or a4-mm irrigated tip catheter (n=59).Results In the primary procedure, sinus rhythm (SR) was restored by ablation directly in75patients (62.5%), the remaining45patients whose AF could not be terminated by ablation accepted electrical cardioversion. During a median follow-up period of5.1years (3.2to7.5years), stable SR was maintained in48patients without medication (40.0%). There was a higher long-term success in patients whose AF were terminated by ablation directly than patients whose AF were not terminated (49.3vs.24.4%; p=0.007). No significant difference was found in the long-term success between different types of ablation catheter (41.0%vs.39.0%; p=0.823).Conclusion Linear catheter ablation without CPVI is effective for persistent AF. AF termination by ablation associated with a better long-term outcome than by cardioversion. The8-mm tip and4-mm irrigated tip catheters were equally safe and effective for persistent AF ablation using a pure linear ablation strategy.