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type=\u0022text\/css\u0022 rel=\u0022stylesheet\u0022 href=\u0022\/\/d282kpwvnogo5m.cloudfront.net\/sites\/default\/files\/advagg_css\/css__ce2QY63WIanKyr8eSq7eavr1XQRRmFD6ZSmwpyJi8lM__zXwFqpqmxrZOXXcd_TpBQpjuELbmIP9wBR5UuTDWAO4__YJWWMMdfCJuAFm5cUEp88OsodhO3ZA-2lzRfoBsSlk4.css\u0022 media=\u0022all\u0022 \/\u003E\n\u003Clink rel=\u0027stylesheet\u0027 type=\u0027text\/css\u0027 href=\u0027\/sites\/all\/modules\/contrib\/panels\/plugins\/layouts\/onecol\/onecol.css\u0027 \/\u003E\u003C\/head\u003E\u003Cbody\u003E\u003Cdiv class=\u0022panels-ajax-tab-panel panels-ajax-tab-panel-sageoa-tab-art\u0022\u003E\u003Cdiv class=\u0022panel-display panel-1col clearfix\u0022 \u003E\n  \u003Cdiv class=\u0022panel-panel panel-col\u0022\u003E\n    \u003Cdiv\u003E\u003Cdiv class=\u0022panel-pane pane-highwire-markup\u0022 \u003E\n  \n      \n  \n  \u003Cdiv class=\u0022pane-content\u0022\u003E\n    \u003Cdiv class=\u0022highwire-markup\u0022\u003E\u003Cdiv xmlns=\u0022http:\/\/www.w3.org\/1999\/xhtml\u0022 id=\u0022content-block-markup\u0022 xmlns:xhtml=\u0022http:\/\/www.w3.org\/1999\/xhtml\u0022\u003E\u003Cdiv class=\u0022article fulltext-view \u0022\u003E\u003Cspan class=\u0022highwire-journal-article-marker-start\u0022\u003E\u003C\/span\u003E\u003Cdiv class=\u0022section abstract\u0022 id=\u0022abstract-1\u0022\u003E\u003Ch2\u003ESummary\u003C\/h2\u003E\n            \u003Cp id=\u0022p-1\u0022\u003EThe underlying mechanisms of atrial fibrillation (AF) and its initiation are not well understood, yet catheter ablation can effectively terminate AF in many patients. This article discusses the benefits of ablation for patients with AF.\u003C\/p\u003E\n         \u003C\/div\u003E\u003Cul class=\u0022kwd-group\u0022\u003E\u003Cli class=\u0022kwd\u0022\u003EInterventional Techniques \u0026amp; Devices Arrhythmias\u003C\/li\u003E\u003C\/ul\u003E\u003Cul class=\u0022kwd-group clinical-trial\u0022\u003E\u003Cli class=\u0022kwd\u0022\u003EInterventional Techniques \u0026amp; Devices\u003C\/li\u003E\u003Cli class=\u0022kwd\u0022\u003ECardiology \u0026amp; Cardiovascular Medicine\u003C\/li\u003E\u003Cli class=\u0022kwd\u0022\u003EArrhythmias\u003C\/li\u003E\u003C\/ul\u003E\u003Cp id=\u0022p-2\u0022\u003EThe underlying mechanisms of atrial fibrillation (AF) and its initiation are not well understood, yet catheter ablation can effectively terminate AF in many patients. Ravi Kishore Amancharla, MD, Health City Cayman Islands, Grand Cayman, discussed the benefits of ablation for patients with AF.\u003C\/p\u003E\u003Cp id=\u0022p-3\u0022\u003EThere are 2 major competing theories about the mechanism of AF. The \u201cspatially localized\u201d theory suggests that AF is the result of automaticity or localized reentry, whereas the \u201cspatially meandering\u201d theory suggests that AF is the result of multiple-wave reentry. Dr. Amancharla stated that initiation of AF is likely a result of both focal triggers and abnormal substrate.\u003C\/p\u003E\u003Cp id=\u0022p-4\u0022\u003ECatheter ablation of AF focuses on likely focal triggers, and the method used depends on the location. A majority of foci are located within the pulmonary vein [Haissaguerre M et al. \u003Cem\u003EN Engl J Med\u003C\/em\u003E 1998], as the muscular sleeve of atrial tissue can be found several centimeters into the adjoining region of the vein. By placing multiple catheters into the pulmonary veins, the location of the trigger can be isolated. However, the triggers may not consistently arise from the same location; therefore, the method changes to ablation of the entire segment of the pulmonary vein. Yet, the muscle sleeve can extend deeper into the atrium, so a large portion of the pulmonary vein is disconnected from the atrium, to lower the risk of recurrence due to better isolation of the pulmonary vein. Despite these improvements, the 5-year recurrence rate at a single center was about 30% following a single procedure (\u003Ca id=\u0022xref-fig-1-1\u0022 class=\u0022xref-fig\u0022 href=\u0022#F1\u0022\u003EFigure 1\u003C\/a\u003E). According to Dr. Amancharla, these data suggest that ablation works, but multiple procedures are required for sustained success. The inconsistent results of pulmonary vein isolation may be a result of variable anatomy, inaccurate delineation of the ostium and antrum, the inability to produce an enduring transmural lesion without gaps, and targeting the wrong mechanism. Incorporating newer imaging techniques can help limit these issues, as can the use of a cryoballoon, a circular ablation catheter, and contact force ablation catheters.\u003C\/p\u003E\u003Cdiv id=\u0022F1\u0022 class=\u0022fig pos-float  odd\u0022\u003E\u003Cdiv class=\u0022highwire-figure\u0022\u003E\u003Cdiv class=\u0022fig-inline-img-wrapper\u0022\u003E\u003Cdiv class=\u0022fig-inline-img\u0022\u003E\u003Ca href=\u0022http:\/\/d282kpwvnogo5m.cloudfront.net\/content\/spmdc\/14\/24\/27\/F1.large.jpg?width=800\u0026amp;height=600\u0026amp;carousel=1\u0022 title=\u0022Ablation vs Medical Therapy in Atrial Fibrillation\u0022 class=\u0022fragment-images colorbox-load\u0022 rel=\u0022gallery-fragment-images-863862856\u0022 data-figure-caption=\u0022Ablation vs Medical Therapy in Atrial Fibrillation\u0022 data-icon-position=\u0022\u0022 data-hide-link-title=\u00220\u0022\u003E\u003Cimg class=\u0022fragment-image\u0022 alt=\u0022Figure 1.\u0022 src=\u0022http:\/\/d282kpwvnogo5m.cloudfront.net\/content\/spmdc\/14\/24\/27\/F1.medium.gif\u0022\/\u003E\u003C\/a\u003E\u003C\/div\u003E\u003C\/div\u003E\u003Cul class=\u0022highwire-figure-links inline\u0022\u003E\u003Cli class=\u00220 first\u0022\u003E\u003Ca href=\u0022http:\/\/d282kpwvnogo5m.cloudfront.net\/content\/spmdc\/14\/24\/27\/F1.large.jpg?download=true\u0022 class=\u0022highwire-figure-link highwire-figure-link-download\u0022 title=\u0022Download Figure 1.\u0022 data-icon-position=\u0022\u0022 data-hide-link-title=\u00220\u0022\u003EDownload figure\u003C\/a\u003E\u003C\/li\u003E\u003Cli class=\u00221\u0022\u003E\u003Ca href=\u0022http:\/\/d282kpwvnogo5m.cloudfront.net\/content\/spmdc\/14\/24\/27\/F1.large.jpg\u0022 class=\u0022highwire-figure-link highwire-figure-link-newtab\u0022 target=\u0022_blank\u0022 data-icon-position=\u0022\u0022 data-hide-link-title=\u00220\u0022\u003EOpen in new tab\u003C\/a\u003E\u003C\/li\u003E\u003Cli class=\u00222 last\u0022\u003E\u003Ca href=\u0022\/highwire\/powerpoint\/14799\u0022 class=\u0022highwire-figure-link highwire-figure-link-ppt\u0022 data-icon-position=\u0022\u0022 data-hide-link-title=\u00220\u0022\u003EDownload powerpoint\u003C\/a\u003E\u003C\/li\u003E\u003C\/ul\u003E\u003C\/div\u003E\u003Cdiv class=\u0022fig-caption attrib\u0022\u003E\u003Cspan class=\u0022fig-label\u0022\u003EFigure 1.\u003C\/span\u003E \n            \u003Cp id=\u0022p-5\u0022 class=\u0022first-child\u0022\u003EAblation vs Medical Therapy in Atrial Fibrillation\u003C\/p\u003E\n         \u003Cq class=\u0022attrib\u0022 id=\u0022attrib-1\u0022\u003EReproduced from Piccini JP et al. Pulmonary vein isolation for the maintenance of sinus rhythm in patients with atrial fibrillation: a meta-analysis of randomized, controlled trials. \u003Cem\u003ECirc Arrhythm Electrophys.\u003C\/em\u003E 2009;2:626\u2013633. With permission from Lippincott Williams and Wilkins\/Wolters Kluwer Health.\u003C\/q\u003E\u003Cdiv class=\u0022sb-div caption-clear\u0022\u003E\u003C\/div\u003E\u003C\/div\u003E\u003C\/div\u003E\u003Cp id=\u0022p-6\u0022\u003EIn some patients, other mechanisms beyond the pulmonary vein should be considered, particularly in patients who have persistent to permanent disease. The pulmonary vein plays a lesser role as a trigger for disease in persistent and permanent AF [Fisher JD et al. \u003Cem\u003EPacing and Clin Electrophysiol\u003C\/em\u003E 2006]. As a result, the ablation strategy should change. The atrial substrate must be identified via electrophysiologic mechanisms and structure.\u003C\/p\u003E\u003Cp id=\u0022p-7\u0022\u003EFor linear lesions, areas of the left atrium are identified to reduce the critical mass, which are required for multiple-wave reentry. Commonly used lines include the perimitral and roof lines [Cabrera JA et al. \u003Cem\u003EEur Heart J\u003C\/em\u003E 2006], which function to compartmentalize the atria into segments that reduce the risk of recurrence.\u003C\/p\u003E\u003Cp id=\u0022p-8\u0022\u003ETargeting complex potentials, as indicated by complex fractionated atrial electrograms (CFEs), is typically used as an adjuvant strategy with pulmonary vein isolation or linear ablation. CFEs are composed of \u2265 2 deflections or a continuous deflection from baseline of a prolonged activation complex over a 10-second recording. However, Dr. Amancharla commented that the opinion of most electrophysiologists is that targeting only CFEs is no longer recommended.\u003C\/p\u003E\u003Cp id=\u0022p-9\u0022\u003EAnother method that can terminate persistent AF is alcohol ablation via the Marshall vein, which is a rudimentary structure that connects the proximal coronary sinus to the atrial appendage. However, the Marshall vein also supplies multiple ganglion plexi; therefore, Dr. Amancharla postulated that the mechanism of AF termination is blockade of the autonomic nervous system.\u003C\/p\u003E\u003Cp id=\u0022p-10\u0022\u003EIn conclusion, Dr. Amancharla stated that the lesson learned from this stepwise approach of ablation is that up to \u223c87% of patients experience AF termination with 3 hours of ablation. Importantly, the trigger is terminated slowly, and the exact trigger may not necessarily be known. However, despite the limitations of ablation, it is still favored over medical therapy in patients who have been failed by an antiarrhythmic agent, according to a systematic review (\u003Ca id=\u0022xref-fig-1-2\u0022 class=\u0022xref-fig\u0022 href=\u0022#F1\u0022\u003EFigure 1\u003C\/a\u003E) [Piccini JP et al. \u003Cem\u003ECirc Arrhythm\u003C\/em\u003E 2009].\u003C\/p\u003E\u003Cul class=\u0022copyright-statement\u0022\u003E\u003Cli class=\u0022fn\u0022 id=\u0022copyright-statement-1\u0022\u003E\u00a9 2014 MD Conference Express\u00ae\u003C\/li\u003E\u003C\/ul\u003E\u003Cspan class=\u0022highwire-journal-article-marker-end\u0022\u003E\u003C\/span\u003E\u003C\/div\u003E\u003Cspan id=\u0022related-urls\u0022\u003E\u003C\/span\u003E\u003C\/div\u003E\u003Ca href=\u0022http:\/\/mdc.sagepub.com\/content\/14\/24\/27.abstract\u0022 class=\u0022hw-link hw-link-article-abstract\u0022 data-icon-position=\u0022\u0022 data-hide-link-title=\u00220\u0022\u003EView Summary\u003C\/a\u003E\u003C\/div\u003E  \u003C\/div\u003E\n\n  \n  \u003C\/div\u003E\n\u003C\/div\u003E\n  \u003C\/div\u003E\n\u003C\/div\u003E\n\u003C\/div\u003E\u003Cscript type=\u0022text\/javascript\u0022 src=\u0022http:\/\/mdc.sagepub.com\/sites\/all\/modules\/highwire\/highwire\/plugins\/highwire_markup_process\/js\/highwire_figures.js?nzow7p\u0022\u003E\u003C\/script\u003E\n\u003Cscript type=\u0022text\/javascript\u0022 src=\u0022http:\/\/mdc.sagepub.com\/sites\/all\/modules\/highwire\/highwire\/plugins\/highwire_markup_process\/js\/highwire_openurl.js?nzow7p\u0022\u003E\u003C\/script\u003E\n\u003C\/body\u003E\u003C\/html\u003E"}