Mechanisms of Atrial Fibrillation Patient Selection Patient Selection for AF Ablation Shown in the table are some of the many Estimated Outcomes and Risks of AF Ablation The estimates provided on this table A B C D More Less variables which may impact patient selection Single Multiple are not based on the outcomes of large Optimal Patient Optimal Patient for catheter ablation of AF, either because Success Procedure Procedures prospective multicenter clinical trials. Variable they impact patient outcomes or they reflect Optimal patient 60% - 80% 80% - 90% These estimates are based on a review of Symptoms highly minimally symptomatic symptomatic the severity of the patient’s symptoms and Less optimal patient 50% - 70% 70% - 80% the published literature. It is recognized response to antiarrhythmic drug therapy. It is that the outcomes of AF ablation depend Class 1 and 3 drugs failed ≥ 1 0 Poor candidate < 40% 40% - 60% important to recognize that there are no ab- on a large number of variables including longstanding AF type paroxysmal solute cut-offs to determine which patients those shown in the table. In addition, the persistent Major complication rates: 2% - 12% are and are not candidates for AF ablation. technique and tools used may also impact Age younger (< 70 yrs) older ( ≥ 70 yrs) Left atrial flutter 2% - 5% Although this table has suggested certain outcomes. And finally, the experience of Vascular/access related 1% - 5% LA size smaller (< 5 cm) larger ( ≥ 5 cm) age and left atrial size cut-offs to determine the operator and of the ablation center at Cardiac tamponade 0.5% - 3% Structure and Shown in the Figure is a schematic drawing of the left and right atria as viewed from Ejection fraction normal reduced which patients are better candidates for AF which the procedure is performed also the posterior. The extension of muscular fibers onto the PVs can be appreciated. In Congestive Stroke 0.5% - 2% Mechanisms of no yes ablation, these are estimates and are not impact success and complication rates. heart failure Atrial Fibrillation yellow are the four major left atrial autonomic ganglionic plexi and axons (superior based on large prospective clinical trials. PV stenosis < 1% left, inferior left, anterior right, and inferior right). In blue is the coronary sinus which Other cardiac disease no yes The only absolute contraindications for AF Phrenic nerve injury < 0.5% is enveloped by muscular fibers which have connections to the atria. Also in blue is Pulmonary disease no yes ablation identified by the consensus writ- Adapted from Circulation, Esophageal perforation < 0.2% the vein and ligament of Marshall which travels from the coronary sinus to the region ing group were the presence of a left atrial Am J Cardiol, Tex Heart Inst J Sleep apnea no yes Mitral valve entrapment < 0.1% between the left superior PV and the left atrial appendage. thrombus or the inability of a patient to be Obesity no yes Acute coronary occlusion < 0.1% B: the large and small reentrant wavelets that play a role in initiating and systemically anticoagulated during and fol- Prior stroke/TIA no yes Death < 0.1% sustaining AF. lowing the ablation procedure. C: the common locations of PV (red) and also the common sites of origin of non PV triggers (shown in green). D: a composite of the anatomic and arrhythmic mechanisms of AF. Areas of Consensus Indications for Surgical AF Ablation n If additional linear lesions are applied, line com- Follow-up and Clinical Trial Considerations A B C D Definitions, Indications, pleteness should be demonstrated by mapping or Abalation Techniques n Symptomatic AF patients undergoing other cardiac Blanking Period pacing maneuvers. surgery. n A blanking period of three months should be em- n Ablation of the cavotricuspid isthmus is recom- AF Definition n Selected asymptomatic AF patients undergoing ployed after ablation when reporting outcomes. cardiac surgery in whom the ablation can be performed mended only in patients with a history of typical n Paroxysmal AF is defined as recurrent AF(> 2 episodes) with minimal risk. atrial flutter or inducible cavotricuspid isthmus Definition of Success that terminates spontaneously within seven days. dependent atrial flutter. n Stand-alone AF surgery should be considered for n Freedom from AF/flutter/tachycardia off antiarrhyth- n Persistent AF is defined as AF which is sustained symptomatic AF patients who prefer a surgical approach, n If patients with long-standing persistent AF are mic therapy is the primary endpoint of AF ablation. beyond seven days, or lasting less than seven days but approached, ostial PV isolation alone may not be have failed one or more attempts at catheter ablation, or n For research purposes, time to recurrence of AF necessitating pharmacologic or electrical cardioversion. sufficient. Schematic of Figure shows the circumferential ablation lesions, which are created in a circumfer- are not candidates for catheter ablation. following ablation is an acceptable end point after AF n Longstanding persistent AF is defined as continuous ential fashion around the right and the left PVs. The primary endpoint of this ablation ablation, but may under represent true benefit. Common Lesion Pre-procedure Management strategy is the electrical isolation of the PV musculature. AF of greater than one-year duration. Post Procedure Management Sets Employed n Freedom from AF at various points following ablation n The term permanent AF is not appropriate in the con- n Patients with persistent AF who are in AF at the time B: some of the most common sites of linear ablation lesions. These include a “roof may be a better marker of true benefit and should be in AF Ablation text of patients undergoing catheter ablation of AF as it of ablation should have a TEE performed to screen for Anticoagulation Strategies line” connecting the lesions encircling the left and and/or right PVs, a “mitral considered as a secondary endpoint of ablation. thrombus. isthmus” line connecting the mitral valve and the lesion encircling the left PVs at the refers to a group of patients where a decision has been n Heparin should be administered during AF ablation n Adapted from Circulation, Am J made not to pursue restoration of sinus rhythm by any Atrial flutter and other atrial tachyarrhythmias level of the left inferior PV, and an anterior linear lesion connecting either the “roof Ablation Techniques procedures to achieve and maintain an ACT of 300 to Cardiol, Tex Heart Inst J. should be considered as treatment failures. line” or the left or right circumferential lesion to the mitral annulus anteriorly. Also means, including catheter or surgical ablation. 400 sec. n Ablation strategies which target the PVs and/or n An episode of AF/flutter/tachycardia detected by shown is a linear lesion created at the cavotricuspid isthmus. This lesion is generally Indications for Catheter AF Ablation n Low molecular weight Heparin or intravenous PV antrum are the cornerstone for most AF ablation monitoring should be considered a recurrence if it has placed in patients who have experienced cavotricuspid isthmus dependent atrial Heparin should be used as a bridge to resumption of n Symptomatic AF refractory or intolerant to at least procedures. a duration of 30 seconds or more. flutter clinically or have it induced during EP testing. systemic anticoagulation following AF ablation. one Class 1 or 3 antiarrhythmic medication. n If the PVs are targeted, complete electrical isolation n Single procedure success should be reported in all C: the addition of additional linear ablation lesions between the superior and inferior n Coumadin is recommended for all patients for at n In rare clinical situations, it may be appropriate to should be the goal. PVs resulting in a figure of 8 lesion set. Also shown is an encircling lesion of the trials of catheter ablation of AF. perform AF ablation as first line therapy. least two months following an AF ablation procedure. superior vena cava directed at electrical isolation of the superior vena cava. SVC n For surgical PV isolation, entrance and/or exit block n Decisions regarding the use of Coumadin more than Repeat Procedures isolation is performed if focal firing from the SVC can be demonstrated. A subset of n Selected symptomatic patients with heart failure should be demonstrated. two months following ablation should be based on the n Repeat procedures should be delayed for at least operators empirically isolate the SVC. and/or reduced ejection fraction. n Careful identification of the PV ostia is mandatory to patient’s risk factors for stroke and not on the pres- three months following initial ablation, if the patient’s n The presence of a left atrial thrombus is a contra- avoid ablation within the PVs. D: some of the most common sites of ablation lesions when complex fractionated ence or type of AF. symptoms can be controlled with medical therapy. electrograms are targeted. indication to catheter ablation of AF. n If a focal trigger is identified outside a PV at the time n Discontinuation of Warfarin therapy post ablation of an AF ablation procedure, it should be targeted if is generally not recommended in patients who have a possible. CHADs score ≥ 2. Heart Rhythm Society Tel: (202) 464-3400 1400 K St NW, Suite 500 Fax: (202) 464-3401 SM Washington DC 20005 www.HRSonline.org SM Background Shown in the figure are some of the many During the past decade, catheter ablation of atrial fibrillationvariables (AF) which has mayevolved impact rapidly patient from selection for catheter ablation of AF, either because a highly experimental unproven procedure, to its current status as a commonly performed they impact patient outcomes or they reflect POCKet GUide 0 ablation procedure in many major hospitals throughout thethe severity world.