EP Lab Digest - May 2008 - (Page 10)

10 COVER STORY MAY 2008 A HYBRID APPROACH TO THE CURE OF ATRIAL FIBRILLATION Continued from cover History The patient was a 61-year-old retired male with a history of persistent AF for 7 years. His arrhythmic events were initially paroxysmal but had progressed to persistent AF. He had previously failed sotalol and propafenone. He also had mild coronary artery disease, hypertension, obesity, and hyperlipidemia. His echocardiogram revealed a left atrium (LA) size of 6.0 cm and mild mitral regurgitation (MR). Three weeks earlier he had undergone endocardial catheter-based AF ablation with ostial isolation of all four pulmonary veins, left inferior pulmonary vein (LI)-mitral isthmus line, roof line ablation, and cavotricuspid isthmus line ablation. At hospital discharge he was in sinus rhythm, which he maintained for just eight days before reverting back to AF. He was subsequently brought in for a TEE and cardioversion, and following this, the addition of amiodarone and warfarin. He maintained sinus rhythm for two days but reverted back to AF. He was increased to amiodarone 400 mg a day, but still had AF despite cardioversion. He was initiated on diltiazem 360 mg daily for rate control. He was then referred to electrophysiologist Dr. Srijoy Mahapatra in the Atrial Fibrillation Center at the University of Virginia. During his clinic visit he reported significant fatigue and a strong sense of an irregular heartbeat, and felt better when in sinus rhythm. He requested further treatment, with the hope of maintaining sinus rhythm long term. The patient was offered three treatment options: 1) continue amiodarone and undergo another attempt at cardioversion; 2) undergo another attempt at endocardial ablation; or 3) undergo surgical ablation with a Mini-Maze approach. He chose the surgical option, and was referred to Dr. Gorav Ailawadi, a cardiovascular surgeon. The thorascopic Mini-Maze was originally developed by Dr. Randall Wolf at the University of Cincinnati. 1 The procedure is a minimally invasive, off-pump, epicardial bipolar radiofrequency ablation. The procedure consists of: ablation of the ganglionic plexi (GP) of the left atrium (Figures 1A and 1B), isolation of the pulmonary veins (Figure 2), division of the ligament of Marshall (LOM), and amputation of the left atrial appendage in order to decrease the potential for left-sided clot formation and the risk for subsequent stroke. The GP of the left atrium, found in the epicardial fat pad regions, have increasingly become targets during AF ablation procedures. Excessive nerve activity is believed to be responsible for the initiation and sustaining of AF. Ablation of these GP regions in the left heart has resulted in denervation and elimination of AF. 2 The ligament of Marshall is the remnant of the left common cardinal vein, and contains nerve trunks and ganglia. 3 Surgical Procedure Per their protocol, Drs. Ailawadi and Mahapatra were both in attendance for the surgical procedure. After informed consent was obtained, general anesthetic was administered and the TEE probe was inserted. The patient was placed in the right lateral decubitus position, and the left chest was prepped and draped. Dr. Ailawadi made separate 2-10 mm incisions and a third 6 cm incision. It is important to note that the ribs are not spread during this procedure to minimize postoperative pain. The pericardium was carefully opened, avoiding injury to the phrenic nerve. The leftsided pulmonary veins were identified. A space was created between the left superior pulmonary vein and the PA. The ligament of Marshall was identified and divided. At this point, atrial mapping and stimulation were performed by Dr. Mahapatra. Entrance block was not present for the left superior vein, indicating a break in the original endocardial ablation line. Positive GP, identified by high-frequency stimulation with an ablation pen (AtriCure, Inc., West Chester, Ohio), are those in which a vagal response is found, resulting in a heart rate decrease by as much as 50%. Ganglia L7 exhibited a positive response. Dr. Ailawadi now used the dissector to encircle the left superior and inferior veins. A bipolar ablation clamp (AtriCure, Inc.) was passed carefully around the left-sided pulmonary veins, and the jaws of the clamp were closed. Four separate bipolar radiofrequency ablation lines were created. Next, with the ablation pen, GP re-mapping and stimulation were performed. No positive ganglia were found, and entrance block was obtained for the left pulmonary veins. The superior portion of the left atrium was dissected and subsequently ablated across to the right side to create a roof line lesion. Block was confirmed. The left atrial appendage Figure 1A. Left-sided pulmonary veins, ganglionic plexi, and ligament of Marshall. (2008 AtriCure, Inc. Adapted from Oklahoma Health Sciences Center). The patient was offered three treatment options: 1) continue amiodarone and undergo another attempt at cardioversion; 2) undergo another attempt at endocardial ablation; or 3) undergo surgical ablation with a Mini-Maze approach. Figure 1B. Right-sided pulmonary veins and ganglionated plexi. (2008 AtriCure, Inc. Adapted from Oklahoma Health Sciences Center) was excised. An 8 mm chest tube was then inserted and the skin was closed. Next the patient was placed in the left See A HYBRID APPROACH TO THE CURE OF ATRIAL FIBRILLATION page 12

Table of Contents Feed for the Digital Edition of EP Lab Digest - May 2008

EP Lab Digest - May 2008 Is There an Under-Referral of Women for Atrial Fibrillation Ablation? A Hybrid Approach to the Cure of Atrial Fibrillation Contents Letter from the Editor Spotlight Interview: University of Michigan Health System 10-Minute Interview: Amit J. Shanker, MD Modular EP Units: Are They Possible? One Hospital’s Experience All About My Job: Technician Supervisor (New Column!) Alcohol Septal Ablation in the Cath Lab: What is it All About? About the Canadian Heart Rhythm Society: Interview with Martin J. Gardner, MD, FRCP(C), FACC Email Discussion Group: May 2008 Second Annual Salary Survey My First Year in Electrophysiology: What Have I Got Myself Into? Highlight on Technology: Video-Audio Integration for the EP Lab On the Horizon: A New Remote Catheter Manipulation System Striving for Excellence in the Care of Cardiac Patients Five Reasons to Participate with a Professional Organization Suspected Shunting of Defibrillation Energy in the EP Lab Can Digital Music Players Cause Interference with Implantable Devices? ECG 101: Ambulatory ECG Monitoring Events Calendar Industry News and Products Classifieds Advertisers Index

EP Lab Digest - May 2008

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