JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
throughout the endovascular approach with the esophageal temperature being monitored with a single sensor esophageal temperature probe placed under fluoroscopy. Venous access is performed at both the right and left femoral veins and once access is established, 3000 to 5000 units of heparin is administered. A duodecapolar catheter (St. Jude Medical, St Paul, MN) is placed along the lateral right atrial all and into the coronary sinus via the right femoral vein. A 10 Fr intravascular ultrasound catheter (St. Jude) is then placed in the right atrium to aid in performing transseptal puncture, guiding catheter location and monitoring for any cardiac complications. A 5.0- 6.0 Fr quadripolar diagnostic catheter is advanced to the right ventricular apex for pacing and sensing. With a St Jude steerable sheath positioned at the interatrial septum, a single transseptal puncture is performedwith the use of a Brockenbrough-1 needle under fluoroscopic and ultrasound guidance. Additional heparin is then administered with continual infusion and activated clotting time monitored with a goal of > 350 seconds via intraprocedural iStat (Abbot, Princeton, New Jersey) monitoring. With the use of the St. Jude Velocity Ensite-Precision mapping system and a 20-pole circular catheter, an electro-anatomical map of the left atrium and pulmonary veins is created. If the patient presented in atrial fibrillation, complex fractional atrial electrograms are also mapped during the anatomical mapping of the left atrium. Endovascular lesion sets are then applied with radiofrequency ablation with a St. Jude irrigated bidirectional ablation catheter. Wide area circumferential ablation with carinal lesions (if accessible) is performed around all pulmonary veins. A power cutoff of 30 watts and 15 watts is utilized along the anterior and posterior walls respectively. If a temperature rise in the esophagus greater than 0.2 degrees is seen, the radiofrequency ablation is discontinued in the area. A roof line is placed connecting the upper pulmonary veins along a posterior course as anatomically allowed. Integrity of the roof line is verified by changes in activation of the coronary sinus catheter compared to baseline and presence of split potentials along the line. Ablation of pre-procedural documented atrial tachycardias is then performed if deemed clinically relevant. Further lesions are then applied at the mapped complex fractionated electrogram (CFAE) sites. Confirmation of isolation of all pulmonary veins is then performed by demonstrating entrance and exit block with a St. Jude circular duodecapolar catheter. Adenosine and/or isoproterenol were not routinely used. If atrial fibrillation persists despite these lesion sets, typically no electrical cardioversion is performed to reduce the risk of post operative cerebrovascular accident while awaiting the epicardial approach. Once isolation of all pulmonary veins and integrity of roof line has been confirmed, catheter and sheaths are withdrawn from the left atrium. Once within the right atrium, a cavo-tricuspid isthmus ablation line is performed regardless of whether or not atrial flutter has beenpreviouslyobserved. Inaddition, lesions are applied along the coronary sinus os. Once completed, heparin is then reversedwith protamine and sheaths are removed from the femoral vein with manual compression utilized for hemostasis.
Implantable loop recorders we then placed in all patients to allow for continuous cardiac monitoring after discharge. Epicardial Approach The epicardial approach is performed on day two also under general anesthesia. The electrophysiologist was present in the room to direct application of lesions based on available EnSite maps from the endocardial procedure. A double-lumen endotracheal tube is utilized for selective lung ventilation and a transesophageal echocardiography probe as well as an esophageal temperature probe is in place throughout the surgical approach. Surgery is started on the patient’s right side after deflation of the right lung and with placement of three ports. Dissection is then performed to the pericardium with focus on localizing the phrenic nerve and esophagus. Right- sided ganglionated plexi (GP) are localized by burst pacing. If a “vagal response” is provoked, radiofrequency ablation is performed in this area. The right-sided pulmonary veins are then clamped utilizing the Atricure ablation clamp (Atricure, Mason, OH) and further dissection is performed posteriorly. An Atricure linear pen is utilized to ablate within the posterior left atrial wall as well as initiating the first-half of a roof line connecting the upper pulmonary veins. Focus is then turned to ablating areas that posed difficulties from an endovascular approach due to anatomy or safety. Further epicardial lesions are applied in areas of endovascularly-mapped CFAE regions as well as any clinically relevant sites of atrial tachycardia that were previously localized. After direct visualization of re-inflation of the right lung, ports are removed and access points are closed. Attention is then directed to the left side. Similarly, after deflation of the left lung, 3-4 ports are placed. Further dissection is then performed posteriorly. The ablation pen is further utilized to complete lesion sets to the posterior wall and finish the roof line as well as to complete lesions to further GPs and prior mapped sites that proved difficult via endovascular approach. The vein of Marshall is then localized and dissected from the left atrium. Ablation is performed within the ridge of the appendage. The posterior wall between the roof line and the mitral isthmus is completely ablated. Once ablations are completed, attention is turned to left atrial appendage closure using the AtriCure Atriclip. Termination of atrial fibrillation is not a procedural endpoint and once the procedure is deemed complete, if atrial fibrillation persists, direct current cardioversion is applied to restore sinus rhythm. The left lung is then reinflated under direct visualization, ports removed and the left side closed. Mitral isthmus lines are not performed. Post Operative Care Oral anticoagulation is continued in all patients post conversion to sinus rhythm for at least 3 months. Thereafter, continuation of anticoagulation agent is determined by the patients’ overall risk (CHADS-VASc score), 14,15 bleeding risk and patient preference.
J La State Med Soc VOL 169 MAY/JUNE 2017 73
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