Author + information
- Received February 21, 2006
- Revision received April 18, 2006
- Accepted May 8, 2006
- Published online October 3, 2006.
- Oussama M. Wazni, MD,
- Walid Saliba, MD,
- Tamer Fahmy, MD, PhD,
- Dhanunjaya Lakkireddy, MD,
- Sergio Thal, MD,
- Mohamed Kanj, MD,
- David O. Martin, MD, MPH,
- J. David Burkhardt, MD,
- Robert Schweikert, MD and
- Andrea Natale, MD⁎ ()
- ↵⁎Reprint requests and correspondence:
Dr. Andrea Natale, Section of Pacing and Electrophysiology, Electrophysiology Laboratory, Center for Atrial Fibrillation, Department of Cardiovascular Medicine, Cleveland Clinic Foundation, Desk F 15, 9500 Euclid Avenue, Cleveland, Ohio 44195.
Objectives We describe the clinical and electrophysiologic characteristics and management of post “cut and sew” Maze arrhythmias in symptomatic patients.
Background The Cox Maze procedure was developed as a surgical treatment of atrial fibrillation. Until recently, invasive electrophysiologic studies in patients with symptomatic post-operative arrhythmias in this patient population have not been described.
Methods The management and clinical course of consecutive patients with post-Maze arrhythmias refractory to antiarrhythmic drugs (AADs) between January 2000 and December 2003 are presented.
Results Twenty-three patients (15 men) presented 14 ± 14 months after Maze surgery for treatment of atrial fibrillation (AF). Eight patients underwent “cut and sew” Maze for lone AF with no other surgical indication. Fifteen patients underwent the “cut and sew” Maze procedure in addition to another surgical procedure: mitral valve surgery (11 patients) and coronary artery bypass graft surgery (4 patients). Eight patients (35%) had recurrent AF secondary to recovered conduction around the lines encircling the pulmonary veins. Five patients were documented to have focal atrial tachycardia, which was mapped to the coronary sinus in 3 patients, to the posterolateral right atrium in 1 patient, and to the left atrial (LA) septum in 1 patient. Four patients had right atrium incisional atrial flutter (AFL), and 6 had LA incisional AFL, which was mapped around the mitral valve annulus in 4 patients and around the right pulmonary veins in 2 patients. Twenty-two of the 23 patients were treated successfully with radiofrequency ablation. At 1-year follow-up, 19 patients were arrhythmia-free and taking no AADs.
Conclusions After surgical “cut and sew” Maze, approximately one-third of patients experiencing atrial arrhythmias have AF secondary to pulmonary vein-left atrium conduction recovery. Moreover, incisional AFL seems to be a common finding in this group of patients. Catheter-based mapping and ablation of these arrhythmias seems to be feasible and effective.
The Cox Maze procedure was developed as a surgical treatment of atrial fibrillation (AF) (1,2). Restoration of sinus rhythm has been reported to be successful in 75% to 95% of patients (1–6). Although previous studies have focused mainly on sinus node function, invasive electrophysiologic studies in patients with symptomatic post-operative arrhythmias in this patient population have not been described.
In this study we describe the clinical and electrophysiologic characteristics and management of post-surgical “cut and sew” Maze arrhythmias in symptomatic patients.
Between January 2000 and December 2003, 23 patients with symptomatic post-Maze arrhythmias refractory to antiarrhythmic drugs (AADs) were evaluated in our laboratories. All patients had undergone the “cut and sew” Maze procedure.
Electrophysiology study protocol
All AADs were discontinued 5 half-lives before ablation. Amiodarone was discontinued 4 to 5 months before the procedure in patients taking this medication. Coumadin was discontinued 48 h before the procedure, and all patients underwent transesophageal echocardiography to exclude intracardiac thrombi.
After informed consent, all patients underwent electrophysiological study with atrial mapping and subsequent ablation.
Right and left atrial mapping and ablation
Electrode catheters were positioned under fluoroscopic guidance. A 7-F, 20-pole catheter (2 mm inter-electrode spacing; Daig Corporation, Minnetonka, Minnesota) was placed around the tricuspid annulus, and a 6-F octapolar catheter (2 mm inter-electrode spacing, EP Technologies 1000, Sunnyvale, California) was used to record His-bundle potentials.
A 6-F quadripolar catheter (2-5-2 mm inter-electrode spacing, Daig Corporation) was placed at the right ventricular apex. Coronary sinus (CS) recordings were performed from a 6-F decapolar catheter (2-5-2 mm inter-electrode spacing, Daig Corporation) advanced through the right internal jugular vein. Mapping was performed with either a 4-mm or 8-mm tip mapping and ablation catheter. Bipolar intracardiac electrograms were used with filtering between 30 and 500 Hz. These were recorded and stored digitally on a computerized system simultaneously with 12-lead surface electrocardiograms.
The CARTO 3-dimensional electro-anatomical mapping system (Biosense Webster, Diamond Bar, California) was used for navigation mapping and ablation.
Left atrial mapping was performed via trans-septal catheterization. Intravenous heparin was given to keep the activated clotting time >350 s.
In patients with focal atrial tachycardia (AT), radiofrequency current was delivered at the site of earliest atrial activation as mapped by electro-anatomical and activation mapping.
An initial activation map during tachycardia was first done with annotation of the low-voltage and scarred areas (<0.1 mV). Areas of slow conduction having double potential or fractionated electrograms were tagged. The critical isthmus was defined by activation mapping on the CARTO system (Biosense Webster) and by entrainment. Once the circuit was identified, ablation was performed along the most accessible part of the circuit so as to transect the identified isthmus.
Successful ablation was defined as termination of atrial flutter (AFL) during ablation, demonstration of bidirectional block across the isthmus with differential pacing when possible, and identification of double potentials separated by at least 70 ms and non-inducibility of AFL by right and left atrial rapid and programmed pacing in the drug-free state and after administration of isoproterenol infusion (1–6 μg/min).
Additionally, in patients with AFL and evidence of pulmonary vein-left atrium (PV-LA) reconnection, pulmonary vein (PV) antral isolation was also performed.
In patients with recurrence of AF, PV antral isolation was performed as described previously (7,8). Intracardiac echocardiographic (ICE) guided mapping and ablation of all PV’s ostia was performed with a 10-F, 64-element phased-array ultrasound-imaging catheter (AcuNave, Acuson, Mountain View, California) introduced through an 11-F sheath via the left femoral vein. A decapolar circular mapping catheter (Biosense Webster) was used for circular mapping and isolation of all PV. Great care was exercised to avoid entanglement of the Lasso in the mitral valves, especially in patients with prosthetic valves. Ablation was extended to the pulmonary vein “antrum” in front of the tube-like portion of the pulmonary veins. Energy delivery was titrated while monitoring for microbubbles formation. Our anticoagulation protocol, with a target of activated clotting time of 350 to 400 s, has also been described previously (9).
Follow-up was scheduled at 1, 3, 6, and 12 months. Patients were monitored with Holter recording before discharge, at 3, 6, and 12 months follow-up. In addition, an arrhythmia transmitter was used to monitor events during the 1st month after ablation and was repeated 3 months after the procedure. Patients were asked to record 3 times daily even if asymptomatic. Additional monitoring was considered beyond 3 months for patients with recurrence of symptoms. After 3 months, anticoagulation was stopped unless there were other indications for chronic anticoagulation (such as prosthetic valves) or if patients experienced recurrent arrhythmia.
Between January 2000 and December 2003, 23 patients (15 men) with a mean age of 64 ± 12 years presented with arrhythmias refractory to AADs 14 ± 14 months after “cut and sew” Maze surgery for treatment of AF (Table 1).Eight patients underwent the “cut and sew” Maze for lone AF with no other surgical indication. Fifteen patients underwent the “cut and sew” Maze in addition to another surgical procedure: mitral valve replacement (4 bioprosthetic and 7 mechanical valves) and coronary artery bypass graft surgery (4 patients). The documented postoperative presenting arrhythmia was recurrent AF in 8 patients (Fig. 1),AT in 5 patients, and AFL in 10 patients (Figs. 2 and 3).⇓⇓
Findings on electrophysiologic study
Eight patients (35%) had recurrent AF secondary to recovered conduction around the lines encircling the pulmonary veins (Fig. 1).
Five patients were found to have focal AT (cycle length = 449 ± 85 ms), which was mapped to the CS (3 patients), to the posterolateral right atrium (1 patient), and to the LA septum (1 patient).
Six patients had left AFL, whereas 4 had right atrium incisional AFL (cycle length = 260 ± 42 ms).
Of the 6 patients with AFL, 4 had mitral annulus flutter. The isthmus in these patients was found between the mitral annulus and the dense posterior scar. In 2 patients ablation from the right inferior PV to the mitral annulus terminated the flutter, whereas in the remaining 2 patients this resulted in prolongation of the tachycardia cycle length without termination. In 1 of these 2 patients, further lesions from the left inferior PV to the mitral annulus were required for termination, whereas in the other patient extension of the ablation line along the anterior septal aspect of the right pulmonary veins resulted in flutter termination.
Two patients had flutter around the right pulmonary veins. In these patients an area of double potentials was identified on the upper posterior wall, but ablation at that site had no effect, whereas ablation in the anterior septal line resulted in termination (Fig. 3).
None of the patients with left AFL required ablation in the CS.
In 3 of the 4 patients with right atrial incisional flutter around the posterior atriotomy, the flutter was terminated by an ablation line connecting scar tissue to the superior vena cava. In the fourth patient, radiofrequency ablation was unsuccessful at multiple sites. This patient had multiple right atrial arrhythmias in the setting of severe mitral regurgitation and severe biatrial enlargement.
In this patient cohort presented in our study, fluoroscopy time was 90 ± 50 min and total procedure time was 5.1 ± 2.8 h.
At 1-year follow-up, 19 patients were arrhythmia-free and taking no AADs.
One patient with mitral annulus AFL had recurrence of AFL, and another patient had recurrence of AF. Both patients were re-ablated successfully. A third patient had recurrence of AT that was successfully ablated with an irrigation catheter at another institution.
To our knowledge, this is the first report of electrophysiologic findings in patients presenting with recurrent tachyarrhythmia after surgical “cut and sew” Maze procedures. In the present series we found that even after surgical “cut and sew” Maze, PV-LA reconnection is possible and that approximately one-third of patients experiencing atrial arrhythmias have AF. Moreover, incisional AFL seems to be a common finding in this group of patients, occurring in nearly one-half of those with recurrent symptomatic arrhythmias.
Although reportedly very effective, the long-term success rate varies widely, depending on the surgical approach and type of follow-up (1,2,4,5,10–13).
Recently, Albage et al. (14) reported that the inducibility of AF/AFL on electrophysiologic study 1 year after surgery was predictive of clinical arrhythmia. Ishii et al. (15) determined that AT of some form occurred in 43% of patients after the Maze procedure and that most of these arrhythmias were AF. In this cohort, electrophysiologic study and catheter ablation were performed on only 12 patients, with the majority undergoing atrioventricular nodal ablation and permanent pacemaker implantation 15. There is little reported on the invasive electrophysiologic management of post-Maze arrhythmias.
We found that AF recurrence after the “cut and sew” Maze was secondary to recovery of conduction around the lines encircling the pulmonary veins. This was effectively treated with pulmonary vein antral isolation with only 1 recurrence after 1 year of follow-up. This is very promising given the fact that these patients had already undergone complex surgery.
Intra-operative electrophysiologic confirmation of pulmonary vein isolation, although difficult, might be essential to avoid recurrent AF.
Furthermore, 48% of the patients had incisional AFL, implying that the nature of the surgery itself—regardless of achievement of pulmonary vein isolation—creates a substrate that can lead to another arrhythmia complicating this procedure. In the Maze procedure, incisional lines are made to isolate the pulmonary veins with the posterior LA wall by encircling them all-in-one and also connecting the isolated area by creating lines to the mitral annulus and to the amputated appendage stump. Importantly, cryoablation lesions are also placed in the bridge between the circular line and the 2 connecting lines as well as in the CS, where it is applied at −60°C for 2 min (10).
Therefore, possible gaps might exist between the connecting suture lines, because of non-transmural lesions in some areas, especially around the thick mitral annulus tissue. Reentry circuits might therefore occur more commonly around the mitral annulus, scar areas, and on the external edge of the isolated areas as described in our cohort of patients.
The approximate incidence of post-Maze atrial arrhythmias cannot be discerned from this cohort of patients, because these were from our center as well as from other institutions. However, the success rate defined as late freedom of AF has been reported to be 90% (3). Generally, although the success rate has been reported by Cox et al. (10) to be as high as 97%, a recent systematic review has found the mean success rate since 1995 to be as low as 84% (16). Furthermore, the success rate in patients with concomitant mitral valve surgery has been reported to be 75% to 82% (17).
After the surgical “cut and sew” Maze procedure approximately one-third of patients experiencing atrial arrhythmias have recurrence of AF secondary to PV-LA conduction recovery. Moreover, incisional AFL seems to be a common finding in this group of patients. Percutaneous catheter-based mapping and ablation of these arrhythmias seems to be feasible and effective, although this is technically challenging, as evidenced by the prolonged fluoroscopy and procedure times.
- Abbreviations and Acronyms
- antiarrhythmic drug
- atrial fibrillation
- atrial flutter
- atrial tachycardia
- left atrium/atrial
- Received February 21, 2006.
- Revision received April 18, 2006.
- Accepted May 8, 2006.
- American College of Cardiology Foundation
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