© 2015 Wiley Periodicals, Inc.
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Stand Alone Totally Endoscopic Epimyocardial Ablation in Patients with Persistent Atrial Fibrillation and Significant Atrial Dilatation Florian Mathias Wagner, M.D., Simon Pecha, M.D., Lenard Conradi, M.D., and Hermann Reichenspurner, M.D., Ph.D. Department of Cardiovascular Surgery, University Heart Center Hamburg, Hamburg, Germany ABSTRACT Background: To analyze safety and efficacy of surgical totally endoscopic epimyocardial ablation in patients (pts) turned down for interventional catheter therapy due to long-standing persistent atrial fibrillation (pAF) combined with significant atrial dilatation (> 5 cm). Methods: Since December 2010, 15 pts were referred for surgical ablation due to persistent AF combined with biatrial dilatation (left atrium [LA] 5.0 W 0.6 cm). Mean age was 52 W 6 years, body mass index (BMI) 38 W 6, duration of AF 2.8 W 1.2 years, left ventricular end diastolic diameter (LVEDD) 5.8 cm W 0.6 cm. Ablation was performed via a bilateral endoscopic approach using bipolar RF energy application. Monitoring was achieved by an event recorder (Reveal XT Medtronic, Inc., Minneapolis, MN, USA) or repeated 24-hours Holter electrocardiogram. Results: All pts successfully received bilateral pulmonary vein isolation R box lesion R trigonal lesion R left atrial appendage resection. Mean duration of procedure was 235 W 70 minutes. There was no intraoperative complication; however, one patient had persistent left phrenic nerve palsy. Mean hospital stay was 4 W 2 days, mean follow-up time was 21 W 11 months. Incidence of sinus rhythm (SR) was 67, 73, and 80% at discharge, three months, and 12 months follow-up. Mean LA diameter was reduced from 58.1 mm W 6.0 mm preoperative to 49.7 mm W 5.4 mm (p = 0.004) at 12 months follow-up. Incidence of SR was 86% at latest follow-up (mean time 21 months). All pts currently in SR (13/15 = 86%) are of class I or III antiarrhythmic drugs. Conclusion: Totally endoscopic left atrial ablation including left atrial resection can safely be performed. It achieved excellent rates of SR restoration in patients with long-standing persistent AF combined with significant atrial dilatation. doi: 10.1111/jocs.12523 (J Card Surg 2015;30:469–473)
Atrial fibrillation (AF) is the most common sustained arrhythmia and its prevalence is increasing with age. It can lead to heart failure and thromboembolic events, including stroke. Furthermore, AF results in an increased number of hospitalizations and reduction in quality of life.1,2 Besides pharmacological therapy, established treatment options recommended in guidelines include interventional catheter-based as well as surgical ablation.3 Most concepts of surgical atrial ablation are based on the Cox Maze III procedure performed on the arrested heart during use of extracorporeal circulation. Despite excellent long-term
Conflict of interest: None declared. Address for correspondence: PD Dr. Florian Mathias Wagner, Department of Cardiovascular Surgery, University Heart Center Hamburg, Martinistr. 52, 20246 Hamburg, Germany. Fax: þ49-(0)407410-57926; e-mail: [email protected]
success rates, this procedure remained of limited use by a small group of surgeons due to surgical complexity, its time-consuming character, and relevant potential morbidity.4 With replacement of the cut-and-sew principle by thermally generated transmural atrial lesions by various energy sources, this concept termed the Cox maze IV procedure led to widespread application primarily with concomitant procedures during cardiac surgery.5–8 Furthermore, advances in design of ablation tools, enabling port-access to the heart, allowed for less invasive ablation procedures. Due to these innovations, in recent years minimally invasive stand-alone AF surgery by a totally thoracoscopic approach has emerged a new promising treatment option in symptomatic patients with atrial fibrillation, not eligible for catheter ablation or high risk of failure after catheter ablation.9 Since December 2010, a series of patients considered unfavorable for catheter-based ablation due to long-standing persistent AF
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combined with atrial enlargement >5 cm, arterial hypertension, and obesity have been referred by our electrophysiology department. We report our initial experience on the safety, feasibility, and results of thoracoscopic epicardial bipolar radiofrequency ablation in these patients. MATERIALS AND METHODS Patients Between December 2010 and June 2013, 15 patients underwent thoracoscopic epimyocardial bipolar radiofrequency ablation for long-standing persistent atrial fibrillation. Patients with long-standing AF and significantly enlarged left atrium (LA) with a history of unsuccessful catheter ablation or those who were not eligible for catheter ablation were considered for this procedure. Institutional review board approval was obtained to report these cases. Baseline patient characteristics are shown in Table 1. Mean patients age was 52.5 6.3 years, and 66.7% of patients were male. Mean LA diameter was enlarged to 58.0 mm, while mean left ventricular ejection fraction (LVEF) 46.6%. The mean duration of AF was 2.8 1.2 years. Three patients (20%) had a thromboembolic or ischemic stroke prior to surgery. One patient had a DDD permanent pacemaker. Surgical technique After induction of anesthesia and intubation with a double-lumen endotracheal tube, all patients received transesophageal echocardiography to exclude left atrial appendage (LAA) thrombus formation. Two thoracoscopic working ports were introduced in the right fourth and sixth intercostal spaces at the midaxillary line and a camera port was introduced via a right fifth intercostal space at the anterior axillary line. The pericardium was opened longitudinally from the superior vena cava to the diaphragm approximately 2 cm anterior to the phrenic nerve with care to prevent nerve injury. An illuminating and articulating dissector with a guiding sheath was introduced around the pulmonary veins. After removal of the dissector, the sheath was used as a guide for introduction of the ablation clamp (Isolator EMR2
TABLE 1 Patient Characteristics Patients n = 15 Age (years) Gender (female/male) Body mass index Atrial fibrillation duration (years) Left atrial diameter (mm) Left ventricular ejection fraction (%) Prior stroke n (%) Diabetes n (%) Renal insuffiency n (%) Pacemaker preoperative n (%) Arterial hypertension Chronic obstructive pulmonary disease n (%) Coronary artery disease n (%)
52.5 6.3 5/10 38 6.4 2.8 1.2 58.1 6.0 46.6 12.0 3 (20.0) 3 (20.0) 1 (6.7) 1 (6.7) 11 (73.3) 1 (6.7) 4 (26.7)
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Synergy Bipolar Handpiece; AtriCure, Inc., Cincinnati, OH, USA). Prior to ablation, a bipolar sense-pace element (Transpolar Pen Max5–Bipolar Pen; AtriCure, Inc.) was used to determine and record (EP recording system ORLab; AtriCure, Inc.) electrical activity on the right and left atrium as well as on the PV. Right-sided pulmonary vein isolation was performed with 5–10 ablation cycles until bidirectional block was confirmed for each PV. After dissection of the oblique and transverse sinuses, connecting roof- and bottom lines were created by a linear ablation device (CoolRail CR1 linear ablation tool or 20-mm nonirrigated Isolator Linear Pen; both AtriCure, Inc.) to the opposite PVs achieving a box lesion of the entire posterior left atrial wall. A trigonal line was added from the left atrial roof to the non-coronary sinus of the aortic valve. After discontinuation of left lung ventilation, two working-ports and one camera port were installed as on the right side but 2 cm more posterior. After opening of the pericardium posterior to the course of the phrenic nerve, the ligament of Marshall was dissected and instrumentation was used as before for the ablation. After the identical mapping procedure, epimyocardial PV ablation was conducted with confirmation of bidirectional block. Next stimulation and sensing parameter measurements were performed from within the box to confirm bidirectional block of the posterior wall. Finally, the left atrial appendage was resected to its base, using a stapling device (Endo Gia Universal with violet Universal Roticulator 60 mm; Covidien, Dublin, Ireland). Statistical analysis All statistical analyses were performed with SPSS statistical software version 18.0 (SPSS, Inc., Chicago, IL, USA) Continuous values are expressed as mean standard deviation and were compared with Student’s t-test. Categorical variables are displayed as frequency and percentages and were compared using the chisquare test or Fisher’s exact test as appropriate. A p-value of 0.5% and/or duration of single AF episode >30 seconds. ER-documented AF episodes were manually validated. In patients without ER, a 24-hour Holter–ECG was conducted 3, 6, and 12 months postoperatively. In this group, any episode of AF with duration longer than 30 seconds was regarded as AF recurrence. Antiarrhythmic drugs and anticoagulation regimens were maintained for three months postoperatively in all patients, and then adapted according to either ER or 24-hour ECG rhythm results and embolic risk profile. In patients without contraindication, amiodarone was used as the first-line antiarrhythmic therapy started during the ablation procedure. Otherwise, other class I
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WAGNER ET AL. TOTALLY ENDOSCOPIC EPIMYOCARDIAL ABLATION
or class III antiarrhythmic drugs were prescribed for at least three months postoperatively. At the time of follow-up, electrical cardioversion was initiated in patients with recurrence of AF. Patients with recurrence of AF or occurrence of other atrial tachyarhythmias six months postoperatively were considered for additional catheter-based ablation.
RESULTS Perioperative data and outcome There was no intraoperative death and none of the patients experienced a perioperative stroke. All three patients with previous catheter-based ablation were found to have at least one PV still electrically connected to the heart. Mean procedural time was 235 70 minutes, and all patients received successful bilateral pulmonary vein isolation, box and trigonal lesion; all but one had complete left atrial appendage resection. The longest procedure time was 381 minute in a female patient with a BMI of 42. Successful intraprocedural restoration of SR was achieved in all patients by external electrical cardioversion. One patient with BMI 40 developed postprocedural persistent left phrenic nerve palsy. Another patient with systemic immunosuppression due to previous liver transplantation had a port siterelated infection requiring intravenous antibiotic treatment. Mean hospital stay was 4 2 days. Thoracic drains could all be removed within 24 hours, except one who had persistent and excessive clear pleural fluid production for 72 hours. No patient showed procedure related bleeding and none required any blood transfusion. An electrical cardioversion was performed in four patients after the blanking period. At latest follow-up, all patients with successful ablation were free of symptoms; furthermore, two patients with ablation failure had a reduction in AF-related symptoms. No patient expierienced a stroke during the follow-up period. Rhythm results Mean time of follow-up was 21 months. The overall SR conversion rate was 66.7 and 73.3% at discharge and after three months. At six and 12 months, 73.3 and 80.0% of patients were in SR (Fig 1). Incidence of SR was 86% at latest follow up (mean time 21 months). After six and 12 months and at latest follow-up, SR rate of AAD was 73, 80, and 86%, respectively. Despite amputating the LAA and stable SR, our cardiologists did not stop oral anticoagulation with phenprocoumon or coumadin in patients with CHADS score >1. One patient received an additional catheter-based isthmus ablation six months postoperatively due to atypical left atrial flutter. Successful complete isolation of PVs and box was confirmed during this procedure. A gap in the roof lesion was observed during catheter ablation. Afterwards, the patient was in SR for further 12 months. Twenty-four months after surgical ablation, 24-hour Holter–ECG detected recurrence of atrial flutter and the patient received re-catheter ablation but developed recurrent atrial fibrillation during follow-up. One other
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patient experienced postoperative right atrial flutter and also received an additional catheter-based ablation. Afterwards, the patient was in stable SR. Preoperative range of LA diameter was 50–65 mm. There was a significant reduction in the LA diameter seen at last follow-up, which may reflect atrial remodelling (58.1 mm 6.0 mm vs. 49.7 mm 5.4 mm p ¼ 0.004). No patient had preoperative significant MR or TR, so no changes in mitral or tricuspid function could be observed postoperatively. No significant changes in LVEF were seen between baseline and 12-month follow-up (46.6% 12.0% vs. 48.3 11.3; p ¼ 0.69). DISCUSSION This study reports our initial experience with a totally endoscopic approach for epimyocardial left atrial ablation including amputation of the left atrial appendage in 15 patients. All of these patients were highly symptomatic, had long-standing persistent AF, and had significant atrial enlargement combined with significant abundance of body weight rendering them not only a technical challenge but also with poor likelihood of catheter-based ablational success.10,11 Freedom from AF was 80% at one year and 86% at latest follow-up. We did not observe differences between results obtained by continuous or Holter ECG. Furthermore, significant reduction of LA diameter was documented in patients with constant SR most likely reflecting atrial myocardial remodeling. The majority of surgical ablation reports comprises studies in patients with persistent AF undergoing open heart surgery. Described results vary between 50 and 85% post-procedural freedom from AF after one year.3,5,6 However, due to very different etiological driving forces of AF mainly related to additional cardiac pathologies, one cannot compare success rates in concomitant to those observed in patients with lone AF. Few studies have reported on results of lone AF ablation in recent years. Castella and colleagues reported results in a series of 34 patients of whom 17 presented with persistent (pAF) or longstanding persistent AF (lpAF).12 They performed isolated epimyocardial endoscopic PVI combined with amputation of the LAA. After 12 months,
Figure 1. Sinus rhythm rate during follow-up.
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freedom from AF was 82% after paroxysmal AF (PAF) and 60% after pAF and 20% after lpAF. Difference in success rates might be due to lack of additional lines to create isolation of the entire posterior left atrial wall as achieved in our study. However, there is still an ongoing electrophysiological discussion about the significance of such lines.13 In their study including 89 patients treated with bipolar radiofrequency lone AF ablation surgery, Weimar et al. showed freedom from AF of 90% after oneyear follow-up.9 The only head to head comparison in a prospective randomized trial of surgical versus catheterbased atrial ablation (FAST) involved 124 patients with AF type paroxysmal in 67% and persistent in 33%.14 The ablation protocol included PVI plus equal distribution of additional lines (catheter: roof and mitral isthmus; surgical: roof, trigone and box) of 71% in both groups. Rhythm outcome was significantly superior after endoscopic surgical ablation achieving freedom from LA arrhythmia in 69% after PAF and 56% after pAF, although the procedural adverse event rate was significantly elevated after surgical ablation (34% vs. 16% postcatheter ablation). The major adverse event rate in the present study was in an acceptable range with only one phrenic nerve palsy which was comparable to numbers reported from series with more complex catheter-based ablations.13 In patients with medical refractory symptomatic paroxysmal AF, catheter-based ablation is certainly still the primary line of treatment due to its minimal invasive nature requiring only local anesthesia and peripheral vessel access combined with comparable rhythm outcome and low adverse event rate. Totally endoscopic surgical AF ablation should be considered in patients with persistent AF, particularly if long-standing or associated with an enlarged atrium >5 cm, since potential rhythm outcome is superior to catheter ablation results in this population. Exclusion criteria are severe comorbidities corresponding to a high surgical risk. Furthermore, patients with severe structural heart disease should not be treated with this minimally invasive stand-alone ablation technique, but should be evaluated for a cardiac surgical procedure with concomitant surgical AF ablation. Despite satisfactory rhythm outcome in this series, 13.3% of patients developed atrial tachycardia, mainly atypical atrial flutter. Gillinov and colleagues observed this phenomenon in 10% of patients after surgical concomittant left atrial ablation including PVI and posterior wall isolation. Introduction of a mitral isthmus line from the ostium of the left inferior pulmonary vein to the mitral annulus abolished this complication.15 Even though easily applied during open heart surgery, this line remains a challenge via an epicardial approach on the beating heart. Thanks to modern electrophysiological mapping and guiding tools treatment of atrial tachycardia and flutter is a cornerstone of catheter-based intervention. Therefore, a combination of both approaches in one setting should further improve overall outcome. Limitations The main limitation is the small patient population and the retrospective character of this study. Freedom from
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AF might have been overestimated since only 33% of patients had continuous rhythm monitoring with 24-hour Holter-ECG monitoring in all others. Furthermore, we did not perform transesophageal echocardiography during follow-up to monitor success of LAA exclusion. REFERENCES n LE, Cannom DS: 2011 ACCF/AHA/HRS 1. Fuster V, Ryde focused updates incorporated into the ACC/AHA/ESC 2006 Guidelines for the management of patients with atrial fibrillation: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines developed in partnership with the European Society of Cardiology and in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. J Am Coll Cardiol 2011;57(11): e101–198. 2. Flaker GC, Belew K, Beckman K, et al.: Asymptomatic atrial fibrillation: Demographic features, prognostic information from the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study. Am Heart J 2005;149(4):657–663. 3. Calkins H, Kuck KH, Cappato R, et al.: HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: Recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design: A report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation. Developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology (ESC) and the European Cardiac Arrhythmia Society (ECAS); and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS). Endorsed by the governing bodies of the American College of Cardiology Foundation, the American Heart Association, the European Cardiac Arrhythmia Society, the European Heart Rhythm Association, the Society of Thoracic Surgeons, the Asia Pacific Heart Rhythm Society, and the Heart Rhythm Society. Heart Rhythm 2012;9(4):632–696. 4. Cox JL, Ad N, Palazzo T, et al.: Current status of the Maze procedure for the treatment of atrial fibrillation. Semin Thorac Cardiovasc Surg 2000;12(1):15–19. 5. Barnett SD, Ad N: Surgical ablation as treatment for the elimination of atrial fibrillation: A meta-analysis. J Thorac Cardiovasc Surg 2006;131(5):1029–1035. 6. Gillinov AM, Bhavani S, Blackstone EH, et al.: Surgery for permanent atrial fibrillation: Impact of patient factors and lesion set. Ann Thorac Surg 2006;82(2):502–513. 7. Damiano RJ, Jr, Schwartz FH, Bailey MS, et al.: The Cox maze IV procedure: Predictors of late recurrence. J Thorac Cardiovasc Surg 2011;141(1):113–121. 8. Wisser W, Khazen C, Deviatko E, et al.: Microwave and radiofrequency ablation yield similar success rates for treatment of chronic atrial fibrillation. Eur J Cardiothorac Surg 2004;25(6):1011–1017. 9. Weimar T, Vosseler M, Czesla M, et al.: Approaching a paradigm shift: Endoscopic ablation of lone atrial fibrillation on the beating heart. Ann Thorac Surg 2012;94(6):1886–1892. 10. Jeevanantham LV, Ntim W, Navaneethan SD, et al.: Metaanalysis of the effect of radiofrequency catheter ablation
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on left atrial size, volumes and function in patients with atrial fibrillation. Am J Cardiol 2010;105:1317–1326. 11. Uijl DW, den Delgado, Bertini M, et al.: Impact of left atrial fibrosis and left atrial size on the outcome of catheter ablation for atrial fibrillation. Heart 2011;97(22):1847– 1851. 12. Castella M, Pereda D, Mestres CA, et al.: Thoracoscopic pulmonary vein isolation in patients with atrial fibrillation and failed percutaneous ablation. J Thorac Cardiovasc Surg 2010;140:633–638.
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13. Brooks AG, Stiles MK, Laborderie J, et al.: Outcomes of long-standing persistent atrial fibrillation ablation: A systematic review. Heart Rhythm 2010;7(6):835–846. 14. Boersma LVA, Castella M, Boven W van, et al.: Atrial fibrillation catheter ablation versus surgical ablation treatment (FAST): A 2-center randomized clinical trial Circulation 2012;125:25–30. 15. Gillinov AM, Blackstone EH, McCarthy PM. Atrial fibrillation: Current surgical options and their assessment. Ann Thorac Surg 2002;74(6):2210–2217.
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Stand Alone Totally Endoscopic Epimyocardial Ablation in Patients with Persistent Atrial Fibrillation and Significant Atrial Dilatation Florian Mathias Wagner, M.D., Simon Pecha, M.D., Lenard Conradi, M.D., and Hermann Reichenspurner, M.D., Ph.D. Department of Cardiovascular Surgery, University Heart Center Hamburg, Hamburg, Germany ABSTRACT Background: To analyze safety and efficacy of surgical totally endoscopic epimyocardial ablation in patients (pts) turned down for interventional catheter therapy due to long-standing persistent atrial fibrillation (pAF) combined with significant atrial dilatation (> 5 cm). Methods: Since December 2010, 15 pts were referred for surgical ablation due to persistent AF combined with biatrial dilatation (left atrium [LA] 5.0 W 0.6 cm). Mean age was 52 W 6 years, body mass index (BMI) 38 W 6, duration of AF 2.8 W 1.2 years, left ventricular end diastolic diameter (LVEDD) 5.8 cm W 0.6 cm. Ablation was performed via a bilateral endoscopic approach using bipolar RF energy application. Monitoring was achieved by an event recorder (Reveal XT Medtronic, Inc., Minneapolis, MN, USA) or repeated 24-hours Holter electrocardiogram. Results: All pts successfully received bilateral pulmonary vein isolation R box lesion R trigonal lesion R left atrial appendage resection. Mean duration of procedure was 235 W 70 minutes. There was no intraoperative complication; however, one patient had persistent left phrenic nerve palsy. Mean hospital stay was 4 W 2 days, mean follow-up time was 21 W 11 months. Incidence of sinus rhythm (SR) was 67, 73, and 80% at discharge, three months, and 12 months follow-up. Mean LA diameter was reduced from 58.1 mm W 6.0 mm preoperative to 49.7 mm W 5.4 mm (p = 0.004) at 12 months follow-up. Incidence of SR was 86% at latest follow-up (mean time 21 months). All pts currently in SR (13/15 = 86%) are of class I or III antiarrhythmic drugs. Conclusion: Totally endoscopic left atrial ablation including left atrial resection can safely be performed. It achieved excellent rates of SR restoration in patients with long-standing persistent AF combined with significant atrial dilatation. doi: 10.1111/jocs.12523 (J Card Surg 2015;30:469–473)
Atrial fibrillation (AF) is the most common sustained arrhythmia and its prevalence is increasing with age. It can lead to heart failure and thromboembolic events, including stroke. Furthermore, AF results in an increased number of hospitalizations and reduction in quality of life.1,2 Besides pharmacological therapy, established treatment options recommended in guidelines include interventional catheter-based as well as surgical ablation.3 Most concepts of surgical atrial ablation are based on the Cox Maze III procedure performed on the arrested heart during use of extracorporeal circulation. Despite excellent long-term
Conflict of interest: None declared. Address for correspondence: PD Dr. Florian Mathias Wagner, Department of Cardiovascular Surgery, University Heart Center Hamburg, Martinistr. 52, 20246 Hamburg, Germany. Fax: þ49-(0)407410-57926; e-mail: [email protected]
success rates, this procedure remained of limited use by a small group of surgeons due to surgical complexity, its time-consuming character, and relevant potential morbidity.4 With replacement of the cut-and-sew principle by thermally generated transmural atrial lesions by various energy sources, this concept termed the Cox maze IV procedure led to widespread application primarily with concomitant procedures during cardiac surgery.5–8 Furthermore, advances in design of ablation tools, enabling port-access to the heart, allowed for less invasive ablation procedures. Due to these innovations, in recent years minimally invasive stand-alone AF surgery by a totally thoracoscopic approach has emerged a new promising treatment option in symptomatic patients with atrial fibrillation, not eligible for catheter ablation or high risk of failure after catheter ablation.9 Since December 2010, a series of patients considered unfavorable for catheter-based ablation due to long-standing persistent AF
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combined with atrial enlargement >5 cm, arterial hypertension, and obesity have been referred by our electrophysiology department. We report our initial experience on the safety, feasibility, and results of thoracoscopic epicardial bipolar radiofrequency ablation in these patients. MATERIALS AND METHODS Patients Between December 2010 and June 2013, 15 patients underwent thoracoscopic epimyocardial bipolar radiofrequency ablation for long-standing persistent atrial fibrillation. Patients with long-standing AF and significantly enlarged left atrium (LA) with a history of unsuccessful catheter ablation or those who were not eligible for catheter ablation were considered for this procedure. Institutional review board approval was obtained to report these cases. Baseline patient characteristics are shown in Table 1. Mean patients age was 52.5 6.3 years, and 66.7% of patients were male. Mean LA diameter was enlarged to 58.0 mm, while mean left ventricular ejection fraction (LVEF) 46.6%. The mean duration of AF was 2.8 1.2 years. Three patients (20%) had a thromboembolic or ischemic stroke prior to surgery. One patient had a DDD permanent pacemaker. Surgical technique After induction of anesthesia and intubation with a double-lumen endotracheal tube, all patients received transesophageal echocardiography to exclude left atrial appendage (LAA) thrombus formation. Two thoracoscopic working ports were introduced in the right fourth and sixth intercostal spaces at the midaxillary line and a camera port was introduced via a right fifth intercostal space at the anterior axillary line. The pericardium was opened longitudinally from the superior vena cava to the diaphragm approximately 2 cm anterior to the phrenic nerve with care to prevent nerve injury. An illuminating and articulating dissector with a guiding sheath was introduced around the pulmonary veins. After removal of the dissector, the sheath was used as a guide for introduction of the ablation clamp (Isolator EMR2
TABLE 1 Patient Characteristics Patients n = 15 Age (years) Gender (female/male) Body mass index Atrial fibrillation duration (years) Left atrial diameter (mm) Left ventricular ejection fraction (%) Prior stroke n (%) Diabetes n (%) Renal insuffiency n (%) Pacemaker preoperative n (%) Arterial hypertension Chronic obstructive pulmonary disease n (%) Coronary artery disease n (%)
52.5 6.3 5/10 38 6.4 2.8 1.2 58.1 6.0 46.6 12.0 3 (20.0) 3 (20.0) 1 (6.7) 1 (6.7) 11 (73.3) 1 (6.7) 4 (26.7)
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Synergy Bipolar Handpiece; AtriCure, Inc., Cincinnati, OH, USA). Prior to ablation, a bipolar sense-pace element (Transpolar Pen Max5–Bipolar Pen; AtriCure, Inc.) was used to determine and record (EP recording system ORLab; AtriCure, Inc.) electrical activity on the right and left atrium as well as on the PV. Right-sided pulmonary vein isolation was performed with 5–10 ablation cycles until bidirectional block was confirmed for each PV. After dissection of the oblique and transverse sinuses, connecting roof- and bottom lines were created by a linear ablation device (CoolRail CR1 linear ablation tool or 20-mm nonirrigated Isolator Linear Pen; both AtriCure, Inc.) to the opposite PVs achieving a box lesion of the entire posterior left atrial wall. A trigonal line was added from the left atrial roof to the non-coronary sinus of the aortic valve. After discontinuation of left lung ventilation, two working-ports and one camera port were installed as on the right side but 2 cm more posterior. After opening of the pericardium posterior to the course of the phrenic nerve, the ligament of Marshall was dissected and instrumentation was used as before for the ablation. After the identical mapping procedure, epimyocardial PV ablation was conducted with confirmation of bidirectional block. Next stimulation and sensing parameter measurements were performed from within the box to confirm bidirectional block of the posterior wall. Finally, the left atrial appendage was resected to its base, using a stapling device (Endo Gia Universal with violet Universal Roticulator 60 mm; Covidien, Dublin, Ireland). Statistical analysis All statistical analyses were performed with SPSS statistical software version 18.0 (SPSS, Inc., Chicago, IL, USA) Continuous values are expressed as mean standard deviation and were compared with Student’s t-test. Categorical variables are displayed as frequency and percentages and were compared using the chisquare test or Fisher’s exact test as appropriate. A p-value of 0.5% and/or duration of single AF episode >30 seconds. ER-documented AF episodes were manually validated. In patients without ER, a 24-hour Holter–ECG was conducted 3, 6, and 12 months postoperatively. In this group, any episode of AF with duration longer than 30 seconds was regarded as AF recurrence. Antiarrhythmic drugs and anticoagulation regimens were maintained for three months postoperatively in all patients, and then adapted according to either ER or 24-hour ECG rhythm results and embolic risk profile. In patients without contraindication, amiodarone was used as the first-line antiarrhythmic therapy started during the ablation procedure. Otherwise, other class I
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or class III antiarrhythmic drugs were prescribed for at least three months postoperatively. At the time of follow-up, electrical cardioversion was initiated in patients with recurrence of AF. Patients with recurrence of AF or occurrence of other atrial tachyarhythmias six months postoperatively were considered for additional catheter-based ablation.
RESULTS Perioperative data and outcome There was no intraoperative death and none of the patients experienced a perioperative stroke. All three patients with previous catheter-based ablation were found to have at least one PV still electrically connected to the heart. Mean procedural time was 235 70 minutes, and all patients received successful bilateral pulmonary vein isolation, box and trigonal lesion; all but one had complete left atrial appendage resection. The longest procedure time was 381 minute in a female patient with a BMI of 42. Successful intraprocedural restoration of SR was achieved in all patients by external electrical cardioversion. One patient with BMI 40 developed postprocedural persistent left phrenic nerve palsy. Another patient with systemic immunosuppression due to previous liver transplantation had a port siterelated infection requiring intravenous antibiotic treatment. Mean hospital stay was 4 2 days. Thoracic drains could all be removed within 24 hours, except one who had persistent and excessive clear pleural fluid production for 72 hours. No patient showed procedure related bleeding and none required any blood transfusion. An electrical cardioversion was performed in four patients after the blanking period. At latest follow-up, all patients with successful ablation were free of symptoms; furthermore, two patients with ablation failure had a reduction in AF-related symptoms. No patient expierienced a stroke during the follow-up period. Rhythm results Mean time of follow-up was 21 months. The overall SR conversion rate was 66.7 and 73.3% at discharge and after three months. At six and 12 months, 73.3 and 80.0% of patients were in SR (Fig 1). Incidence of SR was 86% at latest follow up (mean time 21 months). After six and 12 months and at latest follow-up, SR rate of AAD was 73, 80, and 86%, respectively. Despite amputating the LAA and stable SR, our cardiologists did not stop oral anticoagulation with phenprocoumon or coumadin in patients with CHADS score >1. One patient received an additional catheter-based isthmus ablation six months postoperatively due to atypical left atrial flutter. Successful complete isolation of PVs and box was confirmed during this procedure. A gap in the roof lesion was observed during catheter ablation. Afterwards, the patient was in SR for further 12 months. Twenty-four months after surgical ablation, 24-hour Holter–ECG detected recurrence of atrial flutter and the patient received re-catheter ablation but developed recurrent atrial fibrillation during follow-up. One other
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patient experienced postoperative right atrial flutter and also received an additional catheter-based ablation. Afterwards, the patient was in stable SR. Preoperative range of LA diameter was 50–65 mm. There was a significant reduction in the LA diameter seen at last follow-up, which may reflect atrial remodelling (58.1 mm 6.0 mm vs. 49.7 mm 5.4 mm p ¼ 0.004). No patient had preoperative significant MR or TR, so no changes in mitral or tricuspid function could be observed postoperatively. No significant changes in LVEF were seen between baseline and 12-month follow-up (46.6% 12.0% vs. 48.3 11.3; p ¼ 0.69). DISCUSSION This study reports our initial experience with a totally endoscopic approach for epimyocardial left atrial ablation including amputation of the left atrial appendage in 15 patients. All of these patients were highly symptomatic, had long-standing persistent AF, and had significant atrial enlargement combined with significant abundance of body weight rendering them not only a technical challenge but also with poor likelihood of catheter-based ablational success.10,11 Freedom from AF was 80% at one year and 86% at latest follow-up. We did not observe differences between results obtained by continuous or Holter ECG. Furthermore, significant reduction of LA diameter was documented in patients with constant SR most likely reflecting atrial myocardial remodeling. The majority of surgical ablation reports comprises studies in patients with persistent AF undergoing open heart surgery. Described results vary between 50 and 85% post-procedural freedom from AF after one year.3,5,6 However, due to very different etiological driving forces of AF mainly related to additional cardiac pathologies, one cannot compare success rates in concomitant to those observed in patients with lone AF. Few studies have reported on results of lone AF ablation in recent years. Castella and colleagues reported results in a series of 34 patients of whom 17 presented with persistent (pAF) or longstanding persistent AF (lpAF).12 They performed isolated epimyocardial endoscopic PVI combined with amputation of the LAA. After 12 months,
Figure 1. Sinus rhythm rate during follow-up.
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freedom from AF was 82% after paroxysmal AF (PAF) and 60% after pAF and 20% after lpAF. Difference in success rates might be due to lack of additional lines to create isolation of the entire posterior left atrial wall as achieved in our study. However, there is still an ongoing electrophysiological discussion about the significance of such lines.13 In their study including 89 patients treated with bipolar radiofrequency lone AF ablation surgery, Weimar et al. showed freedom from AF of 90% after oneyear follow-up.9 The only head to head comparison in a prospective randomized trial of surgical versus catheterbased atrial ablation (FAST) involved 124 patients with AF type paroxysmal in 67% and persistent in 33%.14 The ablation protocol included PVI plus equal distribution of additional lines (catheter: roof and mitral isthmus; surgical: roof, trigone and box) of 71% in both groups. Rhythm outcome was significantly superior after endoscopic surgical ablation achieving freedom from LA arrhythmia in 69% after PAF and 56% after pAF, although the procedural adverse event rate was significantly elevated after surgical ablation (34% vs. 16% postcatheter ablation). The major adverse event rate in the present study was in an acceptable range with only one phrenic nerve palsy which was comparable to numbers reported from series with more complex catheter-based ablations.13 In patients with medical refractory symptomatic paroxysmal AF, catheter-based ablation is certainly still the primary line of treatment due to its minimal invasive nature requiring only local anesthesia and peripheral vessel access combined with comparable rhythm outcome and low adverse event rate. Totally endoscopic surgical AF ablation should be considered in patients with persistent AF, particularly if long-standing or associated with an enlarged atrium >5 cm, since potential rhythm outcome is superior to catheter ablation results in this population. Exclusion criteria are severe comorbidities corresponding to a high surgical risk. Furthermore, patients with severe structural heart disease should not be treated with this minimally invasive stand-alone ablation technique, but should be evaluated for a cardiac surgical procedure with concomitant surgical AF ablation. Despite satisfactory rhythm outcome in this series, 13.3% of patients developed atrial tachycardia, mainly atypical atrial flutter. Gillinov and colleagues observed this phenomenon in 10% of patients after surgical concomittant left atrial ablation including PVI and posterior wall isolation. Introduction of a mitral isthmus line from the ostium of the left inferior pulmonary vein to the mitral annulus abolished this complication.15 Even though easily applied during open heart surgery, this line remains a challenge via an epicardial approach on the beating heart. Thanks to modern electrophysiological mapping and guiding tools treatment of atrial tachycardia and flutter is a cornerstone of catheter-based intervention. Therefore, a combination of both approaches in one setting should further improve overall outcome. Limitations The main limitation is the small patient population and the retrospective character of this study. Freedom from
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AF might have been overestimated since only 33% of patients had continuous rhythm monitoring with 24-hour Holter-ECG monitoring in all others. Furthermore, we did not perform transesophageal echocardiography during follow-up to monitor success of LAA exclusion. REFERENCES n LE, Cannom DS: 2011 ACCF/AHA/HRS 1. Fuster V, Ryde focused updates incorporated into the ACC/AHA/ESC 2006 Guidelines for the management of patients with atrial fibrillation: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines developed in partnership with the European Society of Cardiology and in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. J Am Coll Cardiol 2011;57(11): e101–198. 2. Flaker GC, Belew K, Beckman K, et al.: Asymptomatic atrial fibrillation: Demographic features, prognostic information from the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study. Am Heart J 2005;149(4):657–663. 3. Calkins H, Kuck KH, Cappato R, et al.: HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: Recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design: A report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation. Developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology (ESC) and the European Cardiac Arrhythmia Society (ECAS); and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS). Endorsed by the governing bodies of the American College of Cardiology Foundation, the American Heart Association, the European Cardiac Arrhythmia Society, the European Heart Rhythm Association, the Society of Thoracic Surgeons, the Asia Pacific Heart Rhythm Society, and the Heart Rhythm Society. Heart Rhythm 2012;9(4):632–696. 4. Cox JL, Ad N, Palazzo T, et al.: Current status of the Maze procedure for the treatment of atrial fibrillation. Semin Thorac Cardiovasc Surg 2000;12(1):15–19. 5. Barnett SD, Ad N: Surgical ablation as treatment for the elimination of atrial fibrillation: A meta-analysis. J Thorac Cardiovasc Surg 2006;131(5):1029–1035. 6. Gillinov AM, Bhavani S, Blackstone EH, et al.: Surgery for permanent atrial fibrillation: Impact of patient factors and lesion set. Ann Thorac Surg 2006;82(2):502–513. 7. Damiano RJ, Jr, Schwartz FH, Bailey MS, et al.: The Cox maze IV procedure: Predictors of late recurrence. J Thorac Cardiovasc Surg 2011;141(1):113–121. 8. Wisser W, Khazen C, Deviatko E, et al.: Microwave and radiofrequency ablation yield similar success rates for treatment of chronic atrial fibrillation. Eur J Cardiothorac Surg 2004;25(6):1011–1017. 9. Weimar T, Vosseler M, Czesla M, et al.: Approaching a paradigm shift: Endoscopic ablation of lone atrial fibrillation on the beating heart. Ann Thorac Surg 2012;94(6):1886–1892. 10. Jeevanantham LV, Ntim W, Navaneethan SD, et al.: Metaanalysis of the effect of radiofrequency catheter ablation
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