Download Full paper

Asian Cardiovascular
and Thoracic Annals
http://aan.sagepub.com/
Radiofrequency ablation of atrial fibrillation during mitral valve surgery
Farouk Oueida, Mohamed Ahmed Elawady and Khalid Eskander
Asian Cardiovascular and Thoracic Annals published online 21 January 2014
DOI: 10.1177/0218492313519990
The online version of this article can be found at:
http://aan.sagepub.com/content/early/2014/01/20/0218492313519990
Published by:
http://www.sagepublications.com
On behalf of:
The Asian Society for Cardiovascular Surgery
Additional services and information for Asian Cardiovascular and Thoracic Annals can be found at:
Email Alerts: http://aan.sagepub.com/cgi/alerts
Subscriptions: http://aan.sagepub.com/subscriptions
Reprints: http://www.sagepub.com/journalsReprints.nav
Permissions: http://www.sagepub.com/journalsPermissions.nav
>> OnlineFirst Version of Record - Jan 21, 2014
What is This?
Downloaded from aan.sagepub.com by guest on June 5, 2014
Original Article
Radiofrequency ablation of atrial
fibrillation during mitral valve surgery
Asian Cardiovascular & Thoracic Annals
0(0) 1-4
ß The Author(s) 2014
Reprints and permissions:
sagepub.co.uk/journalsPermissions.nav
DOI: 10.1177/0218492313519990
aan.sagepub.com
Farouk Oueida1, Mohamed Ahmed Elawady2 and
Khalid Eskander1
Abstract
Objectives: Atrial fibrillation is the most common form of arrhythmia in mitral valve disease. Radiofrequency ablation is most
commonly used for atrial fibrillation ablation during mitral valve surgery.
Methods: This prospective study evaluated the midterm outcomes of intraoperative radiofrequency atrial fibrillation ablation
during mitral valve surgery.
Results: 52 patients were eligible for the study. Fifteen (28.8%) had a transseptal approach and 37 had a left atriotomy. Mitral
valve replacement was performed in 16 patients, mitral valve repair in 31, and tricuspid repair in 8. Mean cross- clamp time
was 58.14. Æ 20.08 min, and mean cardiopulmonary bypass time was 71.28 Æ 20.31 min. The mean ablation time was 6.41 Æ
0.21 min. There was no postoperative mortality. Sinus rhythm was documented in 44 (84.6%) patients on discharge, and 8 (15.4%)
were discharged with atrial fibrillation; 2 of them returned to sinus rhythm after 3 months. After 12 months of follow-up, 46
(88.5%) patients were in sinus rhythm.
Conclusion: Left atrial monopolar radiofrequency ablation during mitral valve surgery is a safe procedure with a high success
rate.
Keywords
Anti-arrhythmia agents, atrial fibrillation, catheter ablation, heart atria, heart valve prosthesis implantation, mitral valve
Introduction
Atrial fibrillation (AF) is the most common form of
arrhythmia in mitral valve disease, with incidence ran- ging
from 30% to 84%. 1 AF may cause heart failure and
thromboembolic complications, leading to increased
morbidity and mortality, with a high financial burden.
Medical treatment in persistent AF is not the best option due
to high failure rates of up to 84%.2 The Cox maze operation
with its modifications is the gold standard for surgical
treatment of AF, with nearly 100% success rates, but it is a
complex procedure need- ing surgical experience. The Cox
maze also requires a
long crossclamp time and there is a higher incidence of
bleeding.3,4 This has led to the evolution of less invasive
surgical techniques with the same surgical concepts as the
Cox maze procedure but replacing the scissors in the cutand-sew method by power sources to create the lines of
conduction block without cutting the tissue. These include
radiofrequency (RF), microwave, laser, high-frequency
focused ultrasound, and cryoablation. 5
Since the year 2000, RF has been one of the most commonly used methods for ablation. 5,6 The aim of this study
was to evaluate the midterm results of left atrial monopolar
RF ablation for persistent AF during mitral valve surgery.
Patients and methods
A prospective study was undertaken to evaluate the
midterm results of intraoperative radiofrequency abla- tion
during mitral valve operations in Saud Al Babtain
1
Cardiac Surgery Department, Saud Al-Babtain Cardiac Centre,
Dammam, Saudi Arabia
2
Cardiothoracic Surgery Department, Banha Faculty of Medicine, Banha
University, Egypt
Corresponding author:
Mohamed Ahmed Elawady, MD, Cardiothoracic Surgery Department,
Banha Faculty of Medicine, Banha University, Banha 2344, Egypt.
Email: [email protected]
Downloaded from aan.sagepub.com by guest on June 5, 2014
2
Asian Cardiovascular & Thoracic Annals 0(0)
Cardiac Center, Dammam, Saudi Arabia. After approval
by the institutional ethics and research com- mittee, all
patients provided signed consent for surgery including the
ablation procedure. Inclusion criteria were elective mitral
valve surgery, left ventricular ejec- tion fraction 535%, and
persistent preoperative AF. Exclusion criteria were: age
>70 years; chronic obstructive pulmonary disease; poor left
ventricular function (ejection fraction <35%); renal failure
on regular dialysis; active endocarditis; emergency, urgent,
or redo surgery; postoperative low cardiac output syndrome;
and associated ischemic heart dis- ease. There were 52
patients eligible for the study: 18 (34.6%) had rheumatic
mitral disease, 34 (65.4%) had degenerative mitral valve
disease; and 8 (15.4%) also had tricuspid valve disease.
Table 1 summarizes their preoperative data.
From the day of admission until the day of dis- charge,
all patients had a daily standard 12-lead elec- trocardiogram
(ECG). Postoperatively, all patients in the surgical intensive
care unit were monitored via a bedside arrhythmia monitor
(Siemens SC 9000XL). Postoperatively, they were
monitored in the ward by continuous ECG telemetry
monitoring (Siemens). If a patient developed AF, a 12-lead
ECG was obtained; a second 12-lead ECG was carried out
if the patient returned to sinus rhythm. All patients had
preoperative transthoracic echocardiography using a Vivid
7 machine (GE Medical Systems, Vingmed, Norway).
Patients with suspected left atrial thrombus had pre-
operative
transesophageal
echocardiography.
Coronary angiography was carried out in patients >40years old or with history of ischemic heart disease.
All patients were anesthetized with propofol and fentanyl, using a target-controlled intravenous anesthesia
protocol. Each patient had a central venous catheter and
Swan-Ganz catheter with invasive monitoring of blood
pressure. All patients had transesophageal echocardiography pre-bypass and immediately after wean- ing
from cardiopulmonary bypass. Patients had either a median
sternotomy or a limited right anterior
thoracotomy. All operations were performed using a
conventional cardiopulmonary bypass machine with
crossclamping of the aorta and cardioplegia.
Cardiopulmonary bypass was conducted using a mem- brane
oxygenator and moderate hypothermia. The mitral valve
was approached by either a left or right atriotomy using a
transseptal approach. RF ablation was performed under
crossclamping after mitral valve repair or replacement. RF
ablation was undertaken using a Medtronic Cardioblate
68000 Surgical Ablation System Generator Device and a
model 60813 Standard Cardioblate Surgical Ablation Pen.
The generator power was set at 30 W, and lesions were
produced at a temperature of 701C-801C. Linear lesions in
the left atrium were produced according to the scheme
presented in Figure 1. Each 1-cm long seg- ment of the
ablation line was created by dragging the distal tip of the
Cardioblate pen gently across the endo- cardial tissue under
the surgeon's vision, moving in an oscillating motion at 1
cmÁsÀ1 for approximately 20 s until the targeted
endocardium became pale. The first ablation line was
created around the right and left pul- monary veins. One
lesion connected the left lower pul- monary vein with the
mitral annulus at the base of the posterior leaflet. The left
atrial appendage was sewn in all patients. Two pacemaker
wires were placed: one in the right atrium and the second in
the ventricle; they were cut before patients were discharged
home.
Oral anticoagulation was administered to all patients.
They were started on subcutaneous lowmolecular-weight heparin until the target international
normalized ratio was reached. Oral anticoagulants were
discontinued after the 3rd month in mitral valve repair cases
with sinus rhythm. According to our protocol, all patients
had an intraoperative amiodarone infusion with a loading
dose of 300 mg followed by continuous infusion of a total
of 1200 mg over the next 24 h. Amiodarone was
administered orally for 3 months
Table 1. Preoperative data of 52 patients with atrial fibrillation and
mitral valve disease.
Variable
No. of patients
Mean age (years)
43.22 Æ 6.23
Male
31 (59.6%) 21
Female
(40.4%)
Ejection fraction
51.46% Æ 6.59%
Mean PA pressure (mm Hg)
47.5 Æ 11.4 5.77 Æ
Mean left atrial size (cm)
0.68
PA: pulmonary artery.
Figure 1. Scheme of ablation. Note: the left atrial appendage
is sewn.
Downloaded from aan.sagepub.com by guest on June 5, 2014
Oueida et al.
3
after discharge. All patients underwent transthoracic
echocardiography before discharge, and a 12-lead ECG and
transthoracic echocardiography at 1, 3, 6, and 12 months
during outpatient visits.
All demographic data, preoperative, operative, and
postoperative data were collected, and statistical ana- lysis
was conducted using SPSS version 18.0 software (SPSS,
Inc., Chicago, IL, USA). Values of continuous variables are
expressed as mean Æ standard deviation. Categorical
variables are expressed as numbers and percentages.
Results
Eight (15.4%) patients had a small right anterior thoracotomy approach, and 44 (84.6%) had a midline sternotomy. In 15 (28.8%) patients, the transseptal approach
was used, the other 37 had a left atriotomy. Two (3.8%)
patients had a left atrial thrombus. The left atrial appendage
was closed in all patients. Mitral valve replacement was
performed in 21 (40.4%) patients, and 31 (59.6%) had mitral
valve repair. Table 2 summarizes the surgical data.
Intraoperatively, 41 patients had sinus rhythm immediately,
and 3 returned to sinus rhythm after electrical cardioversion.
Thus on arrival at the intensive care unit, 44 patients had
sinus rhythm; 6 of them had one or more attack of AF during
hospital stay but returned to sinus rhythm pharmacologically
with no need for electrical cardioversion. No patient
required permanent pacemaker implantation before
discharge. Sinus rhythm was documented in 44 (84.6%)
patients on discharge, and 8 (15.4%) were dis- charged with
AF. One patient was reexplored for bleed- ing. The
postoperative data are summarized in Table 3. Superficial
sternal wound infection was found in one (1.9%) patient.
There was no hospital mortality. Mean left atrial size before
discharge was 5.43 cm in patients with sinus rhythm, and
6.13 cm in those with persistent AF. Of the 8 patients
discharged in AF,
Table 2. Operative data of 52 patients with atrial fibrillation and
mitral valve disease.
Variable
No. of patients
Mitral valve repair
31
Mitral valve replacement
21
2 retuned to sinus rhythm after 3 months. At the 6- and 12month follow-up, the total number in sinus rhythm was
unchanged at 46, giving a total success rate of 88.46%.
Discussion
Persistent postoperative AF is associated with a higher
incidence of postoperative complications, especially
thromboembolic manifestations and low cardiac output
syndrome, particularly in patients with border- line left
ventricular function. 7 RF ablation involves complete
isolation of the pulmonary veins and exclu- sion of the left
atrial appendage, to prevent the path- way of transmission
between both the left atrial appendage and the mitral valve
to the pulmonary veins.8 The advantage of left atrial vs.
biatrial ablation is debatable. Some studies found no
significant difer- ence between left-side and right-side
ablation, except for an increase in cardiopulmonary bypass
time,9 whereas other studies confirmed the efcacy of biatrial
compared to left atrial ablation. 10 Although the inci- dence
of injury to important structures such as the cir- cumflex
artery is relatively high in monopolar compared to bipolar
RF ablation, most studies found no diference between
modes regarding the success
rate.11
Some studies have used postoperative continuous
monitoring, either invasive or noninvasive, to follow up
patients. 12,13 Continuous monitoring allows a higher degree
of confidence in detecting the real inci- dence of sinus
rhythm recovery and occurrence of tran- sient attacks of
arrhythmias, compared to the interval monitoring used in
our study. Unfortunately, such modalities of monitoring
were not available in our center during our study.
Our in-hospital success rate for AF ablation was 84.12%
with a 1-year success rate of 88.14%, which agrees with
previous studies that documented success rates of 80% to
92% for concomitant AF ablation during mitral valve
surgery.14,15 Most studies have shown the importance of
postoperative antiarrhythmic drugs in maintaining and even
restoring AF patients to sinus rhythm. Also, many studies
have confirmed the
Table 3. Postoperative data of 52 patients with atrial fibrillation and
mitral valve disease.
Mechanical valve
6
Tissue valve
15
Variable
No. of patients
Tricuspid valve repair
8
Ventilation time (h)
6.48 Æ 4.65
Cardiopulmonary bypass time (min)
71.28 Æ 20.31
Intensive care unit stay (h)
58.52 Æ 11.91
Crossclamp time (min)
53.14 Æ 17.08
Hospital stay (days)
8.18 Æ 1. 92
Ablation time (min)
6.41 Æ 0.21
Reexploration
1 (1.9%)
Downloaded from aan.sagepub.com by guest on June 5, 2014
4
Asian Cardiovascular & Thoracic Annals 0(0)
importance of at least 3 months of postoperative antiarrhythmic medication to achieve the maximum success rate
for the ablation procedure. 16 In our study, 2 patients with
postoperative persistent AF had restor- ation of sinus rhythm
after 3 months. Many factors afect the success rate of RF
ablation, but enlarged left atrium was reported in many
studies to be the main cause for failure of ablation.
Sunderland and col- leagues17 considered left atrial size >6
cm to be a pre- dictor of failure of AF ablation. Patients
with rheumatic disease are more prone to failure because
their atrial tissues are thicker and more fibrosed which
impairs the penetration of RF power, and hence afects the
isolation of the pulmonary veins.18 In our study, all patients
with persistent AF post-abla- tion had rheumatic disease,
with mean left atrial size >6 cm compared to 5.43 cm in
patients with sinus rhythm.
The limitations of this study include the relatively small
number of patients, which did not allow us to perform
multivariate analysis between patients with persistent AF
and those with sinus rhythm, to analysis the factors for
success or failure of RF ablation. However, we concluded
that left atrial monopolar RF ablation during mitral valve
surgery is a safe procedure with a high success rate,
especially in nonrheumatic patients with left atrial size <6
cm.
Funding
This research received no specific grant from any funding
agency in the public, commercial, or not-for-profit sectors.
Conflict of interest statement
None declared.
References
1. Benjamin EJ, Wolf PA, D'Agostino RB, Silbershatz H,
Kannel WB and Levy D. Impact of atrial fibrillation on the risk
of death: the Framingham Heart Study. Circulation 1998; 98:
946-952.
2. Hersi A, Wyse DG. Management of atrial fibrillation.
Curr Probl Cardiol 2005;30:175-234. Available at: http://
www.researchgate.net/publication/7955751_Management_
of_atrial_fibrillation. Accessed December 16, 2013.
3. Shemin RJ, Cox JL, Gillinov AM, Blackstone EH and
Bridges CR Workforce on Evidence-Based Surgery of the
Society of Thoracic Surgeons. Guidelines for reporting data and
outcomes for the surgical treatment of atrial fib- rillation. Ann
Thorac Surg 2007; 83: 1225-1230.
4. Raanani E, Albage A, David TE, Yau TM and Armstrong
S. The efficacy of the Cox/maze procedure combined with mitral
valve surgery: a matched control study. Eur J Cardiothorac
Surg 2001; 19: 438-442.
5. Nitta T, Ishii Y and Sakamoto S. Surgery for atrial fibrillation: recent progress and future perspective. Gen Thorac
Cardiovasc Surg 2012; 60: 13-20.
6. Sie HT, Beukema WP, Misier AR, et al. Radiofrequency
modified maze in patients with atrial fibrillation undergo- ing
concomitant cardiac surgery. J Thorac Cardiovasc Surg 2001;
122: 249-256.
7. Go AS, Hylek EM, Phillips KA, et al. Prevalence of diagnosed atrial fibrillation in adults: national implications for
rhythm management and stroke prevention: the
AnTicoagulation and Risk Factors in Atrial Fibrillation
(ATRIA) Study. JAMA 2001; 285: 2370-2375.
8. Chen Y, Maruthappu M and Nagendran M. How effective is unipolar radiofrequency ablation for atrial fibrilla- tion
during concomitant cardiac surgery? Interact Cardiovasc
Thorac Surg 2012; 14: 843-847.
9. Wang J, Meng X, Li H, Cui Y, Han J and Xu C.
Prospective randomized comparison of left atrial and bia- trial
radiofrequency ablation in the treatment of atrial fibrillation.
Eur J Cardiothorac Surg 2009; 35: 116-122.
10. Nakagawa H, Lazzara R, Khastgir T, et al. Role of the
tricuspid annulus and the eustachian valve/ridge atrial flutter:
relevance to catheter ablation of the septal isth- mus and a new
technique for rapid identification of abla- tion success.
Circulation 1996; 94: 407-424.
11. Geidel S, Lass M, Boczor S, Kuck KH and Ostermeyer J.
Monopolar and bipolar radiofrequency ablation surgery: 3-year
experience in 90 patients with permanent atrial fibrillation.
Heart Surg Forum 2004; 7: 398-402.
12. Pecha S, Scha¨fer T, Hartel F, et al. Concomitant surgical
atrial fibrillation ablation and event recorder implantation: better monitoring, better outcome? Interact Cardiovasc
Thorac Surg 2013; 16: 465-469.
13. Veasey RA, Segal OR, Large JK, et al. The efficacy of
intraoperative atrial radiofrequency ablation for atrial
fibrillation during concomitant cardiac surgery-the Surgical
Atrial Fibrillation Suppression (SAFS) Study. J Interv Card
Electrophysiol 2011; 32: 29-35.
14. Mesana TG, Kulik A, Ruel M, et al. Combined atrial
fibrillation ablation with mitral valve surgery. J Heart Valve
Dis 2006; 15: 515-520.
15. Cheng DC, Ad N, Martin J, et al. Surgical ablation for
atrial fibrillation in cardiac surgery: a meta-analysis and
systematic review. Innovations 2010; 5: 84-96.
16. McCarthy PM, Kruse J, Shalli S, et al. Where does atrial
fibrillation surgery fail? Implications for increasing effectiveness of ablation. J Thorac Cardiovasc Surg 2010; 139: 860867.
17. Sunderland N, Maruthappu M and Nagendran M. What
size of left atrium significantly impairs the success of maze
surgery for atrial fibrillation? Interact Cardiovasc Thorac Surg
2011; 13: 332-338.
18. Chaiyaroj S, Ngarmukos T and Lertsithichai P.
Predictors of sinus rhythm after radiofrequency maze and
mitral valve surgery. Asian Cardiovasc Thorac Ann 2008; 16:
292-297.
Downloaded from aan.sagepub.com by guest on June 5, 2014