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Interact CardioVasc Thorac Surg 2008;7:80-83. doi:10.1510/icvts.2007.165225 © 2008 European Association of Cardio-Thoracic Surgery
Concomitant irrigated monopolar radiofrequency ablation of atrial fibrillation in adults with congenital heart diseaseDivision of Cardiac Surgery, Beijing Anzhen Hospital, Capital University of Medical Sciences, 36 Wuluju Chaoyang District, Beijing, 100029 China Received 16 August 2007; received in revised form 24 October 2007; accepted 29 October 2007
*Corresponding author. Tel.: +86-10-64456776; fax: +86-10-64419691.
Atrial fibrillation is the most frequent form of atrial arrhythmias in adults with congenital heart disease. Some serious complications are related with the presence of atrial fibrillation after surgery. Because of the complexity and the risk of bleeding, the Maze III procedure has been largely replaced by alternative energy sources. Our experience in using irrigated monopolar radiofrequency ablation to treat atrial fibrillation in adults with congenital heart disease is reported. Seven patients with congenital heart disease and atrial fibrillation underwent irrigated monopolar radiofrequency ablation. All patients were confirmed in permanent fibrillation preoperatively. Six were adult atrial septal defect patients and one was an adult patent ductus arteriosus patient. All patients survived the procedure and discharged in sinus rhythm. There were no complications related to radiofrequency ablation. The time of ablation ranged from 17 to 22 min (average 19.5 min). Follow-up ranged from 3 to 48 months. One patient with mitral valve replacement (MVR) died of cerebral hemorrhage 13 months after surgery. The last electrocardiogram showed that six patients were in sinus rhythm and one patient in junctional rhythm. Irrigated monopolar radiofrequency ablation is an easy, effective, safe and economic concomitant operation to eliminate atrial fibrillation in adult patients with congenital heart defect and atrial fibrillation.
Key Words: Atrial fibrillation; Radiofrequency ablation; Congenital heart disease
Atrial fibrillation (AF) is the most frequent form of atrial arrhythmias in adults with congenital heart disease (CHD). The incidence of AF in adults with atrial septal defect (ASD) varies from 8% to 25%, and it increases with age. The occurrence of atrial arrhythmias does not decrease even when the defect is successfully surgical corrected [1, 2]. Some serious complications, such as brain embolism and stroke, are related with the presence of AF after surgery. The Maze III procedure has been proved to be an effective surgical treatment for AF. This procedure has been largely replaced by surgical ablation for AF using alternative energy sources, due to its complexity, increased operative times, and the risk of bleeding [3, 4]. Atrial compartment surgery and right-sided Maze procedure had been used to treat AF associated with congenital heart disease and proved to be effective for reducing late recurrent AF [5]. Irrigated monopolar radiofrequency ablation (IMRA) as a concomitant operation with congenital heart defect correction is seldom reported [6]. Herein, we report our experience in using IMRA to treat AF in adults with CHD.
The study was approved by our Institutional Review Board, and individual consent was obtained before operation. From April 2003 to January 2007, seven patients with CHD and AF underwent IMRA. Preoperative echocardiogram showed that all patients were in permanent fibrillation. Six were adult ASD patients and one was an adult patent ductus arteriosus (PDA) patient. Because of the associated intracardiac malformations, all patients were preoperatively evaluated as unsuitable for transcatheter treatment. There were six female and one male, and the age ranged from 19 years to 60 years (mean, 47.1 years). Cardiac catheterization was performed in five cases, and Qp/Qs ranged from 1.9 to 2.7. The clinical information is summarized in Table 1.
The operation was performed under cardiopulmonary bypass. Cold, antegrade blood cardioplegic solution was used in all patients. A large PDA was sutured directly with 3-0 polypropylene (Ethicon, Somerville, NJ) reinforced with pledgets in one case. Closure of ASD with heterologous pericardial patch was performed in six patients. Concomitant TVP was performed using annuloplastic ring (Medtronic, Inc., Minneapolis, MN) in five patients. Mitral valve replacement, mitral valve plasty, and pulmonary valve plasty were performed in one case, respectively. IMRA (Cardioblate Surgical Ablation System; Medtronic, Inc., Minneapolis, MN) was performed in each patient. Irrigation flow rate was 5 ml/min, power was 25 W, pen movement was 0.5 cm/s.nt of 0.5 cm/s. Ablation was performed in both the right and left atrium. Right atrial appendage was removed, and right atrial ablation lines included: (1) from the superior vena cava (SVC) cannulation to inferior vena cava (IVC) cannulation; (2) from the excised right appendage to the tricuspid valve annulus; (3) from the IVC to the coronary sinus; and (4) from coronary sinus to tricuspid valve annulus. In the left atrium, the appendage was routingly excised and the left atrial ablation lines were as follows: (1) around the base of left appendage; (2) around the left and right pulmonary veins; (3) a line connecting the two pulmonary veins circles; and (4) connecting the middle of the line to the posterior mitral valve annulus. All patients received 300 mg amiodarone intravenously over 20 min on the first postoperative day. An oral dose of 300 mg of amiodarone was given for three months after surgery. No anti-arrhythmia drugs or beta blockers were used after three months. Follow-up time ranged from 3 to 45 months (average 24.4 months). Electrocardiograms were performed at discharge, 3, 6, 9, 12, 24 months and the latest follow-up. Twenty-hour electrocardiogram monitoring was performed at twelve months after surgery and the latest follow-up. Rhythm success was defined as freedom from AF and atrial flutter as determined by postoperative electrocardiograms.
All patients survived the procedure and discharged in sinus rhythm. There were no major complications related to the radiofrequency ablation. There were no soft tissues or cardiac perforations. The time of ablation ranged from 17 to 22 min (average 19.5 min). Follow-up ranged from 3 to 48 months (average 24.4 months). The patient with mitral valve replacement (MVR) died of cerebral hemorrhage 13 months after surgery. The last electrocardiogram showed that she was in sinus rhythm. Five patients were in sinus rhythm and one patient in junctional rhythm.
Some congenital heart diseases, such as ASD, PDA, which can cause the right or left atrium dilatation and conduction disturbances, are commonly associated with AF. Because the symptoms appear relatively late, sometimes, the diagnosis is postponed until their adulthood. The incidence of AF increases with age, and it does not disappear even when the defects are successfully surgical corrected [2]. Previous researches have demonstrated that timely closure of a congenital heart defect can prevent the occurrence of AF. Gatzoulis and his colleagues had demonstrated that older age (>40 years) at the time of surgery, the more likelihood there was of preoperative atrial flutter or fibrillation, and the more likelihood of postoperative atrial flutter or fibrillation [7]. AF is associated with a twofold or threefold increase in risk of adverse events, including permanent or transient stroke, acute myocardial infarction, and death. To restore sinus rhythm in patients with CHD and AF, at the time of intracardiac repair, may have better long-term results. The Maze procedure has been recognized as the most effective surgical treatment of AF [8]. A concomitant right-sided Maze procedure at the time of intracardiac repair is also recommended for AF in CHD. On the contrary, Kobayashi and his colleagues found the restrictive right-sided Maze procedure was not reliable, the recurrence of AF was high [9]. Due to the complexity and risk of bleeding, the Maze III procedure has been largely replaced by surgical ablation for AF using alternative energy sources. Recent advances in the understanding of the pathogenesis of AF and development of new ablation technologies enable surgeons to create linear left atrial lesions and remove the left atrial appendage rapidly and safely [10, 11]. The saline-irrigated cooled-tip radiofrequency ablation system is an alternative source of energy used to ablate AF. It has been proved to be a rapid, safe, and effective alternative to a standard Maze procedure for surgical treatment of AF. The mid- and long-term results are satisfactory and freedom from AF is 75–87% [6, 12]. Comparing with other alternative energy sources, such as the bipolar radiofrequency ablation system and cryoablation system, the monopolar radiofrequency ablation system is cheaper. Therefore, it is a good choice to use this system to restore the sinus rhythm in patients with CHD and AF, especially in the developing countries. To achieve a transmural lesion is the key point to eliminate AF. With the irrigated monopolar radiofrequency ablation system, heated tissues can be cooled by saline. It is helpful to achieve a deep and wide transmural lesion, and minimize the risk of damage to the pulmonary veins and adjacent mediastinal structures. No complications associated with ablation occurred in our patients. Unlike other instruments, the pen is flexible and can be made into different shapes and angles. Its tip can reach anywhere the surgeon wants. The left appendage is removed during radiofrequency ablation. It is useful to diminish the incidence of stroke after surgery. Most strokes in AF patients are thought to be caused by thrombi from the left appendage. Surgical excision of the left appendage is an effective way to avoid this serious complication. During the mean 24.4 months follow-up, no stroke occurred in our patients. Very good results can be achieved with radiofrequency ablation. Raman and his colleagues have reported that freedom from AF was 84% at 3 months, 90% at 6 months, and 100% at 12 months after radiofrequency ablation. All patients at 12 and 18 months were in sinus rhythm [13]. Our results are also encouraging. All patients were free from AF at discharge. During follow-up, six patients are in sinus rhythm and one in junctional rhythm. No patient needs a pacemaker implantation. This study has some limitations. First, there are only seven patients in our group, the number is limited. Second, the duration of AF is relatively short; the average duration of AF is only 15.4 months. Third, the dimension of left atrium is not too large, the largest one is 58 mm. Halkos and his colleagues have demonstrated that the diameter of left atrium is an important risk factor for postoperative AF after radiofrequency ablation procedures. In patients with left atrial diameter <6.0 cm, 88.2% were free from AF, while in patients with left atrial diameter of 6.0 cm or greater, only 40% were free from AF [14]. The duration of atrial fibrillation was also a risk factor involved in postoperative recurrence of atrial fibrillation after radiofrequency surgery [15]. In conclusion, for adult patients with congenital heart defect and atrial fibrillation, irrigated monopolar radiofrequency ablation is a safe, effective and economic concomitant operation to eliminate AF with satisfactory results.
The authors acknowledge Dr. Gus J. Vlahakes, Chief, Division of Cardiac Surgery, Massachusetts General Hospital, for reviewing this manuscript.
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Abstract
1. Introduction
