Surgical Treatment of Supraventricular Tachycardia: Experience With 61 Patients Gennady V. Knyschov, MD, Alexander S. Stychinsky, MD, Valery P. Zalevsky, MD, Vjacheslav P. Yaroschenko, MD, and Pave1 A. Almiz, MD Cardiovascular Surgery Institute, Kiev, Union of Soviet Socialist Republics
Sixty-one patients underwent operation for supraventricular tachycardia: 52 had tachycardia associated with the atrioventricular accessory pathways; 9 patients had other forms of tachycardia. Accessory pathways were successfully divided in 92.3% of the patients. Classic endocardial approach was used in 30 patients; closed heart ablation of the accessory pathways was performed in 22 patients. There were two reoperations for return of conduction through the accessory pathways. Six patients
underwent cryoablation of the His bundle through the right atrial approach. Four patients underwent attempts at curative operations for atrioventricular node reentry tachycardia, atrial flutter, and atrial ectopic tachycardia. Concomitant cardiac surgical procedures were performed in 14 patients. Operative mortality was 1.6%.A satisfactory result, without tachycardia and without medication, was achieved in 93.4% of all patients. (Ann Thorac Surg 1991;52:11414)
D
multiple APs; 4 of them had right free wall and posterior septal connections, 2 patients had multiple right free wall APs, and 1 had multiple left free wall APs. One patient had both anterior and posterior septal APs. Right free wall and anterior septal APs were ablated by closed technique on the beating heart without cardiopulmonary bypass. The heart was exposed through a median sternotomy. After completion of the epicardial mapping, dissection of the fat pad in the AV grove was performed. Wide dissections were used to mobilize coronary vessels. The fat pad was separated from the atrial wall toward the top of the external wall of the ventricle. The small vessels were divided. Once dissection has been completed, a cryoprobe with an active part 4 mm in diameter and l5 mm long was through the entire length Of the dissection to incorporate part of the atrial wall, the adjacent AV junction, and the adjacent ventricular wall. The number Of applications varied from 4 to 7. The Zone Of freezing was extended 2.5 to 3 cm on each side of the determined location of the AP. Free mobilization of the fat pad allowed avoidance of contact between cryoprobe and coronary vessels during cryothermia. For ablation of anterior septal pathways we mobilized the AV fat pad in the right coronary fossa. The tricuspid valve annulus was exposed toward the AV junctional area. Then the tip of the cryoprobe was put into the space created between the atrial wall and the aortic root, and cryoablation (-70°C for 2 minutes) was applied. Left free wall APs in 6 patients were ablated by a closed heart technique similar to that used for right free wall APs. The left anterolateral thoracotomy was employed in these cases. In 5 patients we used a transatrial approach for interruption of left free wall APs. The surgical technique used was analogous to the technique developed by Sealy and Gallagher [9]. The only distinction was appli-
uring the past two decades surgery has become an acceptable mode for the treatment of supraventricular tachycardia. A variety of operative techniques are used in ablation of the accessory pathways (APs) [l-61 as well as in operation for other tachycardias [7, 81. This report describes our initial experience with 61 patients who underwent surgical treatment of supraventricular tachycardia.
Material and Methods Between January 1987 and May 1990 a total of 61 patients underwent investigations and operations for supraventricular tachycardia at our institution. All patients had medically refractory tachyarrhythmia. Indications for operation included a reentry tachycardia using the A P ~ in 49 patients and atrial fibrillation with atrioventricular (AV) conduction through ~p~ in 2. one patient had both tachycardia caused by Aps and tachycardia due to AV node reentrv. Nine Datients had supraventricular tachycardias not involving APs. Four of them had paroxysmal atrial flutter, 2 had chronic atrial fibrillation with rapid ventricular response, 2 had AV nodal reentrant tachycardia, and 1 patient had ectopic atrial tachycardia. The patients’ ages varied from 4 to 68 years, and 16 of them had some other cardiac disorder. All patients underwent preoperative electrophysiological study; intraoperative cardiac mapping was performed in all patients. Free wall connections were found in 24 patients (right free wall in 13 patients and left free wall in 11 patients). Eighteen patients had posterior septal APs and 2 had anterior septal connections. Eight patients had Accepted for publication June 17, 1991. Address reprint requests to Dr Stychinsky, Cardiovascular Surgery Institute, St. Rasina ll, Kiev 252110, USSR.
0 1991 by The Society of Thoracic Surgeons
0003-4975/91/$3.50
1142
KNYSCHOV ET AL SUPRAVENTRICULAR TACHYCARDIA
cation of the cryoprobe on the top of the left ventricle after completion of the dissection of the AV groove. Posterior septal connections were divided through the right atrium. These operations were performed with the use of cardiopulmonary bypass and cold cardioplegia. We used the most commonly employed technique [3, 8, 101 including supraannular incision in the posterior septal area with consequent extensive dissection. In all patients in whom correction of concomitant cardiac lesions was performed, a transatrial approach for interruption of an AP was used. Before the chest was closed, epicardial mapping was performed repeatedly to assess antegrade and retrograde conduction. During the first 8 to 9 days after operation, AV and ventriculoatrial conduction were checked daily with the aid of temporary wire electrodes. In 2 patients with AV nodal reentry tachycardia, discrete cryolesions were applied around the borders of the triangle of Koch according to the technique proposed by Holman and associates [7]. In 1 of those patients two APs were divided. Six patients underwent cryoablation of the His bundle through the right atrial approach: 3 for paroxysmal atrial flutter, 2 for chronic atrial fibrillation, and 1 for AV nodal reentry tachycardia. Four of those patients had concomitant cardiac lesions that required surgical correction, and 1 patient had thrombi in the left atrium that resulted in multiple embolic episodes. For these reasons surgical ablation of the His bundle was performed instead of a transvenous catheter procedure. Excision of an ectopic focus in the right atrium was performed in 1 patient with ectopic tachycardia. In 1 patient with paroxysmal atrial flutter and an atrial septal defect we made an attempt to identify a possible circle of reentry on the basis of a consequence of atrial activation and the localization of a conduction delay zone. One part of this circle was cryoablated, and the other part was excised. Concomitant cardiac surgical procedures were performed in 14 patients including repair of atrial septal defects in 4 patients, correction of Ebstein's anomaly in 3, mitral valve replacement in 2, mitral valvotomy in 2, and other procedures in 3.
Results Table 1 demonstrates the operative results in 52 patients with APs. As can be seen in Table 1, the APs were successfully interrupted in 90% of patients. Epicardial mapping before completion of the operation demonstrated that conduction through the AP was absent in all patients. Return of conduction over an AP occurred in 5 of them within the first week postoperatively: in 2 patients with posterior septal APs ablated by endocardia1 dissection and in 2 patients with left free wall and 1 with right free wall connections ablated by the epicardial approach. Two of those 5 patients (one with posterior septal and 1 with left lateral AP) underwent successful reoperation. There was one postoperative death in a patient who underwent interruption of a left free wall AP and open
Ann Thorac Surg 1991;52:11414
Table 1 . Results of Operation for lnterruption of Accesso,ry Pathways in 52 Patients
Localization of AP Posterior septal Right free wall Left free wall Multiple Anterior septal Total AP
=
No. of Patients
No. of Patients With Divided AP
18 13 11 8 2
16 12
52
47 (90.4%)
9 8
2
accessory pathway
mitral valvotomy. This patient died of pulmonary insufficiency. One patient had permanent complete heart block because of interruption of the posterior septal AP. F'ostoperative complications are listed in Table 2. Thus, all accessory AV and ventriculoatrial connections were successfully divided in 92.3% of patients. All patients in whom conduction through the AP was absent before discharge were free of tachycardia in follow-up. In 5 of 6 patients who underwent cryoablation of the His bundle, permanent complete heart block was achieved; in 1 patient AV conduction was only modified but it slowed significantly the heart rate during atrial fibrillation. Two patients who underwent perinodal cryoablation for AV nodal reentry tachycardia remained in sinus rhythm. The tachycardia could not be initiated in both patients by atrial and ventricular stimulation at electrophysiological study after operation. On follow-up they were free of symptoms. In 1 patient who underwent curative operation for atrial flutter, the atrial stimulation after operation initiatedl an atrial tachycardia with cycle length of 330 milliseconds (the cycle length of atrial flutter before operation was 220 milliseconds). The paroxysms after operation did not occur spontaneously during a 10-month period without any medication. In the patient with ectopic atrial tachycardia, epicardial mapping after excision of the ectopic focus showed an activation begun from sinus node region. He remains fully asymptomatic more than 1 year after operation.
Table 2 . Complications After 54 Operations for Interruption of Accessory Patlzways in 52 Patients" Complication Temporary low cardiac output Severe pneumonia necessitating ventilation Wound infection Lymphorrea necessitating reopening Overall incidence of complications was 14.8%
No. of Patients
Ann Thorac Surg 1991;52:11414
KNYSCHOV ET AL SUPRAVENTRICULAR TACHYCARDIA
Table 3 . Results of Operatiori for Tachycardias Not Associated With Accessory Pathways Variable No. of patients No. clinical SVT
Postoperative complications Operative mortality Late mortality
No. of Patients
10" 10 0 0
0
Including 1 patient in whom curative operation for atrioventricular nodal reentrant tachycardia was performed in addition to ablation of an accessory pathway. SVT
=
supraventricular tachycardia
Results of operations for supraventricular tachycardias not associated with APs are summarized in Table 3.
Comment Today the most experienced centers report excellent results of surgical treatment of the Wolff-Parkinson-White syndrome with success rate greater than 90% and mortality less than 1%[3, 8, 111. The endocardial approach is the most commonly employed, but there are surgeons who use a closed heart technique [2,4-61. Is the ablation of APs by closed heart technique reasonable? We obtained return of conduction over an AP in 2 (6%) of the 30 patients who were operated on by the open heart technique and in 3 (13%)of 22 who underwent external ablation of the AP. In the former group both recurrences occurred after ablation of posterior septal APs. Among patients who were operated on by the closed heart technique, all three recurrences occurred after ablation of free wall APs. Thus, when ablation of free wall connections was performed by the endocardial approach we had no recurrences, whereas in 20 patients with free wall APs operated on by the epicardial approach the frequency of recurrences was 15%. It may be concluded that the endocardial dissection technique for ablation of free wall APs is more successful than the epicardial one. However, we have considerations that do not allow us to reject epicardial dissection as method of ablation of free wall APs. In our clinic the operations with cold cardioplegic cardiac arrest are associated with greater mortality and morbidity in comparison with those without cardiopulmonary bypass. In our series all complications occurred in patients who were operated on with cardiopulmonary bypass. Therefore, the ablation of the APs by a closed heart technique seems to us more safe than by an open heart technique. The analysis shows that in 2 patients with recurrences after closed heart operations we made obvious errors. In 1 patient the zones of freezing did not overlap each other. In the other patient the ventricular wall near the valve annulus had been perforated by the tip of the cryoprobe. After repair of the defect, application of the cryoprobe around its borders were not done. In all cases of recurrence there was no evidence of conduction over APs
1143
immediately after operation. It reappeared from 20 hours to 7 days postoperatively. An epicardial mapping during reoperation in 1 of the patients who underwent closed heart operation and repeated electrophysiological study in another patient showed that conduction in both occurred through the same AP as before the first operation. Thus there was no error in initial localization of the AP and there were no other concomitant obscured APs. The cause of recurrence was insufficient "traumatization" of the AP. It seems that if the all steps of the procedure are carefully performed, closed heart ablation of free wall APs can be used. In our little experience with anterior septal pathways we did not observe AV conduction disorders either in the early or in the late follow-up. In 1 patient temporary second-degree AV block occurred during freezing. Freezing was interrupted, the tip of the cryoprobe was moved more externally, and then freezing was resumed. We suppose that in both patients with anterior septal pathways we really ablated anterior septal APs. The cryomapping at the place of the earliest right atrial activation adjacent to the aortic root did not interrupt conduction over the AP, which indicates that the AP coursed more internally. The freezing in the space created after dissection resulted in the interruption of conduction through the AP. Our first successful attempts at curative operation for AV nodal reentry tachycardia and atrial flutter allow us to employ these methods more widely. We now use ablation of the His bundle only in patients with atrial fibrillation who require correction of concomitant cardiac lesions.
References 1. Sealy WC. Direct surgery for arrhythmias. Chest 1982;82:
33844.
2. Guiraudon GM, Klein GJ, Gulamhusein S, et al. Surgical repair of Wolff-Parkinson-White syndrome: a new closedheart technique. Ann Thorac Surg 1984;37:67-71. 3. Cox JL, Gallagher JJ, Cain ME. Experience with 118 consecutive patients undergoing operation for the Wolff-ParkinsonWhite syndrome. J Thorac Cardiovasc Surg 1985;90:49G501. 4. Bredikis J, Bredikis A. Cryosurgical ablation of left parietal wall accessory atrioventricular connections through the coronary sinus without the use of extracorporeal circulation. J Thorac Cardiovasc Surg 1985;90:199-205. 5. Guiraudon GM, Klein GJ, Sharma A, et al. Surgical ablation of posterior septal accessory pathway in the Wolff-Parkinson-White syndrome by a closed-heart technique. J Thorac Cardiovasc Surg 1986;92:406-13. 6 . Bokeria LA, Mikhailin SI, Revishvili AS, Baturkin LJ, Rybalov AG. Epicardial electric shock ablation of accessory pathways in preexcitation syndrome. In: Fontaine G, Scheinmann M, eds. Ablation in cardiac arrhythmias. Mount-Kisco, NY: Futura, 1987:467-78. 7. Holman WL, Ikeshita M, Lease JG, et al. Elective prolonga-
tion of atrioventricular conduction by multiple discrete cryolesion. A new technique for the treatment of paroxysmal supraventricular tachycardia. J Thorac Cardiovasc Surg 1982;
84:55&61. 8. lohnson DC, Nunn GR, Richards DA, Uther JB, Ross DL.
1144
KNYSCHOV ET AL SUPRAVENTRICULAR TACHYCARDIA
Surgical therapy for supraventricular tachycardia, a potentially curable disorder. J Thorac Cardiovasc Surg 1987;93: 913-8. 9. Sealy WC, Gallagher JJ. Surgical treatment of left free-wall accessory pathways of atrioventricular conduction of the Kent type. J Thorac Cardiovasc Surg 1981;81:69%706.
Ann Thorac Surg 1991;52:11414
10. Sealy WC, Gallagher JJ. The surgical approach to the :septa1
area of the heart based on experiences with forty-five patients with Kent bundles. J Thorac Cardiovasc Surg 1980;79:542-9. 11. Iwa T, Mitsui T, Misaki T, et al. Radical surgical cure of Wolff-Parkinson-White syndrome: the Kanazawa experience. J Thorac Cardiovasc Surg 1986;91:225-33.
Notice From the American Board of Thoracic Surgery The American Board of Thoracic Surgery began its recertification process in 1984. Diplomates interested in participating in this examination should maintain a documented list of the operations they performed during the year prior to application for recertification. This practice review should consist of 1 year’s consecutive major operative experiences. (If more than 100 cases occur in 1 year, only 100 need to be listed.) They should also keep a record of their attendance at approved postgraduate medical education activities for the 2 years prior to application. A minimum of 100 hours of approved CME activity is required. In place of a cognitive examination, candidates for recertification will be required to complete both the general thoracic and cardiac portions of the SESATS IV syllabus (Self-Education/Self-Assessment in Thoracic Surgery). It is not necessary for candidates to purchase
SESATS IV booklets prior to applying for recertification. SESATS IV booklets will be forwarded to candidates after their applications have been accepted. Diplomates whose 10-year certificates will expire in 1994 may begin the recertification process in 1992. This new certificate will be dated 10 years from the time of expiration of the original certificate. Recertification is also open to any diplomate with an unlimited certificate and will in no way affect the validity of the original certificate. The deadline for submission of applications is May 1, 1992. A recertification brochure outlining the rules and requirements for recertification in thoracic surgery is available upon request from the American Board of Thoracic Surgery, One Rotary Center, Suite 803, Evanston, IL 60201.
Sixty-one patients underwent operation for supraventricular tachycardia: 52 had tachycardia associated with the atrioventricular accessory pathways; 9 patients had other forms of tachycardia. Accessory pathways were successfully divided in 92.3% of the patients. Classic endocardial approach was used in 30 patients; closed heart ablation of the accessory pathways was performed in 22 patients. There were two reoperations for return of conduction through the accessory pathways. Six patients
underwent cryoablation of the His bundle through the right atrial approach. Four patients underwent attempts at curative operations for atrioventricular node reentry tachycardia, atrial flutter, and atrial ectopic tachycardia. Concomitant cardiac surgical procedures were performed in 14 patients. Operative mortality was 1.6%.A satisfactory result, without tachycardia and without medication, was achieved in 93.4% of all patients. (Ann Thorac Surg 1991;52:11414)
D
multiple APs; 4 of them had right free wall and posterior septal connections, 2 patients had multiple right free wall APs, and 1 had multiple left free wall APs. One patient had both anterior and posterior septal APs. Right free wall and anterior septal APs were ablated by closed technique on the beating heart without cardiopulmonary bypass. The heart was exposed through a median sternotomy. After completion of the epicardial mapping, dissection of the fat pad in the AV grove was performed. Wide dissections were used to mobilize coronary vessels. The fat pad was separated from the atrial wall toward the top of the external wall of the ventricle. The small vessels were divided. Once dissection has been completed, a cryoprobe with an active part 4 mm in diameter and l5 mm long was through the entire length Of the dissection to incorporate part of the atrial wall, the adjacent AV junction, and the adjacent ventricular wall. The number Of applications varied from 4 to 7. The Zone Of freezing was extended 2.5 to 3 cm on each side of the determined location of the AP. Free mobilization of the fat pad allowed avoidance of contact between cryoprobe and coronary vessels during cryothermia. For ablation of anterior septal pathways we mobilized the AV fat pad in the right coronary fossa. The tricuspid valve annulus was exposed toward the AV junctional area. Then the tip of the cryoprobe was put into the space created between the atrial wall and the aortic root, and cryoablation (-70°C for 2 minutes) was applied. Left free wall APs in 6 patients were ablated by a closed heart technique similar to that used for right free wall APs. The left anterolateral thoracotomy was employed in these cases. In 5 patients we used a transatrial approach for interruption of left free wall APs. The surgical technique used was analogous to the technique developed by Sealy and Gallagher [9]. The only distinction was appli-
uring the past two decades surgery has become an acceptable mode for the treatment of supraventricular tachycardia. A variety of operative techniques are used in ablation of the accessory pathways (APs) [l-61 as well as in operation for other tachycardias [7, 81. This report describes our initial experience with 61 patients who underwent surgical treatment of supraventricular tachycardia.
Material and Methods Between January 1987 and May 1990 a total of 61 patients underwent investigations and operations for supraventricular tachycardia at our institution. All patients had medically refractory tachyarrhythmia. Indications for operation included a reentry tachycardia using the A P ~ in 49 patients and atrial fibrillation with atrioventricular (AV) conduction through ~p~ in 2. one patient had both tachycardia caused by Aps and tachycardia due to AV node reentrv. Nine Datients had supraventricular tachycardias not involving APs. Four of them had paroxysmal atrial flutter, 2 had chronic atrial fibrillation with rapid ventricular response, 2 had AV nodal reentrant tachycardia, and 1 patient had ectopic atrial tachycardia. The patients’ ages varied from 4 to 68 years, and 16 of them had some other cardiac disorder. All patients underwent preoperative electrophysiological study; intraoperative cardiac mapping was performed in all patients. Free wall connections were found in 24 patients (right free wall in 13 patients and left free wall in 11 patients). Eighteen patients had posterior septal APs and 2 had anterior septal connections. Eight patients had Accepted for publication June 17, 1991. Address reprint requests to Dr Stychinsky, Cardiovascular Surgery Institute, St. Rasina ll, Kiev 252110, USSR.
0 1991 by The Society of Thoracic Surgeons
0003-4975/91/$3.50
1142
KNYSCHOV ET AL SUPRAVENTRICULAR TACHYCARDIA
cation of the cryoprobe on the top of the left ventricle after completion of the dissection of the AV groove. Posterior septal connections were divided through the right atrium. These operations were performed with the use of cardiopulmonary bypass and cold cardioplegia. We used the most commonly employed technique [3, 8, 101 including supraannular incision in the posterior septal area with consequent extensive dissection. In all patients in whom correction of concomitant cardiac lesions was performed, a transatrial approach for interruption of an AP was used. Before the chest was closed, epicardial mapping was performed repeatedly to assess antegrade and retrograde conduction. During the first 8 to 9 days after operation, AV and ventriculoatrial conduction were checked daily with the aid of temporary wire electrodes. In 2 patients with AV nodal reentry tachycardia, discrete cryolesions were applied around the borders of the triangle of Koch according to the technique proposed by Holman and associates [7]. In 1 of those patients two APs were divided. Six patients underwent cryoablation of the His bundle through the right atrial approach: 3 for paroxysmal atrial flutter, 2 for chronic atrial fibrillation, and 1 for AV nodal reentry tachycardia. Four of those patients had concomitant cardiac lesions that required surgical correction, and 1 patient had thrombi in the left atrium that resulted in multiple embolic episodes. For these reasons surgical ablation of the His bundle was performed instead of a transvenous catheter procedure. Excision of an ectopic focus in the right atrium was performed in 1 patient with ectopic tachycardia. In 1 patient with paroxysmal atrial flutter and an atrial septal defect we made an attempt to identify a possible circle of reentry on the basis of a consequence of atrial activation and the localization of a conduction delay zone. One part of this circle was cryoablated, and the other part was excised. Concomitant cardiac surgical procedures were performed in 14 patients including repair of atrial septal defects in 4 patients, correction of Ebstein's anomaly in 3, mitral valve replacement in 2, mitral valvotomy in 2, and other procedures in 3.
Results Table 1 demonstrates the operative results in 52 patients with APs. As can be seen in Table 1, the APs were successfully interrupted in 90% of patients. Epicardial mapping before completion of the operation demonstrated that conduction through the AP was absent in all patients. Return of conduction over an AP occurred in 5 of them within the first week postoperatively: in 2 patients with posterior septal APs ablated by endocardia1 dissection and in 2 patients with left free wall and 1 with right free wall connections ablated by the epicardial approach. Two of those 5 patients (one with posterior septal and 1 with left lateral AP) underwent successful reoperation. There was one postoperative death in a patient who underwent interruption of a left free wall AP and open
Ann Thorac Surg 1991;52:11414
Table 1 . Results of Operation for lnterruption of Accesso,ry Pathways in 52 Patients
Localization of AP Posterior septal Right free wall Left free wall Multiple Anterior septal Total AP
=
No. of Patients
No. of Patients With Divided AP
18 13 11 8 2
16 12
52
47 (90.4%)
9 8
2
accessory pathway
mitral valvotomy. This patient died of pulmonary insufficiency. One patient had permanent complete heart block because of interruption of the posterior septal AP. F'ostoperative complications are listed in Table 2. Thus, all accessory AV and ventriculoatrial connections were successfully divided in 92.3% of patients. All patients in whom conduction through the AP was absent before discharge were free of tachycardia in follow-up. In 5 of 6 patients who underwent cryoablation of the His bundle, permanent complete heart block was achieved; in 1 patient AV conduction was only modified but it slowed significantly the heart rate during atrial fibrillation. Two patients who underwent perinodal cryoablation for AV nodal reentry tachycardia remained in sinus rhythm. The tachycardia could not be initiated in both patients by atrial and ventricular stimulation at electrophysiological study after operation. On follow-up they were free of symptoms. In 1 patient who underwent curative operation for atrial flutter, the atrial stimulation after operation initiatedl an atrial tachycardia with cycle length of 330 milliseconds (the cycle length of atrial flutter before operation was 220 milliseconds). The paroxysms after operation did not occur spontaneously during a 10-month period without any medication. In the patient with ectopic atrial tachycardia, epicardial mapping after excision of the ectopic focus showed an activation begun from sinus node region. He remains fully asymptomatic more than 1 year after operation.
Table 2 . Complications After 54 Operations for Interruption of Accessory Patlzways in 52 Patients" Complication Temporary low cardiac output Severe pneumonia necessitating ventilation Wound infection Lymphorrea necessitating reopening Overall incidence of complications was 14.8%
No. of Patients
Ann Thorac Surg 1991;52:11414
KNYSCHOV ET AL SUPRAVENTRICULAR TACHYCARDIA
Table 3 . Results of Operatiori for Tachycardias Not Associated With Accessory Pathways Variable No. of patients No. clinical SVT
Postoperative complications Operative mortality Late mortality
No. of Patients
10" 10 0 0
0
Including 1 patient in whom curative operation for atrioventricular nodal reentrant tachycardia was performed in addition to ablation of an accessory pathway. SVT
=
supraventricular tachycardia
Results of operations for supraventricular tachycardias not associated with APs are summarized in Table 3.
Comment Today the most experienced centers report excellent results of surgical treatment of the Wolff-Parkinson-White syndrome with success rate greater than 90% and mortality less than 1%[3, 8, 111. The endocardial approach is the most commonly employed, but there are surgeons who use a closed heart technique [2,4-61. Is the ablation of APs by closed heart technique reasonable? We obtained return of conduction over an AP in 2 (6%) of the 30 patients who were operated on by the open heart technique and in 3 (13%)of 22 who underwent external ablation of the AP. In the former group both recurrences occurred after ablation of posterior septal APs. Among patients who were operated on by the closed heart technique, all three recurrences occurred after ablation of free wall APs. Thus, when ablation of free wall connections was performed by the endocardial approach we had no recurrences, whereas in 20 patients with free wall APs operated on by the epicardial approach the frequency of recurrences was 15%. It may be concluded that the endocardial dissection technique for ablation of free wall APs is more successful than the epicardial one. However, we have considerations that do not allow us to reject epicardial dissection as method of ablation of free wall APs. In our clinic the operations with cold cardioplegic cardiac arrest are associated with greater mortality and morbidity in comparison with those without cardiopulmonary bypass. In our series all complications occurred in patients who were operated on with cardiopulmonary bypass. Therefore, the ablation of the APs by a closed heart technique seems to us more safe than by an open heart technique. The analysis shows that in 2 patients with recurrences after closed heart operations we made obvious errors. In 1 patient the zones of freezing did not overlap each other. In the other patient the ventricular wall near the valve annulus had been perforated by the tip of the cryoprobe. After repair of the defect, application of the cryoprobe around its borders were not done. In all cases of recurrence there was no evidence of conduction over APs
1143
immediately after operation. It reappeared from 20 hours to 7 days postoperatively. An epicardial mapping during reoperation in 1 of the patients who underwent closed heart operation and repeated electrophysiological study in another patient showed that conduction in both occurred through the same AP as before the first operation. Thus there was no error in initial localization of the AP and there were no other concomitant obscured APs. The cause of recurrence was insufficient "traumatization" of the AP. It seems that if the all steps of the procedure are carefully performed, closed heart ablation of free wall APs can be used. In our little experience with anterior septal pathways we did not observe AV conduction disorders either in the early or in the late follow-up. In 1 patient temporary second-degree AV block occurred during freezing. Freezing was interrupted, the tip of the cryoprobe was moved more externally, and then freezing was resumed. We suppose that in both patients with anterior septal pathways we really ablated anterior septal APs. The cryomapping at the place of the earliest right atrial activation adjacent to the aortic root did not interrupt conduction over the AP, which indicates that the AP coursed more internally. The freezing in the space created after dissection resulted in the interruption of conduction through the AP. Our first successful attempts at curative operation for AV nodal reentry tachycardia and atrial flutter allow us to employ these methods more widely. We now use ablation of the His bundle only in patients with atrial fibrillation who require correction of concomitant cardiac lesions.
References 1. Sealy WC. Direct surgery for arrhythmias. Chest 1982;82:
33844.
2. Guiraudon GM, Klein GJ, Gulamhusein S, et al. Surgical repair of Wolff-Parkinson-White syndrome: a new closedheart technique. Ann Thorac Surg 1984;37:67-71. 3. Cox JL, Gallagher JJ, Cain ME. Experience with 118 consecutive patients undergoing operation for the Wolff-ParkinsonWhite syndrome. J Thorac Cardiovasc Surg 1985;90:49G501. 4. Bredikis J, Bredikis A. Cryosurgical ablation of left parietal wall accessory atrioventricular connections through the coronary sinus without the use of extracorporeal circulation. J Thorac Cardiovasc Surg 1985;90:199-205. 5. Guiraudon GM, Klein GJ, Sharma A, et al. Surgical ablation of posterior septal accessory pathway in the Wolff-Parkinson-White syndrome by a closed-heart technique. J Thorac Cardiovasc Surg 1986;92:406-13. 6 . Bokeria LA, Mikhailin SI, Revishvili AS, Baturkin LJ, Rybalov AG. Epicardial electric shock ablation of accessory pathways in preexcitation syndrome. In: Fontaine G, Scheinmann M, eds. Ablation in cardiac arrhythmias. Mount-Kisco, NY: Futura, 1987:467-78. 7. Holman WL, Ikeshita M, Lease JG, et al. Elective prolonga-
tion of atrioventricular conduction by multiple discrete cryolesion. A new technique for the treatment of paroxysmal supraventricular tachycardia. J Thorac Cardiovasc Surg 1982;
84:55&61. 8. lohnson DC, Nunn GR, Richards DA, Uther JB, Ross DL.
1144
KNYSCHOV ET AL SUPRAVENTRICULAR TACHYCARDIA
Surgical therapy for supraventricular tachycardia, a potentially curable disorder. J Thorac Cardiovasc Surg 1987;93: 913-8. 9. Sealy WC, Gallagher JJ. Surgical treatment of left free-wall accessory pathways of atrioventricular conduction of the Kent type. J Thorac Cardiovasc Surg 1981;81:69%706.
Ann Thorac Surg 1991;52:11414
10. Sealy WC, Gallagher JJ. The surgical approach to the :septa1
area of the heart based on experiences with forty-five patients with Kent bundles. J Thorac Cardiovasc Surg 1980;79:542-9. 11. Iwa T, Mitsui T, Misaki T, et al. Radical surgical cure of Wolff-Parkinson-White syndrome: the Kanazawa experience. J Thorac Cardiovasc Surg 1986;91:225-33.
Notice From the American Board of Thoracic Surgery The American Board of Thoracic Surgery began its recertification process in 1984. Diplomates interested in participating in this examination should maintain a documented list of the operations they performed during the year prior to application for recertification. This practice review should consist of 1 year’s consecutive major operative experiences. (If more than 100 cases occur in 1 year, only 100 need to be listed.) They should also keep a record of their attendance at approved postgraduate medical education activities for the 2 years prior to application. A minimum of 100 hours of approved CME activity is required. In place of a cognitive examination, candidates for recertification will be required to complete both the general thoracic and cardiac portions of the SESATS IV syllabus (Self-Education/Self-Assessment in Thoracic Surgery). It is not necessary for candidates to purchase
SESATS IV booklets prior to applying for recertification. SESATS IV booklets will be forwarded to candidates after their applications have been accepted. Diplomates whose 10-year certificates will expire in 1994 may begin the recertification process in 1992. This new certificate will be dated 10 years from the time of expiration of the original certificate. Recertification is also open to any diplomate with an unlimited certificate and will in no way affect the validity of the original certificate. The deadline for submission of applications is May 1, 1992. A recertification brochure outlining the rules and requirements for recertification in thoracic surgery is available upon request from the American Board of Thoracic Surgery, One Rotary Center, Suite 803, Evanston, IL 60201.
