The conduction system in truncus arteriosus and its surgical significance. A study of five cases.

Atrioventricular block may occasionally occur after surgical correction of truncus arteriosus. We therefore studied the conduction system by means of serial sections in five cases of truncus (one after surgical intervention) to delineate the course of the conduction system and its relationship to the ventricular septal defect and the membranous septum. In general, the ventricular septal defect is in the anterior septum, confluent with the truncus, and the atrioventricular bundle is posterior and unrelated to the rim of the ventricular septal defect. In cases in which the ventricular septal defect is anterior and separated from the membranous septum by distinct muscle, the ventricular septal defect can be surgically closed without injury to the atrioventricular bundle. If the ventricular septal defect is related to the membranous septum, the atrioventricular bundle may be close to the ventricular septal defect and susceptible to surgical injury. If muscle separates the ventricular septal defect from the membranous septum, the branching bundle is close to the ventricular septal defect and also is susceptible to surgical injury. In one operated case there was partial dissolution of the left bundle branch, and the right bundle branch was involved in surgical closure of the defect. In summary, in truncus the conduction system varies in its course and is related to the location of the ventricular septal defect and its relationship to the membranous septum. The ventricular septal defect may be close to or related to the membranous septum, and the atrioventricular bundle and the beginning of the bundle branches may be vulnerable to surgical injury.     

Mattress Stitch—A Modified Shallow Stitching in the Surgical Closure of Large Perimembranous Ventricular Septal Defect in Infants

Objectives: The purpose of this study was to assess the feasibility of the mattress suturing technique in repairing large perimembranous ventricular septal defects (VSDs) in infants.Methods: This was a retrospective review of 120 patients undergoing surgical closure of perimembranous VSD between 2010 and 2012. The mattress suturing technique was performed to close the infero-posterior rim of the perimembranous VSD in 60 patients (Group I) while the conventional shallow suturing method was used in the others (Group II). Propensityscore matching was performed to adjust for potential baseline confounders, which resulted in 120 patients matched to 95 patients. Perioperative outcomes were compared.Results: Postoperative mortality in both groups was zero. Two patients in Group II developed atrioventricular block (1 complete heart block and 1 temporal II-degree atrioventricular block) compared with none in Group I (p >0.05). Complete right bundle branch block was found in four patients in Group I and 12 patients in Group II (p = 0.035). Mean follow-up time was 26.6 ± 8.9 months. Three patients in Group II developed a small residual VSD while only one patient in Group I did during the follow-up period (p >0.05).Conclusions: The mattress suturing technique produced results comparable with the conventional shallow suturing method and seems to be of value in reducing the incidence of complete right bundle branch block. It appears to provide an optional method for surgical closure of large perimembranous VSDs in infants.     

Avoidance of surgical right bundle branch block in ventricular septal defect

Right bundle branch block (RBBB) has been the most frequent conduction disturbance in postoperative patients with a large ventricular septal defect. It has long been considered as an insignificant postoperative sequela. However, recent documentation of its possible deleterious effects on cardiac performance led us to modify the standard technique in an attempt to avoid the postoperative RBBB. In addition to approaching the defect through the right atriotomy special care was taken for suture placement at the inferior margin and the antero-inferior corner of the defect of perimembranous type. With this technical modification, the frequency of surgical RBBB in patients with a large perimembranous defect has decreased from 31.3 to 8.3 per cent.     

Clinical appraisal of his bundle electrocardiogram taken under cardiotomy in congenital heart disease

The specialized conduction system in the heart was electrophysiologically delineated under cardiotomy in 74 patients with congenital heart disease primarily to determine the topographic relationship of the conduction system to intracardiac structures. Histological study was also done to evaluate the electrophysiological data. Differences were found between the ordinary ventricular septal defect (VSD), inlet-type perimembranous defect, and the ordinary tetralogy of Fallot (TOF), outlet-type perimembranous defect. A superficial run of the His bundle along the lower rim summit of defect was often demonstrated electrophysiologically in large VSD of types II or III, whereas the bundle took marked leftward course in TOF. The right bundle branch (RBB) ran beneath or slightly posterior to the Lancisi equivalent structure (LES) in VSD, while it ran underor slightly anterior to LES in TOF. This papillary muscle could be a rough landmark of the RBB. The course of the RBB in OTF, however, had to be histologically confirmed, since its deep location made electrophysiological delineation difficult. All the sites with a high deflection were the areas where the conduction system was histologically demonstrated beneath the endocardium.     

Intraoperative device closure of perimembranous ventricular septal defects without cardiopulmonary bypass: preliminary results with the perventricular technique

OBJECTIVE: In infants undergoing closure of perimembranous ventricular septal defects, cardiopulmonary bypass remains one of the factors that prolongs hospital stay and morbidity. A new technique was used to close the defects under echocardiographic guidance without cardiopulmonary bypass to prevent the deleterious effects of bypass. METHODS: Recently, the Amplatzer membranous ventricular septal defect device (AGA Medical Corp, Golden Valley, Minn) was introduced. The device has a double-disc design with a short connecting waist. The left ventricular disc has an eccentric design to prevent encroachment on the aortic valve leaflets. Eight Yucatan miniature pigs with naturally occurring perimembranous ventricular septal defects underwent closure of the defect in the operating room by using the perventricular technique. After median sternotomy, a purse-string suture was placed on the free wall of the right ventricle. An angiocatheter was advanced in the right ventricle, and through the catheter, a wire was advanced from the right ventricle through the ventricular septal defect into the left ventricle. A delivery sheath and the dilator were advanced over the wire. The wire and catheter were removed, and an appropriately sized Amplatzer membranous device was advanced through the sheath. The device was deployed under echocardiographic guidance with the heart beating. RESULTS: The procedure was successful in all animals. There was no incidence of device embolization, heart block, or aortic insufficiency. Angiograms at 3 and 6 months revealed no residual defects and no aortic insufficiency. Pathologically, the devices were completely endothelialized when examined grossly. CONCLUSIONS: The perventricular technique appears to be excellent for closure of perimembranous ventricular septal defects in the operating room. The technique might be feasible in smaller babies, who are high-risk candidates for closure in the catheterization laboratory. Cardiopulmonary bypass and prolonged hospital stay are avoided.     

Surgical anatomy of the atrioventricular conduction bundle in tetralogy of Fallot. New findings relevant to the position of the sutures

To avoid three of the causes of right ventricular end-diastolic pressure elevation, complete heart block, residual leakage, and fixing of tricuspid septal leaflet, we studied detailed anatomy of the posteroinferior corner of the ventricular septal defect of tetralogy of Fallot in 81 specimens. A new stitching method was applied in 79 patients with tetralogy of Fallot. Sixty-eight specimens (84%) had perimembranous outlet ventricular septal defect with a membranous flap 4.5 +/- 2.6 mm long. Thirteen (16%) had a muscle bar separating the defect from the central fibrous body area. The width was 5.8 +/- 1.7 mm. Microscopic study revealed that the membranous flap is a safe structure for suturing because of the thick posterior extension of the trabecular septomarginalis. In the clinical application of a new stitching method that uses the membranous flap, all patients showed sinus rhythm and no patient had complete heart block. We conclude that a membranous flap can be used safely as a suture line to avoid conduction tissue damage without using the tricuspid septal leaflet.     

Morphology of ventricular septal defects in complete transposition. Surgical implications.

Postmortem examination of 62 hearts with complete transposition (concordant atrioventricular and discordant ventriculoarterial connections) and an accompanying ventricular septal defect was performed to determine the morphologic variability of ventricular septal defects and to explore the surgical implications of these defects. Particular attention was directed toward assessing alignment of the outlet septum relative to the muscular septum. Coronary arterial distributions were also evaluated, but specific patterns of distribution did not correlate with morphology of the defect. Of 49 hearts with a normally aligned outlet septum, there were 24 perimembranous, 21 muscular, and 2 doubly committed and juxtaarterial defects. Two hearts had both perimembranous and muscular defects. Twelve of the 21 muscular defects were "central," being surrounded entirely by muscle and located just below the leaflets of the pulmonary valve, and 9 were located in the inlet or apical trabecular septum. There were 13 hearts with malalignment of the outlet septum, anteriorly in 11 and posteriorly in 2. All with anterior malalignment had a subpulmonary defect that was perimembranous in 7 and muscular in 4. Both defects with posterior malalignment had a subaortic perimembranous defect. Because variations in morphology of a ventricular septal defect have a direct impact on selection of the most suitable surgical repair, specific operative approaches are discussed.     

Traumatic ventricular septal defect with tricuspid incompetence. Surgical treatment

The authors report a case of traumatic ventricular septal defect associated with tricuspid incompetence after blunt injury of the chest. This case is the third one described in the literature. This case includes several unusual features: (1) the patient was a 52 year old man. Wounds of the heart usually happen to younger people; (2) clinical manifestations were immediately important; (3) there was a left bundle branch block on the electrocardiogram; (4) surgical treatment was performed as an emergency (less than a fortnight after the accident).     

Detachment of the anterior leaflet of the tricuspid valve to expose perimembranous ventricular septal defects

BACKGROUND: Detachment of the septal leaflet of the tricuspid valve has been described for better access to perimembranous ventricular septal defects. Detachment confined to the anterior leaflet is less known, although it provides a better exposure of the subaortic area and puts less jeopardy on the conduction tissues. METHODS: Data regarding 49 consecutive patients who had congenital perimembranous ventricular septal defect closure were retrospectively reviewed. Thirty-three patients (67%) underwent temporary detachment of the anterior leaflet of the tricuspid valve. The defect was closed with a Gore-Tex patch and a continuous suture. In 10 patients (29%), concomitant right ventricular outflow tract enlargement was performed. Follow-up was obtained in every patient (median time, 11 months; range, 2 to 26 months). RESULTS: No early or late death occurred. Closure of the ventricular septal defect was complete, with no more than trivial residual jet leaks found in perioperative echocardiography. All patients were in sinus rhythm. The tricuspid valve never showed more than mild insufficiency after repair. No patient showed subaortic obstruction. CONCLUSIONS: Detachment of the anterior leaflet of the tricuspid valve to expose the ventricular septal defect is a safe approach that allows rapid closure of the defect with a continuous suture and provides excellent results.     

Repair of complete atrioventricular septal defects: results with maintenance of the coronary sinus on the right atrial side

BACKGROUND: This study was undertaken to determine that maintaining coronary sinus on the right atrial side during the surgical repair of complete atrioventricular septal defect (AVSD) does not increase the risk of postoperative complete heart block. METHODS: This is a retrospective study of 51 consecutive patients who underwent biventricular repair of complete AVSD from September 2000 to January 2005. Electrocardiograms and operative data were analyzed. RESULTS: The mean age was 13.3 months (4 to 60). In all the 51 patients, except 13 cases, repair was performed using the two-patch technique. All atrial septal defects were closed using the patch technique with the coronary sinus maintained on the right atrial side in 48 (94%) cases. The cleft in the neomitral valve was closed in all patients. Associated lesions were repaired in four patients (7.8%); coarctation of aorta in two patients; multiple ventricular septal defects (VSD) with coronary sinus type-total anomalous pulmonary venous drainage and right-sided diaphragmatic eventration in one patient; and tetralogy of Fallot in one patient. There were five deaths (9.8%) in a series. The mean hospital stay was 11.8 days. During the same hospitalization, reintervention was required in two cases: one for residual VSD and the other for a severely dysplastic regurgitant mitral valve. Mean follow-up was 11.3 months. One patient required reoperation for residual VSD, residual atrial septal defect, and moderate mitral regurgitation 5 months after the initial repair. Except for first-degree heart block documented in nine cases and right bundle branch block in two cases, all patients remained in sinus rhythm on follow-up electrocardiography as preoperatively documented. No patient required prolonged cardiac pacing in the postoperative period. CONCLUSION: We believe that maintenance of the coronary sinus on the right side can be safely accomplished in the majority of complete AVSD repair as long as careful attention is paid to the anatomy of the conduction system. This technique did not increase the risk of postoperative heart block and permanent pacemaker insertion was not required.     

A new method of closing the ventricular septal defect in corrected transposition of the great arteries

A new method of closing a perimembranous malalignment ventricular septal defect (VSD) in corrected transposition of the great arteries (TGA) of the [S,L,L] type is presented. The method consists of combined approaches to the VSD through both a right atriotomy and an aortotomy without a ventriculotomy. The VSD is patched obliquely from the morphological right ventricular side of the septum, cranially through the aortic valve to the left ventricular side of the septum, caudally through the mitral valve. Although this method has been successfully applied in only one adult patient, some advantages may be expected: (1) prevention of trauma to the His bundle, which runs along the anterosuperior rim of the VSD on the left ventricular side; and (2) prevention of trauma to the tricuspid, mitral, and aortic valves without having to open the ventricles. We believe that this new method warrants a further trial as possibly better for closure of the VSD in corrected TGA of the [S,L,L] type.     

A histologic study on prevention of surgical conduction disturbance, with special reference to the relationship between the central portion of the A-V bundle and adjacent structures

The present study was aimed to examine the course of the proximal portion of the His bundle (HB). Twenty-six hearts was histologically investigated, 5 normal, 13 with isolated perimembranous ventricular septal defect (VSD) and with tetralogy of Fallot (TOF). Following items were analyzed by serial sectioning: 1. Distance from axis of the nonbranching bundle (NBB) to the lower irm of VSD. 2. Deviation of the penetrating bundle (PB) and the NBB to the right ventricular septal endocardium. 3. Distance from the HB to the attachment of the tricuspid septal leaflet (ALS). 4. Level of the HB under the provision that the ASL level is zero. 5. Length and distance of the HB. Results: 1. In inlet type VDSs, the NBB-VSD distance was 0.40 +/- 0.27 mm, indicating that the conduction system maintained nearly the same level as the ASL. 2. In trabecular and infundibular type VDSs, the NBB-VSD distances were 1.57 +/- 0.80 mm and 1.75 +/- 0.35 mm, and the HB-ASL distances were 1.70 +/- 1.23 mm and 1.10 +/- 1.13 mm, respectively. 3. In membranous type TOF, the NBB lay more superficially than in muscular type. Conclusion: inlet type VSD and perimembranous type TOF have anatomic features in which the proximal His bundle tends to be jeopardized by suturing for VSD closure.     

Left thorax approach to repair doubly committed juxta‐arterial ventricular septal defect with Da Vinci robotic system

Robotic repair of the ventricular septal defect was performed mainly for perimembranous type via right thorax approach. Minimally invasive strategies for doubly committed juxta‐arterial ventricular septal defect were limited. Here, for the first time, we successfully repaired a doubly committed juxta‐arterial ventricular septal defect with Da Vinci robotic system via left thorax approach. The technique could provide excellent exposure of surgical field and accurate repair, with the advantage of reducing trauma and shortening the overall length of stay.     

Late postoperative results after repair of tetralogy of Fallot

Two hundred and eighty two survivors after complete correction of tetralogy of Fallot were analyzed in late follow up periods. The method of the reconstruction of right ventricular outflow tract was non-transannular path (NTAP) in 110 patients and transannular patch in 172. In the group of TAP, pulmonary regurgitation occurred in all and the cardio-thoracic ratio was larger than the ratio in the group of NTAP (p less than 0.05). Postoperative ECG at rest showed complete right bundle branch block (CRBBB) in 224 patients and 6 of them showed sudden death in their follow up period. However, there were no sudden deaths in 41 patients without CRBBB. The rate of reoperation after intracardiac repair was 4.25% and the causes were residual pulmonary stenosis and residual ventricular septal defect, and there were no significant differences of the reoperation rate between NTAP-group and TAP-group.     

Surgical substrates of postoperative junctional ectopic tachycardia in congenital heart defects

BACKGROUND: Junctional ectopic tachycardia is a major cause of postoperative morbidity after surgery for congenital cardiac disease. To elucidate the mechanism of junctional ectopic tachycardia, surgical correlations were studied in four types of congenital heart defects involving closure of a ventricular septal defect, relief of right ventricular outflow tract obstruction, or both. METHODS: Between 1997 and 1999, a total of 343 consecutive patients underwent repair of tetralogy of Fallot (n = 114), common truncus arteriosus (n = 10), ventricular septal defect (n = 161), and atrioventricular septal defect (n = 58). Variables studied included demographic and bypass data, surgical approaches toward ventricular septal defect closure and relief of right ventricular outflow tract obstruction, and resection as opposed to division of muscle bundles. RESULTS: Junctional ectopic tachycardia occurred most frequently after repair of tetralogy of Fallot (n = 25; 21.9%), with no cases occurring after repair of common trunk, 6 occurring after repair of ventricular septal defect (3.7%), and 6 occurring after repair of atrioventricular septal defect (10.3%). Stepwise logistic regression revealed that resection of muscle bundles (P <.0001), higher bypass temperatures (P <.03), and relief of right ventricular outflow tract obstruction through the right atrium (P <.05) significantly and independently predicted postoperative junctional ectopic tachycardia. CONCLUSIONS: Relief of right ventricular outflow tract obstruction appears to be more important in the causation of junctional ectopic tachycardia than does ventricular septal defect closure, which may explain the higher incidence of this complication after tetralogy of Fallot repair. Muscular resection seems to be more arrhythmogenic than is simple division. Increased traction through the right atrium for relief of right ventricular outflow tract obstruction would fit the hypothesis that enhanced automaticity of the His bundle, the morphologic substrate for junctional ectopic tachycardia, may result from direct trauma or infiltrative hemorrhage of the conduction system. When feasible, techniques avoiding both extensive muscle resection and excessive traction should be applied during resection of right ventricular outflow tract obstruction.     

A histologic study on "surgical landmarks" of the specialized conduction system, with particular reference to the adjacent structure

The conduction system in 29 cardiac specimens was histologically investigated as to the course and its surgical landmarks. The course varied individually, but was relatively inherent to the type of ventricular septal defect (VSD) (classification by Soto, et al.). The His bundle distributed as reported hitherto. Interesting features were noted in the relationship between the right bundle branch (RBB) and its adjacent papillary muscles. Our definition used for certain papillary muscles is merely to point the topographic site. The RBB ran beneath or slightly anterior to upper accessory papillary muscles (AcPMs) or uppermost AcPM, regardless of the type of perimembranous VSD. It ran posterior to the medial papillary muscle (MPM), with wider variation. In tetralogy of Fallot (TOF), it ran beneath or slightly anterior to the MPM. Relationships described above may be unitarily expressed as below, providing that Van Mierop's embryologic hypothesis on the conus defect anomaly (i.e.,: the uppermost AcPM being often morphologically interpreted as the MPM) is valid: -"The RBB runs beneath or slightly anterior to the upper(most) AcPM, regardless of the type of VSD. Such an arrangement was often observed in other anomalies too. The relationship between the RBB and upper or uppermost AcPM was modified by the attitude of the trabecula septomarginalis. Informations thus obtained have significantly lowered conduction disturbances in our experience.     

Late recovery of atrioventricular conduction after pacemaker implantation for complete heart block associated with surgery for congenital heart disease

OBJECTIVES: Pacemaker implantation is a standard recommendation for patients with persistent complete heart block following surgery for congenital heart disease. This study was performed to determine the incidence and clinical significance of late recovery of atrioventricular conduction following pacemaker implantation. METHODS: Between 1990 and 2001, 5662 open cardiac procedures for congenital heart defects were performed at our institution. The postoperative course of all patients with complete heart block in whom a permanent pacemaker was implanted was followed on a monthly basis, by either clinical or transtelephonic follow-up. RESULTS: A total of 72 patients with persistent postoperative complete heart block underwent pacemaker implantation. After insertion of the pacemaker, recovery of atrioventricular conduction was recognized in 7 of 72 patients (9.6%) at a median of 41 days (18-113 days) after the initial cardiac operation. These included 3 patients with ventricular septal defect, 2 with ventricular inversion or single ventricle, and 1 each with left ventricular outflow tract obstruction and atrioventricular septal defect. During a mean follow-up of 4.4 +/- 2.6 years, there was no late recurrence of heart block. Three patients had residual right bundle branch block and 1 had first-degree atrioventricular block. CONCLUSIONS: Atrioventricular conduction may return in a small but significant percentage of patients following pacemaker implantation for complete heart block associated with congenital heart surgery. When recovery of atrioventricular conduction occurs within the first months after surgery it appears reliable, which suggests that lifelong cardiac pacing may not be necessary in these individuals.     

Further observations on the morphology of atrioventricular septal defects

Certain morphologic aspects of atrioventricular septal defects ("endocardial cushion defects," "atrioventricular canal malformations") remain controversial. It is still not clear which precise lesions should not be placed in this category. For example, is an "isolated" cleft of the mitral valve or a perimembranous inlet ventricular septal defect to be so described? It is also not fully accepted that the left atrioventricular valve in these lesions bears little resemblance to a morphologically mitral valve. We have investigated these problems by both observation and mensuration. We determined the junctional circumference of the left atrioventricular valve leaflets and the ventricular dimensions in 130 atrioventricular septal defects (95 with common valve orifice and 35 with separate right and left atrioventricular orifices); in 50 hearts with perimembranous ventricular septal defects (20 extending into the inlet septum and 30 with outlet or trabecular extensions); in seven hearts with isolated cleft of the mitral valve, and in 10 normal hearts. All specimens came from the cardiopathological collection of Children's Hospital of Pittsburgh. The measurements showed conclusively that the atrioventricular septal defects were all directly comparable irrespective of the detailed morphology of the atrioventricular valve or valves. The group of atrioventricular septal defects was totally discrete as compared with all the other specimens that had normal atrioventricular septation. The left atrioventricular valve in atrioventricular septal defects is basically a three-leaflet valve which differs from the normal mitral valve in terms of its leaflet, its chordal support, and the arrangement of its papillary muscle. Its only similarity with the normal mitral valve is that it resides in the morphologically left ventricle and guards the left atrioventricular junction.     

Surgical management of the conal (supracristal) ventricular septal defect

Surgical management of the conal (supracristal) ventricular septal defect differs significantly from the management of the perimembranous (infracristal) ventricular septal defect. The absence of a portion of the conal septum can lead to prolapse of the right cusp of the aortic valve, which predisposes these patients to aortic insufficiency. Between January 1980 and December 1989, 36 children with conal ventricular septal defect underwent intracardiac repair. Diagnosis was by echocardiography, cardiac catheterization, and intraoperative exploration. Preoperative evaluation showed that 26 patients (72%) had aortic valve prolapse and 16 (44%) had aortic insufficiency. Pulmonary-to-systemic flow ratios ranged from 1:1 to 3.5:1 (mean 2.0:1.0). Ten patients (27%) were believed to have clinical congestive heart failure. Age at the time of operation ranged from 2 weeks to 18 years (mean 5.5 years). Operative exposure was through the pulmonary artery (26), aorta (4), right ventricle (3), or right atrium (3). Simultaneous aortic valve suspension for aortic insufficiency was performed in four patients. Operative survival was 100%. Follow-up is complete in all patients and ranges from 0.5 to 9 years (mean 4.3 years). All patients are in normal sinus rhythm. No residual ventricular septal defects have been identified. Twenty-three of 36 patients (64%) have no evidence of aortic insufficiency; 12 of 36 (33%) have trivial or mild aortic insufficiency. One patient with initial severe aortic insufficiency underwent repeat aortic valvuloplasty 3 years after ventricular septal defect closure and aortic valve suspension. No patients have required aortic valve replacement. Surgical management of the conal ventricular septal defect differs from that of the perimembranous ventricular septal defect in two critical aspects. The operative approach should be through the pulmonary artery. This allows the best exposure of the remaining conal septum and the pulmonary and aortic valve leaflets, facilitating closure of the defect without injury to the valves or conduction system. Conal ventricular septal defects should undergo early closure, regardless of shunt volume, to prevent progressive aortic insufficiency.     

Conotruncal repair of tetralogy of Fallot under 2 years old

From October 1985 to September 1990, a repair within the conotruncal portion of the right ventricle-Conotruncal repair-was used for the primary repair of consecutive 34 patients with tetralogy of Fallot under the age of 2 years. There were three summarized points of this maneuver: the first was non-use of the tricuspid septal leaflet for closure of the ventricular septal defect, the second was short patch infundibuloplasty with a large monocusp, and the last was total resection of the infundibular septum. Length of the patch infundibuloplasty was just 30% of the right ventricle length according to our formula: 30% of RV (cm) = 1.28 X BSA (m2) + 1.10. The VSD patch was placed between the pulmonary annulus and the ventricular septal crest, consisting of the membranous flap and the posterior extension of the trabecula septomarginalis. The right ventricular (RV) to systemic arterial pressure ratio was 0.49 +/- 0.15 (N = 33) and central venous pressure was 10.2 +/- 1.9 cmH2O (N = 33) six hours after ICU admission and 8.4 +/- 1.5 cmH2O (N = 7) 18 days after operation. RV end-diastolic volume showed no increase after operation: 105 +/- 31 before repair to 104 +/- 23% of Normal after repair in the same patients. Post-operative intubation period was 14 +/- 8 hours and hospital admission period was 17 +/- 6 days after operation. All patients were in sinus rhythm. The 28% of patients showed incomplete right bundle branch block (RBBB) and other 28% of patients showed complete RBBB.(ABSTRACT TRUNCATED AT 250 WORDS)