Current results with the Mustard operation in isolated transposition of the great arteries

Primary Prevention of Sudden Cardiac Death in Adults with Transposition of the Great Arteries: A Review of Implantable Cardioverter-Defibrillator Placement

Transposition of the great arteries encompasses a set of structural congenital cardiac lesions that has in common ventriculoarterial discordance. Primarily because of advances in medical and surgical care, an increasing number of children born with this anomaly are surviving into adulthood. Depending upon the subtype of lesion or the particular corrective surgery that the patient might have undergone, this group of adult congenital heart disease patients constitutes a relatively new population with unique medical sequelae. Among the more common and difficult to manage are cardiac arrhythmias and other sequelae that can lead to sudden cardiac death. To date, the question of whether implantable cardioverter-defibrillators should be placed in this cohort as a preventive measure to abort sudden death has largely gone unanswered. Therefore, we review the available literature surrounding this issue.

The relationship between blood pressure, pulse pressure and right ventricular function following an atrial switch procedure for complete transposition of the great arteries

BACKGROUND

The pressure overload may be responsible for the failure of the systemic ventricle. No study so far has evaluated the association between arterial blood pressure values and right ventricular function in adults with atrially corrected complete transposition.

METHODS

This was a retrospective analysis. The studied population consisted of 60 patients with complete transposition, 11.5+/-2.7 years after atrial switch procedure, divided into subgroups according to the severity of systemic ventricular dysfunction (right ventricular ejection fraction < or = 0.40 vs. > 0.40), and the severity of perfusion abnormalities in the radionuclide study (absent or mild vs. moderate-to-severe).

RESULTS

All patients had blood pressure values (systolic 109.1+/-11.7 mm Hg and diastolic 72.3+/-9.7 mm Hg) within the normal range. Systolic blood pressure values correlated inversely with right ventricular ejection fraction (r = -0.450; p < 0.001). Compared to patients with systolic blood pressure below median values, patients with "elevated" blood pressure had lower right ventricular ejection fraction (32.6+/-6.3 vs. 38.9.+/-7.2; p < or = 0.002) and more significant perfusion abnormalities (1.5+/-1.0 vs. 2.9+/-1.5; p < or = 0.001). In a multivariate backward logistic regression model age at surgery and at the time of the study, systolic blood pressure at rest predicted impaired right ventricular ejection fraction (p < 0.02). Greater pulse pressure at peak exercise female sex were associated with greater more severe perfusion abnormalities (p < 0.01).

CONCLUSIONS

There is a significant correlation between blood pressure values and indices of right ventricular dysfunction in patients who underwent an atrial switch procedure for complete transposition. Blood pressure values might be considered as a surrogate end point in these patients.

Left ventricular assist device for right side assistance in patients with transposition

Right (systemic) ventricular dysfunction is well described after Senning operations for transposition of the great arteries, and patients with congenitally corrected transposition of the great arteries. Transplantation remains the only definitive therapy for refractory heart failure, however patients may deteriorate clinically prior to the availability of a donor heart. This report details the implantation of a TCI Heartmate (Thoratec Corp., Pleaston, CA) as a morphologic right ventricular assist device to bridge these patients to transplantation.

Superior vena cava syndrome following neonatal cardiac surgery

OBJECTIVE: To review the incidence, diagnosis, and management of superior vena cava syndrome (SVCS) after surgery for congenital heart disease. DESIGN: Retrospective clinical review. All patients were computer registered. Our database includes daily follow-up. SETTING: Pediatric cardiac surgery intensive care unit in a university hospital. PATIENTS: A total of 1853 consecutive pediatric cardiac operations performed in 285 neonates and 1568 older children from 1993 to 1999 are reviewed. MEASUREMENTS AND MAIN RESULTS: The diagnosis of SVCS was suspected clinically: Color changes and swelling of the upper part of the body, confirmed by echo-Doppler, showed no or minimal flow in the superior vena cava at the beginning and collateral flow later on. Nine patients developed SVCS (0.5%). All the study patients were neonates. The prevalence of SVCS in our neonatal patients was 3.15% (nine of 285), with no SVCS in older children. Accompanying complications included chylothorax (five), hydrocephalous (four)-three of whom required ventriculoperitoneal shunt during follow-up. Thrombolytic therapy was used in five patients, and thrombectomy was used in one patient. The ventilation period ranged from 4 to 46 days (mean 20.1 days), and the length of hospital stay ranged from 37 to 120 days (mean 61.3 days). No mortality was observed during follow-up. CONCLUSIONS: SVCS is an uncommon, severe complication following neonatal cardiac surgery. It may cause chylothorax, hydrocephalus, and severe respiratory complications leading to high morbidity. Early diagnosis and thrombolytic therapy may prevent the progression of this syndrome to its subsequent sequels.

Arrhythmia and survival in patients >18 years of age after the mustard procedure for complete transposition of the great arteries

Increasing numbers of patients who underwent Mustard repair as children are now adults. Loss of sinus rhythm, supraventricular arrhythmias, and sudden death have been described in pediatric series. However, little is known about the clinical course of adult patients. This retrospective cohort study examined 86 consecutive adults (age >18 years) who had undergone the Mustard procedure and were referred to an adult congenital cardiac clinic for ongoing follow-up. The incidence and predictors of arrhythmia, congestive heart failure, and death were determined. The median follow-up period was 8 years after age 18 or 23 years after Mustard repair. There were 8 deaths (9%), 2 were sudden. Congestive heart failure (CHF) requiring hospital admission occurred in 9 patients (10%). Pulmonary hypertension and systemic ventricular dysfunction were independent risk factors for death or CHF. Only 29 patients (34%) remained arrhythmia-free. Forty-one patients (48%) had at least 1 episode of supraventricular tachycardia (SVT), with most patients (30, 73%) having atrial flutter. SVT after the age of 18 was associated with CHF. Pulmonary hypertension, systemic ventricular dysfunction, and junctional rhythm before age 18 were independent risk factors for SVT. Pacemakers were implanted in 19 patients (22%); 13 of those were beyond age 18. Thus, adult survivors of the Mustard procedure continue to be at risk for premature death, CHF and supraventricular tachyarrhythmia.

Transoesophageal echocardiographic assessment of obstruction to the pulmonary venous pathway in children with Mustard or Senning repair

The morphology and mechanism of obstruction to the pulmonary venous pathway in patients following either Mustard or Senning repair of complete transposition was assessed using transoesophageal echocardiography. Seven patients underwent catheterization and complete transoesophageal study in both transverse and longitudinal planes, followed by balloon dilation of the obstructed venous pathway in five of seven under transoesophageal echocardiography guidance. A complete scan of both systemic and venous pathway was obtained in all patients. Four patients with a Mustard repair were found to have a 'tubular' baffle, with stenosis resulting from a discrete wedge of tissue arising from the atrial free wall in association with fibrous adhesions to the baffle. In the three patients with a Senning repair the intra-atrial baffle showed a characteristic 'peaked' appearance, with stenosis of the venous pathway stenosis related directly to contracture of the patch used to augment the atrial free wall. The mechanism of obstruction appears to be inherent to the different surgical techniques. Indwelling transoesophageal echocardiography provided immediate haemodynamic and morphologic assessment of the efficacy of dilation of the obstructed venous pathway.

Arrhythmia and mortality after the Mustard procedure: a 30-year single-center experience

OBJECTIVES

Our purpose was to assess the risk factors for late mortality, loss of sinus rhythm and atrial flutter after the Mustard operation.

BACKGROUND

The Mustard operation provides correction of cyanosis with low surgical risk in transposition of the great vessels. However, right ventricular failure, loss of sinus rhythm, atrial flutter and death are frequent long-term complications.

METHODS

Records of 534 children who underwent the Mustard operation at a single center since 1962 were reviewed for demographic, anatomic, electrocardiographic and physiologic predictors and outcomes.

RESULTS

There were 52 early deaths (9.7%). Survival analysis was undertaken for 478 early survivors with a mean follow-up interval of 11.6 +/- 7.2 years. There were 77 late deaths (16.1%), with sudden death (n = 31) the most frequent cause. Survival estimates were 89% at 5 years and 76% at 20 years of age. Risk factors were an earlier date of operation, operative period arrhythmia and an associated ventricular septal defect. Risk (hazard) of late death declined in the first decade, with further peaks in the second decade. Sinus rhythm was present in 77% at 5 years and 40% at 20 years. Loss of sinus rhythm was associated with previous septectomy, postoperative bradycardia and late atrial flutter. Freedom from atrial flutter was 92% at 5 years and 73% at 20 years of age. Risk factors for atrial flutter were the occurrence of perioperative bradyarrhythmia, reoperation and loss of sinus rhythm during follow-up. Risk of atrial flutter demonstrates a late increase.

CONCLUSIONS

Ongoing loss of sinus rhythm and late peaks in the risk of atrial flutter and death necessitate continued follow-up.

Balloon-expandable stenting in pediatric cardiology

Intravascular stent placement in Pediatric Cardiology has provided one of the most interesting and effective means of catheter treatment of congenital lesions. In the 5 years since it has been performed, balloon-expandable stent placement has provided relief of many previously untreatable vascular stenoses and has resulted in improvement of blood flow, reduction of right ventricular pressure and, in many cases, dramatic improvement of symptoms. In this article, the background of balloon-expandable stent placement is discussed, and specific observations are offered regarding the technique of implantation. The generally excellent results are presented and a number of novel problems and pitfalls are outlined. Finally, a brief summary of the wide ranging applicability of stent implantation is discussed, along with some of the important and imaginative new directions for the therapy.

Arrhythmias and intracardiac conduction after the arterial switch operation

Intraatrial baffling procedures such as the Mustard or Senning repair of transposition of the great arteries have been associated with a high incidence of cardiac arrhythmias. These abnormalities are thought to arise from trauma to the sinus node and atrial muscle during the procedure. In the arterial switch operation, there is little intraatrial manipulation other than the repair of the atrial septal defect. In theory, rhythm disturbances after the arterial switch operation should be less prevalent. From January 1, 1983, to December 31, 1990, 390 patients (230 with intact ventricular septum and 160 with a coexisting ventricular septal defect) underwent an arterial switch operation. Electrocardiograms and 24-hour Holter monitor studies were obtained in the 364 survivors at hospital discharge and during follow-up. Limited intracardiac electrophysiologic studies were performed 6 to 12 months after the operation.

RESULTS

Atrioventricular node function was preserved in most patients; seven patients (2%) had first-degree, two (0.7%) second-degree, and five (1.7%) had complete atrioventricular block (all with coexisting ventricular septal defect). All five patients with complete heart block received a permanent pacemaker. In those patients not having a permanent pacemaker, sinus rhythm was present in 96% on the surface electrocardiogram and 99% during 24-hour Holter monitor studies (1 month to 8.5 years, mean 2.1 years after the operation). Intracardiac electrophysiologic studies (n = 158) demonstrated normal corrected sinus node recovery times and AH intervals in 97% of patients. Atrial ectopy was present in 152 of 172 (81%) patients, with the majority (64%) of patients having only occasional premature beats without repetitive forms. Ventricular ectopy was a frequent finding during 24-hour monitoring. At hospital discharge 70% had ventricular ectopy; these values fell to 57% (in patients with intact ventricular septum) and 30% (in patients with a coexisting ventricular septal defect) at follow-up. In the early postoperative period, there were 25 episodes of supraventricular tachycardia (14 of which required therapy), 6 episodes of junctional ectopic tachycardia, and 9 episodes of ventricular tachycardia. The incidence of supraventricular tachycardia had fallen to 5% at follow-up, with no atrial flutter or fibrillation noted. Three patients had ventricular tachycardia on follow-up Holter studies. In summary, our results confirm the theoretical advantages of anatomic correction over atrial level correction of transposition of the great arteries with respect to preservation of sinus node function and low incidence of clinically significant tachyarrhythmias.

Anatomic correction for post-mustard pulmonary venous obstruction

Pulmonary artery banding and arterial switch operation as a two-stage approach have offered a surgical solution to the failing right ventricle after intraatrial repair of the transposition of the great arteries. Banding of the pulmonary artery increases the resistance to the left ventricular output and, therefore, "prepares" the left ventricle for supporting the systemic circulation and arterial switch operation. We report a case of anatomic correction for transposition of the great arteries after intraatrial repair (Mustard's operation) in which the left ventricle was retrained serendipitously as a consequence of pulmonary venous obstruction complicating Mustard's procedure.

Staged conversion to arterial switch for late failure of the systemic right ventricle

Late failure of the systemic right ventricle is seen in up to 10% of patients after atrial switch for transposition of the great arteries and in patients with atrioventricular and ventriculoarterial discordance. Since 1981, 24 such patients have entered a program to achieve conversion to arterial switch. The primary diagnoses were transposition of the great arteries with ventricular septal defect (n = 10), transposition of the great arteries with intact ventricular septum (n = 5), Taussig-Bing anomaly (n = 4), and atrioventricular and ventriculoarterial discordance (n = 5). The mean interval from atrial switch to right ventricular failure was 7 years. Four patients underwent direct conversion to arterial switch, with one operative death. In 3 of these patients the initial left ventricular pressure was high. The fourth patient was too sick to undergo banding, and he required left ventricular assist device support after switch conversion. The other 20 patients underwent 34 procedures to place or tighten a pulmonary artery band to prepare the left ventricle to tolerate systemic pressure. There was one band-related operative death. Twelve patients have thus far gone on to switch conversion 13 days to 5 years (mean, 26 months) after banding. In total, therefore, 16 patients have had an arterial switch with atrial reconstruction. The early mortality for switch conversion was 2 of 16 (12.5%; 70% confidence limits, 4% and 27%), with one late death 12 months after operation. Including operative mortality, the 1-year actuarial survival probability after conversion was 80% (70% confidence limits, 62% and 92%). All survivors are asymptomatic.(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler evaluation of superior caval venous pathways after Mustard and Senning operations

Doppler waveforms from the superior caval vein were analysed to evaluate the patency of superior caval venous pathways following venous redirection (Mustard and Senning) operations for complete transposition. The group consisted of 26 unselected survivors of Mustard (9 patients) and Senning operations (17 patients). Patients were examined a mean of 5.9 (range 0.1-15.3) years following operation and their age at study ranged from 0.4-25.3 years, mean 7.3 years. Doppler waveforms were correlated with digital subtraction angiograms, which were performed in every patient within 24 hours of the Doppler study. Totally occluded superior caval venous pathways were identified in 3 patients with digital subtraction angiography. The remaining patients had angiographically patent pathways. In the 23 patients with patent pathways, Doppler waveforms demonstrated an initial systolic peak smaller than a second diastolic peak. In the 3 patients with totally occluded pathways, the pattern of the waveform was reversed, with the systolic larger than the diastolic peak. Doppler examination of the superior caval vein is a quick and simple bedside method of accurately determining patency of superior caval venous pathways after atrial redirection procedures for complete transposition.

The asymptomatic child a long time after the Mustard operation for transposition of the great arteries

We studied 36 asymptomatic children 7.7 +/- 2.5 years after a Mustard operation. Fifteen children had sinus rhythm on all electrocardiograms made during follow-up. Only 2 had normal 24-hour Holter recordings throughout follow-up, 6 had periods of supraventricular tachycardia, and 3 had periods of atrial flutter. The electrophysiological evaluation of sinus node function was normal in 5 of the 31 children who were studied. The behavior of the atrial myocardium was electrophysiologically abnormal in most of the children. Atrioventricular node function, on the contrary, was normal in nearly all of the children. Eleven children had normal hemodynamics. Four had severe or complete obstruction of the superior vena cava, 1 had a severe pulmonary venous obstruction, 3 had a severe left ventricular outflow tract obstruction, and 2 had a large left-to-right shunt. Only 3 children had normal hemodynamic and electrophysiological studies. We conclude that the absence of symptoms and a normal routine examination of children a long time after a Mustard operation does not exclude hemodynamic and electrophysiological abnormalities, which can sometimes be severe. In view of these disappointing results, we decided to replace the Mustard operation with the arterial switch operation in children with transposition of the great arteries.

Intracardiac causes of superior vena cava obstruction

Most causes of superior vena cava (SVC) obstruction are extracardiac. In rare instances, an intracardiac process may obstruct the venous return from the SVC. This is illustrated by a report of a patient with a congenital coronary artery fistula to the right atrium obstructing the SVC return. We propose a classification and clinical approach to the differential diagnosis of SVC obstruction.

Cardiopulmonary adaptation at rest and during exercise 10 years after Mustard atrial repair for transposition of the great arteries

Discordance exists between apparently reduced systemic right ventricular function and the reported asymptomatic state of many patients after atrial repair for transposition of the great arteries. To evaluate this clinical observation, cardiopulmonary response to exercise in 17 asymptomatic patients with no significant postoperative hemodynamic abnormalities was assessed by upright bicycle ergometry according to a modified Jomes protocol 11.5 +/- 1.5 years after Mustard atrial repair. Seventeen age- and sex-matched normal adolescents constituted the control group. Incremental exercise was performed to determine maximum work capacity, heart rate, blood pressure, oxygen saturation, and minute ventilation. Cardiac output was computed at rest and during steady-state exercise by a carbon dioxide rebreathing method at 50% of the maximum workload achieved during incremental exercise. Height and weight were similar in patients and controls (p greater than .05). Resting pulmonary function variables were normal in all subjects. At peak exercise, respiratory quotient was greater than 1 in both patients and controls (1.12 +/- 0.09 and 1.09 +/- 0.08 respectively, p greater than .05). Patients achieved a lower peak heart rate (172 +/- 14 vs 185 +/- 11 beats/min, p less than .01), lower maximum work capacity (2.3 +/- 0.6 vs 3.3 +/- 0.7 W/kg, p less than .01). The ratio of minute ventilation at peak exercise to maximum resting voluntary ventilation was normal (less than or equal to 80%) in both groups. The ventilatory equivalent for oxygen was similar at rest, but significantly higher in patients than in control subjects at peak exercise (42 +/- 7 vs 36 +/- 5, p less than .006).(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term follow-up of right ventricular function after Mustard operation for transposition of the great arteries

As development of right ventricular (RV) failure is a potential risk after Mustard operation for transposition of the great arteries, 17 patients were reexamined 5-13 years postoperatively. Comparisons were made with healthy controls. There were no clinical signs of heart failure. Echocardiographically determined RV end-diastolic diameter was increased to 2.5 +/- 0.8 cm (controls: 1.5 +/- 0.4 cm, p less than 0.001). Comparison of RV systolic time intervals (STI) in patients with normal left ventricular (LV) STI revealed decreased RV function, with RPEPI 165 +/- 19 msec (controls 126 +/- 12, p less than 0.001) and RPEP/RVET 0.484 +/- 0.096 (controls 0.284 +/- 0.045, p less than 0.001). Nuclear angiography demonstrated decreased RV ejection fraction (EF), viz. 42.8 +/- 6.6% (normal RV 53 +/- 6%, LV 68 +/- 9%, p less than 0.001). Only two patients showed normal (5%) rise in RV-EF during exercise. There was no evidence of deterioration with passage of time. The results do not justify use of anatomic repair at our center, since the perioperative mortality might then be higher than in the Mustard or Senning procedures.

Implantation of balloon-expandable intravascular grafts by catheterization in pulmonary arteries and systemic veins

The purpose of this investigation was to evaluate the efficacy and safety of implanting expandable intravascular stents in pulmonary arteries and systemic veins. Twenty-seven balloon-expandable grafts were placed in 13 mongrel dogs under anesthesia. A long sheath was introduced over a wire and catheter or dilator into the pulmonary artery or target vein. A collapsed stainless steel expandable mesh stent was placed over the balloon of an angioplasty catheter. The catheter with the mounted stent was advanced through the sheath. The stent expanded to the diameter of the balloon as the balloon was inflated, and remained expanded as the balloon was deflated. The stent was expanded further with a larger balloon in 11 instances. Eleven stents were placed successfully in pulmonary arteries (out of thirteen attempted), and 11 of 14 were installed in tributaries of the precava or postcava. Three inadvertent embolizations of the devices occurred. All three devices that embolized lodged in the pulmonary arteries and did not obstruct flow. Seven dogs were recatheterized at intervals ranging from 56 to 278 days. Twelve stents were patent and nonobstructive, and two were malpositioned, one of which was obstructed. Three animals were killed 2 months (two dogs) and 9 months (one dog) after the implantations. The stents (four in the pulmonary arteries and two in veins) were completely covered with neointima and were patent, without thrombosis. These stents hold promise for definitive dilation of congenital or postoperative vessel stenoses.

Senning's procedure for transposition of the great arteries

The outlook for children with transposition of the great arteries (TGA) improved dramatically with the advent of the atrial repair. This procedure, first successfully performed by Ake Senning, followed years of unsuccessful attempts at correction by a number of surgeons using a variety of techniques. Senning's procedure expanded on the concept experimentally proposed by Albert of redirecting venous return at the atrial level to achieve physiological correction. The Senning procedure was largely abandoned when Mustard's technique was introduced in 1964, but has enjoyed a resurgence as a number of its potential advantages became more fully appreciated. Today, patients with TGA are increasingly undergoing repair by the arterial switch technique. Not all patients, however, are suitable candidates for this approach, and its success will be measured against the ingenious procedure described by Senning more than a quarter of a century ago.

Survival after balloon atrial septostomy for complete transposition of great arteries

Mortality before surgery must be taken into account when comparing the surgical mortality of atrial redirection procedures (Mustard's or Senning's operation) and the arterial switch operation for patients with complete transposition. This is because the switch operation is usually performed within the neonatal period or early infancy but Mustard's or Senning's operation usually after 4 months of age. The outcome of balloon atrial septostomy was therefore assessed in all 102 infants with transposition of the great arteries (plus or minus associated anomalies) who underwent the procedure at our hospital in the 10 years from January 1975 to December 1984. We considered the procedure to have been unsuccessful if the patient died from any cause (including other surgical procedures) between the septostomy and subsequent interatrial repair (Mustard's operation) or arterial switch operation. Eighteen patients died, although in only two was this as a direct result of the septostomy. Statistical analysis showed that low weight, presence of a persistent arterial duct, and coarctation of the aorta were significant risk factors. Early survival of infants with transposition of the great arteries has been dramatically improved after the introduction of balloon atrial septostomy. Nevertheless, there is considerable attrition before definitive repair, which must be included in the prediction of overall outcome.

Late results of the Mustard procedure in transposition of the great arteries

Thirty-five patients were discharged from the hospital after a Mustard procedure and have been followed a mean of 4.5 years. Thirty remain in a stable atrial or sinus rhythm, 3 have required hospitalization and medication to control atrial dysrhythmias, 1 is in a junctional rhythm, and 1 requires a pacemaker. In no patient has there been clinical evidence of systemic or pulmonary venous baffle obstruction. Twenty-two patients have had an elective postoperative cardiac catheterization, which has confirmed the absence of baffle obstruction. We attribute the lack of baffle obstruction and the low incidence of atrial dysrhythmias to several technical points in the operation including: direct high cannulation of the superior vena cava, aggressive resection of the atrial septum except in the region of the atrioventricular node, an extremely large pericardial baffle trimmed in the manner of Brom, sharp divergence of the upper and lower limbs of the inferior suture line away from one another and toward the caval orifices once they enter the right atrium, and very superficial endocardial bites of the baffle suture line in the region of the sinoatrial and atrioventricular nodes.

Fate of long-term survivors of Mustard procedure (inflow repair) for simple and complex transposition of the great arteries

Between 1967 and 1976, 106 children with transposition of the great arteries (TGA) (55 simple, 51 complex) survived the Mustard procedure. Late death occurred in 8 patients (1 simple, 7 complex TGA). Cardiac arrhythmia developed in 31 patients, 6 of whom required a permanent pacemaker. Postoperative cardiac catheterization showed mild superior vena cava obstruction in 4 patients, mild pulmonary venous obstruction in 3, and baffle leak in 4. Only 1 of these patients underwent reoperation elsewhere for a baffle leak. Two other patients had reoperation for subpulmonary stenosis and 1, for tricuspid regurgitation. The actuarial survival at 18 years is 92 +/- 2.3%, and the event-free survival is 83 +/- 3.8% (95% confidence limits). Eighty-seven patients are in New York Heart Association Functional Class I, and 3 are in Class II. The results of this study show that the long-term survival and event-free survival have been satisfactory. Late death was significantly higher in patients with complex TGA (p = .027). Postoperative arrhythmia was common, but only 6 patients required permanent pacemakers and the incidence of late complications and reoperation has been low.

Arrhythmias after the Mustard operation for transposition of the great arteries: a long-term study

This study presents follow-up data on 95 patients with transposition of the great arteries who underwent a Mustard intraatrial baffle operation. The patients were followed up serially by means of scalar electrocardiograms and 24 hour Holter monitoring studies. The latter study was effective in documenting abnormal rhythm patterns when the standard electrocardiogram was within normal limits. Twenty percent of the patients had atrial arrhythmias at the time of hospital discharge. new rhythm disturbances were recognized during each year of follow-up; 75% of the patients had atrial rhythm disorders by the sixth year. Slow junctional rhythm was the most common rhythm disturbance found. Complete heart block did not occur. Supraventricular tachycardia occurred within the context of the tachycardia/bradycardia syndrome in 8 of 10 patients, and in all it was documented after hospital discharge. The incidence of sudden death in this series was 3%. Six of the patients have had pacemaker insertions and there have been no deaths among these individuals. It was observed that the slow atrial or junctional rhythms that appeared after intraatrial correction of transposition of the great arteries rarely progressed to life-threatening rhythm disorders in childhood or adolescence, but the prognosis in adult life remains unknown. The three deaths in the series occurred in patients with a history of supraventricular tachyarrhythmias. Elimination of arrhythmias caused by extensive intraatrial surgery is one of the potential advantages of the arterial switch operation for correction of transposition of the great arteries.

Surgery for transposition of the great arteries: recent experience in the west of Scotland

From January 1980 to May 1983, 38 children underwent corrective surgery for transposition of the great arteries using the Mustard operation at the Royal Hospital for Sick Children in Glasgow. Twenty-nine children (Group 1) had 'simple' transposition, four (Group 2) had transposition and ventricular septal defect and five (Group 3) presented with complex anomalies. Operative mortality was zero for Groups 1 and 2. In Group 3, two children died within 30 days of operation. In the follow-up period of between three months and three and a half years there have been three late deaths. This report outlines the presentation, management and short term follow-up of children who have undergone the Mustard operation in this hospital since 1980.

Results of the Damus-Stansel-Kaye procedure for transposition of the great arteries and for double-outlet right ventricle with subpulmonary ventricular septal defect

From 1975 through 1982, the Damus-Stansel-Kaye procedure was performed on 20 patients with complete transposition of the great arteries (TGA) and on 4 with double-outlet right ventricle (DORV) and subpulmonary ventricular septal defect (VSD). The patients ranged from 6 days to 20 years old (median age, 13 months). Associated anomalies included atrial septal defect (24 patients), VSD (14), and others (25). Thirteen patients had had palliative operations previously. Of the 14 hospital deaths (58%), 13 occurred among the 17 patients with one or more risk factors: age less than 18 months, weight less than 10 kg, and left ventricular peak systolic pressure less than 75% of systemic pressure. Follow-up ranged from 12 to 87 months (mean, 51 months). One patient died of cardiac failure two years postoperatively, and 2 required conduit replacement at 40 and 50 months because of stenosis. All 9 survivors are free from major symptoms. The Damus-Stansel-Kaye repair is most suitable for patients with TGA or DORV with subpulmonary VSD who are older than 18 months, weight more than 10 kg, and have a "prepared left ventricle," and whose coronary artery anatomy precludes transplantation.

Cardiac rhythm after the Mustard operation for complete transposition of the great arteries

The Mustard operation corrects the effects of congenital transposition of the great arteries by creating an intraarterial baffle to direct pulmonary venous blood to the tricuspid orifice and systemic venous blood to the mitral orifice. To identify the long-term effects of this procedure, we followed 372 patients with complete transposition of the great arteries who survived the Mustard operation for at least three months. The mean follow-up period was 4.5 years (range, 0.4 to 15.9); the mean age at operation was 2.0 years. Mean resting heart rates were consistently lower than those for age-matched normal children. Seventy-six per cent of the patients had sinus rhythm during the year of operation--a figure that decreased to 57 per cent by the end of the eighth postoperative year. Twenty-five patients died during the follow-up period, nine suddenly. Life-table analysis revealed a cumulative survival rate of 91 per cent for 11 years and 71 per cent for 15 years after the operation. No strong risk factor for sudden unexpected death identified. This study demonstrates that extended survival among patients with transposition can be expected after the Mustard operation. However, over time there is a decreasing prevalence of normal sinus rhythm in survivors, as well as a small risk of sudden death.

Transposition of the great arteries and ventricular septal defect: results with the Senning operation and closure of the ventricular septal defect in infants

From May, 1978, to July, 1982, 46 infants ranging in age from 12 days to 12 months and in weight from 2.1 to 8.4 kg underwent repair of dextrotransposition of the great arteries (D-TGA) and ventricular septal defect (VSD) using a Senning repair and closure of the VSD. Ventricular septal defects were classified as membranous (47.8%), malaligned (28.3%), atrioventricular (AV) canal type (13.0%), subarterial (2.2%), muscular (2.2%), and multiple (6.5%). Hospital mortality was 15.2% and late mortality, 5.1%. Postoperative complications included tricuspid regurgitation (mild in 3 and severe, requiring tricuspid valve replacement, in 3), residual VSD (pulmonary/systemic flow ratio of greater than 2:1) in 3 patients (2, AV canal type and 1, multiple VSDs), pulmonary venous obstruction in 3 patients, and permanent complete heart block in 4 patients (2, AV canal type of VSD also requiring tricuspid valve replacement). Lung biopsy studies showed reversible Heath-Edwards and morphometric changes. No patient was seen with Heath-Edwards III or greater changes. In 10 patients, right ventricular end-diastolic pressures and pulmonary artery pressures at rest were within normal limits one year after operation. As the operative mortality of atrial inversion and arterial switch operations for D-TGA with VSD tends to become comparable, more extensive follow-up data, including cardiac catheterization and coronary arteriography in a large number of patients, will be necessary to establish the superiority of one approach over the other.

Current management of transposition of the great arteries: immediate septostomy, occasional prostaglandin infusion, and early Senning operations

Between January, 1979, and September, 1982, 30 infants with dextro(D)-transposition of the great arteries were managed with the Senning procedure for transposition of ventricular inflow. In 11 infants under 6 months of age, there were no associated cardiac malformations and no hospital deaths. Among 17 infants operated on between the ages of 6 and 12 months, 6 had associated cardiac malformations, and there were 2 hospital deaths. Two infants in the series were over 12 months of age; 1 had an associated malformation, and there were no hospital deaths. Analysis of cardiac rhythms in the postoperative period demonstrates that the first 2 patients operated on continue to have persistent junctional escape rhythm, while the remaining 26 survivors are in sinus rhythm. Twenty-four-hour Holter monitoring performed in 24 patients showed only 9 patients to be in sinus rhythm throughout the entire recording period. Seven patients had occasional atrial and ventricular premature contractions; the remainder had episodes of sinus arrest with junctional escape rhythm. Evidence of pulmonary caval or pulmonary venous obstruction has not appeared in any patient. Recently introduced technical modifications to the Mustard procedure have improved the results of that operation in regard to rhythm disturbances and baffle obstruction to venous return. This series, therefore, does not demonstrate superiority of the Senning procedure over the Mustard procedure. However, since results comparable to those of the Mustard procedure can be obtained in very young infants using the Senning operation along with deep hypothermia and circulatory arrest, the Senning procedure is deemed preferable to the Mustard procedure for this age group because of the ease with which it can be performed and because the procedure eliminates surgical judgment, and thereby surgical error, in the location of suture lines.

Two-dimensional echocardiographic assessment of caval and pulmonary venous pathways after the senning operation

This study reports the 2-dimensional echocardiographic appearance of the caval and pulmonary venous pathways after the Senning procedure in 28 patients and establishes normal values for the caval and pulmonary venous pathway dimensions. Eighteen patients had no caval or pulmonary venous obstruction or tricuspid regurgitation at catheterization; 2 had isolated superior vena caval obstruction, 3 had isolated pulmonary venous obstruction, 4 patients had severe tricuspid regurgitation, and 1 had a large residual ventricular septal defect. The caval and pulmonary venous pathways were imaged in modified 4-chamber and transverse views, and the narrowest dimension of each pathway in each view was measured by 2 independent observers. Dimension measurements were then normalized to the cube root of body surface area. Caval and pulmonary venous pathway "dimension products" were obtained by multiplying the normalized dimension in the 4-chamber view by the normalized dimension in the transverse view. All patients with catheterization-proven caval or pulmonary venous obstruction or tricuspid regurgitation had caval or pulmonary venous pathway dimension products outside the normal range, defined by our measurements in the 18 patients with no caval or pulmonary venous obstruction or tricuspid regurgitation. Thus, 2-dimensional echocardiography can provide both quantitative and qualitative information about the caval and pulmonary venous pathways after the Senning procedure.

Hemodynamic function after the Mustard operation for transposition of the great arteries

Pre- and postoperative cardiac catheterization data and cinenangiocardiograms of 82 patients who survived the Mustard operation for transposition of the great arteries (TGA) were reviewed. The post-operative catheterizations were performed 20 days to 10 years after operation (mean 2.5 years). Forty-six patients (56%) had no or insignificant associated cardiac lesions, whereas 36 (44%) had ventricular septal defect, pulmonary stenosis, or both, and required surgical intervention at the time of the Mustard operation. Postoperatively, 11 patients (13%) had significant systemic venous obstruction. Of the 11 patients, 6 required reoperation, and 2 patients had evidence of restenosis or complete obstruction in the superior vena cava after reoperation. In most patients, superior vena caval obstruction was well tolerated even in the presence of high pressure in the superior vena cava. Pulmonary venous obstruction occurred in 5 patients (6%), 3 of whom had no clinical symptoms despite severe pulmonary venous obstruction, although all had radiographic evidence of pulmonary venous congestion. The incidence of obstruction was drastically reduced after the Mustard operation was modified to include routine enlargement of the pulmonary venous atrium. Tricuspid regurgitation was uncommon (10%), but did occur in patients who had transatrial closure of a ventricular septal defect. Preoperatively, left ventricular outflow obstruction occurred in 38%. In 12 patients an attempt was made to relieve the obstruction at surgery. The 6 patients who had localized obstruction had a good result, but patients with more diffuse narrowing of left ventricular outflow had little or no relief of obstruction. Mild to moderate left ventricular outflow gradients regressed spontaneously in most patients after the Mustard operation.

Management of transposition after the baffes procedure: a case report and review of our experience

A case report details the operative technique used in the repair of complete transposition of the great arteries (TGA), ventricular septal defect (VSD), and pulmonary stenosis in a patient who had had Baffes procedure previously. Experience in managing 10 patients with complete TGA who had undergone a Baffes procedure is discussed. Four patients with a large VSD had pulmonary vascular disease. The condition of 1 of them was improved by a palliative Mustard operation. Four children with isolated TGA underwent a successful modified Mustard repair. The 2 remaining patients had a VSD and pulmonary stenosis; in 1 the condition was palliated by a Glenn shunt. The other is the subject of the case report. The mean interval between the Baffes procedure and the second operation was 11 years. There was 1 late death after secondary repair. Follow-up in the remaining 6 patients at a mean of 10.6 years indicates a favorable outcome.