Long-term ventricular performance after intra-atrial correction of transposition: left ventricular filling is the major limitation

Low Ventricular Stiffness Is Associated With Suboptimal Outcomes in Patients With a Single Right Ventricle After the Fontan Operation: A Novel Phenotype

BACKGROUND

Despite a rigorous screening process, including cardiac catheterization, a subset of patients with a single right ventricle (SRV) demonstrates suboptimal short-term outcomes after the Fontan operation. The goal of this study was to perform a comprehensive assessment of diastolic function in pre-Fontan patients with an SRV using invasive reference-standard measures and determine their associations with post-Fontan outcomes.

METHODS AND RESULTS

Children aged 2 to 6 years with SRV physiology undergoing pre-Fontan heart catheterization were recruited prospectively. Patients were divided into those who had an optimal or suboptimal outcome. A suboptimal outcome was defined as length of stay ≥14 days or heart transplant/cardiac death in first year after Fontan. Patients underwent pressure-volume loop analysis using reference-standard methods. The measure of ventricular stiffness, β, was obtained via preload reduction. Cardiac magnetic resonance imaging for extracellular volume and serum draws for matrix metalloproteinase activity were performed. Of 19 patients with an SRV, 9 (47%) had a suboptimal outcome. Mean age was 4.2±0.7 years. Patients with suboptimal outcomes had lower ventricular stiffness (0.021 [0.009-0.049] versus 0.090 [0.031-0.118] mL-1; P=0.02), lower extracellular volume (25% [28%-32%] versus 31% [28%-33%]; P=0.02), and lower matrix metalloproteinase-2 (90 [79-104] versus 108 [79-128] ng/mL; P=0.01) compared with patients with optimal outcomes. The only invasive measure that had an association with suboptimal outcome was β (P=0.038).

CONCLUSIONS

Patients with an SRV with suboptimal outcome after the Fontan operation had lower ventricular stiffness and evidence of maladaptive extracellular matrix metabolism compared with patients with optimal outcome. This appears to be a novel phenotype that may have important clinical implications and requires further study.

Multi-modality imaging of the systemic right ventricle in congenital heart disease

A comprehensive and structured imaging approach in the evaluation of the systemic right ventricle (sRV) in patients with complete transposition of the great arteries (TGA) after atrial switch procedure and congenitally corrected transposition of the great arteries (ccTGA) is a key for their optimal lifelong surveillance. Despite the improvements in cardiovascular imaging of adults with congenital heart disease (ACHD), the imaging of sRV remains an ongoing challenge due to its complex morphology and the difficulty in applying the existing knowledge for the systemic left ventricle. While cardiac magnetic resonance (CMR) is considered the gold standard imaging method, echocardiographic evaluation is primarily preferred in everyday clinical setting. Although qualitative assessment of its systolic function is primarily used, the introduction of advanced echocardiographic techniques, such as speckle tracking echocardiography (STE) and three-dimensional echocardiography (3DE), has provided new insights into the optimal assessment of the sRV. Standardized quantitative parameters remain to be elucidated, and morphometric and mechanistic studies are warranted to validate reference ranges for the sRV. This review highlights the challenges in the optimal evaluation of sRV and summarizes the available imaging tools. HIGHLIGHTS: CMR is the gold standard imaging method of sRV. Qualitative assessment of the systolic function of sRV is primarily used. Advanced echocardiographic techniques (STE and 3DE) provide optimal sRV assessment. Reference ranges for the sRV indices are warranted to be validated.

Oxygen Uptake Efficiency Slope Predicts Adverse Outcome Following Atrial Switch Procedure

Prior to the 1990s, d-TGA was palliated with the atrial switch procedure resulting in a systemic right ventricle associated with significant long-term morbidity and mortality. Determining the optimal timing of heart transplantation (HT) in these patients has been difficult. While cardiopulmonary exercise testing (CPET) is commonly used to try and risk stratify these patients, traditional exercise parameters have lacked the sensitivity and specificity to assess long-term risk. We sought to assess changes in exercise parameters over time in order to determine if any CPET parameter or combination of parameters could reliably identify risk for adverse outcome in this patient group. A retrospective review of serial CPET for 40 patients over 17 years was completed. Patients with adverse event within 6 months prior to CPET were noted. CPET parameters were compared and linear mixed model regression with repeated measures was performed on serial tests for longitudinal assessment. The linear mixed model regression identified OUES indexed to BSA to be the most sensitive parameter in identifying patients at risk of adverse event and became a stronger predictor of adverse event when combined with peak heart rate. CPET is useful in identifying patients with atrial switch at increased risk of adverse outcome. Indexed OUES and peak heart rate are better prognostic indicators than VO₂ and VE/VCO₂.

Characterization of morphology and function of the 'neo-atria' after a modified Mustard operation

Background: There is a pressing need to improve early and long-term results of the Mustard operation. A modification of the operation was introduced at the Aswan Heart Centre for this purpose which relies on creating new functional atria rather than the two rigid channels in the classical Mustard operation.

Objectives: To evaluate the morphology and function of the neo-atria, shortly after modified mustard operation for a ‘neglected’ patient with TGA, VSD and severe pulmonary hypertension.

Methods: A 6-year-old with neglected TGA, VSD and pulmonary hypertension presented with severe cyanosis, clubbing and haemoconcentration (Hb 22 g/dL), underwent the modified Aswan-Mustard operation (MAM) with rapid smooth postoperative recovery. Repeated 2D echograms and multi-slice CT scans, followed by 3D segmentation, were performed after the operation. The size, shape, and morphology of the neo-atria were measured and measurements of the patterns of instantaneous filling and emptying of the right and left ventricles were quantified.

Results: The neo-systemic venous atrium consisted of three components with a combined volume of 78 mL/m², all of which contributed to the reservoir, conduit, and importantly contractile function of the neo-atrium. The pulmonary venous atrium consisted of two components with a combined volume of 66 mL/m². These measurements were made at atrial end diastole. The volumes of the systemic venous and the pulmonary venous diminished to 51 and 54 mL/m², respectively, at the end atrial systole - indicating relatively preserved contractile functions.

Conclusion: Following the modified Aswan-Mustard operation, neo-atrial function was relatively well preserved compared to the classical operation. The long-term results of these findings and their effects on quality of life need to be studied further.

Management considerations in the adult with surgically modified d-transposition of the great arteries

Dextro-transposition of the great arteries (D-TGA) has undergone a significant evolution in surgical repair, leading to survivors with vastly different postsurgical anatomy which in turn guides their long-term cardiovascular morbidity and mortality. Atrial switch repair survivors are limited by a right ventricle in the systemic position, arrhythmia and atrial baffles prone to obstruction or leak. Functional assessment of the systemic right ventricle is complex, requiring multimodality imaging to include specialised echocardiography and cross-sectional imaging (MRI and CT). In the current era, most neonates undergo the arterial switch operation with increasing understanding of near-term and long-term outcomes specific to their cardiac anatomy. Long-term observations of the Lecompte manoeuvre or coronary stenoses following transfer continue, with evolving understanding to improve surveillance. Ultimately, an understanding of postsurgical anatomy, specialised imaging techniques and interventional and electrophysiological procedures is essential to comprehensive care of D-TGA survivors.

Prevalence of pulmonary hypertension in adults after atrial switch and role of ventricular filling pressures

OBJECTIVE

To assess the prevalence of elevated systemic right ventricular (sRV) end-diastolic pressure and pulmonary arterial hypertension in adults with transposition of the great arteries (TGA) who have undergone atrial switch operation.

METHODS

Forty-two adults (aged ≥18 years) with complete TGA and atrial switch palliation undergoing cardiac catheterisation between 2004 and 2018 at Mayo Clinic, MN, were identified. Clinical, echocardiographic and invasive haemodynamic data were abstracted from the medical charts and procedure logs.

RESULTS

Mean age was 37.6±7.9 years; 28 were male (67%). The Mustard operation was performed in 91% of individuals. Mean estimated sRV ejection fraction by echocardiography was 33.3%±10.9% and ≥moderate tricuspid (systemic atrioventricular valve) regurgitation was present in 15 patients (36%). Mean sRV end-diastolic pressure was 13.2±5.4 mm Hg. An sRV end-diastolic pressure >15 mm Hg was present in 35% of individuals whereas a pulmonary artery wedge pressure (PAWP) >15 mm Hg was seen in 59%. Mean pulmonary artery pressure ≥25 mm Hg was seen in 47.5% of patients with PAWP being >15 mm Hg in all but one patient.

CONCLUSION

In adults after atrial switch, elevated sRV end-diastolic pressure was present in only one-third of patients whereas increased PAWP was seen in almost 60%. These findings are most likely related to a combination of decreased pulmonary atrial (functional left atrium) compliance and, in a subset of patients, pulmonary venous baffle obstruction. Elevation in pulmonary pressures was highly prevalent with concomitant elevation in PAWP being present in essentially all patients.

Non-invasive assessment of liver alterations in Senning and Mustard patients

Background

Adults with congenital heart disease and ventricular dysfunction are prone to liver congestion, leading to fibrosis or cirrhosis but little is known about the prevalence of liver disease in atrial switch patients. Liver impairment may develop due to increased systemic venous pressures. This prospective study aimed to assess non-invasively hepatic abnormalities in adults who underwent Senning or Mustard procedures.

Methods

Hepatic involvement was assessed non-invasively clinically by laboratory analysis, hepatic fibrotic markers, sonography, and liver stiffness measurements [transient elastography (TE) and acoustic radiation force impulse imaging (ARFI)].

Results

Overall, 24 adults who had undergone atrial switch operation (13 Senning, 11 Mustard; four female; median age 27.8 years; range 24-45 years) were enrolled. In liver stiffness measurements, only three patients had values within the normal reference. All other patients showed mild, moderate or severe liver fibrosis or cirrhosis, respectively. Using imaging and laboratory analysis, 71% of the subjects had signs of liver fibrosis (46%) or cirrhosis (25%).

Conclusions

Non-invasive screening for liver congestion, fibrosis or cirrhosis could be meaningful in targeted screening for hepatic impairment in patients with TGA-ASO. As expert knowledge is essential, patients should be regularly controlled in highly specialised centres with cooperations between congenital cardiologists and hepatologists.

Revival and modification of the Mustard operation

OBJECTIVE

The neonatal arterial switch operation is currently the procedure of choice for patients with transposition of the great arteries. However, a large number of patients present too late for the arterial switch operation and are best managed with the atrial switch operation.

METHODS

We have used the Mustard operation in its original form or following a new modification designed to enhance the atrial functions and filling of the left ventricle in an attempt to improve long-term results.

RESULTS

Between July 2013 and November 2018, a total of 101 patients underwent the Mustard operation, 86 with the new modification. The median age at operation was 16 months (6 months to 27 years). A total of 75 patients (74.3%) were male. Median preoperative oxygen saturation was 71%. There were no early deaths and there were 3 late deaths during a median follow-up period of 24.2 months (all in patients with large ventricular septal defect and established pulmonary vascular disease). At the latest follow-up, all patients were in stable sinus rhythm. There were no baffle leaks. Seven patients had asymptomatic narrowing of the superior baffle, and 1 patient required balloon dilatation. Follow-up is 100% complete and includes computed tomography and magnetic resonance imaging at regular intervals (75 patients to date). Computerized analysis of representative subsets showed enhanced rate and pattern of filling of the left ventricle in the modified operation compared with the classic operation.

CONCLUSIONS

The use of the Mustard operation, particularly the modified technique should play an important role in treating late-presenting patients with transposition of the great arteries. Improving the pattern of filling of the left ventricle could enhance the long-term results of the Mustard operation.

Limited Ventricular Preload is the Main Reason for Reduced Stress Reserve After Atrial Baffle Repair

The atrial baffle repair (ABR) significantly improved the fate of patients with transposition of the great arteries (TGA). However, these patients show impaired exercise tolerance and some present severe decline of systemic ventricular function. Intrinsic myocardial weakness, low heart rate response to exercise and diastolic filling impairment are discussed to be causative. Forty-nine long-term survivors with TGA (median age 23.7 year) after ABR were catheterized with measured oxygen consumption in four conditions (baseline, volume, atrial pacing, dobutamine) and the results were compared to 10 normal controls. Median cardiac output was significantly lower in the ABR group (2.2 vs. 2.6 l/min/m²; p = 0.015), and systemic resistance was significantly elevated (28.9 vs. 22.2 U m²; p = 0.04) in comparison with normals. While stroke volume rose by 27% in the control group, it dropped by 7% in patients after ABR at atrial pacing (80/min). Stroke volume increase after dobutamine was significantly lower after ABR in comparison with normal controls (34 vs. 106%; p = 0.001). Higher NYHA class (p = 0.043), degree of tricuspid regurgitation (p = 0.009) and ventricular function (p = 0.028) were associated with lower stroke volume increase. Limited exercise capability of patients after ABR for TGA is primarily due to limited diastolic filling of the ventricles due to stiff non-compliant atrial pathways. Elevated systemic resistance may lead to severe myocardial hypertrophy with possible ischemia and contribute to the multifactorial decline of ventricular function in some patients.

Quantification of systemic right ventricle by echocardiography

Improvements in cardiac imaging have recently focused a great interest on the right ventricle (RV). In patients with congenital heart disease, the right ventricle (RV) may support the systemic circulation (systemic RV). There are 2 different anatomic conditions providing such physiology: the congenitally corrected transposition of the great arteries (ccTGA) and the TGA surgically corrected by atrial switch. During the last decades, evidence is accumulating that progressive systemic RV failure develops leading to considerable morbidity and mortality. Various imaging modalities have been used to evaluate the systemic RV, but echocardiography is still predominantly used in clinical practice, allowing an anatomic and functional approach of the systemic RV function and the potential associated anomalies. The goal of this review is to offer a clinical perspective of the non-invasive evaluation of the systemic RV by echocardiography.

Comparison of pressure-volume loop and echocardiographic measures of diastolic function in patients with a single-ventricle physiology

Echocardiographic measurements of diastolic function have not been validated against invasive pressure-volume loop (PVL) analysis in the single-ventricle population. The authors hypothesized that echocardiographic measures of diastolic function would correlate with PVL indices of diastolic function in patients with a single-ventricle physiology. The conductance-derived PVL measures of diastolic function included the isovolumic relaxation time constant (τ), the maximum rate of ventricular pressure decline (peak -dP/dt), and a measure of passive diastolic stiffness (μ). The echocardiographic measures included Doppler inflow patterns of the dominant atrioventricular valve (DAVV), tissue Doppler velocities (TDI) at the lateral (ventricular free wall) component of the DAVV annulus, and the TDI-derived isovolumic relaxation time (IVRT'). The correlation between PVL and echocardiographic measures was examined. The study enrolled 13 patients at various stages of surgical palliation. The median age of the patients was 3 years (range 3 months to 19 years). τ correlated well with Doppler E:A (r = 0.832; p = 0.005), lateral E:E' (r = 0.747; p = 0.033), and IVRT' (r = 0.831; p = 0.001). Peak -dP/dt also was correlated with IVRT' (r = 0.609; p = 0.036), and μ also was correlated with IVRT' (r = 0.884; p = 0.001). This study represents the first-ever comparison of diastolic echocardiographic and PVL indices in a single-ventricle population. The findings show that Doppler E:A, lateral E:E', and IVRT' correlate well with PVL measures of diastolic function. This study supports further validation of echocardiographic measures of diastolic function versus PVL measures of diastolic function in the single-ventricle population.

Cardiac Intensive Care of the Adult With Congenital Heart Disease: Basic Principles in the Management of Common Problems

Although there has been an intense interest in the care of the adult with congenital heart disease (ACHD), these guidelines are usually not focused on the concepts of immediate postoperative care. The 2 most common perioperative complications are heart failure and atrial dysrhythmias. The broad etiological categories for ACHD and heart failure include primary pump failure (systolic dysfunction) and hypertrophy (diastolic dysfunction) of the right, left, or single ventricle. Some conditions with a pressure-loaded systemic right ventricle as well as patients with a functionally single ventricle may be particularly prone to develop heart failure; in others, right heart failure may occur in patients with Ebstein anomaly or with tetralogy of Fallot after corrective repair but with varying degrees of pulmonary insufficiency, and left heart failure can be a result of mitral or aortic insufficiency. The management of postoperative atrial tachycardia in the ACHD patient actually begins prior to surgery. Assessment of arrhythmia history, complete determination of risk, inducibility and arrhythmia substrate, preoperative planning of pacing sites, and optimal pacing strategies all assist to bring about optimal postoperative outcomes. Ideal perioperative care of the ACHD involves a multidisciplinary team of pediatric and adult cardiologists, pediatric and adult intensivists, cardiac surgeons, and nursing staff along with a myriad of adult subspecialists such as pulmonology, nephrology, endocrinology, and others including psychiatry.

Unnatural history of the right ventricle in patients with congenitally malformed hearts

The long-term outcome of patients with congenitally malformed hearts involving abnormal right ventricular morphology and haemodynamics is variable. In most instances, the patients are at risk for right ventricular failure, in part due to morphological differences between the right and left ventricles and their response to chronic volume and pressure overload. In patients after repair of tetralogy of Fallot, and after balloon valvotomy for valvar pulmonary stenosis, pulmonary regurgitation is the most significant risk factor for right ventricular dysfunction. In patients with a dominant right ventricle after Fontan palliation, and in those with systemic right ventricles in association with surgically or congenitally corrected transposition, the right ventricle is not morphologically capable of dealing with chronic exposure to the high afterload of the systemic circulation. In patients with Ebstein's malformation of the tricuspid valve, the degree of atrialisation of the right ventricle determines how well the right ventricle will function as the pump for the pulmonary vascular bed.

Application of classic heart failure definitions of asymptomatic and symptomatic ventricular dysfunction and heart failure symptoms with preserved ejection fraction to patients with systemic right ventricles

Heart failure guidelines classify patients into subgroups with asymptomatic versus symptomatic ventricular dysfunction versus heart failure with a preserved ejection fraction. In this study, this approach was applied in a series of patients with complete transposition of the great arteries after atrial switch to assess to what extent this classification fits patients with systemic right ventricles. The study included stable adult patients after atrial switch, stratified according to preserved versus impaired systolic function (fractional area change > or =0.40 vs <0.40), absence versus presence of symptoms, absence versus presence of significant tricuspid regurgitation (TR), and normal versus elevated brain natriuretic peptide (BNP) levels. Twenty-two of 42 participants (52.4%; mean age 18.2 +/- 2.8 years) had preserved systolic function, and 20 (47.6%) had impaired systolic function; 10 patients (23.8%) had asymptomatic right ventricular (RV) dysfunction. The latter more frequently had significant TR (p = 0.04) and elevated BNP levels (p = 0.008), compared with asymptomatic patients with preserved systolic function. Normal BNP levels independently predicted preserved RV function in all patients (odds ratio 6.4, 95% confidence interval 1.03 to 39.1, p = 0.04) and in asymptomatic patients (odds ratio 14.4, 95% confidence interval 1.2 to 176.2, p = 0.03). Heart failure symptoms with preserved systolic function were present in 5 patients (11.9%), including 3 patients with significant TR. In conclusion, asymptomatic RV dysfunction and heart failure symptoms with preserved systolic function are common in patients with systemic right ventricles. BNP levels can be used to predict preserved systolic RV function, especially in asymptomatic patients. Heart failure symptoms with preserved RV systolic function can be frequently explained by the coexistence of significant TR.

Left ventricular function in patients with transposition of the great arteries operated with atrial switch

In patients operated with atrial switch for transposition of the great arteries (TGA), the left ventricle (LV) supports the pulmonary circulation and is thus pressure unloaded. Evaluation of LV function in this setting is of importance, as LV functional abnormalities have been documented and might contribute to development of symptoms. The ventricular contraction pattern in 14 Senning-operated TGA patients and 14 healthy controls was studied using tissue Doppler and magnetic resonance imaging. In the subpulmonary LV free wall, longitudinal strain was greater than circumferential strain (-23.6 +/- 3.6% vs. -19.1 +/- 3.2%, p = 0.002) as in the normal right ventricle (RV) (-30.7 +/- 3.3% vs. -15.8 +/- 1.3%, p < 0.001), but opposite to findings in the normal LV (-16.5 +/- 1.7% vs. -25.7 +/- 3.1%, p < 0.001). Subpulmonary strain and strain rate values were intermediate between those in the normal LV and RV. Ventricular free-wall torsion was reduced in the subpulmonary LV compared with both the normal LV (5.7 +/- 3.2 degrees vs. 16.7 +/- 5.6 degrees , p < 0.001) and RV (5.7 +/- 3.2 degrees vs. 11.4 +/- 2.6 degrees , p < 0.05). Furthermore, early diastolic filling of the subpulmonary LV differed from that of the normal LV. The subpulmonary LV displayed predominantly longitudinal shortening, as did its functional counterpart, the normal RV. However, the degree and rate of both longitudinal and circumferential shortening were intermediate between those of the normal LV and RV. This could represent a partial adaptation to the reduced pressure load. Decreased ventricular torsion and diastolic abnormalities might indicate subclinical ventricular dysfunction.

Diastolic biventricular impairment at long-term follow-up after atrial switch operation for complete transposition of the great arteries: an exercise tissue Doppler echocardiography study

OBJECTIVE

The aim of this study was to investigate regional myocardial function after atrial switch operation for transposition of the great arteries (TGA) using tissue Doppler echocardiography with strain rate (SR) imaging.

METHODS

In all, 24 patients with TGA aged 12 to 33 years and 10 control subjects underwent tissue Doppler echocardiography/SR imaging at rest and during bicycle exercise at 1 and 2 W/kg. Longitudinal function was quantified by strain, SR, and peak velocities measured in the free wall of the systemic ventricle, in septum and in the lateral wall of the subpulmonary ventricle.

RESULTS

In patients with TGA, both ventricles showed reduced peak systolic SR values at rest. The increase in peak early diastolic velocity with exercise was reduced in the systemic ventricle (-47 +/- 23 mm/s at rest to -73 +/- 35 mm/s at 2 W/kg, P < .05) and absent in the subpulmonary ventricle (-78 +/- 38 mm/s at rest to -75 +/- 19 mm/s at 2 W/kg) of patients with TGA.

CONCLUSION

Exercise tissue Doppler echocardiography/SR imaging identified severely reduced relaxation reserve of both ventricles as typical feature of myocardial dysfunction after atrial repair for TGA.

The future of adult patients after Mustard or Senning repair for transposition of the great arteries

BACKGROUND

After Mustard or Senning repair for transposition of the great arteries (d-TGA), qualitative assessment of the systemic right ventricle remains difficult. We wanted to evaluate the relationship between demographic and echocardiographic variables, and exercise performance.

METHODS

In 22 consecutive d-TGA patients (9 Mustard and 13 Senning) a standard transthoracic echocardiogram was performed. Peak oxygen consumption (peak VO2, ml/kg/min) was obtained by a bicycle stress test. Cardiac index (CI) at rest, 50 W, and 100 W was calculated from cardiac output, obtained by CO2 rebreathing.

RESULTS

The group of patients consisted in 15 male and 7 female with a median age of 21 (range 17-34) years. On echocardiographic evaluation, right ventricular function was normal in one, slightly impaired in 11, moderately impaired in 9, and severely impaired in one. Peak VO2 was 27.4+/-7.9 ml/kg/min, which was 64+/-16% of predicted values in normals. CI at rest, 50 Watt, and 100 Watt, were 2.7+/-0.5, 5.6+/-1.2, and 6.8+/-1.1 l/min/m2, respectively. No relationship between echocardiographic parameters and exercise capacity was found. Age correlated significantly with CI at 50 and 100 W (rho=-0.44, P=0.045 and rho=-0.77, P=0.0001, respectively). Finally, simple regression analysis identified a linear relationship between age and CI at 100 W (bèta=-0.54 and R2=0.29, P=0.014).

CONCLUSIONS

Maximal exercise capacity is reduced in adult patients after Mustard or Senning repair. Standard echocardiographic 2D-measurements are insufficient to determine the reduction in their functional capacity. The inverse relationship between age and the cardiac indices suggests an age dependent and progressive diminution of systemic ventricular function.

Presence of a ventricular septal defect and the Mustard operation are risk factors for late mortality after the atrial switch operation: thirty years of follow-up in 417 patients at a single center

BACKGROUND

Survival and functional status of patients with transposition of the great arteries treated by atrial switch are reported to be reasonably good within the first 15 postoperative years. However, in some patients, the function of the systemic right ventricle deteriorates, leading to significant morbidity or even to late mortality. This study seeks to identify risk factors for late death.

METHODS AND RESULTS

Records of 329 patients after the Senning operation and 88 after the Mustard operation at a single center were retrospectively reviewed for demographic, anatomic, and echocardiographic predictors and outcomes. Mean follow-up interval was 19.1+/-6.5 years and was 95% complete. Survival 25 years after the Mustard procedure was 75.9+/-4.8% and after the Senning procedure was 90.9+/-2.3% (P=0.002). Mustard patients died more often of arrhythmia than Senning patients (P<0.001) and needed more baffle-related reoperations (P<0.0001). Ventricular septal defect closure at the time of the atrial switch operation (hazard rate=2.3; 95% confidence interval, 1.1 to 4.7; P=0.025) and the Mustard operation (hazard rate=2.0; 95% confidence interval, 1.01 to 3.8; P=0.045) emerged as independent risk factors for late mortality in multivariate analysis. At follow-up, 85.8% of the patients led a normal life with full-time work, and 11.8% were able to do part-time work. Only 2.4% experienced noticeable limitation of activities.

CONCLUSIONS

Our patient data reveal satisfactory results at long term in this historic collective. Patients who had undergone ventricular septal defect closure at the time of the atrial switch operation and those who had undergone a Mustard operation are at higher risk for late death. Close follow-up, especially of these subgroups, is warranted.

Pregnancy outcomes after atrial repair for transposition of the great arteries

Increasingly, women born with complete transposition of the great arteries who have undergone atrial repair by either the Senning or the Mustard procedure are reaching childbearing age. This study reports on pregnancy outcomes after the atrial repair of transposition of the great arteries. Record review and standardized questionnaires were used to ascertain the outcomes of 70 pregnancies reported in 40 women (36 Mustard procedures, 4 Senning procedures). Of the 70 pregnancies, 54 resulted in 56 live births, 10 in miscarriages, and 6 in therapeutic abortions. At pregnancy, 31 women were in New York Heart Association class I, 8 were in class II, and 1 was in class III. Thirty-nine percent of the infants were delivered prematurely and weighed 2,714 +/- 709 g; 28% were delivered by cesarean section, 8 for cardiac indications. Maternal complications included arrhythmias in 5 women and hemoptysis in 2 women. Heart failure occurred in 6 women, developing during the second and third trimesters. Postpartum cardiac events developed 2 to 9 days postpartum: heart failure in 5 women, atrial fibrillation in 1 woman, and decreased oxygen saturation due to a new atrial baffle leak in 1 woman. Severe right ventricular (RV) failure led to cardiac transplantation after delivery in 1 woman; another developed heart failure and then died suddenly 1 month after delivery. There was 1 late death, 4 years after the patient's last pregnancy. In conclusion, pregnancy after atrial repair carries a moderate degree of risk and should be undertaken with caution.

Quantitative MRI comparison of pulmonary hemodynamics in mustard/senning-repaired patients suffering from transposition of the great arteries and healthy volunteers at rest

In Mustard/Senning-repaired (MSR) patients, the right and left ventricles (RV, LV) act as the systemic and pulmonary ventricle, respectively. The purpose of the study was to compare non-invasively, at rest, pulmonary ventricle systolic function and hemodynamics in MSR patients with those of healthy volunteers. Velocity-encoded MR imaging was performed at the level of the main pulmonary artery (MPA) in ten male patients late after a Mustard/Senning correction performed early in infancy and in ten male volunteers. Both blood flow and MPA cross-sectional area variations were recorded over a complete cardiac cycle. MPA distensibility, body surface area (BSA)-normalized pulmonary ventricle systolic power and work were significantly lower in the MSR patients compared to volunteers. In particular, BSA-normalized LV systolic power and work in MSR patients were equal to 82 and 77% on average of those of the RV in volunteers (0.32 vs. 0.39 W/m2 and 0.10 vs. 0.13 J/m2), respectively. We conclude that in MSR patients at rest two unrelated findings were observed: (1) a reduced MPA distensibility and (2) a significantly lower systolic mechanical performance of the pulmonary LV compared to that of the RV in healthy volunteers. The latter quantification indirectly confirms the lowest systemic RV systolic mechanical performance previously published.

Angiotensin Receptor Blockade and Exercise Capacity in Adults With Systemic Right Ventricles

Background— Pharmacological blockade of the renin-angiotensin system improves exercise tolerance in patients with left ventricular dysfunction, yet its impact on patients with systemic right ventricles (RVs) remains unknown.

Methods and Results— A multicenter, randomized, double-blind, placebo-controlled, crossover clinical trial was performed to assess the effects of losartan on exercise capacity and neurohormonal levels in patients with systemic RVs. Of 29 patients studied (age, 30.3±10.9 years), 21 had transposition of the great arteries with a Mustard baffle, and 8 had congenitally corrected transposition of the great arteries. Baseline values were as follows: V̇ o 2 max, 29.8±5.6 mL · kg −1 · min −1 (73.5±12.9% predicted value); RV ejection fraction, 41.6±9.3%; N-terminal pro brain natriuretic peptide (NT-proBNP), 257.7±243.4 pg/mL (normal <125 pg/mL); and angiotensin II, 5.7±4.9 pg/mL (normal <5.0 pg/mL). Comparing losartan to placebo showed no differences in V̇ o 2 max (29.9±5.4 versus 29.4±6.2 mL · kg −1 · min −1 ; P =0.43), exercise duration (632.3±123.0 versus 629.9±140.7 seconds; P =0.76), and NT-proBNP levels (201.2±267.8 versus 229.7±291.5 pg/mL; P =0.10), despite a trend toward increased angiotensin II levels (15.2±13.8 versus 8.8±12.5 pg/mL; P =0.08).

Conclusions— In adults with systemic RVs, losartan did not improve exercise capacity or reduce NT-proBNP levels. Minimal baseline activation of the renin-angiotensin system may explain this lack of benefit and imply an alternative pathophysiological mechanism for the progressive ventricular dysfunction and impaired exercise capacity observed in such patients.

Anesthetic Management and Outcome of Complex Late Arterial-Switch Operations for Patients With Transposition of the Great Arteries and a Systemic Right Ventricle

OBJECTIVE

For patients with transposition of the great arteries and a systemic right ventricle, complex late arterial-switch operations (double switch, switch conversion, Senning-Rastelli) after the newborn period have been described recently to restore the morphologic left ventricle to the systemic circulation. The purpose of this study was to describe the anesthetic management and perioperative outcome of this group of patients and to compare them with a control group of patients who had primary arterial-switch operations in the neonatal period.

DESIGN

Retrospective database and medical record review with 3:1 control:case ratio.

SETTING

Tertiary care academic children's hospital.

PARTICIPANTS

Patients undergoing complex late-arterial switch operations after the newborn period.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Thirteen patients were identified in the complex late-switch group and 43 in neonatal arterial-switch group. There were no perioperative deaths, no new gross neurologic deficits, and all patients were discharged home in both groups. Anesthetic and bypass times were significantly longer in the late-switch group (745 v 558 minutes, p < 0.001, and 382 v 243 minutes, p < 0.001, respectively). Transfusion requirements were similar between the groups. The incidence of arrhythmia (92% v 9%, p < 0.001), use of pacing systems (69% v 9%, p < 0.001), cardioversion (15% v 0%, p = 0.05), and pharmacologic treatment of arrhythmias (69% v 0%, p < 0.01) intraoperatively were significantly higher in the complex late-switch group.

CONCLUSIONS

Patients presenting for complex late corrective operations for transposition of the great arteries require long and complex anesthetics. Despite these challenges, perioperative outcomes are excellent.

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.

In the Footsteps of Senning: Lessons Learned From Atrial Repair of Transposition of the Great Arteries

The Senning operation has evolved from being the initial surgical correction that allowed survival in complete transposition of the great arteries to an integral part of the anatomic repair of congenitally corrected transposition. In patients with complete transposition, the Senning operation has given satisfactory initial and long-term surgical results, but the potential for right ventricular failure and atrial arrhythmias have drastically reduced its indications in the current era. The long-term follow-up and pertinent postoperative issues of the Senning operation will be reviewed, along with its newfound role in the anatomic repair of congenitally corrected transposition.

Cardiac resynchronization therapy: a novel adjunct to the treatment and prevention of systemic right ventricular failure

OBJECTIVES

This study aimed to evaluate the technical feasibility and hemodynamic benefit of cardiac resynchronization therapy (CRT) in patients with systemic right ventricle (RV).

BACKGROUND

Patients with a systemic RV are at high risk of developing heart failure. Cardiac resynchronization therapy may improve RV function in those with electromechanical dyssynchrony.

METHODS

Eight patients (age 6.9 to 29.2 years) with a systemic RV and right bundle-branch block (n = 2) or pacing from the left ventricle (LV) (n = 6) with a QRS interval of 161 +/- 21 ms underwent CRT (associated with cardiac surgery aimed at decrease in tricuspid regurgitation in 3 of 8 patients) and were followed-up for a median of 17.4 months.

RESULTS

Change from baseline rhythm to CRT was accompanied by a decrease in QRS interval (-28.0%, p = 0.002) and interventricular mechanical delay (-16.7%, p = 0.047) and immediate improvement in the RV filling time (+10.9%, p = 0.002), Tei index (-7.7%, p = 0.008), estimated RV maximum +dP/dt(+45.9%, p = 0.007), aortic velocity-time integral (+7.0%, p = 0.028), and RV ejection fraction by radionuclide ventriculography (+9.6%, p = 0.04). The RV fractional area of change increased from a median of 18.1% before resynchronization to 29.5% at last follow-up (p = 0.008) without a significant change in the end-diastolic area (+4.0%, p = NS).

CONCLUSIONS

The CRT yielded improvement in systemic RV function in patients with spontaneous or LV pacing-induced electromechanical dyssynchrony and seems to be a promising adjunct to the treatment and prevention of systemic RV failure.

Regional right and left ventricular function after the Senning operation: an ultrasonic study of strain rate and strain

BACKGROUND

Systemic right ventricular dysfunction is a major concern in the follow-up of patients who underwent an atrial redirection procedure for transposition (concordant atrio-ventricular and discordant ventriculo-arterial connections). No good non-invasive method is currently available for quantifying right ventricular function.

AIMS

We have used ultrasonically based imaging of strain rate and strain to quantify regional deformation in the right ventricle after the Senning operation, comparing properties of regional deformation of the right ventricle with right ventricular ejection fraction as measured using magnetic resonance imaging.

METHODS

In 20 asymptomatic patients who had undergone the Senning procedure, we measured peak systolic strain rate and systolic strain values in the right ventricular free wall, the septum and the left ventricular lateral wall using colour Doppler myocardial imaging, comparing the data with findings obtained in 30 healthy subjects. Global right ventricular ejection fraction was assessed using magnetic resonance imaging.

RESULTS

Properties of deformation of the right ventricular free wall were reduced and homogeneous after the Senning procedure compared to normals, with significantly lower values for peak systolic strain rate and systolic strain (-1.1 +/- 0.4 vs. -2.5 +/- 0.9 s(-1); p < 0.05 and -16 +/- 7% vs. -38 +/- 13%; p < 0.05, respectively). There was a significant correlation between regional longitudinal right ventricular systolic strain values and right ventricular ejection fraction (r = -0.87, p < 0.001). In the septum, peak systolic strain rate was again reduced and homogeneous (-1.2 +/- 0.4 vs. -1.8 +/- 0.5 s(-1); p < 0.05 vs. normals). Also in the left ventricle, the lateral wall peak systolic strain rate and systolic strain values were reduced (-1.5 +/- 0.5 vs. -2.1 +/- 0.9 s(-1); p < 0.05 and -20 +/- 6% vs.-25 +/- 9%; p < 0.05, vs. normals, respectively).

CONCLUSIONS

Properties of regional longitudinal deformation of the systemic right ventricle are reduced after the Senning procedure compared to normal controls, and correlate well with global right ventricular performance. These findings suggest that ultrasonic strain rate and strain imaging could be used in the non-invasive follow-up of ventricular function in these patients.

Systemic ventricular function in patients with transposition of the great arteries after atrial repair: a tissue Doppler and conductance catheter study

OBJECTIVES

The aim of this study was to assess the utility of tissue Doppler echocardiography in the setting of repaired transposition of the great arteries when the right ventricle (RV) functions as the systemic ventricle.

BACKGROUND

Myocardial acceleration during isovolumic contraction, "isovolumic myocardial acceleration" (IVA), has been validated as a sensitive non-invasive method of assessing RV contractility. Although traditional indexes may be less valid for the abnormal RV, the relative insensitivity of IVA to an abnormal load makes it a potentially powerful clinical tool for the assessment of RV disease.

METHODS

We examined 55 controls and 80 patients (mean age 22 years) with transposition, who had undergone atrial repair at age 8 (0.3 to 72) months. A subgroup of 12 underwent cardiac catheterization. The RV systolic function was derived by analysis of pressure-volume relationships and IVA both at rest and during dobutamine stress. In all 80, myocardial velocities were sampled in the RV free wall.

RESULTS

During dobutamine (10 microg/kg/min for 10 min), the increase of IVA mirrored the increase in end-systolic elastance (r = 0.69, p < 0.02). In the group as a whole, IVA was reduced compared with the subpulmonary RV and the systemic left ventricle of controls. There was abnormal wall motion in 44 patients, which was associated with reduced IVA. Diastolic myocardial velocities were also abnormal but unrelated to the presence of wall motion abnormalities.

CONCLUSIONS

The IVA can accurately assess changes in RV contractile function in patients with an RV as the systemic ventricle. Global long-axis RV function is reduced in patients with transposition, and this is associated with abnormal regional function.

Quantitative MRI comparison of systemic hemodynamics in Mustard/Senning repaired patients and healthy volunteers at rest

The purpose of the present study was to non-invasively compare ascending aortic blood flow and cross-sectional area (CSA) variations vs time in Mustard or Senning repaired (MSR) patients against those of healthy volunteers at rest. Velocity-encoded MR imaging was performed in 10 male patients (age range 18-24 years, median age 20.5 years) late after a Mustard or Senning correction, and in 10 male healthy volunteers (age range 21-25 years, median age 22.5 years), at the upper part of the ascending aorta. Both aortic cross-sectional area (CSA) and blood-flow variations were recorded over a complete cardiac cycle, with a 30-ms time of resolution. The body-surface area (BSA), the mean CSA over the systolic phase, and the BSA-normalized systemic ventricle power and work were significantly lower in the patient series compared with those of the volunteer series. The BSA-normalized right ventricle (RV) power and work of MSR patients were equal to 87 and 83% on average of those of the left ventricle (LV) of healthy volunteers. We conclude that, at rest, the mechanical performance of the systemic RV in MSR patients is significantly lower than that of the LV in healthy volunteers. Furthermore, the significantly lower aortic CSA found in MSR patients than in healthy volunteers may reveal an increase in the vasomotor tone.

Transposition complexes in the adult: a changing perspective

This study has shown the heterogeneous group of patients with discordant ventricular arterial relations, their management and problems encountered during follow up. Patients after surgery for transposition are still relatively young by cardiology standards and their problems continue to evolve; nevertheless the future is becoming clearer. However there are still important lessons to be learnt by continued and diligent observation and systematic, multicenter research. It is important to maintain a low threshold for thorough re-evaluation of patients whenever new symptoms are discovered. Indeed, patients should undergo regular detailed investigations at timely intervals. It is vital that this evolving group of adult patients, as with most patients emerging from a childhood with other congenital heart malformations, is managed by cardiologists fully trained in congenital heart disease.

Effect of atrial flutter on exercise tolerance in patients with grown-up congenital heart (GUCH)

OBJECTIVES

To assess the effect of atrial flutter (AFL) on exercise tolerance in patients with grown-up congenital heart (GUCH), exercise tests with modified Bruce protocol were performed in 20 patients aged 21 to 62 years with GUCH (11 females, 9 males) during symptomatic AFL and again 24 to 48 hours after DC conversion to sinus rhythm (SR). At the same time, cardiac function was assessed by means of transthoracic Doppler echocardiography.

RESULTS

Mean exercise duration was significantly less during AFL (6.4 +/- 4.1 min) versus SR (10.9 +/- 3.7 min) (P <.001). Heart rate was faster at rest and peak exercise while in AFL (106 +/- 21 beats/min vs 77 +/- 14 beats/min, P <.001, and 157 +/- 31 beats/min vs 129 +/- 24 beats/min, P <.01, respectively). Systolic blood pressure was lower at peak exercise with AFL (112 +/- 25 mm Hg vs 137 +/- 24 mm Hg, P <.001), as was mean blood pressure increase (5.3 +/- 24.3 mm Hg vs 22.6 +/- 15.8 mm Hg) compared with SR (P <.01). Four of the 6 patients after Fontan surgery had a decrease of 16 mm Hg in systolic blood pressure at peak exercise when in AFL. The reasons for exercise termination during AFL were mainly breathlessness, chest pain, or presyncope, whereas in SR it was caused by fatigue. Echocardiography during AFL showed shorter isovolumic relaxation time (40 +/- 20 ms) compared with SR (50 +/- 20 ms) (P <.05). Ventricular long-axis excursion was reduced (left 1.0 +/- 0.3 cm vs 1.2 +/- 0.4 cm, septal 0.5 +/- 0.2 cm vs 0.7 +/- 0.3 cm, and right 0.7 +/- 0.2 cm vs 0.9 +/- 0.4 cm respectively, P <.001 for all), as were peak pulmonary and aortic flow velocities (85 +/- 30 cm/s vs 105 +/- 50 cm/s, P <.001, and 137 +/- 118 cm/s vs 143 +/- 114 cm/s, P <.02) compared with sinus rhythm. There was a close correlation between exercise duration and blood pressure increase (r = 0.6), left-sided long-axis excursion and blood pressure increase (r = 0.57), and between aortic flow velocity and right-sided long-axis excursion (r = 0.71).

CONCLUSIONS

Atrial flutter causes dramatic reduction in exercise tolerance in patients with GUCH, and the combination of fast heart rate and hypotension may contribute to the development of presyncope, particularly in those with Fontan surgery. Marked improvement in effort tolerance and cardiac dynamics occurs after regaining SR. Thus, improving the quality of life in patients with GUCH requires maintaining SR.

Abnormalities of right ventricular long axis function after atrial repair of transposition of the great arteries

BACKGROUND

While volume derived global indices of right ventricle (RV) function are frequently abnormal after the Mustard procedure, the mechanism for these abnormalities is poorly understood. RV muscle fibres are predominantly arranged longitudinally and thus indices derived in the long axis may better describe RV function.

METHODS

20 survivors of the Mustard operation were studied (age 7.8–37.3 years, median 14.2 years). Long axis recordings from the apical four chamber view were obtained with the M mode cursor positioned through the lateral angle of the tricuspid valve annulus. M mode traces were recorded on paper and later digitised to derive total atrioventricular ring excursion, peak lengthening rate, and peak shortening rate. These data were averaged and compared with control data for the normal RV and left ventricle (LV).

RESULTS

RV total atrioventricular ring excursion was lower than that for the RV (p < 0.0001) or LV (p < 0.005) of controls. Peak lengthening rate was lower than the normal RV (p < 0.0001) and LV (p < 0.0001) rates. Furthermore, peak shortening rate was less than that of normal RV (p < 0.0001) and normal LV (p < 0.005) controls.

CONCLUSION

Systemic RV long axis function is notably reduced compared with that of either the normal subpulmonary RV or the systemic LV. This presumably reflects the response of the predominantly longitudinally arranged myocardial fibres to increased afterload. However, such measurements may provide a more sensitive marker for progressive changes in global function during long term follow up.

Abnormalities of right ventricular long axis function after atrial repair of transposition of the great arteries

BACKGROUND

While volume derived global indices of right ventricle (RV) function are frequently abnormal after the Mustard procedure, the mechanism for these abnormalities is poorly understood. RV muscle fibres are predominantly arranged longitudinally and thus indices derived in the long axis may better describe RV function.

METHODS

20 survivors of the Mustard operation were studied (age 7.8-37.3 years, median 14.2 years). Long axis recordings from the apical four chamber view were obtained with the M mode cursor positioned through the lateral angle of the tricuspid valve annulus. M mode traces were recorded on paper and later digitised to derive total atrioventricular ring excursion, peak lengthening rate, and peak shortening rate. These data were averaged and compared with control data for the normal RV and left ventricle (LV).

RESULTS

RV total atrioventricular ring excursion was lower than that for the RV (p < 0.0001) or LV (p < 0.005) of controls. Peak lengthening rate was lower than the normal RV (p < 0.0001) and LV (p < 0.0001) rates. Furthermore, peak shortening rate was less than that of normal RV (p < 0.0001) and normal LV (p < 0.005) controls.

CONCLUSION

Systemic RV long axis function is notably reduced compared with that of either the normal subpulmonary RV or the systemic LV. This presumably reflects the response of the predominantly longitudinally arranged myocardial fibres to increased afterload. However, such measurements may provide a more sensitive marker for progressive changes in global function during long term follow up.

Transposition of the Great Arteries

Transposition of the great arteries (TGA) is a lethal condition without intervention. Cross-sectional echocardiography is the diagnostic investigation of choice. Intravenous infusion of prostaglandin is employed to maintain ductal patency and allow mixing of blood, thus improving tissue oxygenation. Balloon atrial septostomy is recommended once the diagnosis is made. The arterial switch is accepted as the best option for simple TGA. Late follow-up includes survivors of the intra-atrial repair (Mustard and Senning operations), and the emerging cohort of survivors of the arterial switch procedure. Arrhythmia, baffle stenosis, tricuspid valve dysfunction, systemic ventricular dysfunction, and sudden death may occur late during follow-up after the Mustard or Senning procedure. There are less data for late follow-up after arterial switch; however, late death is rare, usually is related to reoperation, and important arrhythmias are uncommon. The long-term fate of the coronary circulation is unknown but coronary arterial obstruction has been reported. Continuing long-term surveillance is essential to detect the development of late problems in all groups of survivors.

Role of ischemia and infarction in late right ventricular dysfunction after atrial repair of transposition of the great arteries

OBJECTIVES

This study was conducted to assess whether myocardial ischemia and/or infarction are involved in the pathogenesis of late right ventricular dysfunction in adult survivors of atrial baffle repair for transposition of the great arteries in infancy.

BACKGROUND

The medium-term success of intraatrial baffle repair for transposition of the great arteries is good, with many patients surviving into adult life, but prognosis can be limited by progressive right ventricular dysfunction. We hypothesized that ongoing myocardial ischemia and/or infarction are important factors in the pathogenesis of this complication. Radionuclide techniques offer an opportunity to study both myocardial perfusion and concomitant ventricular wall motion.

METHODS

Dipyridamole sestamibi single-photon emission computed tomography followed by rest sestamibi single-photon emission computed tomography was used to assess right ventricular myocardial perfusion, wall motion, wall thickening and ejection fraction in 22 adolescents/young adults who had undergone atrial baffle repair for simple transposition of the great arteries at median 6.7 (range 0.5 to 54) months of age. The patients were aged 10 to 25 (median 15.5) years; 19 in New York Heart Association class I, 2 in class II and 1 in class III. All were in a regular cardiac rhythm during the studies. The right ventricular tomographic images were examined in three parallel and two orthogonal planes, analyzed in 12 segments.

RESULTS

Perfusion defects were evident in all patients in at least one segment, in either the rest or stress images. Twelve patients (55%) demonstrated fixed defects only, nine (41%) had fixed and reversible defects and one (4.5%) had reversible defects only. Concomitant wall-thickening abnormalities occurred in 83% of segments with fixed perfusion defects, mirrored by a reduction in wall motion in 91% of segments analyzed. Right ventricular ejection fraction was correlated with age (R = 0.62; p = 0.002), and with wall-thickening abnormalities (R = 0.60; p < 0.005).

CONCLUSIONS

Reversible and fixed perfusion defects with concordant regional wall motion abnormalities occur in the right (systemic) ventricle 10 to 20 years after Mustard repair for transposition of the great arteries; this may be important in the pathogenesis of late right ventricular dysfunction in this group.