Right and left ventricular performance 10 years after Mustard repair of transposition of the great arteries

Atrial Correction (Modified Senning) of Transposition of the Great Arteries and Intact Atrial Septum with Regressed Left Ventricle and Pulmonary Hypertension: A Video Presentation

A 3-year-old male child diagnosed as D-transposition of the great arteries and intact atrial septum with regressed left ventricle, Yacoub’s Type-B coronary arterial pattern, successfully underwent modified Senning operation under moderately hypothermic cardiopulmonary bypass and St. Thomas based cold blood cardioplegia. At 8 months of follow-up, there was no mitral or tricuspid regurgitation with good biventricular function in Ross clinical score of 2.

Late outcome of 132 Senning procedures after 20 years of follow-up

BACKGROUND

Risk factors and rates of reoperation, arrhythmias, systemic right ventricular dysfunction (RVD), and late death after a Senning procedure were investigated.

METHODS

One-hundred thirty-two patients underwent a Senning operation between 1977 and 2004 (105 simple and 27 complex transpositions of the great arteries). Mean follow-up time was 19.5 ± 6.6 years. Surviving patients were evaluated by transthoracic echocardiography and electrocardiography. Right ventricular function was assessed in 70 patients by isotopic ventriculography or magnetic resonance imaging.

RESULTS

Operative and late mortality were 5.3% (7/132) and 9.6% (12/125), respectively. Nine patients were reoperated for left ventricular outflow tract obstruction or baffle stenosis. Survival rate was 91.5%, 91%, 89%, and 88% at 1, 5, 10, and 20 years, respectively. Probability of maintaining permanent sinus rhythm was 80%, 65%, 55%, and 44%. Twelve patients required pacemaker implantation. Probability of no supraventricular tachycardia, atrial flutter/fibrillation or ventricular tachycardia was 95.5%, 91.5%, 88%, and 75%, respectively. These parameters were similar for simple and complex transposition. Probability of right ventricular ejection fraction >40% was 100% at 5 and 10 years, and 98% at 20 years for simple transposition, and 100%, 92%, and 58% for complex transposition. This difference was statistically significant. Risk factors for RVD were complex transposition (p < 0.001), body weight (p = 0.008), no cardioplegia (p < 0.001), and tricuspid valve regurgitation (p = 0.004).

CONCLUSIONS

Senning procedure results in very good long-term survival out to 20 years. Both RVD and baffle stenosis were rare, but there was a concerning incidence of arrhythmia over time suggesting careful long-term surveillance.

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.

Impact of pregnancy on the systemic right ventricle after a Mustard operation for transposition of the great arteries

OBJECTIVES

We sought to determine the impact of pregnancy on the systemic right ventricle (RV) after a Mustard operation for transposition of the great arteries.

BACKGROUND

Dysfunction of the RV remains a continuing problem after a Mustard operation. Concerns exist about the potentially deleterious effects of pregnancy on this ventricle.

METHODS

The records of 16 women who completed 28 pregnancies were reviewed for clinical status, echocardiographic evaluation of RV dimensions, RV function, and tricuspid regurgitation (TR) before, during, and after pregnancy.

RESULTS

Women were in New York Heart Association functional class I (n = 21) and II (n = 7) before pregnancy. The functional class deteriorated in six women, with no return to the pre-pregnancy level after delivery in two. Data on RV dimensions were available in 18 pregnancies, on RV function in 21, and on TR in 20. Before pregnancy, RV dilation was absent (n = 4), mild/moderate (n = 12), or severe (n = 2) and progressed in five women (31%), with no recovery in all patients at the last follow-up. Right ventricular systolic dysfunction was absent (n = 16), mild/moderate (n = 4), or severe (n = 1) before pregnancy and progressed in four women (25%), with no recovery in three cases. Tricuspid regurgitation was absent (n = 8), mild (n = 9), or moderate (n = 3) before pregnancy and deteriorated in eight women (50%), with no recovery in three patients.

CONCLUSIONS

Pregnancy after a Mustard operation is clinically well tolerated but carries a risk of RV dysfunction, which is sometimes irreversible.

Cardiovascular response to physical exercise in adult patients after atrial correction for transposition of the great arteries assessed with magnetic resonance imaging

OBJECTIVE

To assess with magnetic resonance imaging (MRI) cardiovascular function in response to exercise in patients after atrial correction of transposition of the great arteries (TGA).

METHODS

Cardiac function at rest and during submaximal exercise was assessed with MRI in 27 patients with TGA (mean (SD) age 26 (5) years) late (23 (2) years) after atrial correction and in 14 control participants (25 (5) years old).

RESULTS

At rest, only right ventricular ejection fraction was significantly lower in patients than in controls (56 (7)% v 65 (7)%, p < 0.05). In response to exercise, increases in right ventricular end diastolic (155 (55) ml to 163 (57) ml, p < 0.05) and right ventricular end systolic volumes (70 (34) ml to 75 (36) ml, p < 0.05) were observed in patients. Furthermore, right and left ventricular stroke volumes and ejection fraction did not increase significantly in patients. Changes in right ventricular ejection fraction with exercise correlated with diminished exercise capacity (r = 0.43, p < 0.05).

CONCLUSIONS

In patients with atrially corrected TGA, MRI showed an abnormal response to exercise of both systemic right and left ventricles. Exercise MRI provides a tool for close monitoring of cardiovascular function in these patients, who are at risk for late death.

Disturbed atrioventricular electromechanical function long after Mustard operation for transposition of great arteries: a potential contributing factor to atrial flutter

OBJECTIVE

The objectives were to study atrial and ventricular electromechanical function in patients long after Mustard repair for transposition of great arteries and to identify possible causes and physiologic disturbances in those with recurrent atrial flutter.

METHODS

Electromechanical atrial and ventricular function was assessed in 22 patients (11 women) aged 27 +/- 5 years, 10 to 29 (mean 24) years after initial Mustard operation with electrocardiography and echocardiography. The study subjects involved 12 patients with documented atrial flutter and the remaining 10 without history of atrial arrhythmia served as controls. All patients were studied while in sinus rhythm.

RESULTS

There was no difference in age, gender, or age at original Mustard surgery between the 2 patient groups. The P wave and QRS duration were significantly broader in patients compared with controls (128 +/- 14 ms vs 100 +/- 10 ms, P <.05 and 120 +/- 20 ms vs 93 +/- 6 ms, P <.01). Right ventricular end diastolic dimension was not different, whereas left ventricular fraction shortening was less (20% +/- 10% vs 35% +/- 12%, P <.01) in the patient group. Left and septal total ventricular long axes amplitude were significantly lower in patients compared with controls (1.4 +/- 0.4 cm vs 1.7 +/- 0.3 cm, P <.05 and 0.6 +/- 0.2 cm vs 1.0 +/- 0.3 cm, P <.01). Right-sided total long axis excursion was equally reduced in the 2 groups (1.0 +/- 0.3 cm). Septal and right-sided but not left-sided "a" wave was smaller in the patients (1.2 +/- 1 mm vs 3 +/- 1.2 mm, P <.001 and 1 +/- 1.3 mm vs 3 +/- 0.9 mm, P <.01). Right atrial electromechanical delay was significantly longer in patients with respect to controls (110 +/- 14 ms vs 84 +/- 25 ms, P <.001), but on the left there was no difference. The P wave duration correlated closely with right atrial electromechanical delay, r = 0.79, P <.003. Significant tricuspid regurgitation was found in 9 of 12 patients but none of the controls.

CONCLUSION

Right ventricular dysfunction is present long after Mustard operation for transposition of great arteries whether flutter occurs. However, in patients with history of atrial flutter, evidence of left ventricular dysfunction, significant tricuspid regurgitation, impaired right atrial electrical and mechanical function, and reversed onset of atrial systole is also present. The consistent association of the disturbed atrial and ventricular electromechanical behavior suggests a multifactorial etiology for atrial arrhythmia.

Long-term assessment and serial evaluation of cardiorespiratory exercise performance and cardiac function in patients with atrial switch operation for complete transposition

BACKGROUND

At present, a considerable number of patients survive who underwent an atrial switch operation for correction of complete transposition. Our study aimed to assess their long-term exercise performance and the serial evolution of cardiac function.

METHODS

We studied 22 patients 5 to 17 years after an atrial switch operation, and followed them serially for 3.5 +/- 2 years after the first evaluation. Cardiorespiratory exercise function was assessed by analysis of gas exhange and by determination of the ventilatory anaerobic threshold. Echocardiography was performed on all evaluations.

RESULTS

All patients were in Class I of the classification of the New York Heart Association at all assessments. Ventilatory anaerobic threshold, however, was significantly lower than normal. It averaged 77.9% +/- 13.7 of the normal mean value at the initial evaluation, and remained stable when re-evaluated later (76.2 +/- 13.7%). At the initial study, the increase in oxygen uptake during graded exercise was below the 95% confidence limit in 6 of the patients, and was below this level in 10 patients at re-assessment. The subnormal values for oxygen uptake during submaximal exercise were associated with moderate to severe haemodynamic dysfunction. At echocardiography, 15 of 17 patients studied twice had mild to moderate right ventricular dilation and tricuspidregurgiation, which remained virtually the same at reasssesment. A stable sinus rhythm was initially present in 17 patients, and persisted in 15 patients during follow-up.

CONCLUSION

At medium term follow-up, cardiorespiratory exercise performance remains stable in patients after atrial switch repair. Serial exercise testing appears useful, because in individual patients in the present study, a decreasing exercise tolerance correlated with development of haemodynamic sequels.

Late arrhythmia in adults with the mustard procedure for transposition of great arteries: a surrogate marker for right ventricular dysfunction?

OBJECTIVE

To examine the relation between ventricular dysfunction and late clinical arrhythmia in adults who underwent the Mustard procedure for transposition of the great arteries.

DESIGN

Observational study based on periodic outpatient assessment of biventricular function.

SETTING

Tertiary referral centre.

INTERVENTIONS

Analysis of data from 12 lead ECGs, echocardiography, exercise radionuclide ventriculography, and magnetic resonance imaging.

MAIN OUTCOME MEASURES

Clinical outcome and late onset clinical arrhythmia during follow up. ECG and ventricular function indices obtained before arrhythmia onset were used for analysis.

RESULTS

51 patients (mean (SD) age 25.7 (5.0) years) fulfilled entry criteria at a mean of 23.4 (4.0) years after the Mustard procedure. Late arrhythmia occurred in 11 (22%): sustained atrial flutter/fibrillation in 10, ventricular tachycardia in one. Compared with patients who remained arrhythmia free, patients with arrhythmia had longer QRS (129 (26) v 112 (16) ms, p = 0.01), greater QT dispersion (107 (28) v 51 (24) ms, p < 0.001), and increased ratio of right to left ventricular end diastolic diameter (2.4 (0.9) v 1.7 (0.7), p = 0.02), but no difference in wall thickness. Systemic ejection fraction was also reduced in the arrhythmia subgroup (at rest: 34.1 (13)% v 47 (16)%, p = 0.04; during exercise: 37.8 (12)% v 52 (17)%, p = 0.03). QRS duration correlated with right ventricular end diastolic diameter (r = 0.59, p < 0.001), suggesting a possible mechano-electric relation after the Mustard procedure. QT dispersion was the only predictor of clinical arrhythmia in multivariate analysis.

CONCLUSIONS

Impaired ventricular function in adults with the Mustard procedure for transposition of the great arteries relates to clinical arrhythmia. Late atrial flutter/fibrillation may be a surrogate marker for ventricular dysfunction, and these patients may also be at risk of ventricular tachycardia.

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.

Comparison of the right and left ventricle as a systemic ventricle during exercise in patients with congenital heart disease

BACKGROUND

Few studies have investigated the clinical advantages of surgical correction with the morphologic left ventricle (MLV) instead of the morphologic right ventricle as a systemic ventricle (SV) in patients with congenital heart disease.

METHODS

Twenty-four healthy control subjects (group A1), 6 patients with isolated congenitally corrected transposition of the great arteries (TGA) (group A2), 16 patients with TGA who had undergone an arterial switch operation (group B1), 18 patients with TGA who had undergone a venous switch operation (group B2), 9 patients with atrioventricular and ventriculoarterial discordance who had undergone a double switch operation (group C1), and 6 patients with atrioventricular and ventriculoarterial discordance who had undergone a conventional external conduit operation from the MLV to the pulmonary artery (group C2), performed treadmill exercise testing. Their heart rate (HR), oxygen uptake (VO2), and oxygen pulse (O2 pulse), which reflects individual stroke volume, were measured, and contractile function was assessed by echocardiography.

RESULTS

The peak HR for the patients after a definitive operation were significantly lower than that in group A1 and was correlated with peak VO2 (r =.67, P <.0001). The peak VO2 and peak O2 pulse for the groups A2 and B2 were significantly lower than those for the groups A1 and B1, respectively. The peak O2 pulse data were strongly correlated with those of peak VO 2 (r = 0.91, P <.0001). The left ventricular ejection fraction was significantly lower in groups B1 and C1 than in group A1 and was correlated with peak VO 2 (r =.50, P <.01). No significant differences in VO2, HR, and O 2 pulse at peak exercise were observed between groups C1 and C2.

CONCLUSIONS

Chronotropic incompetence and an impaired response of the stroke volume of the MRV during exercise are partly responsible for the reduced exercise capacity in groups A2 and B2 compared with groups with the MLV as an SV, and the SV function at rest is also related to exercise capacity. Superiority of the double-switch operation compared with the conventional conduit operation was not observed. A longer-term follow-up is necessary before the advantages of these 2 operations can be compared.

Endocardial fibroelastosis in L-transposition of the great arteries with Ebstein's anomaly: revisited

Ebstein's anomaly is a congenital deformity of the tricuspid valve consisting mainly of leaflet malinsertion. Clinical presentation varies from asymptomatic patients to those with congestive heart failure secondary to significant valvular regurgitation and low right ventricular output. We report here the case of an infant with a diagnosis of corrected transposition of the great arteries and Ebstein's deformity of the left-sided tricuspid valve who developed pulmonary hypertension and endocardial fibroelastosis, two unusual associations with this lesion. We also discuss the pathophysiology of this association and related literature.

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

OBJECTIVE

To establish the incidence of systolic and diastolic dysfunction of the right and left ventricle in a large cohort of patients after Mustard or Senning operations and to assess changes in the incidence on long term follow up.

DESIGN

Postoperative case-control study using radionuclide ventriculography. Ejection fractions, peak filling rates, rapid filling periods and fractions, slow filling periods and fractions, and atrial contraction periods and fractions were studied.

SETTING

Tertiary care centre, ambulatory and hospital inpatient care.

PATIENTS

A convenience sample of 153 patients studied at median age of 6.9 years (median 4.4 years after surgery). In 99 cases another study was available at a median age of 15.3 years (median 13 years after surgery and 8.8 years after the first study).

RESULTS

Respective incidences of dysfunction in the first and the second study were as follows: ejection fraction-right ventricle 7.8% and 8.1%, left ventricle 7.2% and 10.1%: peak filling rate-right ventricle 0% and 4.2%, left ventricle 14.3% and 29.5% (p < 0.05); rapid filling period-right ventricle 18.3% and 11.6%, left ventricle 30.2% and 30.5%; slow filling period-right ventricle 4.8% and 3.2%; left ventricle 11.9% and 23.2%; atrial contraction period-right ventricle 0.8% and 4.2%, left ventricle 15.1% and 26.3%; rapid filling fraction-right ventricle both 0%, left ventricle 82.5% and 79.0%; slow filling fraction-right ventricle 0.8% and 4.2%, left ventricle 37.3% and 30.5%; atrial contraction fraction-right ventricle both 0%, left ventricle 79.4% and 71.6%.

CONCLUSIONS

The incidence of systolic ventricular dysfunction is 8% (right ventricle) and 10% (left ventricle) 13 years after surgery, without a significant increase over the eight year follow up. Diastolic filling is abnormal in up to 80% of patients and left ventricular peak filling rate deteriorates with time.

Cardiorespiratory response to exercise after venous switch operation for transposition of the great arteries

STUDY OBJECTIVES

This study reports on the cardiorespiratory response to graded exercise in patients after venous switch operation for transposition of the great arteries.

DESIGN

Several small studies have documented a diminished exercise tolerance after Mustard repair for transposition of the great arteries, little information exists, however, about long-term cardiorespiratory exercise performance in patients who have had the Senning procedure.

PATIENTS

This prospective study reports on the serial long-term (mean, 11 +/- 2.8 years) cardiopulmonary exercise performance of 43 patients (age, 12 +/- 3.1 years) who underwent a Senning procedure, with no significant postoperative abnormalities. Forty-three matched healthy children were also studied as a control group.

MEASUREMENTS AND RESULTS

All underwent exercise testing (Bruce protocol) with metabolic gas exchange to determine parameters at 3 min, anaerobic threshold, similar heart rate (150 beats/min), and peak exercise. Time of exercise was 10.5 +/- 1.9 min in patients and 13.4 +/- 2 min in control subjects (p = 0.0001). Overall, patients reached 73% of peak oxygen uptake achieved by control subjects (32.6 +/- 5.6 vs 44.7 +/- 6 mL/kg/min). Chronotropic response (188 +/- 15.7 vs 166.5 +/- 19.6 beats/min [p = 0.0001]) and oxygen pulse (7.4 +/- 2.9 vs 10.7 +/- 4.2 mL/beat [p = 0.0002]) were lower in patients at peak exercise. Patients had a greater respiratory response to exercise: both respiratory rate and ventilatory equivalent for carbon dioxide were significantly higher at all stages of exercise. Exercise capacity assessed by peak oxygen uptake was correlated with time elapsed since surgical repair (r = 0.48; p = 0.001).

CONCLUSIONS

It is concluded that even in asymptomatic patients, exercise endurance and respiratory response are generally altered as much as 11 +/- 2.8 years after venous switch operation, although early surgical repair is predictive of a better long-term functional result.

Lack of increase in stroke volume during exercise in asymptomatic adolescents in sinus rhythm after intraatrial repair for simple transposition of the great arteries

We studied stroke volume during exercise in 12 male asymptomatic patients in sinus rhythm after intraatrial repair for d-transposition of the great arteries. Data indicate that during exercise, stroke volume did not increase in the patient group, while in control subjects stroke volume increased.

Long-term follow-up (10 to 17 years) after Mustard repair for transposition of the great arteries

BACKGROUND

The management strategies of patients who underwent Mustard repair for transposition (of the great arteries were changed in the 1970s: infants became eligible for direct surgical repair, so Blalock-Hanlon atrioseptostomy could be avoided, and cold cardioplegia was introduced for myocardial preservation. Data are lacking, however, regarding whether these changes have had positive effects on the long-term outcome. We therefore conducted a follow-up study on all 91 patients who underwent a Mustard repair for transposition of the great arteries in our institution between 1973 and 1980 to assess the incidence and clinical importance of sequelae as well as health-related quality of life for these patients.

METHODS

Patients who were alive and could be traced through local registrar's offices received an invitation to participate in the follow-up study, which consisted of an interview, physical examination, echocardiography, exercise testing, and standard 12-lead and 24-hour electrocardiography.

RESULTS

Patients operated on in the first 4 years had a significantly higher mortality rate and higher incidence of sinus node dysfunction than did patients operated on in the subsequent 4 years (25% vs 2% and 41% vs 3%, respectively). In contrast, the incidence of baffle obstruction necessitating reoperation was significantly higher in the second group. There were no significant differences in echocardiographic findings and exercise capacity between patients operated on in the first 4 years and in the subsequent 4 years. None of the patients had right ventricular failure; a mild degree of baffle leakage or obstruction was seen in 22% of the patients, and the mean exercise capacity was decreased to 84% +/- 16% of normal.

CONCLUSION

The changes introduced between 1973 and 1980 have resulted in a considerable reduction of mortality and incidence of sinus node dysfunction but have also resulted in a more frequent need for reoperation.

Right ventricular systolic function in adolescents and young adults after Mustard operation for transposition of the great arteries

This study evaluates long-term ( > 10 years since surgery) right ventricular (RV) systolic function in patients who had previously undergone intraatrial baffle surgery for transposition of the great arteries. Studies suggest these patients are clinically stable and lead satisfactory lifestyles, but long-term ventricular performance is not known. Radionuclide angiocardiography was used to estimate RV ejection fraction in 58 patients a mean of 14 years after the Mustard operation. Repeat studies were performed in 32 patients. The absolute RV ejection fraction of 0.53 +/- 0.10 in our patients did not differ from normal values. Nine patients had a value < 0.42, placing them > 2 SDs below normal. Repeat RV ejection fraction decreased from 0.54 +/- 0.11 to 0.51 +/- 0.11 (p < 0.1) in 32 patients, and > 0.10 in 6. Thus, RV ejection fraction was abnormal in 9 of 58 patients (16%) evaluated > 10 years after a Mustard operation. Repeat studies demonstrate worsening in at least 6 of 32 patients (19%). These postoperative Mustard patients require continued evaluation, even in the absence of overt symptomatology.

Right ventricular performance and mass by use of cine MRI late after atrial repair of transposition of the great arteries

BACKGROUND

The long-term adaptation of the right ventricle after atrial repair of transposition of the great arteries (TGA) remains a subject of major concern. Cine magnetic resonance imaging (MRI), with its tomographic capabilities, allows unique quantitative evaluation of both right and left ventricular function and mass. Our purpose was to use MRI and an age-matched normal population to examine the typical late adaptation of the right and left ventricles after atrial repair of TGA.

METHODS AND RESULTS

Cine MRI was used to study ventricular function and mass in 22 patients after atrial repair of TGA. Images were obtained in short-axis sections from base to apex to derive normalized right and left ventricular mass (RVM and LVM, g/m2), interventricular septal mass (IVSM, g/m2), RV and LV end-diastolic volumes (EDV, mL/m2), and ejection fractions (EF). Results 8 to 23 years after repair were compared with analysis of 24 age- and sex-matched normal volunteers and revealed markedly elevated RVM, decreased LVM and IVSM, normal RV size, and only mildly depressed RVEF. Only 1 of 22 patients had clinical RV dysfunction, and this patient had increased RVM.

CONCLUSIONS

Cine MRI allows quantitative evaluation of both RV and LV mass and function late after atrial repair of TGA. Longitudinal studies that include these measurements should prove useful in determining the mechanism of late RV failure in these patients. On the basis of these early data, inadequate hypertrophy does not appear to be the cause of late dysfunction in this patient group.