Cláudia Regina Pinheiro de Castro

One-year follow-up of the effects of sildenafil on pulmonary arterial hypertension and veno-occlusive disease

We hypothesized that chronic oral administration of the phosphodiesterase-5 inhibitor sildenafil could improve the exercise capacity and pulmonary hemodynamics in patients with pulmonary arterial hypertension (PAH) on the basis of previous short-term studies. We tested this hypothesis in 14 subjects with PAH, including seven patients with the idiopathic form and seven patients with atrial septal defects, but no other congenital heart abnormalities. Patients were subjected to a 6-min walk test and dyspnea was graded according to the Borg scale. Pulmonary flow and pressures were measured by Doppler echocardiography. Patients were given sildenafil, 75 mg orally three times a day, and followed up for 1 year. Sildenafil therapy resulted in the following changes: increase in the 6-min walk distance from a median value of 387 m (range 0 to 484 m) to 462 m (range 408 to 588 m; P < 0.01), improvement of the Borg dyspnea score from 4.0 (median value) to 3.0 (P < 0.01), and increased pulmonary flow (velocity-time integral) from a median value of 0.12 (range 0.08 to 0.25) to 0.23 (range 0.11 to 0.40; P < 0.01) with no changes in pulmonary pressures. In one patient with pulmonary veno-occlusive disease diagnosed by a lung biopsy, sildenafil had a better effect on the pulmonary wedge pressure than inhaled nitric oxide (15 and 29 mmHg, respectively, acute test). He walked 112 m at baseline and 408 m at one year. One patient died at 11 months of treatment. No other relevant events occurred. Thus, chronic administration of sildenafil improves the physical capacity of PAH patients and may be beneficial in selected cases of veno-occlusive disease.

Aortopulmonary window. Clinical and surgical assessment of 18 cases

OBJECTIVE Aortopulmonary window (APW) is an uncommon congenital malformation. Its clinical presentation is dependent on the size of the defect and on the associated lesions. We evaluated our experience with this anomaly and compared it with 296 cases reported in the literature. METHODS Retrospective study of 18 patients diagnosed as having APW (age range from 13 days to 31 years, 13 (72.2%) females), divided into two groups: Group A (GA): 10 patients with isolated APW, and Group B (GB): 8 patients with associated lesions. RESULTS Heart failure occurred in 14 patients, and cyanosis in 3:2 from GB (tetralogy of Fallot--TF, and double outlet right ventricle--DORV), and one from GA with pulmonary hypertension. In 5 patients from GA the diagnosis of mitral regurgitation was made based on a systolic murmur and LV hypertrophy on the EKG. In GB, clinical findings were determined by the associated defect. Diagnosis was established by echocardiography in 11 (61.2%) of the patients. In 3 patients, a wrong diagnosis of mitral regurgitation was made, in 1 a patent ductus arteriosus was diagnosed and in 3 others, the diagnosis of APW was masked by other important associated defects (2 cases of DORV and 1 case of TF). The diagnosis was made by catheterization in 3 (16.6%) patients, by surgery in 3 (16.6%) and by necropsy in 1 (5.5%). Corrective surgery was performed in 14 (77.7%) patients, with one immediate death and good long-term follow-up in the remaining patients. CONCLUSION APW can be confused with other defects. Clinical findings, associated with an adequate echocardiogram can provide the information for the correct diagnosis.

The myocardium in tetralogy of Fallot: a histological and morphometric study

BACKGROUND: Patients with Tetralogy of Fallot frequently develop ventricular dysfunction in the postoperative period. The histological basis of this functional alteration has been scarcely studied. OBJECTIVE: To evaluate myocardial remodeling in anatomical specimens, comparing the subepicardial and subendocardial regions, especially because the subendocardial region is easily approached by means of endomyocardial biopsy. METHODS: Transmural sections of myocardium from the right ventricular (RV) inflow tract, anterior wall and infundibulum, and from the left ventricular (LV) free wall were evaluated regarding the degree of cardiomyocyte hypertrophy, vascularization and interstitial fibrosis were analyzed. RESULTS: The mean diameter of subendocardial cardiomyocytes is similar to that of subepicardial cardiomyocytes in all regions, except for the RV infundibulum, in which subendocardial cardiomyocytes are significantly larger in relation to those of the subepicardium (p=0.007). The amount of interstitial collagen is in the upper limits of normal and was similar in the subendocardial layers in comparison with the subpericardial layer of each region; however, it was greater in the inflow tract and RV anterior wall than in the LV lateral wall. The numerical density of subendocardial capillaries was similar to that of the subepicardium and was lower than the mean minus two standard deviations of normal in all regions and layers, except for the infundibulum, in which the subepicardium showed normal values and the subendocardium showed values lower than the mean minus two standard deviations. CONCLUSION: The postnatal myocardial changes in Tetralogy of Fallot are homogeneously distributed in the subepicardial and subendocardial halves of the ventricular walls, except for the infundibulum, which has peculiar remodeling characteristics and, therefore, is not representative of the other ventricular regions and layers for morphometric studies.BACKGROUND Patients with Tetralogy of Fallot frequently develop ventricular dysfunction in the postoperative period. The histological basis of this functional alteration has been scarcely studied. OBJECTIVE To evaluate myocardial remodeling in anatomical specimens, comparing the subepicardial and subendocardial regions, especially because the subendocardial region is easily approached by means of endomyocardial biopsy. METHODS Transmural sections of myocardium from the right ventricular (RV) inflow tract, anterior wall and infundibulum, and from the left ventricular (LV) free wall were evaluated regarding the degree of cardiomyocyte hypertrophy, vascularization and interstitial fibrosis were analyzed. RESULTS The mean diameter of subendocardial cardiomyocytes is similar to that of subepicardial cardiomyocytes in all regions, except for the RV infundibulum, in which subendocardial cardiomyocytes are significantly larger in relation to those of the subepicardium (p=0.007). The amount of interstitial collagen is in the upper limits of normal and was similar in the subendocardial layers in comparison with the subpericardial layer of each region; however, it was greater in the inflow tract and RV anterior wall than in the LV lateral wall. The numerical density of subendocardial capillaries was similar to that of the subepicardium and was lower than the mean minus two standard deviations of normal in all regions and layers, except for the infundibulum, in which the subepicardium showed normal values and the subendocardium showed values lower than the mean minus two standard deviations. CONCLUSION The postnatal myocardial changes in Tetralogy of Fallot are homogeneously distributed in the subepicardial and subendocardial halves of the ventricular walls, except for the infundibulum, which has peculiar remodeling characteristics and, therefore, is not representative of the other ventricular regions and layers for morphometric studies.

Factors influencing outcomes in patients with Eisenmenger syndrome: a nine-year follow-up study:

In patients with Eisenmenger syndrome, life expectancy is usually longer than in patients with other forms of pulmonary arterial hypertension (PAH). We conducted a cohort study in which patients were followed over a long period of time in an attempt to identify potential predictors of clinical outcomes. Sixty-seven treatment-naïve patients were enrolled (age range = 12–60 years; median age = 33 years). Baseline demographic, diagnostic, and functional parameters, plasma levels of endothelial dysfunction markers, and treatment-related data were tested for possible correlations with event-free survival. Patients were started on oral PAH drugs at the beginning of follow-up (n = 23), during follow-up (n = 33), or remained untreated (n = 11). The duration of follow-up was 0.54–9.89 years (median = 7.13 years), with an overall survival rate of 82% and an event-free survival rate of 70%. The estimated mean for event-free survival time was 7.71 years (95% confidence interval [CI] = 6.86–8.55 years). Of the 16 variables that were analyzed, the duration of exposure to PAH drugs was identified as an independent protective factor (hazard ratio [HR] = 0.25 for quartiles, 95% CI = 0.14–0.47, P < 0.001). The initial functional class (HR = 3.07; 95% CI = 1.01–9.34; P = 0.048), the severity of right ventricular dysfunction (HR = 2.51 [mild, moderate or severe dysfunction]; 95% CI = 1.22–5.19; P = 0.013) and plasma von Willebrand factor concentration (HR = 1.74 for quartiles; 95% CI = 1.07–2.83; P = 0.026) were identified as risk factors. The length of exposure to oral PAH therapies influences survival favorably in Eisenmenger patients. This may be of interest for communities where access to medications is restricted.

Two-year follow-up of pulmonary arterial hypertension patients treated with sildenafil

Resumen Fundamento: Los efectos a largo plazo de las drogas desarrolladas para el control de la hipertension arterial pulmonar (HAP) son poco conocidos, ya que los estudios multicentricos en general tienen una duracion de 12 a 16 semanas.Objetivo: Evaluar la evolucion a dos anos, en pacientes con HAP sometidos a monoterapia con sildenafil (inhibidor de la fosfodiesterasa-5), con respecto a la capacidad funcional.Metodos: Veinticuatro pacientes (edades entre 8 y 54 anos) con HAP idiopatica (HAPI, n = 9) o asociada a cardiopatias congenitas (HAP-CCg, n = 15) fueron tratados con sildenafil durante dos anos, con dosis diarias que variaron de 60 a 225 mg (tres tomas), por via oral. La capacidad fisica fue evaluada por la distancia caminada en el test de 6 minutos (DC6M) y por el grado de disnea al final de la caminata (escala de Borg), siendo tambien registrada la saturacion periferica de oxigeno (SpO26M, oximetria de pulso).Resultados: En los 18 pacientes que completaron dos anos de seguimiento, hubo un incremento progresivo y sostenido en la DC6M, tanto en el grupo HAPI (de 239 ± 160 m a 471 ± 66 m, p = 0,0076) como en el grupo HAP-CCg (de 361 ± 144 m a 445 ± 96m, p = 0,0031), con mejora de la disnea al final de la caminata (p < 0,05 en ambos). No hubo disminucion de la SpO26M en los grupos considerados; en particular, pacientes con HAP-CCg evolucionaron de 77 ± 20% a 79 ± 16% (p = 0,5248). Hubo 5 obitos (tres en el grupo HAPI) y una perdida de seguimiento en el periodo.Conclusion: En dos anos de seguimiento, el sildenafil demostro ser util en el control de la condicion funcional de pacientes con HAP, con mejora significativa en las dos etiologias consideradas. (Arq Bras Cardiol 2010;94(5):653-659)Palabras clave: Inhibidores de fosfodiesterasa/analisis, hipertension, hipertension pulmonar, capacidad vital, vasodilatadores.mas alla de 12-16 semanas en la mayoria de las vecesBACKGROUND The long-term effects of drugs developed for the control of pulmonary arterial hypertension (PAH) are little known, since multicenter studies usually last 12 to 16 weeks. OBJECTIVE To evaluate the two-year outcome of PAH patients receiving monotherapy with sildenafil (a phosphodiesterase-5 inhibitor), with regard to their functional capacity. METHODS Twenty four patients (ages between 8 and 54 years) with idiopathic PAH (IPAH, n = 9) or congenital heart disease-associated PAH (CHD-PAH, n = 15) were treated with sildenafil for two years, with daily oral doses ranging from 60 to 225 mg (tid). Physical capacity was assessed by the distance walked in the 6-minute walk test (DW6M) and by the degree of dyspnea at the end of the walk (Borg scale); peripheral oxygen saturation was also recorded (SpO(2)6M, pulse oximetry). RESULTS In the 18 patients who completed the two-year follow-up, there was a progressive and sustained increase in DW6M, both in the IPAH group (from 239 +/- 160 m to 471 +/- 66 m, p = 0.0076) and in the CHD-PAH group (from 361 +/- 144 m to 445 +/- 96 m, p = 0.0031), with improvement of dyspnea at the end of the walk (p<0.05 for both groups). No decrease in SpO(2)6M was observed in the groups; in patients with CHD-PAH, in particular, SpO(2)6M went from 77 +/- 20% to 79 +/- 16% (p = 0.5248). Five deaths occurred (three in the IPAH group) and one patient was lost to follow-up during the study period. CONCLUSION In a two-year follow-up, sildenafil proved useful in the control of the functional status of PAH patients, with significant improvement in both groups considered.

Seguimento de dois anos em pacientes com hipertensão arterial pulmonar sob tratamento com sildenafila

Resumen Fundamento: Los efectos a largo plazo de las drogas desarrolladas para el control de la hipertension arterial pulmonar (HAP) son poco conocidos, ya que los estudios multicentricos en general tienen una duracion de 12 a 16 semanas.Objetivo: Evaluar la evolucion a dos anos, en pacientes con HAP sometidos a monoterapia con sildenafil (inhibidor de la fosfodiesterasa-5), con respecto a la capacidad funcional.Metodos: Veinticuatro pacientes (edades entre 8 y 54 anos) con HAP idiopatica (HAPI, n = 9) o asociada a cardiopatias congenitas (HAP-CCg, n = 15) fueron tratados con sildenafil durante dos anos, con dosis diarias que variaron de 60 a 225 mg (tres tomas), por via oral. La capacidad fisica fue evaluada por la distancia caminada en el test de 6 minutos (DC6M) y por el grado de disnea al final de la caminata (escala de Borg), siendo tambien registrada la saturacion periferica de oxigeno (SpO26M, oximetria de pulso).Resultados: En los 18 pacientes que completaron dos anos de seguimiento, hubo un incremento progresivo y sostenido en la DC6M, tanto en el grupo HAPI (de 239 ± 160 m a 471 ± 66 m, p = 0,0076) como en el grupo HAP-CCg (de 361 ± 144 m a 445 ± 96m, p = 0,0031), con mejora de la disnea al final de la caminata (p < 0,05 en ambos). No hubo disminucion de la SpO26M en los grupos considerados; en particular, pacientes con HAP-CCg evolucionaron de 77 ± 20% a 79 ± 16% (p = 0,5248). Hubo 5 obitos (tres en el grupo HAPI) y una perdida de seguimiento en el periodo.Conclusion: En dos anos de seguimiento, el sildenafil demostro ser util en el control de la condicion funcional de pacientes con HAP, con mejora significativa en las dos etiologias consideradas. (Arq Bras Cardiol 2010;94(5):653-659)Palabras clave: Inhibidores de fosfodiesterasa/analisis, hipertension, hipertension pulmonar, capacidad vital, vasodilatadores.mas alla de 12-16 semanas en la mayoria de las vecesBACKGROUND The long-term effects of drugs developed for the control of pulmonary arterial hypertension (PAH) are little known, since multicenter studies usually last 12 to 16 weeks. OBJECTIVE To evaluate the two-year outcome of PAH patients receiving monotherapy with sildenafil (a phosphodiesterase-5 inhibitor), with regard to their functional capacity. METHODS Twenty four patients (ages between 8 and 54 years) with idiopathic PAH (IPAH, n = 9) or congenital heart disease-associated PAH (CHD-PAH, n = 15) were treated with sildenafil for two years, with daily oral doses ranging from 60 to 225 mg (tid). Physical capacity was assessed by the distance walked in the 6-minute walk test (DW6M) and by the degree of dyspnea at the end of the walk (Borg scale); peripheral oxygen saturation was also recorded (SpO(2)6M, pulse oximetry). RESULTS In the 18 patients who completed the two-year follow-up, there was a progressive and sustained increase in DW6M, both in the IPAH group (from 239 +/- 160 m to 471 +/- 66 m, p = 0.0076) and in the CHD-PAH group (from 361 +/- 144 m to 445 +/- 96 m, p = 0.0031), with improvement of dyspnea at the end of the walk (p<0.05 for both groups). No decrease in SpO(2)6M was observed in the groups; in patients with CHD-PAH, in particular, SpO(2)6M went from 77 +/- 20% to 79 +/- 16% (p = 0.5248). Five deaths occurred (three in the IPAH group) and one patient was lost to follow-up during the study period. CONCLUSION In a two-year follow-up, sildenafil proved useful in the control of the functional status of PAH patients, with significant improvement in both groups considered.

Seguimiento de dos años en pacientes con hipertensión arterial pulmonar bajo tratamiento con sildenafil

Resumen Fundamento: Los efectos a largo plazo de las drogas desarrolladas para el control de la hipertension arterial pulmonar (HAP) son poco conocidos, ya que los estudios multicentricos en general tienen una duracion de 12 a 16 semanas.Objetivo: Evaluar la evolucion a dos anos, en pacientes con HAP sometidos a monoterapia con sildenafil (inhibidor de la fosfodiesterasa-5), con respecto a la capacidad funcional.Metodos: Veinticuatro pacientes (edades entre 8 y 54 anos) con HAP idiopatica (HAPI, n = 9) o asociada a cardiopatias congenitas (HAP-CCg, n = 15) fueron tratados con sildenafil durante dos anos, con dosis diarias que variaron de 60 a 225 mg (tres tomas), por via oral. La capacidad fisica fue evaluada por la distancia caminada en el test de 6 minutos (DC6M) y por el grado de disnea al final de la caminata (escala de Borg), siendo tambien registrada la saturacion periferica de oxigeno (SpO26M, oximetria de pulso).Resultados: En los 18 pacientes que completaron dos anos de seguimiento, hubo un incremento progresivo y sostenido en la DC6M, tanto en el grupo HAPI (de 239 ± 160 m a 471 ± 66 m, p = 0,0076) como en el grupo HAP-CCg (de 361 ± 144 m a 445 ± 96m, p = 0,0031), con mejora de la disnea al final de la caminata (p < 0,05 en ambos). No hubo disminucion de la SpO26M en los grupos considerados; en particular, pacientes con HAP-CCg evolucionaron de 77 ± 20% a 79 ± 16% (p = 0,5248). Hubo 5 obitos (tres en el grupo HAPI) y una perdida de seguimiento en el periodo.Conclusion: En dos anos de seguimiento, el sildenafil demostro ser util en el control de la condicion funcional de pacientes con HAP, con mejora significativa en las dos etiologias consideradas. (Arq Bras Cardiol 2010;94(5):653-659)Palabras clave: Inhibidores de fosfodiesterasa/analisis, hipertension, hipertension pulmonar, capacidad vital, vasodilatadores.mas alla de 12-16 semanas en la mayoria de las vecesBACKGROUND The long-term effects of drugs developed for the control of pulmonary arterial hypertension (PAH) are little known, since multicenter studies usually last 12 to 16 weeks. OBJECTIVE To evaluate the two-year outcome of PAH patients receiving monotherapy with sildenafil (a phosphodiesterase-5 inhibitor), with regard to their functional capacity. METHODS Twenty four patients (ages between 8 and 54 years) with idiopathic PAH (IPAH, n = 9) or congenital heart disease-associated PAH (CHD-PAH, n = 15) were treated with sildenafil for two years, with daily oral doses ranging from 60 to 225 mg (tid). Physical capacity was assessed by the distance walked in the 6-minute walk test (DW6M) and by the degree of dyspnea at the end of the walk (Borg scale); peripheral oxygen saturation was also recorded (SpO(2)6M, pulse oximetry). RESULTS In the 18 patients who completed the two-year follow-up, there was a progressive and sustained increase in DW6M, both in the IPAH group (from 239 +/- 160 m to 471 +/- 66 m, p = 0.0076) and in the CHD-PAH group (from 361 +/- 144 m to 445 +/- 96 m, p = 0.0031), with improvement of dyspnea at the end of the walk (p<0.05 for both groups). No decrease in SpO(2)6M was observed in the groups; in patients with CHD-PAH, in particular, SpO(2)6M went from 77 +/- 20% to 79 +/- 16% (p = 0.5248). Five deaths occurred (three in the IPAH group) and one patient was lost to follow-up during the study period. CONCLUSION In a two-year follow-up, sildenafil proved useful in the control of the functional status of PAH patients, with significant improvement in both groups considered.

El miocardio en la tetralogía de Fallot: estudio histológico y morfométrico

BACKGROUND: Patients with Tetralogy of Fallot frequently develop ventricular dysfunction in the postoperative period. The histological basis of this functional alteration has been scarcely studied. OBJECTIVE: To evaluate myocardial remodeling in anatomical specimens, comparing the subepicardial and subendocardial regions, especially because the subendocardial region is easily approached by means of endomyocardial biopsy. METHODS: Transmural sections of myocardium from the right ventricular (RV) inflow tract, anterior wall and infundibulum, and from the left ventricular (LV) free wall were evaluated regarding the degree of cardiomyocyte hypertrophy, vascularization and interstitial fibrosis were analyzed. RESULTS: The mean diameter of subendocardial cardiomyocytes is similar to that of subepicardial cardiomyocytes in all regions, except for the RV infundibulum, in which subendocardial cardiomyocytes are significantly larger in relation to those of the subepicardium (p=0.007). The amount of interstitial collagen is in the upper limits of normal and was similar in the subendocardial layers in comparison with the subpericardial layer of each region; however, it was greater in the inflow tract and RV anterior wall than in the LV lateral wall. The numerical density of subendocardial capillaries was similar to that of the subepicardium and was lower than the mean minus two standard deviations of normal in all regions and layers, except for the infundibulum, in which the subepicardium showed normal values and the subendocardium showed values lower than the mean minus two standard deviations. CONCLUSION: The postnatal myocardial changes in Tetralogy of Fallot are homogeneously distributed in the subepicardial and subendocardial halves of the ventricular walls, except for the infundibulum, which has peculiar remodeling characteristics and, therefore, is not representative of the other ventricular regions and layers for morphometric studies.BACKGROUND Patients with Tetralogy of Fallot frequently develop ventricular dysfunction in the postoperative period. The histological basis of this functional alteration has been scarcely studied. OBJECTIVE To evaluate myocardial remodeling in anatomical specimens, comparing the subepicardial and subendocardial regions, especially because the subendocardial region is easily approached by means of endomyocardial biopsy. METHODS Transmural sections of myocardium from the right ventricular (RV) inflow tract, anterior wall and infundibulum, and from the left ventricular (LV) free wall were evaluated regarding the degree of cardiomyocyte hypertrophy, vascularization and interstitial fibrosis were analyzed. RESULTS The mean diameter of subendocardial cardiomyocytes is similar to that of subepicardial cardiomyocytes in all regions, except for the RV infundibulum, in which subendocardial cardiomyocytes are significantly larger in relation to those of the subepicardium (p=0.007). The amount of interstitial collagen is in the upper limits of normal and was similar in the subendocardial layers in comparison with the subpericardial layer of each region; however, it was greater in the inflow tract and RV anterior wall than in the LV lateral wall. The numerical density of subendocardial capillaries was similar to that of the subepicardium and was lower than the mean minus two standard deviations of normal in all regions and layers, except for the infundibulum, in which the subepicardium showed normal values and the subendocardium showed values lower than the mean minus two standard deviations. CONCLUSION The postnatal myocardial changes in Tetralogy of Fallot are homogeneously distributed in the subepicardial and subendocardial halves of the ventricular walls, except for the infundibulum, which has peculiar remodeling characteristics and, therefore, is not representative of the other ventricular regions and layers for morphometric studies.

O miocárdio na tetralogia de Fallot: estudo histológico e morfométrico

BACKGROUND: Patients with Tetralogy of Fallot frequently develop ventricular dysfunction in the postoperative period. The histological basis of this functional alteration has been scarcely studied. OBJECTIVE: To evaluate myocardial remodeling in anatomical specimens, comparing the subepicardial and subendocardial regions, especially because the subendocardial region is easily approached by means of endomyocardial biopsy. METHODS: Transmural sections of myocardium from the right ventricular (RV) inflow tract, anterior wall and infundibulum, and from the left ventricular (LV) free wall were evaluated regarding the degree of cardiomyocyte hypertrophy, vascularization and interstitial fibrosis were analyzed. RESULTS: The mean diameter of subendocardial cardiomyocytes is similar to that of subepicardial cardiomyocytes in all regions, except for the RV infundibulum, in which subendocardial cardiomyocytes are significantly larger in relation to those of the subepicardium (p=0.007). The amount of interstitial collagen is in the upper limits of normal and was similar in the subendocardial layers in comparison with the subpericardial layer of each region; however, it was greater in the inflow tract and RV anterior wall than in the LV lateral wall. The numerical density of subendocardial capillaries was similar to that of the subepicardium and was lower than the mean minus two standard deviations of normal in all regions and layers, except for the infundibulum, in which the subepicardium showed normal values and the subendocardium showed values lower than the mean minus two standard deviations. CONCLUSION: The postnatal myocardial changes in Tetralogy of Fallot are homogeneously distributed in the subepicardial and subendocardial halves of the ventricular walls, except for the infundibulum, which has peculiar remodeling characteristics and, therefore, is not representative of the other ventricular regions and layers for morphometric studies.BACKGROUND Patients with Tetralogy of Fallot frequently develop ventricular dysfunction in the postoperative period. The histological basis of this functional alteration has been scarcely studied. OBJECTIVE To evaluate myocardial remodeling in anatomical specimens, comparing the subepicardial and subendocardial regions, especially because the subendocardial region is easily approached by means of endomyocardial biopsy. METHODS Transmural sections of myocardium from the right ventricular (RV) inflow tract, anterior wall and infundibulum, and from the left ventricular (LV) free wall were evaluated regarding the degree of cardiomyocyte hypertrophy, vascularization and interstitial fibrosis were analyzed. RESULTS The mean diameter of subendocardial cardiomyocytes is similar to that of subepicardial cardiomyocytes in all regions, except for the RV infundibulum, in which subendocardial cardiomyocytes are significantly larger in relation to those of the subepicardium (p=0.007). The amount of interstitial collagen is in the upper limits of normal and was similar in the subendocardial layers in comparison with the subpericardial layer of each region; however, it was greater in the inflow tract and RV anterior wall than in the LV lateral wall. The numerical density of subendocardial capillaries was similar to that of the subepicardium and was lower than the mean minus two standard deviations of normal in all regions and layers, except for the infundibulum, in which the subepicardium showed normal values and the subendocardium showed values lower than the mean minus two standard deviations. CONCLUSION The postnatal myocardial changes in Tetralogy of Fallot are homogeneously distributed in the subepicardial and subendocardial halves of the ventricular walls, except for the infundibulum, which has peculiar remodeling characteristics and, therefore, is not representative of the other ventricular regions and layers for morphometric studies.