Torsional mechanics of the left ventricle in patients after surgical repair of tetralogy of Fallot.

BACKGROUND: This study aimed to test the hypothesis that alteration of left ventricular (LV) torsional mechanics occurs in patients after repair of tetralogy of Fallot (TOF) and is associated with right ventricular (RV) volume overload and changes in LV configuration. METHODS AND RESULTS: Fifty-five TOF patients aged 19.0 ± 8.1 years and 27 age-matched healthy controls were studied. The LV and RV volumes were measured using 3-dimensional echocardiography while LV geometry was quantified by the diastolic eccentricity index (EI). The LV peak systolic torsion and systolic twisting and diastolic untwisting velocities were determined by speckle tracking. Compared with controls, patients had significantly greater RV end-systolic (P < 0.001) and diastolic (P < 0.001) volumes and LV diastolic EI (P < 0.001). In contrast, LV peak apical rotation (P < 0.001), systolic torsion (P = 0.004), systolic twisting velocity (P = 0.001), and diastolic untwisting velocity (P = 0.001) were lower in patients than in controls. For the whole cohort, RV EDV and LV diastolic EI correlated negatively with peak systolic torsion, systolic twisting velocity, and diastolic untwisting velocity (all P ≤ 0.001). Systolic torsion correlated strongly with diastolic untwisting velocity (r = 0.72, P < 0.001), while systolic twisting velocity correlated with LV ejection fraction (r = 0.3, P = 0.005). CONCLUSIONS: LV torsional mechanics is impaired and is negatively related to RV volume overload and LV eccentricity in patients after TOF repair.

Mechanical right ventricular dyssynchrony in patients after atrial switch operation for transposition of the great arteries.

Recent data suggest potential benefits of cardiac resynchronization therapy in the management of right ventricular (RV) dysfunction in congenital heart disease. The aim of this study was to determine the nature, prevalence, and functional implications of mechanical RV dyssynchrony in patients after Senning or Mustard procedures for transposition of the great arteries. Twenty-eight patients (mean age 21.1 +/- 3.5 years) at 19.9 +/- 3.2 years after atrial switch operations and 29 healthy controls were studied. The times from the onset of QRS to peak systolic strain (T epsilon) at the base of and the mid RV free wall, the ventricular septum (VS), and the left ventricular (LV) free wall were determined using tissue Doppler echocardiography. Intraventricular mechanical delay was defined as Delta T epsilon(RV-VS) and interventricular mechanical delay as Delta T epsilon(RV-LV). In patients, the magnitude of RV intra- and interventricular mechanical delay was correlated with cardiac magnetic resonance-derived RV volumes and ejection fractions (n = 26) and treadmill exercise testing parameters (n = 20). Compared with controls, patients had significantly longer Delta T epsilon(RV-VS) (48.1 +/- 50.9 vs 17.0 +/- 16.1 ms, p <0.001) and Delta T epsilon(RV-LV) (63.1 +/- 49.5 vs 19.0 +/- 12.9, p <0.001). Nine patients (32%) exhibited RV dyssynchrony (Delta T epsilon(RV-VS) >49 ms, control mean +/- 2SD), and 16 patients (57%) showed interventricular dyssynchrony (Delta T epsilon(RV-LV) >45 ms). In patients, RV intra- and interventricular mechanical delay was correlated negatively with the RV ejection fraction (both r = -0.42, p = 0.03) and percentage predicted maximum oxygen consumption (r = -0.50, p = 0.03, and r = -0.52, p = 0.02, respectively) and positively with minute ventilation/carbon dioxide production slope (r = 0.49, p = 0.03, and r = 0.56, p = 0.01, respectively). In conclusion, RV dyssynchrony is common in young adults after atrial switch operations and is associated with RV systolic dysfunction and impaired exercise performance.

Oxidative stress in children late after Kawasaki disease: relationship with carotid atherosclerosis and stiffness.

BACKGROUND: Persistent arterial dysfunction in patients with a history of Kawasaki disease (KD) and an integral role of oxidative stress in the development of cardiovascular disease are increasingly recognized. We sought to test the hypothesis that oxidative stress is increased in KD patients and related to carotid atherosclerotic changes and stiffness. METHODS: We compared the serum levels of oxidative stress biomarkers, carotid intima-media thickness (IMT), and carotid stiffness index among KD patients with coronary aneurysms (n = 32), those without coronary complications (n = 19), and controls (n = 32). RESULTS: Compared with controls, patients with coronary aneurysms had significantly higher serum levels of malonaldehyde (2.62 +/- 0.12 microM vs 2.22 +/- 0.07 microM, p = 0.014) and hydroperoxides (26.50 +/- 1.13 microM vs 22.50 +/- 0.62 microM, p = 0.008). A linear trend of the magnitude of oxidative stress in relation to inflammatory damage was observed for malonaldehyde (p = 0.018) and hydroperoxides (p = 0.014) levels. Serum malonaldehyde and hydroperoxide levels correlated positively with carotid IMT (p < 0.001 and p = 0.034, respectively) and stiffness index (p = 0.001 and p = 0.021, respectively). Multiple linear regression analysis identified serum malonaldehyde level as a significant determinant of carotid IMT (beta = 0.31, p = 0.006) and stiffness (beta = 0.27, p = 0.008). CONCLUSION: Our findings suggest oxidative stress is increased in KD patients with coronary aneurysms and is associated with carotid intima-media thickening and stiffening.

Systemic oxygen saturation and coagulation factor abnormalities before and after the fontan procedure.

Coagulation factor abnormalities are believed to predispose to increased risk for thromboembolism after the Fontan procedure. Recent data, however, suggest that coagulation abnormalities may precede the operation. This study determined coagulation factor abnormalities in patients with single-ventricle congenital heart defects before the Fontan procedure and compared the findings with age-matched post-Fontan patients and control subjects. Liver function, coagulation factor levels, and pulse oximetry readings were determined in 11 pre-Fontan patients aged 9.3+/-5.6 years. The results were compared with those of 11 age-matched post-Fontan patients, at 9.1+/-2.4 years after the Fontan procedure, and 11 age-matched controls by simple analysis of variance and post hoc Tukey's test. Liver function was normal in patients before and after surgery apart from mildly elevated bilirubin levels in post-Fontan patients (p=0.027). When compared with controls, pre-Fontan patients had significantly lower levels of protein C; protein S; antithrombin III; and factors II, V, VII, and X and longer prothrombin times (all with p<0.05). When compared with post-Fontan patients, pre-Fontan patients had similarly lower levels of free protein S (p<0.001), protein C (p=0.06), and antithrombin III (p=0.001). Systemic oxygen saturation correlated positively with the levels of anticoagulants (protein C, protein S, antithrombin III) and procoagulants (factors II, V, VII, and X) (all with p<0.05, r=0.33 to 0.61). In conclusion, the findings suggest that coagulation factor abnormalities precede the Fontan procedure and tend to normalize after the operation, relating perhaps to improved systemic oxygenation.

Impact of right ventricular dilation on left ventricular myocardial deformation in patients after surgical repair of tetralogy of fallot.

Left ventricular (LV) dysfunction is 1 of the major determinants of late adverse clinical outcomes in patients after surgical repair of tetralogy of Fallot (TOF). The aim of this study was to test the hypothesis that LV myocardial deformation is impaired in patients after TOF repair and related to right ventricular (RV) dilation and exercise capacity. Longitudinal, radial, and circumferential LV myocardial deformation was determined using speckle-tracking echocardiography in 23 postoperative patients with TOF and compared to that of 23 age-matched controls. Relations between LV strain and strain rate (SR) and RV volumes and exercise parameters were determined in patients. Compared to controls, patients had reduced global LV longitudinal, radial, and circumferential strain (all p values <0.05). Patients with significantly increased RV end-systolic volume (>2 SDs higher than normal; n = 17) had reduced global LV circumferential strain (p = 0.048) and SR (p = 0.038), but similar longitudinal and radial speckle-tracking echocardiographic parameters, compared to those without (n = 6). RV end-systolic volume was correlated inversely with global LV circumferential strain and SR (r = -0.58, p = 0.004, and r = -0.58, p = 0.005, respectively), while RV end-diastolic volume was correlated only with global LV circumferential strain (r = -0.43, p = 0.047). In patients, the LV ejection fraction was correlated with global LV circumferential strain (r = 0.54, p = 0.01) and SR (r = 0.66, p = 0.001) but not with longitudinal or radial speckle-tracking echocardiographic parameters. Using multivariate analysis, global LV circumferential SR (beta = 0.66, p = 0.001) and male gender (beta = 0.46, p = 0.012) were identified as independent predictors of peak oxygen consumption. In conclusion, the negative impact of RV dilation on LV function relates to its influence on LV circumferential strain and SR in patients after TOF repair.

Functional implications of the right ventricular myocardial performance index in patients after surgical repair of tetralogy of Fallot.

The myocardial performance index (MPI) has been proposed to be a simple echocardiographic index of right ventricular (RV) function in patients after surgical repair of tetralogy of Fallot (TOF). However, its functional status remains to be clarified. The functional implications of RV MPI were determined by exploring its relationships with parameters of RV function as derived from cardiovascular magnetic resonance (CMR), and exercise capacity of postoperative TOF patients Thirty patients (11 males), aged 15.6 +/- 3.1 years, who have undergone surgical repair of TOF at 4.0 +/- 1.8 years, were studied. The RV and left ventricular (LV) MPIs determined using pulsed-wave Doppler echocardiography were related to CMR-derived RV and LV ejection fractions, and pulmonary regurgitant fraction and treadmill exercise testing parameters. Log RV MPI correlated positively with log LV MPI (r = 0.38, P = 0.037) and negatively with CMR-derived RV ejection fraction (r = -0.4, P = 0.028) and pulmonary regurgitant fraction (r = -0.4, P = 0.031). No significant correlations were found between LV MPI and any of the CMR parameters. Using receiver operated characteristics analysis, a cutoff value of 0.30 for RV MPI was found to have a sensitivity of 100% and specificity of 74% in predicting a RV ejection fraction <35%. Right ventricular, but not LV, MPI correlated inversely with exercise duration (r = -0.45, P = 0.013) and peak oxygen consumption (VO2 max) (r = -0.56, P = 0.001). Multivariate analysis identified RV MPI (beta = -0.6, P < 0.001), male sex (beta = 0.44, P = 0.01), and duration from surgery (beta = -0.30, P = 0.019) as significant determinants of VO2 max. Increased MPI is a reflection of reduced RV ejection fraction and exercise capacity in patients after TOF repair.

Plasma brain natriuretic peptide levels, right ventricular volume overload and exercise capacity in adolescents after surgical repair of tetralogy of Fallot.

BACKGROUND: Right ventricular (RV) volume overload secondary to pulmonary regurgitation contributes to long-term morbidities in patients after tetralogy of Fallot (TOF) repair. We tested the hypothesis that plasma brain natriuretic peptide (BNP) levels relate to RV volume overload, pulmonary regurgitation, and exercise capacity in adolescents after TOF repair. METHODS: We assessed the RV function echocardiographically and plasma BNP levels in 32 postoperative TOF patients aged 14.7+/-3.1 years and 20 age-matched controls. Eighteen patients further underwent cardiovascular magnetic resonance imaging and 26 had exercise testing. RESULTS: Compared with controls, patients had significantly higher BNP levels (p=0.027), greater indexed RV end-diastolic dimension (p<0.001), increased RV myocardial performance index (p=0.005), and reduced tricuspid annular systolic velocity (p=0.008). Multivariate analysis identified indexed RV end-diastolic dimension as the only significant determinant of plasma BNP levels (beta=0.69, p<0.001). Plasma BNP levels correlated positively with indexed RV end-diastolic volume (r=0.6, p=0.009) and pulmonary regurgitant fraction (r=0.54, p=0.026), and negatively with exercise duration (r=-0.45, p=0.021), peak oxygen consumption (r=-0.43, p=0.03), and minute ventilation at maximal exercise (r=-0.52, p=0.006). Multivariate analysis demonstrated BNP levels (beta=-0.43, p=0.034) and body mass index (beta=-0.40, p=0.036) to be independent predictors of peak oxygen consumption. No relations were found between BNP levels and RV myocardial performance index, tricuspid annular velocities and RV ejection fraction. CONCLUSIONS: In adolescent patients after TOF repair, plasma BNP levels relate to RV volume overload, pulmonary regurgitation and exercise capacity.