Mitochondrial dysfunction is associated with the severity of liver fibrosis in patients after the Fontan operation.

The gold standard for determining the severity of liver disease in Fontan patients is now liver biopsy. Since it is an invasive procedure, this study determined the possibility of applying mitochondrial function from isolated peripheral blood mononuclear cells (PBMCs) as a non-invasive indicator of liver fibrosis. Fontan patients (n = 37) without known liver disease were analysed cross-sectionally. Patients were classified according to their histology using the METAVIR score as follows; F0/F1-no/mild fibrosis; F2-moderate fibrosis; and F3/F4-cirrhosis. Peripheral blood mononuclear cells were assessed for mitochondrial activity and apoptosis. This study did not find any significant differences in cardiac function among the groups according to liver histology. Interestingly, our findings indicated a significant decrease in maximal respiration and spare respiratory capacity, in both the moderate (F2) and cirrhosis (F3/F4) groups compared with the group without significant fibrosis (F0/F1). Moreover, the cirrhosis group exhibited higher levels of apoptosis and lower levels of live cells, compared with both the moderate and no significant fibrosis groups. In conclusion, the degree of liver fibrosis in Fontan patients is strongly correlated with mitochondrial dysfunction in PBMCs. Mitochondrial function and apoptosis could potentially serve as novel markers for tracking the progression of liver fibrosis in these patients.

Aortic Peak Flow Velocity As a Predictor of Fluid Responsiveness in Mechanically Ventilated Children: A Systematic Review and Meta-Analysis.

OBJECTIVES: This meta-analysis aimed to determine the accuracy of the respiratory variations in aortic peak flow velocity (delta Vpeak) in predicting fluid responsiveness and the moderators of that accuracy. DATA SOURCES: We performed searches for studies that used delta Vpeak as a predictor of fluid responsiveness in mechanically ventilated children in PubMed, Embase, Scopus, and CINAHL from inception to June 20, 2022. STUDY SELECTION AND DATA EXTRACTION: Fifteen studies ( n = 452) were included in this meta-analysis. The diagnostic test data of the included studies were synthesized as pooled sensitivity, specificity, and diagnostic odds ratio (DOR) and the area under the curve (AUC) of the summary receiver operating characteristic of delta Vpeak. DATA SYNTHESIS: The delta Vpeak cutoff values applied in these studies had a median of 12.3% (interquartile range, 11.50-13.25%). The pooled sensitivity and specificity of delta Vpeak were 0.80 (95% CI, 0.71-0.87) and 0.82 (95% CI, 0.75-0.87), respectively. The DOR of delta Vpeak was 23.41 (95% CI, 11.61-47.20). The AUC of delta Vpeak was 0.87. Subgroup analyses revealed that the accuracy of delta Vpeak was not moderated by ventilator settings, measures of delta Vpeak, gold standard index, the cutoff gold standard value of responders, type and volume of fluid, duration of fluid challenge, use of vasoactive drugs, general anesthesia, and cardiopulmonary bypass. CONCLUSIONS: By using the cutoff of approximately 12.3%, the delta Vpeak appears to have good accuracy in predicting fluid responsiveness in mechanically ventilated children. The moderators of delta Vpeak predictability are not found.

Prevalence and predictive factors of malnutrition in Thai children with congenital heart disease and short-term postoperative growth outcomes.

Background: Growth restriction is still a common problem in children with congenital heart disease (CHD). Evidence demonstrates that performing cardiac surgery in appropriate timing may result in better growth outcome. Aim: To investigate prevalence and associated factors of malnutrition in pediatric patients with CHD who underwent cardiac surgery. In addition, post-operative growth outcomes at two weeks following cardiac surgery were also assessed. Methods: A retrospective cohort study was conducted in pediatric patients who underwent cardiac surgery at Chiang Mai University Hospital between January and September 2014. Results: One hundred patients with a median age of 28.5 months (range 14-62 months) were enrolled. Two-third of these patients had at least one form of malnutrition before receiving surgical treatment while wasting, stunting and combined wasting-stunting accounted for 23%, 28%, and 15% of patients, respectively. Multiple logistic regression analysis demonstrated that congestive heart failure-related symptoms were significantly associated with increasing risk of malnutrition (adjusted OR 4.4; 95% CI 1.78-11.26, p = 0.001). Two weeks after hospital discharge, wasting patients with regardless of stunting had significantly improved weight for height (WHZ) and weight for length Z-scores (WLZ) compared to growth parameters at the time of cardiac surgery, p = 0.012 and p < 0.001, respectively. Conclusion: The prevalence of acute and chronic malnutrition in pediatric patients with CHD who underwent cardiac surgery was very high in this study. Children with congestive heart failure had a four-time at risk of undernutrition. In short-term, cardiac surgery may mitigate acute malnutrition of these patients.

Liver nodules after the Fontan operation: role of the computerised tomography scan.

Currently, there is an increasing prevalence of liver nodules in patients following the Fontan operation. The appropriate non-invasive modalities have been applied to assess a diagnosis of Fontan-associated liver disease. The aims of this study were to determine the prevalence and associated factors for the presence of liver nodules using CT scan. A cross-sectional study of 34 patients older than 15 years of age was recruited. Ultrasound upper abdomen, ultrasound liver elastography, and CT scan of the upper abdomen were performed after the Fontan operation. The median age of patients was 20 years (range 14-36 years). The median age at the Fontan operation was 7 years (range 5-17 years) and the duration after the Fontan operation was 12 years (range 4-22 years). The prevalence of liver nodules was 62% as detected by CT scans. Hepatic vein pressure in patients with liver nodules was significantly higher than in those without liver nodules. Hepatic vein pressure above 13 mmHg was a factor associated with liver nodules. There was little agreement between the ultrasound of the upper abdomen and CT scan of the upper abdomen in the evaluation of liver nodules. Hepatic pressure was the only associated factor for the occurrence of liver nodules in patients following the Fontan operation. The prevalence of liver nodules was very high after the Fontan operation. The upper abdomen CT scan should be performed for the surveillance of liver nodules in every Fontan patient over the age of 15 years.

Associated Factors of Liver Disease After Fontan Operation in Relation to Ultrasound Liver Elastography.

Although the Fontan operation can improve outcomes, surviving patients still face Fontan-associated liver disease (FALD). The aim of this study was to determine the associated factors of FALD in relation to ultrasound liver elastography. A cross-sectional study was conducted for all patients on whom an ultrasound upper-abdomen and ultrasound liver elastography was performed at more than 1 year after the Fontan operation. The data consisted of the age at operation, type of Fontan operation, and laboratory data such as gamma-glutamyl transferase (GGT), aspartate aminotransferase-to-platelet ratio index (APRI), and fibrosis-4 (FIB-4) score. Cardiovascular evaluations included echocardiography and cardiac catheterization. Eighty patients with a median age of 12 years (range 5-36 years) were eligible for the study. The prevalence of FALD was 41%. For the purpose of univariate logistic regression analysis, the age at the Fontan operation, time elapsed since the Fontan operation, previous Glenn shunt, presence of fenestration, mean pulmonary artery pressure and IVC pressure post-Fontan operation, platelet count, GGT, and FIB-4 score were considered to be factors significantly associated with FALD. Following an adjustment by multivariate logistic regression analysis, age greater than 7 years at the time of Fontan procedure, time elapsed of more than 9 years since the procedure, and GGT level > 130 U/L were found to be significantly associated with FALD. Patients with these factors should be investigated for FALD.

Prevalence and associated factors of renal dysfunction and proteinuria in cyanotic congenital heart disease.

BACKGROUND: Cyanotic nephropathy (CN), seen in 30-50% of patients with congenital cyanotic heart disease (CCHD), affects both tubular and glomerular function, resulting in proteinuria and azotemia. Microalbuminuria is an early marker for glomerular damage and an independent predictor of progressive renal disease. METHODS: A cross-sectional study was conducted. A total of 116 patients aged 1 month to 15 years with CCHD at Chiang Mai University Hospital between 2015 and 2016 were assessed and 94 patients were enrolled. To determine the prevalence and associated factors of significant albuminuria in CCHD patients, baseline characteristics, oxygen saturation, surgery, hemoglobin (Hb), hematocrit (Hct), spot urine albumin, urine protein, and creatinine were obtained. Binary logistic-regression modeling was used to identify associated factors. RESULTS: Prevalence of CN in children with CCHD was 58.51% and 92.55% according to albuminuria and proteinuria staging respectively. Prevalence of significant proteinuria, significant albuminuria, and decreased GFR was 88.30%, 41.49% and 31.91% respectively. Participants with significant albuminuria had fewer previous surgeries (p = 0.05), a longer waiting time for surgery (p = 0.02), enalapril usage (p = 0.04), pulmonary hypertension (p = 0.03), higher Hct z-score (p = 0.03) and lower platelet count (p = 0.001) compared with those without significant albuminuria. Using multivariate logistic regression analysis, waiting duration for surgery (p = 0.04), Hct >40% (p = 0.02), and platelet count <290,000/mm3 (p = 0.04) were predictive of microalbuminuria. CONCLUSIONS: Cyanotic nephropathy can be detected in the first decade of life with the presentation of microalbuminuria. High Hct level and low platelet count were identified as a predictor of microalbuminuria, whereas early cardiac surgery decreased the risk of developing significant albuminuria.

Loss of function in ROBO1 is associated with tetralogy of Fallot and septal defects.

BACKGROUND: Congenital heart disease (CHD) is a common birth defect affecting approximately 1% of newborns. Great progress has been made in elucidating the genetic aetiology of CHD with advances in genomic technology, which we leveraged in recovering a new pathway affecting heart development in humans previously known to affect heart development in an animal model. METHODS: Four hundred and sixteen individuals from Thailand and the USA diagnosed with CHD and/or congenital diaphragmatic hernia were evaluated with chromosomal microarray and whole exome sequencing. The DECIPHER Consortium and medical literature were searched for additional patients. Murine hearts from ENU-induced mouse mutants and transgenic mice were evaluated using both episcopic confocal histopathology and troponin I stained sections. RESULTS: Loss of function ROBO1 variants were identified in three families; each proband had a ventricular septal defect, and one proband had tetralogy of Fallot. Additionally, a microdeletion in an individual with CHD was found in the medical literature. Mouse models showed perturbation of the Slit-Robo signalling pathway, causing septation and outflow tract defects and craniofacial anomalies. Two probands had variable facial features consistent with the mouse model. CONCLUSION: Our findings identify Slit-Robo as a significant pathway in human heart development and CHD.

Vitamin D deficiency and its relationship with cardiac iron and function in patients with transfusion-dependent thalassemia at Chiang Mai University Hospital.

BACKGROUND: Vitamin D deficiency is common in patients with thalassemia. Vitamin D deficiency could be related to cardiac dysfunction. Increased parathyroid hormone (PTH) is also known to be associated with heart failure. OBJECTIVES: To determine the prevalence of Vitamin D deficiency and to explore the impact of Vitamin D deficiency on cardiac iron and function in patients with transfusion-dependent thalassemia. METHOD: A cross-sectional study in patients with Transfusion-dependent thalassemia was conducted. Patients with liver disease, renal disease, type 1 diabetes, malabsorption, hypercortisolism, malignancy, and contraindication for MRI were excluded. Calcium, phosphate, PTH, vitamin D-25OH were measured. CardiacT2* and liver iron concentration (LIC) and left ventricular ejection fraction (LVEF) were determined. Results Sixty-one (33M/28F) patients with Transfusion-dependent thalassemia were enrolled. The prevalence of Vitamin D deficiency was 50.8%. Patients with cardiac siderosis had tendency for lower D-25OH than those without siderosis (15.9 (11.7-20.0) vs. 20.2 (15.85-22.3) ng/mL); p = 0.06). Serum calcium, phosphate, PTH, LIC, cardiac T2*, and LVEF were not different between the groups with or without Vitamin D deficiency. Patients with Vitamin D deficiency had significantly lower hemoglobin levels compared to those without Vitamin D deficiency (7.5 (6.93-8.33) vs. 8.1 (7.30-8.50) g/dL; p = 0.04). The median hemoglobin in the last 12 months was significantly correlated with D-25OH. Cardiac T2* had significant correlation with PTH. CONCLUSION: Vitamin D deficiency is prevalent in patients with Transfusion-dependent thalassemia. Vitamin D level is correlated with hemoglobin level. Vitamin D status should be routinely assessed in these patients. Low PTH is correlated with increased cardiac iron. This study did not demonstrate an association between Vitamin D deficiency and cardiac iron or function in patients with Transfusion-dependent thalassemia.

A Longitudinal Study of Growth and Relation With Anemia and Iron Overload in Pediatric Patients With Transfusion-dependent Thalassemia.

Short stature is one of the most common endocrinopathies in transfusion-dependent thalassemia (TDT). This study aimed to determine the longitudinal pattern of growth in pediatric patients with TDT and study the relationship between growth and hemoglobin level, serum ferritin level/iron overload parameters, and other clinical factors. The interval height-for-age Z-scores (HAZ) of 50 patients with TDT, of a mean age of 13.3±2.8 years, were analyzed using linear mixed model analysis. Nineteen patients (38%) had short stature with HAZ≤-2.0. The prevalence of short stature increased with age. The estimated mean HAZ decreased by 0.19 SD per year from the age of 5 years until approximately 14 years (95% confidence interval [CI], -0.22 to -0.16, P<0.001). Male sex (estimate, -0.28; 95% CI, -0.43 to -0.14; P<0.001), mean 3-year hemoglobin level ≤8 g/dL (estimate, -0.36; 95% CI, -0.53 to -0.19; P<0.001), mean 3-year ferritin level ≥1800 ng/mL (estimate, -0.44; 95% CI, -0.59 to -0.29; P<0.001), and cardiac T2* ≤20 ms (estimate, -1.05; 95% CI, -1.34 to -0.77; P<0.001) were significantly associated with short stature. In conclusion, short stature in patients with TDT is common and relates significantly with increasing age, male sex, hemoglobin level, and iron overload status.

Cardiac dysfunctions in children with drug-resistant epilepsy.

Objective: There were reports of cardiac dysfunction that led to sudden unexpected death in epilepsy (SUDEP) in patients with epilepsy. Early detection of cardiac dysfunction can lead to early management to prevent sudden cardiac death in these patients. The objective of our study is to assess cardiac functions in children with drug-resistant epilepsy (DRE) compared with the normal population by using a standard echocardiogram (SE), tissue Doppler imaging (TDI) and myocardial strain evaluations (MSE). Method: Twenty-seven children who have been diagnosed with DRE based on the International League against Epilepsy (ILAE) were included in the study, along with 27 children whose ages match those of the normal control group. Results: Seventeen children, median age 12 years old, were using more than four anti-seizure medications. Structural brain lesions were the most common cause of epilepsy, 55.6% (15). Generalized tonic-clonic seizures were the most common seizure type, 55.6% (15). Children with DRE had a lower early mitral valve E wave inflow velocity compared with the control group (p < 0.05). They also had lowered early diastolic velocities (e') and myocardial performance index (MPI) when compared with the control group (p < 0.05). There was a statistically significant difference in left ventricular myocardial strain in children with DRE, with an average of -21.1 (IQR -23.5 and -19.4) and control, -25.5 (IQR -27.3 and -24.2). Significance: Children with DRE have an impairment of left ventricular diastolic function and myocardial strain, which could indicate decreased myocardial deformation and contraction compared with controls. These cardiological assessments can be used to evaluate children with DRE for early diagnosis and management of their cardiac dysfunction.

Outcome following acute and recurrent rheumatic fever.

BACKGROUND: Rheumatic carditis is the leading cause of permanent disability caused by damage of the cardiac valve. This study aimed to determine the outcome and predictors of valve surgery in patients with acute rheumatic fever (ARF) and recurrent rheumatic fever (RRF). METHODS: This was a retrospective study of patients diagnosed with ARF and RRF between 2006 and 2021. The predictors of valve surgery were analysed using multivariable Cox proportional regression. RESULTS: The median age of patients with ARF and RRF (n=92) was 11 years (range 5-18). Seventeen patients (18%) were diagnosed with RRF. The most common presenting symptoms included clinical carditis (87%), heart failure (HF) (63%), fever (49%) and polyarthralgia (24%). Patients with moderate-to-severe rheumatic carditis (88%) were given prednisolone. After treatment, the severity of valvular regurgitation was reduced in 52 patients (59%). Twenty-three patients (25%) underwent valve surgery. The incidence of HF, RRF, severe mitral regurgitation on presentation, left ventricular enlargement and pulmonary hypertension was greater in the surgical group than in the non-surgical group. Recurrent rheumatic fever (hazard ratio 7.9, 95% CI 1.9-33.1), tricuspid regurgitation (TR) gradient ≥ 42 mmHg (HR 6.3, 95%CI 1.1-38.7) and left ventricular end-diastolic dimension (LVEDD) ≥6 cm (HR 8.7, 95% CI 2.1-35.9) were predictors of valve surgery (multivariable Cox proportional regression analysis). CONCLUSION: Clinical carditis was the most common presenting symptom in patients with ARF and RRF. The majority of patients responded positively to prednisolone. These findings highlight the predictors of valve surgery following ARF, including RRF, TR gradient ≥ 42 mmHg and LVEDD ≥ 6 cm.Abbreviations: ARF: acute rheumatic fever; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; GAS: group A beta-haemolytic Streptococcus; HF: heart failure; HR: hazard ratio; LVEDD: left ventricular end-diastolic dimension; MR: mitral regurgitation; RHD: rheumatic heart disease; RRF: recurrent rheumatic fever; TR: tricuspid regurgitation.

Correlation between pressure gradient from echocardiography and peak-to-peak pressure gradient from cardiac catheterization or surgery in patients with coarctation of aorta.

The gold standard for assessing pressure gradients (PG) across coarctation involves measurements obtained through cardiac catheterization or surgical intervention. There has been ongoing discussion regarding the accuracy of non-invasive methods for estimating these gradients. This study sought to establish the correlation and agreement between the systolic blood pressure (SBP) gradient between the upper and lower extremities, as well as, the mean and maximum PG derived from echocardiography, in comparison to the peak-to-peak pressure gradient obtained from either cardiac catheterization or surgery. We conducted a retrospective study on patients < 18 years diagnosed with coarctation at Chiang Mai University Hospital from 2011 to 2022. The study involved the measurement of the SBP gradient between the upper and lower extremities, mean and maximum PG using echocardiography, peak-to-peak pressure gradient obtained from cardiac catheterization, and pressure gradient recorded during surgical procedures. The Spearman's correlation and Bland-Altman analysis were employed to assess correlation and agreement. Fifty-four patients with aortic coarctation were enrolled. The mean PG measured by echocardiography showed a significantly moderate correlation (r = 0.78, p < 0.001) and the highest level of agreement according to Bland Altman plots, in comparison to the peak-to-peak pressure gradient measured during both cardiac catheterization and surgical procedure. The max PG demonstrated a notable overestimation compared to the gold standard (mean difference + 13.14 with a slope of biases + 0.64, p < 0.001). The mean PG obtained through echocardiography has more potential to be applied in practical application in predicting pressure gradient in patients with coarctation.

Successful treatment of neonatal pulmonary thrombosis in congenital nephrotic syndrome.

A 21-year-old adult patient with Tetralogy of Fallot presented acutely unwell with a 3-month history of general malaise following dental treatment. Following initial complete repair, he subsequently underwent two right ventricular outflow tract reconstructions with conduits. On admission, transthoracic echocardiography and peripheral blood cultures were suggestive of streptococcal endocarditis. Sequential computed tomography pulmonary angiography demonstrated peripheral emboli with progressive central pulmonary artery filling defects suggestive of thrombi and potential vegetations (Fig 1a and b). Urgent surgery was performed for uncontrolled sepsis and increasing hypoxia. Peri-operative transesophageal echocardiogram confirmed previous findings (Fig 1c; Supplementary Video 1). Having resected the conduit, we performed a peripheral pulmonary embolectomy and resected an abundance of the infected material from the pulmonary arterial tree under low-flow hypothermia; we then proceeded with a jugular venous valved conduit (Contegra®, Medtronic Inc, Minneapolis, Minnesota, United States of America) replacement and tricuspid valve annuloplasty. He made a slow but steady recovery and was discharged home in good health

Pheochromocytoma presenting with QT prolongation and catecholamine-induced myocarditis in a child.

Pheochromocytomas are catecholamine-producing tumors derived from the adrenomedullary chromaffin cells. The presentation is a classic triad of episodic headaches, sweating, and tachycardia. Hypertensive crisis can occur due to profuse catecholamine excess. Unusual manifestations mimicking cardiogenic shock, arrhythmia, and myocarditis have been rarely reported in children. We present a case with uncommon manifestations of pheochromocytoma in a child, including the episodes of exercised-induced presyncope with QT prolongation, and subsequently cardiogenic shock due to fulminant myocarditis. He later developed hypertensive crisis. The adrenal mass on abdominal computed tomography with an increased chromogranin A level and elevated plasma normetanephrine, and the histological study confirmed the diagnosis of pheochromocytoma. Cardiac functions completely recovered after adrenalectomy. Genetic testing was positive for von Hippel-Lindau syndrome. We describe pheochromocytoma crisis presenting with prolonged QT and catecholamine-induced myocarditis. We discuss the clues to assist in the diagnosis of this condition and its appropriate treatment.

Use of cardiac markers for monitoring of doxorubixin-induced cardiotoxicity in children with cancer.

The aim of this study was to evaluate N-terminal probrain natriuretic peptides (NT-pro-BNP), cardiac troponin T, and creatinine kinase, MB isoenzyme (CK-MB) in the determination of subclinical left ventricular (LV) dysfunction by echocardiography in patients treated with doxorubicin. We performed a cross-sectional case study of systolic, diastolic function and tissue Doppler imaging by echocardiography in children with cancer who received a certain cumulative dose of doxorubicin. Blood levels for NT-pro-BNP, cardiac troponin T, and CK-MB were analyzed within 6 hours of the cardiac study. Of 30 patients, 5 (16.7%) had LV dysfunction with an abnormally high NT-pro-BNP level of 363 ± 78 pg/mL, whereas patients with normal LV function had an NT-pro-BNP level of 148 ± 173 pg/mL (P = 0.012). The NT-pro-BNP level not only inversely correlated with fractional shortening (r = -0.43, P = 0.017) and ejection fraction (r = - 0.45, P = 0.013) but also correlated with mitral deceleration time ( r = 0.41, P = 0.021) and a cumulative dose of doxorubicin (r = 0.44, P = 0.014). For tissue Doppler imaging, NT-pro-BNP correlated with a peak systolic velocity at the myocardial segment (Sm) (r = -0.40, P = 0.027). NT-pro-BNP is a sensitive test and has a moderate relationship with the LV systolic and diastolic function, thus making it a useful cardiac marker for the monitoring of early anthracycline cardiotoxicity.

Screening modalities for the diagnosis of Fontan-associated liver disease: evidence from the past for future development.

Approximately 70,000 patients who have undergone the Fontan operation worldwide survive into adulthood, however the majority of these patients are faced with long-term post-operative complications due to specific hemodynamic changes. Fontan-associated liver disease (FALD) is a challenging complication characterized by various spectra. Of these, liver congestion and liver fibrosis potentially lead to cirrhosis and liver nodules. The most serious condition associated with the development of liver nodules is hepatocellular carcinoma. Various non-invasive modalities including blood tests, ultrasound scans of the upper abdomen, ultrasound elastography of the liver, computed tomography scans, magnetic resonance imaging and magnetic resonance elastography of the liver have been used as alternatives to liver biopsies for FALD assessment in post-Fontan patients. To date, a detailed understanding of the pathophysiology and natural history of these patients, and the most appropriate modality for the effective investigation of this condition is incomplete. In this comprehensive review, reports regarding the currently available screening modalities used in the detection of FALD are summarized and discussed. The findings of this review, including identification of any current knowledge gaps, can pave the way for the development of effective future strategies in the surveillance and ultimately the treatment of post-Fontan patients.

Effects of left ventricular function on the exercise capacity in patients with repaired tetralogy of Fallot.

BACKGROUND: Tissue Doppler imaging has been recently used to evaluate ventricular function. Peak oxygen uptake (V•O2peak) has been demonstrated as a predictor for death in adults with repaired tetralogy of Fallot (TOF). The aim of this study was to determine which Doppler parameters correlated with V•O2peak in patients with repaired TOF. METHOD AND RESULTS: Doppler echocardiography, tissue Doppler imaging, and exercise test were performed in 30 patients with TOF after surgical repair. In 30 patients with repaired TOF (median age 14 years, range 9-25 years), 11 patients (37%) were female. Seven patients (median age 12 years) had normal left ventricular diastolic function, whereas the rest of the patients were classified as diastolic dysfunction grade II (median age 15 years; n=15) and III and IV (median age 18 years; n=8). The oxygen uptake at anaerobic threshold (V•O2AT) and peak exercise in patients with left ventricular diastolic dysfunction was significantly lower than that in those with normal diastolic function. Also, V•O2AT and V•O2 peak in patients with diastolic dysfunction grade III and IV were significantly lower than that in those with diastolic dysfunction grade II. Left ventricular early diastolic myocardial velocity was most closely correlated to V•O2peak (r=0.51; P=0.005). Peak early ventricular filling velocity to early diastolic myocardial velocity ratio was significantly correlated with V•O2peak (r=-0.50; P=0.006). CONCLUSION: Left ventricular diastolic dysfunction is correlated with V•O2peak. Left ventricular diastolic function should be a routine echocardiographic assessment in patients with repaired TOF.

Heart rate variability and exercise capacity of patients with repaired tetralogy of Fallot.

Heart rate variability (HRV) has been used as a reliable method to detect cardiac autonomic nervous system activity. Peak oxygen uptake (VO(2) peak) has been a predictor of death for adults with repaired tetralogy of Fallot (TOF). This study investigated the correlation between HRV and exercise capacity in 30 patients with TOF after surgery for total correction. The median age of the patients was 14 years (range, 9-25 years), and the median follow-up period was 11.6 months (range, 5.3-20.2 months). Low- and high-frequency-domain HRV significantly correlated with VO(2) peak (r = 0.56, P = 0.001 and r = 0.44, P = 0.02, respectively). After the 1-year follow-up evaluation, VO(2) peak and HRV analysis did not differ from those at entry to the study. However, low- and high-frequency-domain HRV still correlated significantly with VO(2) peak (r = 0.43, P = 0.03 and r = 0.52, P = 0.007, respectively). Left ventricular early diastolic myocardial velocity was most closely correlated with the VO(2) peak (r = 0.51, P = 0.005). Impaired cardiovascular autonomic control and left ventricular diastolic dysfunction may be responsible for exercise intolerance in patients with repaired TOF. Long-term follow-up evaluation with exercise testing and 24-h Holter monitoring are warranted.

Early detection of ventricular dysfunction by tissue Doppler echocardiography related to cardiac iron overload in patients with thalassemia.

Cardiac T2* MRI is used as a gold standard for cardiac iron quantification in patients with transfusion-dependent thalassemia (TDT). We hypothesized that left ventricular (LV) diastolic dysfunction would reflect the severity of iron overload and can serve as an early detection of cardiac iron deposits. A study was conducted on all patients with TDT. Hemoglobin, serum ferritin and non-transferrin bound iron, together with a complete echocardiography and cardiac T2* MRI, were performed on all patients. Seventy-seven patients with TDT were enrolled (median age 14 years). In the patient group with a mean serum ferritin of > 2500 ng/mL during the past 12 months, there were more patients with severe cardiac iron deposits than in the group with a mean serum ferritin of ≤ 2500 ng/mL. Diastolic dysfunction was absent in all patients with a serum ferritin of < 1000 ng/mL. All patients with cardiac T2* ≤ 20 ms had grade III LV diastolic dysfunction. However, twenty-one percent of patients with cardiac T2* > 20 ms had LV diastolic dysfunction. The differences observed in pulmonary vein atrial reversal duration and mitral A-wave (PVAR-MVA) duration ≥ - 1 ms and an E/E' ratio ≥ 11 were proven to be the associated factors with the cardiac T2* ≤ 20 ms. Increased PVAR-MVA duration and increased E/E' ratio reliably reflected a severe iron overload, according to a cardiac T2* in patients with TDT. LV diastolic dysfunction can occur prior to severe cardiac iron deposition. Tissue Doppler echocardiography has the potential for the early detection of cardiac involvement in patients with TDT .

Carvedilol improves left ventricular diastolic dysfunction in patients with transfusion-dependent thalassemia.

BACKGROUND: Iron overload cardiomyopathy is the most common cause of death in patients with transfusion-dependent thalassemia. AIM: The aim of this study was to determine the efficacy of carvedilol treatment in patients with transfusion-dependent thalassemia who had left ventricular diastolic dysfunction. METHODS: Eighteen patients with transfusion-dependent thalassemia who had left ventricular diastolic dysfunction were enrolled. All patients had normal left ventricular systolic function and were given carvedilol with the target dose of 0.8 mg/kg/day. Ventricular function and the level of cardiac iron were assessed by echocardiography and magnetic resonance imaging at 0, 3, and 6 months. RESULTS: The median age of the patients was 19 years (range 13-25 years). Four patients had severe left ventricular Grade III diastolic dysfunction and fourteen patients had Grade II diastolic dysfunction. The grade of left ventricular diastolic dysfunction was improved at 3 months after the carvedilol treatment. The Doppler parameters, including pulmonary vein atrial reversal velocity, pulmonary vein atrial reversal duration, and the difference of pulmonary vein atrial reversal and the mitral valve atrial contraction wave duration at 3 months after the carvedilol treatment, were significantly lower than these parameters before the treatment. CONCLUSIONS: Among patients with transfusion-dependent thalassemia who had left ventricular diastolic dysfunction without systolic dysfunction, treatment with carvedilol for 3 months was associated with improvement in Doppler parameters of left ventricular diastolic function. However, this finding and its clinical significance need to be confirmed in further double-blind controlled studies.