Developing standard reference data for Thai children from a six-minute walk test.

BACKGROUND: The six-minute walk test (6MWT) is a useful test for pre-and post-treatment comparisons, measuring functional status and predicting morbidity and mortality. The test is not widely used with children because the exact reference data in healthy children are often not known and the test requires concentration and co-operation from the participants, which is harder to manage in children. Data for children have been studied in many countries, but data for Thai children is limited. OBJECTIVE: To establish reference values for a six-minute walking distance (6MWD) of healthy Thai children aged between 9 and 12 years. MATERIAL AND METHOD: A cross-sectional study was conducted in healthy children attending the 4 to 6 grades of seven primary schools in Songkla province in southern Thailand. The tests were conducted according to the American Thoracic Society (ATS) guidelines between June and September 2008. The potential variables were evaluated for their relations and confounding factors. Reference curves were developed. RESULTS: Seven hundred thirty nine students were recruited for the study, 403 boys (54.5%) and 336 girls (45.5%). Only one girl could not complete the test. The mean 6MWD was 677 (+/- 62.2) meters. The average walking distance was 36.4 meters greater in boys than girls (693.5 and 657.1 meters, respectively). The walking distance increased with age from 9 to 12 years of age in boys, but it decreased with age in girls after 11 years old. There were no unexpected events during or after the tests. Multivariate analysis showed that the 6MWD correlated to age, sex, weight and heart rate differences. Age-specific centile curves of 9 to 12 years for the 6MWD in each sex were developed. CONCLUSION: 6MWT a practical simple test, is one of several modalities for objective evaluation of functional exercise capacity. The reference value of 6MWT for healthy Thai children aged 9 to 12 years was calculated and reported.

Positive serology for dengue viral infection in pediatric patients with Kawasaki disease in southern Thailand.

BACKGROUND: The etiologic agent of Kawasaki disease (KD) is unknown, but may be dengue infection because of reported cases of concomitant KD and dengue. METHODS AND RESULTS: Prospective study was conducted to ascertain the relationship of positive serology for dengue infection in pediatric patients presenting with KD. A total of 65 cases were diagnosed with KD during the period of 4 years and of the 48 who had a complete dengue serologic study, 9 had a positive dengue titer. CONCLUSION: In the present study 18.7% of patients had proven dengue infection from a positive serologic study. Further case-control study with other pediatric patients presenting with acute febrile illness needs to be done to support this significant finding.

Epidemiologic study of Kawasaki disease and cases resistant to IVIG therapy in Thailand.

The incidence of Kawasaki disease (KD) in Thailand has never been studied before. We reviewed the data from the National Registry of Thai Children who had KD between 1998-2002 to evaluate the incidence of KD and cases resistant to treatment with intravenous immunoglobulin (IVIG). Resistance to IVIG was defined as remaining febrile at least 48 hours after initial IVIG therapy. There were 710 KD patients in the registry. The incidence of KD was from 2.14 to 3.43 cases per 100,000 children aged 0-5 years. During the acute phase 15.6% of 435 patients were considered as resistant cases. Resistant cases of KD in Thai children are quite common (15.6%) even after IVIG treatment. We found that patients who had high white blood cell counts (> 16,500 cells/mm3) had a higher likelihood of being resistant.

Predicted outcome after repair of tetralogy of Fallot by postoperative pressure ratio between right and left ventricle.

BACKGROUND: The surgical management of tetralogy of Fallot (TOF) has continued to evolve and there are now generally excellent early and long-term results following complete repair. OBJECTIVE: To investigate the early results of the authors' current surgical management of TOF by assessing the perioperative and early to intermediate follow-up period. The authors paid particular attention to the post-operative ratio of right ventricular to left ventricular systolic pressure (RVSP/LVSP), focusing on the presence of low cardiac output, intensive care unit (ICU) stay, prolonged of inotropic support and ventilation support time. STUDY DESIGN: Retrospective study. MATERIAL AND METHOD: Between June 2002 and August 2004, 31 consecutive patients underwent complete repair of TOF. Their mean age was 7.7 +/- 5.1 years (range, 2.9 to 25.3). A previous palliative shunt had been performed in 14 (45.2%) patients. Twenty-three patients (74.2%) were in NYHA FC II. Mean hematocrit and oxygen saturation were 50.9 +/- 10.25% and 80.5 +/- 8.6%, respectively. Mean preoperative ratio of RVSP/LVSP was 1.1 +/- 0.15. The operative approach was transatrial/transpulmonary, and 17 (54.8%) patients required a transannular patch. An extracardiac valve conduit was necessary in 3 (9.7%) patients with pulmonary atresia. RESULTS: There were no operative or late deaths. Two cases were reoperated from cardiac tamponade. Mean postoperative ratio of RVSP/LVSP was 0.53 +/- 0.16. Median ICU and hospital stays were 2.2 and 11 days, respectively. Presence of low cardiac output and prolonged inotropic support were significantly (P < 0.05) related to a RVSP/LVSP ratio of more than 0.5. At median follow-up of 6 months, 29 (93.5%) patients were asymptomatic and all patients were free of significant residual lesion. CONCLUSION: The authors' early results in complete repair of TOF patients are acceptable with a low incidence of morbidity. A postoperative RVSP/LVSP ratio of more than 0.5 was significantly associated to adverse outcome. Late complications may, however, develop, and long term follow-up for early detection of any such complications is essential.

Mitogen-activated protein kinases (p38 and c-Jun NH2-terminal kinase) are differentially regulated during cardiac volume and pressure overload hypertrophy.

Chronic pressure overload (PO) and volume overload (VO) result in morphologically and functionally distinct forms of myocardial hypertrophy. However, the molecular mechanism initiating these two types of hypertrophy is not yet understood. Data obtained from different cell types have indicated that the mitogen-activated protein kinases (MAPKs) comprising c-Jun NH2-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 play an important role in transmitting signals of stress stimuli to elicit the cellular response. We tested the hypothesis that early induction of MAPKs differs in two types of overload on the heart and associates with distinct expression of hypertrophic marker genes, namely ANF, alpha-myosin heavy chain (alpha-MHC), and beta-MHC. In rats, VO was induced by aortocaval shunt and PO by constriction of the abdominal aorta. The PO animals were further divided into two groups depending on the severity of the constriction, mild (MPO) and severe pressure overload (SPO), having 35 and 85% aortic constriction, respectively. Early changes in MAPK activity (2-120 min and 1 to 2 d) were analyzed by the in vitro kinase assay using kinase-specific antibodies for p38, JNK, and ERK2. The change in expression of hypertrophy marker genes was examined by Northern blot analysis. In VO hypertrophy, the activity of p38 was markedly increased (10-fold), without changing the activity of ERK and JNK. However, during PO hypertrophy, the activity of JNK was significantly increased (two- to sixfold) and depended on the severity of the load. The activity of p38 was not changed in MPO hypertrophy, whereas it was slightly elevated (50%) in hearts with SPO. Similarly, ERK activity was not changed in hearts with MPO, but a transient rise in activity was observed in hearts with SPO. The expression of ANF and beta-MHC genes was elevated in both PO and VO hypertrophy; however, this change was much greater in hearts subjected to PO than VO hypertrophy. Alpha-MHC expression was downregulated in PO but remained unchanged in VO hypertrophy hearts. Thus, these results demonstrate differential activation of MAPKs in two types of cardiac hypertrophy and this, in part, may contribute to differential expression of cardiac muscle gene expression, giving rise to unique cardiac phenotype associated with different hemodynamic overloads.

A case report of infant with left ventricular noncompaction.

Left ventricular noncompaction (LVNC) is a rare cardiomyopathy resulting from abnormal arrest during endomyocardial embryogenesis. The authors present a 6-month-old infant with intractable cardiogenic shock and echocardiographic features of LVNC, characterized by excessively prominent ventricular trabeculation and deep intertrabecular recesses as the first case report in Thailand.

Early experience with pediatric cardiac intervention in Songklanagarind Hospital.

BACKGROUND: Nowadays, pediatric cardiac intervention is an effective optional treatment for congenital heart disease (CHD). Several cardiac centers have been established in different regions of Thailand and Songklanagarind Hospital is the newest of these university cardiac centers. OBJECTIVE: To report results and complications of transcatheter treatment for congenital cardiac defects in Songklanagarind Hospital. MATERIAL AND METHOD: The medical database was reviewed for the results and complications of different types of pediatric cardiac intervention from May, 2000 to December, 2003. RESULTS: There were 102 cases of pediatric cardiac intervention. Sixty-seven were patent ductus arteriosus (PDA), 16 were valvular pulmonary stenosis (VPS), 10 were cyanotic CHD which needed balloon atrial septostomy (BAS), 8 were abnormal aorto-pulmonary (AP) collaterals, and 1 was severe valvular aortic stenosis (VAS). Coil embolization was performed in 53 patients with PDA and 8 patients with AP-collateral vessels, 32 of PDAs (60.4%) and all AP-collateral vessels (100%) were completely obliterated within 24 hours. The Amplatzer duct occluder (ADO) was deployed in 14 PDAs with 100% completely obliteration within 24 hours. In those with VPS or VAS, percutaneous balloon valvuloplasty (PBV) was the treatment of choice. The mean peak to peak systolic pressure gradient in VPS was reduced from 62.8 +/- 33.3 mmHg to 33.33 +/- 33.33 mmHg and from 76 mmHg to 49 mmHg in VAS after the procedures. In BAS, the mean diameter of atrial communication increased from 3.0 +/- 0.7 mm to 5.9 +/- 0.4 mm. In coil embolization, 8 had distal PA embolization (15%), 1 had hemolysis (2%) and 1 had decreased dorsalis pedis pulse (2%). One (7%) of the ADO-implanted patients had a weak femoral pulse. Of the VPS cases, 1 died from intractable heart failure, and 1 developed hemiparesis, from which they completely recovered within 6 months. The patient with VAS had a femoral artery complication. CONCLUSION: Pediatric cardiac intervention in Songklanagarind Hospital has satisfactory results with an acceptable complication rate.

Dengue myocarditis.

We report a 13-year-old boy who developed bradycardia and hypotension a day after recovery from dengue hemorrhagic fever. His electrocardiogram, during the bradycardia, showed a junctional rhythm with a rate of 50 beats/minute. This is the first reported case of sinus node dysfunction following dengue infection.

Prevalence of idiopathic long QT syndrome in congenital sensori-neural hearing loss students of Songkhla School for the Deaf.

OBJECTIVES: To survey the prevalence of the long QT syndrome (LQTS), especially Jervell-Lange-Nielsen syndrome (JLNS), in Thai children (The first such study). BACKGROUND: LQTS is a rare inherited disease with a prevalence of 0.21 per cent in children with congenital deafness from other reports. These patients carry a high risk of recurrent syncope and fatal ventricular arrhythmia. STUDY DESIGN: Cross-sectional survey from January 2000 to August 2000. METHOD: A total of 276 children with congenital sensori-neural hearing loss were included. A questionnaire was employed and all children were examined by a pediatric cardiologist to rule out organic heart disease. EKGs were obtained and QTc intervals were blindly measured using standard methods in L2, V5 or any other leads with the longest QTc interval by three pediatric cardiologists. If QTc interval is prolonged, additional EKG (up to 3) were done to confirm the finding. Schwartz criteria was used to identify index cases with LQTS after repeated EKGs, and exercise stress tests. Also, echocardiography were done in patients suspected of having LQTS. RESULTS: A total of 14 children needed a third EKG and more work ups due to persistent long QTc interval after 2 consecutive EKG studies with QTc intervals ranged from 456 msec to 466 msec, and Schwartz score from 1.5 to 2.5. There were 6 twins and no triplets in the study. Finally, two subjects (not twins or siblings) had persistent prolonged QTc intervals after 3 EKG studies. After the exercise stress test, both still had a prolonged QTc interval, not corrected to the normal QTc interval even at the exercise peak. There was no cardiac abnormality either structurally or functionally from the 2D echocardiogram and Doppler color flow study. CONCLUSION: The possible prevalence of JLNS was 0.7 per cent (2/276). Both children were in the low-risk group for having LQTS.

Myocardial diseases in Thai children.

UNLABELLED: Myocardial diseases are among the important causes of mortality and morbidity in children. This drew the authors attention to the study of myocardial diseases in children to find out the outcome, factors affecting the outcome, and management strategies. The authors retrospectively studied children who had been diagnosed with primary myocardial diseases at six university hospitals in Thailand from January 1996 to December 2000. The total number of cases was 209 which accounted for 1.2 per cent of cardiovascular diseases in children. The patients' ages ranged from 0.1-15 years. These myocardial diseases included dilated cardiomyopathy (DCM) 45 per cent, acute myocarditis 27.3 per cent, hypertrophic cardiomyopathy (HCM) 18.2 per cent, hypertrophic obstructive cardiomyopathy (HOCM) 8.1 per cent and restrictive cardiomyopathy (RCM) 1.4 per cent. Fifty-six per cent of the patients were female. Congestive heart failure was the most common presenting symptom (75%). Median ejection fraction (EF) of acute myocarditis was 42 per cent (15-79%) which was significantly higher than DCM (33.5%, 10-57%). Serum cardiac troponin T (cTnT) was also significantly higher in acute myocarditis than in DCM (0.08 ng/ml, 0.01-0.16 vs 0.01 ng/ml, 0.01-0.10). Within the follow-up period of 1 year (0.1-5.5 years), the mortality rates were 18.8 per cent, 17.0 per cent, 5.4 per cent and 33.3 per cent in DCM, acute myocarditis, HCM and RCM respectively. Factors associated with the mortality rate in acute myocarditis were admission to ICU and low left ventricular EF at presentation while IVIG administration and cTnT level did not. CONCLUSION: Primary myocardial diseases are uncommon. Most of the patients had compromised cardiovascular reserve. Admission to ICU and low EF were factors that affected the mortality in acute myocarditis while intravenous immunoglobulin administration did not. Mortality rate in the subacute follow-up period was high in all groups.