The relationship between plasma NT-proBNP level and pacing mode in the patient with implanted permanent pacemaker.

BACKGROUND AND OBJECTIVE: Plasma BNP is current one of the prognostic markers for cardiovascular disease including congestive heart failure. The objective of the present study was to evaluate the level of plasma NT-proBNP in patients who have had permanent pacemaker implantation. MATERIAL AND METHOD: The clinical characteristics and the plasma NT-proBNP level were recorded and obtained from 284 patients with implanted permanent pacemaker followed-up at the Pacemaker Clinic, Siriraj Hospital. The factors associated with abnormal NT-proBNP level were analyzed. RESULTS: Among 284 patients who participated in the present study, 140 patients had NT-proBNP in normal range (level of < 300 pg/ml). 68 patients had NT-proBNP level between 300 to 900 pg/m/ and 76 patients had NT-proBNP level > 900 pg/ml. There were significant correlations between log NT-proBNP with patient's age, left ventricular ejection fraction and serum creatinine level with age and serum creatinine showing positive correlation and left ventricular ejection fraction having a negative correlation. From multiple regression analysis, three factors were associated with high NT-proBNP level: older age, serum creatinine level and ventricular based pacing. The patients with ventricular based pacing mode had higher NT-proBNP level than patients with atrial based pacing mode even after being adjusted for age and serum creatinine adjusted CONCLUSION: In the patient with permanent pacemaker three factors are associated with high NT-proBNP level. These are older age, serum creatinine level, and ventricular based pacemaker.

Prevalences and association of ECG findings and cardiovascular risk factor in Shinawatra employees.

OBJECTIVES: There is significant incline trend in cardiovascular disease (CVD) mortality in developing countries such as Thailand and it is also the major contributor to the burden of premature mortality and morbidity throughout the world. In order to have well-stratified primary prevention plan, this study reports the prevalence of Electrocardiogram (ECG) abnormalities, as categorized by ECG Minnesota coding, and the association with major cardiovascular risk factors in Thailand. MATERIAL AND METHOD: In this study, we use the same data from a previous survey at Shinawatra Employee but only subjects with available ECG's were recruited in our study. Standard supine 12-lead ECG data were collected; all amplitude and intervals were measured and entered into a computer manually. Then the ECG was coded according to Minnesota Coding system. The study characteristics, the prevalence of major cardiovascular risk factors and ECG abnormalities were calculated. RESULTS: A total of 1,485 subjects were recruited in this study, 638 (43.0%) were male and 847 (57.0%) were female. The overall mean aged was 34.4 (5.4). The level of major cardiovascular risk factors among men and women respectively were: total Cholesterol 215.6 (41.0) mg/dl (5.6 (1.1) mmol/l), 202.8 (35.3) mg/dl (5.3 (0.9) mmol/l); LDL-cholesterol 139.1 (37.0) (3.6 (1.0) mmol/l), 123.6 (31.9) (3.2 (0.8) mmol/l). Hypercholesterolemia was 65.3%, 49.8%. The mean systolic and diastolic blood pressures were 121.5 (13.9) mmHg and 81.4 (10.5) mmHg, 111.7 (12.2) mmHg and 74.5 (8.6) mmHg; hypertension 21.0%, 4.2%; fasting blood sugar 95.5 (15.8) mg/dl (5.3 (0.9) mmol/l), 88.0 (8.6) mg/dl (5.1 (0.5) mmol/l); diabetes mellitus 3.3%, 0.5%; body mass index 23.5 (3.5) (kg/m2), 21.3 (3.1) (kg/m2); obesity 30.7%, 11.0%; smoking 12.3%, 14.0%. The prevalence of ECG abnormalities, as categorized based on the Minnesota coding criteria, among men and women respectively were: Q/QS wave abnormalities (Code 1) 2.2%, 0.8%; S-T-J segment depression (Code 4) 0.5%, 1.4%; T-wave inversion (Code 5) 1.4%, 9.6%; atrioventricular conduction abnormalities (Code 6) 2.5%, 0.8%; and ventricular conduction abnormalities (Code 7) 0.2%, 0.2%. CONCLUSIONS: This study reports higher prevalence of having major cardiovascular risk factors as compared to previous epidemiological studies in Thailand which should heighten the Ministry of Public Health concern to launch a better stratified preventive plan to combat the rising of coronary artery disease in the future. Moreover, this study is also the first study to report the prevalence of ECG abnormalities, as determined on the basis of the Minnesota coding criteria, and the association between major cardiovascular risk factors and the prevalences of several electrocardiographic findings in adult men and women in Thailand.

Improvement of quality of life after percutaneous balloon mitral valvulotomy in patients with mitral stenosis: does rhythm matter?

BACKGROUND AND AIM OF THE STUDY: Limited data are available on the effect of percutaneous balloon mitral valvulotomy (PBMV) on quality of life (QoL) in patients with mitral stenosis (MS), and whether the effect is similar between patients in sinus rhythm (SR) and with atrial fibrillation (AF). The study aim was to determine the effect of PBMV on the QoL of such patient groups. METHODS: A total of 130 patients with symptomatic MS and scheduled for PBMV was studied. Patients with AF were predominantly male, and had more severe symptoms, a larger left atrial size and a lower left ventricular ejection fraction (LVEF). Baseline characteristics were collected together with PBMV outcomes. QoL was assessed using the SF-36 questionnaire at baseline, and at one and six months after PBMV. The QoL assessment included eight aspects: physical functioning; role physical; bodily pain; general health; vitality; social functioning; role emotional; and mental health. The raw scale was transformed into a transformed scale from 0 (worst) to 100 (best). Physical and mental subscales were calculated. RESULTS: The cardiac rhythm was AF in 65 patients (50%). QoL on physical and mental scales was significantly improved after PBMV. There was no difference in the effect of PBMV on QoL improvement in patients with AF and SR. QoL improvement was demonstrated in all aspects, except for bodily pain. PBMV also improved NYHA functional class and mitral valve area, but decreased left atrial diameter and right ventricular systolic pressure in both groups. An increase in LVEF was observed in patients with AF CONCLUSION: PBMV was shown to improve QoL in patients with MS, irrespective of their baseline cardiac rhythm.

One-year outcome of cardioversion of atrial fibrillation in patients with mitral stenosis after percutaneous balloon mitral valvuloplasty.

Our objectives were to study the success rate of electrical cardioversion after percutaneous balloon mitral valvuloplasty (PBMV) in patients with symptomatic moderate-to-severe mitral stenosis and atrial fibrillation (AF) and the maintenance rate of sinus rhythm for < or =1 year. We studied patients with mitral stenosis and AF who were scheduled for PBMV. Electrical cardioversion was performed 1 month after PBMV. Amiodarone 200 mg/day was started the day after PBMV. The primary outcomes studied were the rate of successful cardioversion and the maintenance rate of sinus rhythm at 12 months. Of 272 patients scheduled for PBMV, 70 were enrolled. The average age was 45 +/- 10 years. The average mitral valve area was 0.82 +/- 0.22 cm(2). Cardioversion was successful in 50 patients (71%). Logistic regression analysis revealed that left atrial size and associated aortic valvular disease were predictors of successful cardioversion. Of the 50 patients with successful cardioversion, AF recurred in 24 (48%). An increased left atrial diameter was the only factor associated with AF recurrence at 12 months. In conclusion, good candidates for cardioversion after PBMV were those with a left atrial diameter of <60 mm and no associated aortic valvular disease -- approximately 43% of patients with AF scheduled for PBMV. In this group, about 2/3 were in sinus rhythm at 12 months after cardioversion.

The association of apolipoprotein B and low density lipoprotein with cardiovascular risk factors in the Thai population.

BACKGROUND: Although direct and calculated low density lipoprotein cholesterol (LDL-cholesterol) has been widely used as an important predictor for cardiovascular risk, many studies have shown that apolipoprotein B (apo B) may be a more important lipoprotein marker. MATERIAL AND METHOD: We performed a cross-sectional study on 191 volunteers who were Shinawatra employees during their annual physical check up. The following cardiovascular risk factors were recorded or measured: direct and calculated LDL, apo B, gender age, total cholesterol, triglyceride, HDL-cholesterol (HDL), calculated LDL, fasting plasma glucose (FPG), systolic and diastolic blood pressure, smoking status, body mass index (BMI), waist circumference, and waist-hip ratio (WHR). Apo B, direct LDL and calculated LDL levels were tested for their associations with other potential cardiovascular risk factors. RESULTS: There were a total of 76 men and 115 women with an average age of 28.8 +/- 5.4 years. Male gender, cigarette smoking, high cholesterol, high triglyceride, high fasting plasma glucose, hypertension, high WHR and high BMI were associated with increased apo B level. Only male gender and high cholesterol were associated with increased calculated and direct LDL level. The association of direct and calculated LDL-cholesterol level with cardiovascular risk factors appears to be similar. CONCLUSION: We demonstrated that apo B level correlates more with other cardiovascular risk factors compared to direct and calculated LDL-cholesterol. The clinical relevance of this finding needs to be explored in large-scale studies.

Effect of atenolol on symptomatic ventricular arrhythmia without structural heart disease: a randomized placebo-controlled study.

BACKGROUND: Ventricular arrhythmia (VA) from the right ventricular outflow tract (RVOT) is a common problem. Symptomatic patients are usually treated with beta-blockers. There is little data on the systematic evaluation of the efficacy of beta-blocker. We determine the efficacy of atenolol in the treatment of symtomatic VA from RVOT compared with placebo. METHODS AND RESULTS: This was a randomized, double-blinded, placebo-controlled study. We prospectively studied 52 consecutive patients with symptomatic VA. Severity of symptoms, 24-hour ambulatory monitoring (AECG) and quality of life (QOL) were assessed at baseline and 1 month after atenolol. Exercise testing was performed at baseline. Average premature ventricular complex (PVC) count at baseline was 21,407 +/- 1740 beats per 24 hours, and 19% had ventricular tachycardia as measured by AECG. Results of this study showed that atenolol significantly decreased symptom frequency (P =.03), PVC count (P =.001) and average heart rate (P <.001) measured by AECG, whereas placebo significantly decreased symptom frequency (P =.002) but had no effect on PVC count (P =.78) or average heart rate (P =.44). Neither atenolol nor placebo had an effect on QOL. CONCLUSIONS: Atenolol improves symptoms and decreases PVC count from ambulatory monitoring. Placebo improved symptoms to the same extent as atenolol but had no effect on severity of VA. This might be the so-called placebo effect, which is a concern when treating patients or doing research on the effects of a drug.

One-year outcome after radiofrequency catheter ablation of symptomatic ventricular arrhythmia from right ventricular outflow tract.

Although ventricular premature complexes (VPCs) in patients without structural heart disease are benign, many patients experience disabling symptoms. Many patients need long-term medication, which is often ineffective and may have adverse effects. Radiofrequency catheter ablation (RFCA) may be an alternative treatment. RFCA was performed in 33 patients with severely symptomatic VPCs that were refractory to medication. Mean VPCs were 23,987 +/- 2,077 beats/24 hours. Twenty-four-hour ambulatory electrocardiographic monitoring, quality of life, and symptoms were assessed at a screening visit and 1 and 12 months after RFCA. RFCA was successfully performed in 32 patients (97%). This resulted in a significant improvement in symptoms, severity of ventricular arrhythmia, and quality of life at 1 and 12 months after the procedure. There were no major complications related to the procedure. Eight patients (24%) had residual arrhythmia. Five of them underwent repeated ablation with successful results. Thus, catheter ablation is a safe and effective treatment for symptomatic ventricular arrhythmia from the right ventricular outflow tract. It also improves the quality of life. Catheter ablation is a viable alternative to drugs in the presence of disabling symptoms.

Early detection of cardiac involvement in beta-thalassemia children.

BACKGROUND: Beta-thalassemia major and beta-thalassemia/HbE are the important causes of chronic hemolytic anemia in Thailand. The objectives of the study were to determine variables associated with cardiac involvement in asymptomatic beta-thalassemia patients. PATIENTS AND METHOD: The authors studied beta-thalassemia major and beta-thalassemia/HbE patients who came to the clinic between July 1st 1999 and July 31st 2000. There were 211 asymptomatic patients included in study. Their ages ranged from 2.6 to 18.2 years. Previous clinical history including blood transfusion and iron chelation were recorded. All patients received a thorough physical examination, chest X-ray, electrocardiogram and echocardiogram. Patients who had abnormal systolic or diastolic function detected by echocardiogram were identified as having cardiac involvement. RESULTS: Cardiac involvement was found in 26 patients (12.3%). There was no difference in physical examination between patients who had and did not have cardiac involvement. Abnormal chest X-Ray defined as cardiothoracic (CT) ratio>0.55 and electrocardiogram (ECG) findings of left or right ventricular hypertrophy were associated with cardiac involvement. Other associated findings were older age and lower average pretransfusion hematocrit (23 +/- 6.6%). CONCLUSIONS: In asymptomatic beta-thalassemia children, chest X-ray and ECG should be used for screening patients for the detection of cardiac involvement.

Radiofrequency catheter ablation of ventricular tachycardia from right ventricular outflow tract.

From January 1996 to May 2002, 61 patients with ventricular tachycardia from right ventricular outflow tract were referred to Siriraj hospital. All patients underwent clinical examination, Doppler echocardiography and electrophysiologic study. Mapping of ventricular tachycardia was performed by activation mapping and pacemapping. There were 44 females and 17 males with an average age of 41.7 +/- 9.9 years. Presenting symptoms were palpitation (95.1%), presyncope (39.3%), and syncope (26.2%). Six patients were found to have underlying cardiac disease. Radiofrequency catheter ablation was successful in 56 patients (91.8%). There were no major complications. Seven patients (12.5%) had recurrent ventricular tachycardia. Five of them were successfully reablated. The authors concluded that radiofrequency ablation is an effective treatment in patients with ventricular tachycardia from right ventricular outflow tract.

A randomized clinical trial of the efficacy of radiofrequency catheter ablation and amiodarone in the treatment of symptomatic atrial fibrillation.

The limited efficacy and proarrhythmic risks of antiarrhythmia agents have resulted in alternative therapeutic approaches. Radiofrequency ablation has been reported to be an effective treatment of patients with atrial fibrillation. However, there is no randomized clinical trial comparing drug and radiofrequency ablation. The authors randomized 30 patients with chronic atrial fibrillation refractory to medication into amiodarone and radiofrequency ablation. The primary objective of this study was to compare the efficacy of amiodarone and radiofrequency ablation in the maintenance of sinus rhythm at 1 year after randomization. Pulmonary vein isolation and linear ablation of right atrium was the technique used for radiofrequency ablation. There were no significant differences in baseline patient characteristics between the 2 groups. The results of this study showed that the probability of free from atrial fibrillation was better in the radiofrequency ablation group compared to amiodarone (78.6% in the ablation group and 40% in the amiodarone group, p = 0.018). Radiofrequency ablation results in a significant reduction in symptoms relating to atrial fibrillation and a significant improvement in quality of life, whereas amiodarone had no significant effect on symptoms and quality of life. There was an ischemic stroke as a major complication related to radiofrequency ablation. Amiodarone was associated with adverse effects in 46.7 per cent of patients and needed discontinuation in 1 patient. In conclusion, radiofrequency ablation is an effective alternative treatment in patients with atrial fibrillation refractory to medication.

Accuracy of international normalized ratio determined by portable venous-blood coagulation monitor versus a central laboratory.

BACKGROUND: The CoaguChek is a portable monitor unit for measuring the international normalized ratio (INR). The purpose of the study was to evaluate the accuracy of a portable prothrombin time (PT) monitor (CoaguChek, Roche Diagnostics, Mannheim, Germany) compared with the laboratory method. MATERIAL AND METHOD: Paired venous blood INRs were performed in 220 consecutive outpatient tests mainly in anticoagulated (n = 210) and non-anticoagulated (n = 10) individuals. Accuracy was evaluated in 220 tests by parallel assessment of INRs (CoaquChek and laboratory). Accuracy was determined using statistic regression analysis and clinical agreement (expanded and narrow criteria). Agreement in dual INR measurement also was evaluated as a function of increasing INR. RESULTS: The CoaguChek significantly correlated with the laboratory measurement (r = 0.89). The proportion of dual INR measurements that satisfied the clinical relevant expanded, and narrow agreement criteria was 90 per cent and 86 per cent respectively. Eighty-two per cent of all dual measurements were within 0.5 INR units. The accuracy of the portable monitor was greatest for INR values less than 3.0; above this INR level the portable monitor overestimated laboratory INR values. CONCLUSIONS: The CoaguChek is an accurate alternative to laboratory assessment of INR at values < 3.0. The authors suggest the use of the monitor in non anticoagulated patients or anticoagulated patients at values less than 3, as most physicians in Thailand prefer lower INR than in Western countries.

Accuracy of magnetic resonance imaging in the diagnosis of coronary artery disease.

BACKGROUND: Coronary magnetic resonance angiography is a noninvasive method to visualize coronary arteries. The objective of this study was to determine the accuracy of coronary magnetic resonance imaging in the detection of coronary artery stenosis. METHOD: The authors studied 61 patients who were scheduled for their first diagnostic X-ray coronary angiography. Magnetic resonance imaging of the coronary arteries under free-breathing was performed prior to the catheterization schedule. The results were compared. RESULTS: Forty-one out of 61 patients (67.2%) had significant coronary stenosis of at least one major coronary artery. Sixteen (26.2%) had triple vessel disease. A total of 391 of 427 segments had interpretable image quality (91.6%). The diagnostic accuracy of the left main artery, left anterior descending artery, left circumflex artery, and right coronary artery was 96.7 per cent, 90 per cent, 80 per cent and 85.2 per cent respectively. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the detection of any significant coronary disease were 97.6 per cent, 75 per cent, 91.2 per cent, 90.9 per cent and 92.3 per cent respectively. CONCLUSIONS: Coronary magnetic resonance imaging is an accurate non-invasive imaging technique in the detection of coronary artery stenosis.

Transcatheter coil occlusion of small patent ductus arteriosus: experience at Siriraj Hospital.

UNLABELLED: Transcatheter coil occlusion of small-to-moderate-size patent ductus arteriosus (PDA, < 3.5 mm) is well established as a procedure of first choice in many institutions. Its much lower cost compared with surgical ligation or other devices makes it an attractive option, especially in Thailand. PATIENTS AND METHOD: Between September 1995 and June 2000, all patients diagnosed with PDA with audible murmur and echo-Doppler confirmation of diameter less than 3.5 mm were scheduled for transcatheter coil occlusion at the Department of Pediatrics, Faculty of Medicine Siriraj Hospital. The hemodynamic studies were obtained both pre and post occlusion. The immediate and late outcome, including complication were assessed. RESULTS: A total of 77 cases, 78 procedures of transcatheter PDA coil occlusion were performed. Seventy cases (90.9%), comprised of 19 males (27.1%) and 51 females (72.9%) were successfully deployed with coils. The remainder were unsuccessfully deployed and later referred to surgery. The median age of the successful group was 6 years and 6 months and median weight was 16.5 kg. Twenty cases (28.6%) had other associated intra and extracardiac anomalies. All patients were asymptomatic, except one case having bronchopulmonary dysplasia (BPD) from prolonged ventilation. Single-coil occlusions were performed in 74.3 per cent and double-coil occlusions in 25.7 per cent. Conventional 0.038-inch Gianturco coils were deployed in 86.5 per cent. The mean procedure time was 78.1 +/- 35.1 minutes. The mean fluoroscopic time was 20.2 +/- 15.6 minutes. The total complete occlusion rate was 87.7 per cent. Tiny residual flow of PDA was demonstrated by follow-up echocardiogram in 12.3 per cent. Seven per cent of the patients were lost to follow-up. There was no significant difference in PDA size and hemodynamics between the groups of patients with complete occlusion and having residual shunt. Minor complications occurred in 12.9 per cent, including mild left pulmonary artery stenosis (10%), coil embolization to distal pulmonary artery (8.6%), slippage of catheter with coil (2.9%) and decreased dorsalis pedis pulse (1.4%). One late death was found in a BPD patient from pneumonia 2 months after the procedure. CONCLUSION: Transcatheter coil occlusion of PDA is as effective, feasible, safe and less costly than surgical ligation. With improvement in technique and device selection and appropriate case selection, there should be an increase rate of complete occlusion and a decrease in complications.

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.

Cardiac magnetic resonance imaging of atrial septal defect for transcatheter closure.

BACKGROUND: The location, size of the defect and age of the patient are the major determining factors for transcatheter closure of an atrial septal defect (ASD). The precise shape and anatomy surrounding the defect cannot always be understood by the traditional transesophageal (TEE) echocardiographic technique. OBJECTIVES: The authors compared the measurement of ASD size and atrial septal rim using cardiac Magnetic Resonance Imaging (MRI) and TEE to the balloon sizing technique and device size. PATIENTS AND METHOD: Patients having an ASD which met established criteria were selected for evaluation with cardiac MRI and TEE for a closure procedure. Comparison of the ASD imaging and sizing between the different methods was made. RESULTS: There were 22 patients who had complete transcatheter closure. The mean age and standard deviation of the patients was 33.2+/-15.1 (8-67) years old. The mean weight of the patients was 51.6+/-13.1 (20-99) kg. The average cardiac MRI measurement of the ASD was 24.9+/-6.4 mm compared to the TEE measurement of 20.8+/-5.5 mm. The transcatheter balloon measurement of the ASD was 25.2+/-6.9 (11-36) mm and the device closure size was 24.8+/-6.6 (11-36) mm. The correlation coefficient of cardiac MRI to device closure size was r = 0.784 (p < 0.001) when compared to TEE measurement to device closure size; r = 0.761 (p = 0.001). CONCLUSION: The authors demonstrated the capability of the cardiac MRI in assessment of the ASD morphology and anatomy for transcatheter closure of the ASD with an Amplatzer Septal Occluder. Cardiac MRI can provide information about the type, location, size of the defect and direct visualization of the atrial septum anatomy. This detailed information enabled us to provide a safer, more effective application of the ASD occluder.

Serum N-terminal pro-brain natriuretic peptide in normal Thai subjects.

Aminoterminal portion of pro-brain natriuretic peptide (NT-proBNP) appears to be useful in the screening, diagnosis and prognosis of left ventricular dysfunction and congestive heart failure. The purpose of this study was to determine the values of serum NT-proBNP in normal Thai subjects compared with subjects from other countries. The design is a cross sectional study. The authors enrolled 243 consecutive healthy subjects (134 males and 109 females) from the checkup department of Bangkok Hospital for NT-proBNP measurement. The serum fraction was measured for NT-proBNP concentration by using Elecsys 2010 (Roche Diagnostics, Switzerland). The concentrations of NT-proBNP in normal Thai subjects were 33.30 +/- 35.43 pg/ml. The NT-proBNP levels increased with age (age < or = 50 years = 27.56 + 28.77 pg/ml and age > 50 years = 47.20 +/- 45.18 pg/ml, p < 0.001). Females usually have higher NT-proBNP than males (females = 40.42 +/- 31.59 pg/ml, males = 27.51 +/- 37.40 pg/ml, p = 0.0045). This study established the NT-proBNP concentrations in normal Thai subjects, which were not different from other studies. The authors suggested the normal cut-off values for subjects aged < or = 50 years should be 100 pg/ml and the normal cut-off values for subjects aged > 50 years should be 200 pg/ml. The NT-proBNP assay could be used as a rule out marker for heart failure in patients and may trigger further cardiac investigation.

Magnetic resonance imaging abnormalities in right ventricular outflow tract tachycardia and the prediction of radiofrequency ablation outcome.

BACKGROUND: Recent reports have shown abnormalities on cardiac magnetic resonance imaging (MRI) in patients with right ventricular outflow tract (RVOT) tachycardia. OBJECTIVES: OBJECTIVES of this study were to demonstrate abnormalities on MRI and signal-averaged ECG (SAECG) in patients with RVOT tachycardia and their correlation with the outcome of radiofrequency (RF) ablation. METHODS: We studied 41 patients with symptomatic RVOT tachycardia and 15 controls. SAECG and cardiac MRI were performed on every subject. An evaluation of structural abnormality, chamber size, function, and wall motion abnormality of the left and right ventricle was performed by MRI. Focal wall thinning was evaluated by the black blood technique and fatty infiltration was evaluated by the T1 image with and without fat suppression. RESULTS: MRI abnormalities were demonstrated in 24 (58.5%) patients with RVOT tachycardia. The abnormalities included localized wall bulging in 22 (53.7%), focal wall thinning in 10 (24.4%), and fatty replacement in 9 (22%) patients. MRI abnormality was found in only one patient in the control group (P < 0.001). Late potentials from SAECG were demonstrated in six (10.7%) patients but none in the controls (P = 0.117). Among 29 patients who underwent RF ablation, 3 patients had a failed procedure and 3 having arrhythmia recurrence needed repeated ablation. MRI abnormalities and late potentials were associated with an unfavorable outcome of RF ablation. CONCLUSIONS: MRI abnormalities were frequently found in patients with RVOT tachycardia. MRI abnormalities and late potentials can predict outcomes of RF ablation.

Electrocardiographic predictors of long-term outcomes after radiofrequency ablation in patients with right-ventricular outflow tract tachycardia.

AIMS: The objectives of this study were to identify electrocardiographic (ECG) predictors of long-term outcomes after radiofrequency (RF) ablation in patients with right-ventricular outflow tract (RVOT) tachycardia. METHODS AND RESULTS: We correlated ECG characteristics with RF ablation outcomes in 144 patients with RVOT tachycardia who underwent RF ablation for >1 year. Unfavourable RF ablation outcomes were predefined as unsuccessful RF ablation or recurrence of tachycardia requiring repeated ablation. RF ablation was not successful in 11 (7.6%) patients and 16 (12%) patients had arrhythmia recurrence requiring repeated ablation. Average follow-up time was 72.2+/-28.4 months. Selected parameters from univariate analysis included number of RF applications, pacemapping, application of bonus burn, procedure time, monophasic R-wave in lead I, QS pattern in leads I and aVL, QRS duration in leads II and V(2), and right axis deviation, in ventricular tachycardia. From logistic regression analysis, only monophasic R-wave in lead I remained in the final equation (P=0.004, odds ratio 12.9). CONCLUSION: Monophasic R-wave in lead I during RVOT tachycardia is associated with unfavourable outcomes after RF ablation. This finding may help clinicians in the selection of patients for RF ablation and for the prediction of RF ablation outcome.

Predicting fetal anemia by using reference centile charts for liver length, spleen perimeter and umbilical vein maximum flow velocity in Thai fetuses throughout gestation.

AIM: To create reference centile charts for liver length, spleen perimeter and umbilical vein maximum flow velocity (UVVmax) in Thai fetuses in order to predict fetal anemia in Thai fetuses. METHODS: The study was a prospective, cross-sectional study, carried out at the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Faculty of Medicine, Siriraj Hospital, Mahidol University. A total of 780 pregnant women between 13 and 40 weeks' gestation, who attended the antenatal clinic at Siriraj Hospital, Mahidol University, Bangkok, were recruited. Each fetus was measured only once for the purpose of this study. The mean and standard deviation (SD) were estimated at each week of gestation using linear regression modeling. A total of 752 fetuses were measured for fetal liver length, spleen perimeter and UVVmax. Linear regression models were fitted to estimate the mean 95% confidence interval for liver length, spleen perimeter and UVVmax at each gestational age. The centile charts of those parameters were also presented. CONCLUSION: Reference centile charts for fetal liver length, spleen perimeter and UVVmax of Thai fetuses were created.

Heart rate variability in patients with Brugada syndrome in Thailand.

AIMS: Since patients with Brugada syndrome usually have symptoms at nighttime, we hypothesize that changes in autonomic modulation have an important role in the occurrence of the ventricular fibrillation episodes. The objective of this study was to determine the changes in heart rate variability (HRV) in patients with Brugada syndrome compared to asymptomatic subjects with Brugada ECG and controls. METHODS AND RESULTS: We studied 17 patients with Brugada syndrome, 10 asymptomatic subjects with Brugada ECG and 45 controls. Patients with Brugada syndrome and asymptomatic subjects with Brugada ECG underwent echocardiography, exercise stress testing, 24-h Holter monitoring, signal-averaged ECG. Patients with Brugada syndrome also underwent coronary angiography and electrophysiologic study. Time domain and frequency domain HRV analysis were performed at daytime and nighttime. The results of this study showed that patients with Brugada syndrome had lower HRV or lower vagal tone at night compared to the controls. They also had lower heart rate during the day and higher during the night compared to asymptomatic subjects and the controls. CONCLUSION: Patients with Brugada syndrome had low heart rate variability at night which may predispose to the occurrence of VF episodes.