The effect of long-term use of methylphenidate on cardiac autonomic functions and ventricular arrhythmogenesis: a prospective case-control study.

OBJECTIVE: We aimed to assess cardiac autonomic balance with heart rate variability by using 24-hour Holter electrocardiography and also to assess susceptibility to ventricular arrhythmias by using microvolt T wave alternance in children with attention deficit hyperactivity disorder. METHOD: This study was conducted with age- and gender-matched groups of 40 patients taking long-acting methylphenidate for more than a year and 55 healthy controls. Heart rate variability analysis for cardiac autonomic functions and microvolt T wave alternance measurements for susceptibility to ventricular arrhythmias were evaluated by 24-hour Holter electrocardiography. RESULTS: The mean age 10.9 ± 2.7 years, mean duration of therapy 22.76 months, and mean methylphenidate doses were 37.64 mg/day. The study group had considerably higher rMSSD, higher HF, and a lower LF/HF ratio (respectively, p : 0.02, p : 0.001 and p : 0.01). While parasympathetic activity parameters were elevated, sympathetic activity parameters were low during the sleep period. Increase in the microvolt T wave alternance values of the study group was not found to be statistically significant (p > 0.05). CONCLUSION: In children taking long-acting methylphenidate, the autonomic balance was shown to be in favour of the parasympathetic system. Determination of the vulnerability to life-threatening ventricular arrhythmias has been evaluated for the first time in children with attention deficit hyperactivity disorder. Accordingly, microvolt T-wave alternance values give the notion that drug use is safe.

Piccolo in transcatheter PDA closure multi-centre study from premature to adolescent children.

In this multi-centre study, the mid- to long-term efficacy and safety of the Amplatzer Piccolo Occluder in patent ductus arteriosus closure in premature and term infants as well as children were discussed. Methods. Between 2016 and 2021, 645 patients, 152 of whom were less than 1 month old, underwent ductus closure with the Piccolo device from five different centres in Turkey. The median age of the patients was 2.2 years, and the mean narrowest point of duct diameter was 1.8 mm. Sixty-two patients weighed ≤ 1.5 kg, 90 patients 1.5-3 kg, and the mean follow-up was 20.4 months. In 396, the duct was closed by the retrograde route. Ductal anatomy was Type A in 285, C in 72, E in 171, and F in 64 patients. Fluoroscopy duration was 6.2 min. The procedure success rate was 99.1%. Device embolisation occurred in 13 patients (2%), and 11 were retrieved with a snare. Cardiac perforation and death developed in one premature baby. The left pulmonary artery and the descending aorta stenosis were observed in 3 (0.4%) and in 5 patients (0.5%). Results. Piccolo device is safe and effective in closing ductus in all age groups. It has low profile for use in premature and newborn babies, a small embolisation risk, and a low residual shunt rate after closure. Conclusion. The Piccolo device can be considered as close an ideal occluder. The lower profile, smaller delivery catheter size, and symmetry of this device allow for a venous or arterial approach.

Ductus arteriosus diameters in fetuses with early- and late-onset fetal growth restriction.

PURPOSE: Fetal growth restriction (FGR) is a common pregnancy complication that can be associated with several adverse perinatal outcomes. One of these negative outcomes is ductus arteriosus, especially in preterm babies. In this study, intrauterine heart function and ductus diameter were evaluated in babies with FGR. METHODS: Thirty-seven fetuses with FGR were compared with 37 normal-weight fetuses at the same gestational week. In our study, ventricular diameters, aorta, pulmonary artery, ductus arteriosus (DA), aortic arch diameter, and flow traces were examined. In addition, the aorta and aortic isthmus diameters were proportioned to the ductus diameter, and the left ventricular myocardial performance index (MPI) [(ICT + IRT)/ET] was evaluated. RESULTS: There was no difference in DA diameters between the patient and control groups. The intragroup comparison of the cases with early- and late-onset FGR revealed no statistically significant difference between DA diameters. However, the ratios of the aortic annulus diameter/ductus diameter (AOD/DAD) and aortic isthmus diameter/ductus diameter (AID/DAD) were significantly lower in early-onset FGR because the diameter of the DA was greater. In addition, the mod-MPI values were higher in the patient group. CONCLUSIONS: In our study, although the ductal diameters did not change significantly in the patient group, the ductal diameter was greater in the early-onset intrauterine growth restriction (FGR) group compared with other cardiac measurements. The mod-MPI value, a cardiac function indicator, was higher in fetuses with FGR. These findings may be useful for evaluating postnatal cardiac functions in FGR.

Ivabradine in a 15-day-old male neonate with refractory focal atrial tachycardia.

Ivabradine is used to reduce heart rate in children with chronic heart failure and dilated cardiomyopathy, it has recently been used off-label to treat tachyarrhythmias such as ectopic atrial tachycardia and junctional ectopic tachycardia (JET) in children. We report a successful ivabradine experience in a male neonate with refractory focal atrial tachycardia (FAT).

Blood pressure parameters affecting ventricular repolarization in obese children.

BACKGROUND: Ventricular repolarization (VR) increases the risk of sudden cardiac death due to ventricular arrhythmia. We aimed to evaluate the blood pressure (BP) parameters affecting VR in obese children. METHODS: Obese (BMI ≥ 95p) and healthy children ≥ 120 cm between January 2017 and June 2019 were included. Demographic and laboratory data, peripheral and central BPs evaluated by a device capable of ambulatory blood pressure monitoring (ABPM), and pulse wave analysis were assessed. Electrocardiographic ventricular repolarization indices, left ventricular mass index (LVMI), and relative wall thickness (RWT) were calculated. RESULTS: A total of 52 obese and 41 control patients were included. Uric acid, triglyceride, total cholesterol, LDL, and ALT values, systolic and diastolic office BPs, 24-h, daytime and nighttime systolic and mean arterial BPs, daytime diastolic BP SDS levels, daytime and nighttime systolic loads, daytime diastolic load, 24-h, daytime and nighttime central systolic and diastolic BPs, and pulse wave velocity values were significantly higher, whereas 24-h, daytime and nighttime AIx@75 were similar between the groups. fT4 levels of obese cases were significantly lower. QTcd and Tp-ed were higher in obese patients. Although RWT was higher in obese cases, LVMI values and cardiac geometry classifications were similar. The independent factors affecting VR in obese cases were younger age and higher diastolic load at night (B = - 2.83, p = 0.010; B = 0.257, p = 0.007, respectively). CONCLUSION: Obese patients have higher peripheral and central BP, arterial stiffness, and higher VR indices that develop before an increase in LVMI. It would be useful to prevent obesity from an early age and follow up nighttime diastolic load to control VR associated sudden cardiac death in obese children. A higher resolution version of the Graphical abstract is available as Supplementary information.

Complete heart block, severe right ventricular dysfunction in a child with COVID-19 infection.

A young child presented with hepatomegaly, ascites and bradycardia in the setting of COVID-19. Permanent complete atrioventricular block and severe right heart failure were diagnosed. He was treated with surgical epicardial pacemaker implantation. This report is the first description of COVID-19-induced permanent complete atrioventricular block in a child.

Evaluation of electrocardiographic markers of cardiac arrhythmic events and their correlation with cardiac iron overload in patients with ß-thalassemia major.

Iron overload is associated with an increased risk of atrial and ventricular arrhythmias. Data regarding the relationship between electrocardiographic parameters of atrial depolarisation and ventricular repolarisation with cardiac T2* MRI are scarce. Therefore, we aimed to investigate these electrocardiographic parameters and their relationship with cardiac T2* value in patients with ß-thalassemia major. In this prospective study, 52 patients with ß-thalassemia major and 52 age- and gender-matched healthy patients were included. Electrocardiographic measurements of QT, T peak to end interval, and P wave intervals were performed by one cardiologist who was blind to patients' data. All patients underwent MRI for cardiac T2* evaluation. Cardiac T2* scores less than 20 ms were considered as iron overload. P wave dispersion, QTc interval, and the dispersions of QT and QTc were significantly prolonged in ß-thalassemia major patients compared to controls. Interestingly, we found prolonged P waves, QT and T peak to end dispersions, T peak to end intervals, and increased T peak to end/QT ratios in patients with T2* greater than 20 ms. No significant correlation was observed between electrocardiographic parameters and cardiac T2* values and plasma ferritin levels. In conclusion, our study demonstrated that atrial depolarisation and ventricular repolarisation parameters are affected in ß-thalassemia major patients and that these parameters are not correlated with cardiac iron load.

Prolonged T-wave peak-end interval in Down syndrome patients with congenitally normal hearts.

BACKGROUND: Heterogeneity of ventricular repolarization has been assessed using the QT dispersion in Down syndrome (DS) patients with congenitally normal hearts. Novel repolarization indexes, that is, T-wave peak-end (Tp-e) interval and Tp-e/QT ratio, however, have not previously been evaluated in these patients. The aim of this study was therefore to evaluate the Tp-e interval and Tp-e/QT ratio in DS patients without congenital heart defects. METHODS: Tp-e interval, Tp-e dispersion, and Tp-e/QT ratio were compared between 160 DS patients and 110 age- and sex-matched healthy controls on 12-lead surface electrocardiogram. RESULTS: Heart rate, Tp-e interval, Tp-e dispersion, Tp-e/QT and Tp-e/QTc ratios were significantly higher in the DS group than the control group. CONCLUSION: Myocardial repolarization indexes in DS patients with congenitally normal hearts were found to be prolonged compared with those in normal controls. Further evaluation is warranted to elucidate the relationship between prolonged repolarization indexes and arrhythmic events in these patients.

Echocardiographic evaluation of cardiac functions in newborns of mildly preeclamptic pregnant women within postnatal 24-48 hours.

The aim of this study is to detect preeclampsia-related cardiac dysfunction within 24-48 hours of delivery in newborns born from preeclamptic mothers. Forty newborns from mildly preeclamptic mothers formed the study group and the control group was formed by 40 healthy newborns. Cardiac function for the groups were evaluated using conventional echocardiography and myocardial performance index (MPI) within the first 24-48 hours of their lifetime and the results of both groups were compared. A significant difference between the groups was observed especially in the PW Doppler MPI measurements (the left ventricle MPI 0.37 ± 0.09 and 0.26 ± 0.11, p < .001; the right ventricle MPI 0.29 ± 0.08 and 0.26 ± 0.07, p < .035) for the control group and the study group. Elongation in the left and right ventricle MPI was detected to be more significant in terms of comparing systolic and diastolic functions to determine preeclampsia-related cardiac injury in newborns from preeclamptic mothers within the first 24-48 hours of their lifetime. Impact statement Today, the methods which may detect cardiac injury earlier than conventional echocardiographic methods are used for evaluating cardiac functions. Among them, myocardial performance index (MPI) measurement with PW Doppler is the most common ones. While studies are available in the literature evaluating foetal cardiac functions with MPI in foetuses of preeclamptic women, studies evaluating cardiac functions with MPI index within the first 24-48 hours in postnatal period are not available. This is the first study to detect cardiac injury by measuring cardiac functions of the newborns of preeclamptic babies using conventional echocardiography (EF, SF, mitral and tricuspid E/A) and myocardial performance index within the first 24-48 hours of life and compare these values with those of a control group composed of healthy newborns with similar demographic characteristics. According to the results of the study, elongation in right and left ventricle MPI was detected to be more significant compared to systolic and diastolic functions for determining preeclampsia-related cardiac injury in newborns of preeclamptic mothers within 24-48 hours of delivery. Ventricle functions of the newborns of preeclamptic mothers should also be evaluated with MPI measurement besides conventional echocardiographic measurements.

Assessment of early atherosclerosis and left ventricular dysfunction in children with 21-hydroxylase deficiency.

AIM: We analysed 25 children with 21-hydroxylase deficiency who received glucocorticoid and/or mineralocorticoid treatment for at least 12 months to determine the effects of the disease and its treatment on vascular structures and ventricular function. METHODS: Twenty-five patients with 21-hydroxylase-deficient congenital adrenal hyperplasia (CAH) and 25 control subjects were enrolled into this observational, cross-sectional study. The patients were investigated in terms of fasting blood glucose and insulin; fasting serum lipid profile; serum 17-hydroxyprogesterone; dehydroepiandrosterone sulphate; androstenedione; and adrenocorticotropic hormone. M-mode tracings of the wall motion of major arteries were obtained to measure carotid intima-media thickness (cIMT), as well as elasticity and distensibility of the aorta and carotid artery. Conventional and relatively new tissue Doppler imaging techniques were employed to assess ventricular systolic and diastolic functions. RESULTS: The median age and weight of patients were 9·4 years (1·5-16·75) and 35·5 kg (7·5-76·3), respectively. The median duration of treatment was 52·2 months. Tissue Doppler imaging measurements revealed left ventricular diastolic impairment in the patient group compared to the controls. Carotid intima-media thickness, stiffness index, elastic modulus of the aorta and carotid artery were significantly higher; meanwhile, aortic distensibility and carotid distensibility were lower in the patient group, all of which indicates the presence of subclinical atherosclerosis. BMI was found to be an independent variable for cIMT (ß: 0·5, P = 0·01) and aortic stiffness index (ß: 0·52, P < 0·001). CONCLUSION: Cardiovascular function and the elastic properties of major arteries are disturbed in children and adolescents with 21-hydroxylase-deficient CAH.

Global Deformation Parameters Response to Exercise in Adolescents with Repaired Tetralogy of Fallot.

Exercise stress echocardiography is rarely used in the follow-up of children with congenital heart disease following surgical repair. There are no data on global longitudinal strain (GLS) and global circumferential strain (GCS) during exercise in adolescents with repaired tetralogy of Fallot (TOF). The purpose of this prospective study was to investigate GLS and GCS using speckle tracking two-dimensional echocardiography (2D-STE) at rest and during exercise in adolescents with repaired TOF. Twenty patients with repaired TOF and 20 controls were included. The subjects exercised on a semi-supine cycle ergometer using a two-staged 3-min step protocol of 20-40 W at 60-75 rpm. Exercise images with 2D-STE measurements were available for all 40 subjects. In the study group, the GLS values changed significantly between the baseline and third and sixth minute of exercise (-18.10 ± 2.20, -16.23 ± 4.47, -14.22 ± 2.63, respectively, p < 001). GCS did not vary significantly from baseline to end of the exercise testing (-17.49 ± 5.14, -17.15 ± 9.20, -15.66 ± 3.59, respectively, p > 0.05). There was a statistically significant difference between the Stage I longitudinal strain values of the study and control groups (-14.26 ± 9.13 and -20.22 ± 2.88, respectively, p = 0.02) but no significant difference between the Stage II values of these groups (-14.22 ± 2.63 and -15.11 ± 2.45, respectively, p > 0.05). The results revealed significant changes in GLS during exercise in patients with repaired TOF. Data gathered from deformation analysis of 2D-STE during exercise testing can enhance the ability to detect subtle ventricular dysfunction in the follow-up of children with repaired TOF.

Low Iron Stores in Otherwise Healthy Children Affect Electrocardiographic Markers of Important Cardiac Events.

Both an excess of iron and iron deficiency (ID) may lead to significant cardiac problems. Parameters that represent ventricular repolarization heterogeneity, like QT dispersion (QTd), corrected QT dispersion (QTcd), the interval between the peak and the end of the T wave (Tp-e), and Tp-e dispersion, have not been evaluated in otherwise healthy children with low iron levels before. Here we assessed the effects of low iron storage on P wave dispersion (PWd), QTd, Tp-e intervals, and Tp-e dispersion in otherwise healthy children. We prospectively reviewed 283 patients who were referred to pediatric cardiology department for cardiac evaluation due to murmurs and who were found to have no structural heart disease. The patients were divided into three groups according to their ferritin levels: Group 1: ferritin <15 ng/mL (n = 58); Group 2: ferritin 15-25 ng/mL (n = 80); Group 3: ferritin >25 ng/mL (n = 145). P wave duration (PW), QT and Tp-e intervals, and PW, QT, corrected QT (QTc), and Tp-e dispersions were significantly higher in patients whose ferritin level was <15 ng/mL. A negative correlation was found between ferritin level and QT and QTc intervals, and QT, QTc, and Tp-e dispersions. Our results showed that a low serum ferritin level is associated with changes in some ECG parameters such as prolonged PWd, Tp-e interval, QT, QTc, and Tp-e dispersions in otherwise healthy children, and studies of other populations indicated that these parameters may predict arrhythmias in selected patients. These patients may be considered at some risk of developing arrhythmias. Therefore, careful evaluation of these ECG parameters is necessary in otherwise healthy children with low iron stores.

The Impact of 3:1 Ketogenic Diet on Cardiac Repolarization Changes in Children with Refractory Seizures: A Prospective Follow-Up Study.

Background The association between ketogenic diet (KD) and prolonged QT interval, life-threatening ventricular arrhythmias, and sudden death is controversial. Aim We aimed to prospectively evaluate the effect of KD on electrocardiography (ECG) measures in children with refractory epilepsy. Method A total of 70 children with drug-resistant epilepsy who received a KD for at least 12 months were included in the study. The standard 12-lead electrocardiography was performed in all patients before the beginning and in the 12th month of KD. Heart rate, P-wave duration and dispersion, corrected QT interval and QT dispersion, and Tp-e interval were measured. Results All ECG-derived parameters, but P-wave dispersion increased after 12 months of KD compared with the baseline values. However, these changes were not statistically significant. Conclusion A 12-month long 3:1 KD treatment exerts no deleterious effect on cardiac repolarization measures.

Prolonged Tp-e Interval and Tp-e/QT Ratio in Children with Mitral Valve Prolapse.

Although it is considered to be a benign condition, previous studies have shown that a subset of patients with mitral valve prolapse (MVP) may be at risk of ventricular arrhythmia and sudden cardiac death (SCD). Previous studies have suggested that the interval between the peak and the end of the T wave (Tp-e) can be used as a marker for the transmural dispersion of repolarization. Increased Tp-e interval and Tp-e/QT ratio are associated with ventricular arrhythmias and SCD. The aim of this study was to assess alterations in ventricular repolarization by using the Tp-e interval and Tp-e/QT ratio in children with MVP and to investigate their relationships with the degree of valvular regurgitation. This study prospectively investigated 110 children with MVP and 107 age- and sex-matched healthy control subjects. Tp-e interval, Tp-e/QT ratio, and QT and QTc dispersions were measured from a 12-lead electrocardiogram and compared between groups. QT and QTc dispersions, Tp-e interval, and Tp-e/QTc ratio were found to be significantly higher in patients with MVP. A positive correlation was found between Tp-e/QTc ratio and increase in the degree of mitral regurgitation (MR) (p < 0.05; r = 0.2). However, the degree of MR was not associated with QT, QTc, or Tp-e intervals; QT, QTc, or Tp-e dispersions; or Tp-e/QT ratio (all p values >0.05). Individuals with MVP may be more prone to ventricular arrhythmias due to prolonged QTd, QTcd, and Tp-e interval and increased Tp-e/QT and Tp-e/QTc ratios. Therefore, due to their longer life expectancy, children with MVP should be followed up on regarding life-threatening arrhythmias.

A Valuable Tool in Predicting Poor Outcome due to Sepsis in Pediatric Intensive Care Unit: Tp-e/QT Ratio.

OBJECTIVE: To assess the feasibility of 12-lead electrocardiographic (ECG) measures such as P wave dispersion (PWd), QT interval, QT dispersion (QTd), Tp-e interval, Tp-e/QT and Tp-e/QTc ratio in predicting poor outcome in patients diagnosed with sepsis in pediatric intensive care unit (PICU). METHODS: Ninety-three patients diagnosed with sepsis, severe sepsis or septic shock and 103 age- and sex-matched healthy children were enrolled into the study. PWd, QT interval, QTd, Tp-e interval and Tp-e/QT, Tp-e/QTc ratios were obtained from a 12-lead electrocardiogram. RESULTS: PWd, QTd, Tp-e interval and Tp-e/QT, Tp-e/QTc ratios were significantly higher in septic patients compared with the controls. During the study period, 41 patients had died. In multivariate logistic regression analyses, only Tp-e/QT ratio was found to be an independent predictor of mortality. CONCLUSION: The ECG measurements can predict the poor outcome in patients with sepsis. The Tp-e/QT ratio may be a valuable tool in predicting mortality for patients with sepsis in the PICU.

Risk Factors for Thrombosis, Overshunting and Death in Infants after Modified Blalock-Taussig Shunt.

BACKGROUND: The Modified Blalock-Taussig shunt procedure can provide increased flow of blood to the lungs for babies born with certain congenital heart defects. We evaluated 44 subjects under 2 years of age who had a Modified Blalock-Taussig shunt (MBTS) procedure performed from 2009-2013, to investigate risk factors for thrombosis, overshunting and death. METHODS: The study subjects included in our investigation were severely cyanotic newborns with pulmonary stenosis or atresia and duct dependent circulation, and infants having Tetralogy of Fallot with small pulmonary arteries who underwent a MBTS procedure in our facility from 2009-2013. We duly noted patient preoperative characteristics such as hemoglobin, hematocrit, mean platelet volume, prothrombin time and partial thromboplastin time. Our study investigated the risk factors for post-operative overcirculation, thrombosis and death. RESULTS: The age and weight of patients in our study at the time of procedure ranged from 1 day to 20 months old (median 12 days), and 2.4 kg to 12 kg (mean 4.6 kg), respectively. A total of 8 patients died following surgery, and. 4 (9.1%) had shunt thrombosis, of which one died during shunt revision. Partial thromboplastin time was 28.7 seconds in patients with thrombosis, and 35 in all other patients (p = 0.04). Overcirculation was detected in 5 patients; shunt size/body weight was 1.25 in patients who had overcirculation, and 1.06 in all other patients. CONCLUSIONS: It is important to assess risk factors associated with the MBTS operation. The results of our study suggest that a preoperative low aPTT value may be an indicator for thrombosis in infants who have undergone MBTS surgery.

Cardiac Interventions in Pregnant Patients without Fluoroscopy.

INTRODUCTION: Cardiac interventions with fluoroscopy during pregnancy carry significant risks for the fetus. This report reviews three pregnant patients: two of them requiring pacemaker implantation and one underwent diagnostic cardiac catheterization without fluoroscopy. METHODS: The cases were performed using EnSite system (St. Jude Medical Inc., MN, USA) guidance. The necessary cardiac structure geometries were reconstructed with a deflectable quadripolar electrophysiology catheter without fluoroscopy. In two cases, pacemaker leads were connected to the EnSite system for navigation and fixation of leads. In the third case, long sheaths and electrophysiology catheters were used to access the right ventricle and pulmonary artery. Transthoracic echocardiography was also used in all three cases. RESULTS: A 31-year-old woman at 8-week pregnancy was admitted with ventricular septal defect and significant pulmonary hypertension. The patient underwent catheterization to assess for the risk of continuation of pregnancy. There was partial reactivity, it was decided not to terminate the pregnancy, and an uneventful delivery was succeeded at 35 weeks of gestation without complications. The rest of the two pregnant patients were a 28-year-old pregnant woman at 14 weeks of gestation and a 40-year-old woman at 12-week gestation. Both of them presented with symptomatic complete AV block. A single-chamber pacemaker was implanted in the first one, and a dual-chamber pacemaker was implanted in the latter. Pregnancy continued in both without complications. CONCLUSION: Successful cardiac catheterization and pacemaker implantation can be performed safely in selected pregnant patients using an electroanatomic mapping system guidance without fluoroscopy.

Does surgically induced right bundle branch block really effect ventricular function in children after ventricular septal defect closure?

In this prospective study, we aimed to assess left and right ventricular function in terms of the presence of right bundle branch block (RBBB) in the cases with repaired ventricular septal defect (VSD). Fifty-three patients who had VSD surgery at least 1-year preceding admission and 52 healthy controls were enrolled into the study. All the participants underwent electrocardiographic and echocardiographic examination. The cases with RBBB were determined. The conventional and tissue Doppler echocardiographic measurements of the patients with and without RBBB were compared with each other and healthy controls. Twenty-eight of VSD repair groups were male and 25 were female. Control group consisted of 30 males and 22 females. The mean age of the study and control groups was 7.5 ± 5.0 and 6.9 ± 4.3 years, respectively. RBBB was detected in 20 of 53 (37.7 %) operated patients. The only significant difference between the cases with and without RBBB was decreased right ventricular fractional area change (%) in the former group (33 ± 7 vs. 39 ± 5 p < 0.05). When compared to controls, operated group had statistically lower [corrected] tricuspid annular plane systolic excursion (p < 0.05), lower systolic, early diastolic, and late diastolic myocardial velocities, higher left and right ventricular myocardial performance indices, irrespective of the presence of RBBB. The ratios of mitral or tricuspid inflow to left or right ventricular myocardial in early diastolic velocities measured from lateral annular levels were increased in operated group (all p values <0.05). In conclusion, RBBB in the cases with surgical VSD repair might be associated with right ventricular dysfunction. Biventricular systolic and diastolic dysfunction may develop following VSD repair irrespective of the presence of RBBB. Tissue Doppler-derived myocardial performance indices are useful in detection of those subclinical dysfunctions.

Different haemodynamic patterns in head-up tilt test on 400 paediatric cases with unexplained syncope.

OBJECTIVE: To assess haemodynamic patterns in head-up tilt testing on 400 paediatric cases with unexplained syncope. METHODS: Medical records of 520 children who underwent head-up tilt testing in the preceding year were retrospectively evaluated, and 400 children, 264 (66%) girls and 136 (34%) boys, aged 12.6±2.6 years (median 13; range 5-18), with unexplained syncope were enrolled in the study. Age, sex, baseline heart rate, baseline blood pressure, frequency of symptoms, and/or fainting attacks were recorded. The test protocol consisted of 25 minutes of supine resting followed by 20 minutes of 70° upright positioning. Subjects were divided into nine groups according to their differing haemodynamic patterns. RESULTS: There were no statistically significant differences between the groups with regard to age, gender, baseline blood pressure, and frequency of syncope (p>0.05). The response was compatible with orthostatic intolerance in 28 cases (7.0%), postural orthostatic tachycardia syndrome in 24 cases (6.0%), asymptomatic postural orthostatic tachycardia syndrome in 26 cases (6.5%), orthostatic hypotension in seven cases (1.7%), vasovagal syncope in 38 cases (9.5%), and negative in 274 cases (69.2%). Vasovagal syncope response patterns were of type 3 in nine cases (2.2%), type 2A in 10 cases (2.5%), type 2B in two cases (0.5%), and type 1 (mixed) in 17 cases (4.25%). CONCLUSIONS: In the 400 paediatric cases with unexplained syncope, nine different haemodynamic response patterns to head-up tilt testing were discerned. Children with orthostatic intolerance syndromes are increasingly referred to hospitals because of difficulty in daily activities. Therefore, there is need for further clinical trials in these patient groups.