Atrial tachycardia from enhanced automaticity in children: diagnosis and initial management.

Ten patients (aged 0-9 years) with the diagnosis of automatic atrial tachycardia (AAT) from August 1997 to August 2000 were reviewed. Three patients had paroxysmal (repetitive) AAT and the tachycardia was incessant in six (defined as presence of AAT for more than 90% of the time). The type of AAT in one patient was unknown. Four patients presented with congestive heart failure (CHF), one with pre-syncope, one with palpitation, and four were asymptomatic. Six patients (60%) had depressed left ventricular ejection fraction. All patients with CHF had incessant AAT with atrial rate > 220/min and ventricular rate > 200/min at admission. After treatment with antiarrhythmic medications, all patients had adequate control of the AAT (9 had complete elimination of AAT and 1 partial control). Amiodarone (alone, or in combination with digoxin) was effective in 5 of 6 cases (83%), although complete elimination of the AAT was usually delayed (median = 5 days, range 30 minutes to 17 days). Other effective medications were digoxin, digoxin + propranolol and atenolol (all in patients who did not have CHF on presentation). At the time of this report, 3 patients had no AAT off antiarrhythmic medication, 5 patients were still receiving treatment (with good control) and 2 patients died from sepsis during the same admission even though AAT was controlled. All surviving patients had normal ventricular ejection fraction on follow-up. AAT in children is rare, but when it occurs in persistent form at a fast rate, it is usually associated with CHF and is difficult to treat. Amiodarone (+/- digoxin) effectively controls the arrhythmia in the majority of cases, although full effect may take several days. With successful treatment, most patients do well and some can be taken off the medication(s) without recurrence of the arrhythmia.

Complete heart block in children at King Chulalongkorn Memorial Hospital.

The etiologies of complete heart block in thirty-one children (mean age 5.5 +/- 5.2 years, range 0-14 years) diagnosed at King Chulalongkorn Memorial Hospital between 1990-2001 were reviewed. Three main groups of patients were identified: 1) patients who presented in utero or in the newborn period (congenital heart block, n = 6), 2) patients who had complete heart block after cardiac surgery (postoperative heart block, n = 10), and 3) children outside the newborn period with a new diagnosis of complete heart block unrelated to cardiac surgery (unknown etiology, n = 15). Among 15 patients in the last group, 5 were asymptomatic (or minimally symptomatic) with complete heart block unexpectedly found. These patients probably had previously undetected congenital heart block. Two patients had complete heart block associated with mild viral illness, but no bradycardia-related symptom. The etiology for heart block in these 2 patients was unknown. Eight patients probably had recent onset heart block because of new bradycardia-related symptoms, or a previously documented normal heart rate. All patients in this group were female (mean age 4.3 +/- 4.3 years, median 3.5 years). All were diagnosed between August and January, and the majority (75%) had a history of non-specific viral illness in the preceding 2 weeks. Seven patients (87.5%) were acutely symptomatic. Syncope and/or seizure were the most common presenting symptoms. Left ventricular systolic dysfunction was found in only one patient. The etiology of complete heart block in these patients probably was an acute viral myocarditis that preferentially affected the conduction system. Two of these eight patients had complete recovery of the atrioventricular conduction. The rest had no improvement or had only partial recovery and subsequently underwent permanent cardiac pacemaker insertion.

Morbitz type I second degree AV block during recovery from dengue hemorrhagic fever.

Two patients with serologically-proven dengue virus infection and Morbitz type I second degree atrioventricular (AV) block are described. A 7 years old boy (patient 1) with grade 2 and a 7 years old girl (patient 2) with grade 3 illness were admitted to the hospital on the 3rd and the 5th day of the illness, respectively. Both had typical resentation for dengue hemorrhagic fever including fever, hepatomegaly, thrombocytopenia and signs of extravascular leakage. The 7 year old girl also had epistaxis and anemia (Hct 24%). Morbitz type I second degree and 2:1 AV block developed on day 7 (patient 1) and day 8 (patient 2) of the illness, both during recovery periods. Patient 1 also had occasional monomorphic premature ventricular contraction (PVC). There was no other abnormality in the 12-lead EKGS and echocardiograms showed normal ventricular systolic function in both. Other than mild hypokalemia (3.3 and 3.4 mgq/l), serum electrolytes were normal. Neither patients had elevation of serum creatine phosphokinase (CPK). In patient 1, exercise (on day 10) normalized AV conduction and abolished the PVC. Follow up EKG and physical examination at 10 months after the illness was normal. The rhythm in patient 2 resolved to 1st degree AV block (with occasional morbitz type I second degree at night) on day 12. In this patient, exercise resulted in shortening of the PR interval and Valsalva maneuver resulted in further PR prolongation. The patient was well at 1-month follow up with a mormal EKG. Morbitz type I second degree AV block during recovery from dengue hemorrhagic fever may be a transient functional impairment of the AV node, in which altered autonomic tone may play a role.

Dengue infection with central nervous system manifestations.

A prospective observational study was conducted over a seven years period to determine the clinical and laboratory findings of dengue patients with central nervous system manifestations. Thirty serologically confirmed dengue infected patients with central nervous system manifestations were seen at the Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok and at Songkhla Hospital, Songkhla, Thailand. The age ranged between 3 months and 14 years with a mean age of 6.2 years. Seventeen were boys and thirteen were girls. The central nervous system manifestations included alteration of consciousness 76.7%, seizures 63.3%, pyramidal tract signs 36.7%, meningeal signs 30% and headache 26.7%. Eleven patients had primary while 19 had secondary dengue infection. Cerebrospinal fluid examination showed lymphocytic pleocytosis in 6 out of 28 patients while presence of anti-dengue IgM antibodies was detected in 2 out of 19 specimens of cerebrospinal fluid tested. Two patients died, autopsy was done on one patient and examination of the brain was compatible with viral encephalitis.

Transcatheter coil occlusion of patent ductus arteriosus.

Between May 1995 and October 1997, 17 cases of small patent ductus arteriosus (PDA) underwent percutaneous coil occlusion at the Department of Pediatrics, Chulalongkorn Hospital. The mean age was 5.3 +/- 3.6 years (range, 1 year 4 months to 12.0 years); mean weight was 18.9 +/- 11.7 kg (range, 9 to 48 kg). The mean minimum diameter of the PDA was 2.8 +/- 0.6 mm (range, 1.7 to 4.0 mm). PDA occlusion was achieved with one coil in 9 patients and two coils in 8 patients. One patient required the second coil occlusion procedure to occlude the residual PDA leakage. Of the 17 patients, coils were successfully implanted in 15 patients: complete closure of PDA was obtained in 14 patients, confirmed by aortography or by color flow echo imaging or both. In the two unsuccessful coil implantation cases, coils migrated to the distal left pulmonary artery (1 case) and the distal right pulmonary artery (1 case). They could not be retrieved. Both patients had surgical closure of PDA on the following day after the failed procedure. No clinical and chest X-ray showed any evidence of pulmonary complication from the migrated coils up to 1-year follow-up. PDA coil occlusion provides an alternative to surgical closure. The procedure is safe and has a good result.

Cardiovascular manifestations and left ventricular functions in human immunodeficiency virus infection in infants and children in Thailand.

During January through December 1993, twelve symptomatic infants and children (6 females, 6 males) with human immunodeficiency virus infection were prospectively evaluated for their cardiovascular clinical manifestations and ventricular functions, using two-dimensional, M-mode and Doppler echocardiographic examination. From auscultation, the pulmonic component of the second heart sound was accentuated in 8 cases and the murmur of atrioventricula valve regurgitation and pericardial friction rub were audible in 7 and 6 patients, respectively. Cardiomegaly and venous congestion were present on chest roentgenogram in 6 cases and electrocardiogram was abnormal in 5. The echocardiogram demonstrated elevated pulmonary arterial pressure in 9 patients. There were 5 cases of non-tamponade pericardial effusion. Five patients had mitral and pulmonary insufficiency while six had tricuspid insufficiency. The ejection fraction and shortening fraction were increased in all. The incidence of pulmonary hypertension was more frequent than previously reported.

Ventricular functions in children with human immunodeficiency virus infection after ACE-inhibitors.

Nine pediatric symptomatic patients infected with human immunodeficiency virus with elevated pulmonary arterial pressure (MPA pressure) and ejection fraction (EF); and with fractional shortening, (FS) mean velocity of circumferential fiber shortening (MVCfc) and left ventricular peak systolic wall stress (PS) were prospectively evaluated using 2-dimensional and M-mode serial echocardiography and Doppler cardiography after administration of an ACE inhibitor (Inhibace 0.025 mg/kg/D orally) for 12 weeks. The MPA pressure was not decreased, however the MVCfc and PS improved significantly (p < 0.05). Further, long term evaluation is required to determine its effect in preventing dilated cardiomyopathy and elevated mean pulmonary pressure.

Dengue infection with unusual manifestations.

In 1987, 505 serologically confirmed dengue infection patients were admitted to the Department of Pediatrics, Chulalongkorn Hospital, Bangkok, Thailand. Fourteen patients had unusual manifestations which were mostly encephalopathic and hepatopathic. Patients who had unusual manifestations tended to be in the younger age group and had higher mortality.

Cardiac dysfunction in beta-thalassemic children.

The biventricular systolic function was evaluated by M mode and Doppler echocardiography in 16 patients with homozygous beta-thalassemia and beta-thalassemia Hb E disease, aged 5-14 yrs (9.9 +/- 2.4 yr). The left ventricular end-diastolic dimension and left ventricular mass were increased in 88 per cent of the patients. Left ventricular fractional shortening and cardiac index were normal in all but one patient. Fifteen patients had evidence of pulmonary artery hypertension manifested by abnormality in the ratio of right ventricular acceleration time to ejection time (AT/ET). There was good correlation between platelets count and AT/ET (r = -0.70, P = 0.002). Thrombocytosis was noted in 4 patients. Our findings indicated that in beta-thalassemic children, right ventricular dysfunction was detected earlier than left ventricular dysfunction and platelets may play a role in the pathogenesis of pulmonary artery hypertension.

Doppler echocardiographic predictions of pulmonary artery pressure in children with congenital heart disease.

Continuous wave Doppler echocardiography was used to examine the accuracy of predictions of pulmonary artery pressure by means of main pulmonary artery flow velocity in children with congenital heart disease, without pulmonary stenosis. The ratio of acceleration time to ejection time (AT/ET) was correlated to catheterized mean pulmonary artery pressure. The result was: mean pulmonary pressure equal to 120-2.4 (AT/ET x 100), r = 0.92, SEE = 7.9 mmHg, P value less than 10(-6). We then used this equation prospectively to predict mean pulmonary artery pressure in 20 children. The result was: catheterized mean pulmonary artery pressure equal to 0.9 predicted pressure minus 0.3, r = 0.94, SEE = 4.8 mmHg, 95 per cent confidence limit interval of X coefficient was 0.8 to 1.2. This result suggested that continuous wave Doppler predictions of pulmonary artery pressure correlate significantly with values subsequently obtained at catheterization.

Aeromonas infection following a snake bite: a case report.

A twelve year-old Thai boy with fulminating Aeromonas hydrophila infection of the right arm following a snake bite was reported. He recovered uneventfully after appropriate antimicrobial therapy and surgical intervention.