Gall stones in sickle cell disease in the United Kingdom

The prevalence of gall stones was studied prospectively by abdominal ultrasound examination in 131 patients with sickle cell disease aged 10-65 years. Of 95 patients with homozygous sickle cell disease, 55 (58%) had gall stones or had had a cholecystectomy. Gall stones were present in four out of 24 (17%) patients with haemoglobin S + C disease and two out of 12 (17%) with haemoglobin S beta thalassaemia. The presence of gall stones was not related to sex, geographical origin, or haematological variables and was not associated with abnormal results of liver function tests. Symptoms typical of biliary colic were reported by 32 out of 47 adult patients with gall stones, and cholecystitis or cholestasis was diagnosed in 18. Cholecystectomy was performed in 29 patients with good relief of symptoms in most cases. Postoperative complications were common, occurring in 10 of the 28 patients who could be evaluated, but not generally serious; they were considerably lessened by a preoperative exchange transfusion that reduced the haemoglobin S concentration to below 40%. It is suggested that all patients with sickle cell disease should be screened for gall stones and that elective cholecystectomy should be performed in those with symptoms or complications.

Parallel and serial processes in motion detection

Apparent motion was used to explore humans' ability to perceive the direction of motion in the visual field. A marked qualitative difference in this ability was found between short- and long-range motion. For short-range motion, the detection of the direction of motion is characterized by parallel operation over a wide visual field (that is, detection performance is independent of the number of objects in an array). When the positional displacement is large relative to an object's size, the direction of motion is detected in a serial manner. The process of detection is limited in this case by the ability to detect other events, such as appearance and disappearance of an object, and the ability to compute their spatio-temporal relations. The results are consistent with a previously suggested division of the motion detection system into short- and long-range processes. The direction of short-range motion can be perceived in parallel (preattentively), whereas long-range motion is attentive and requires more complicated computations. It seems that the detection of long-range motion is a conjunction task, combining the detection of disappearance and appearance.

Paradoxical hypertension after repair of coarctation of the aorta in children: balloon angioplasty versus surgical repair

The incidence and possible causes of paradoxical hypertension were evaluated in eight children who underwent balloon dilatation and seven children who underwent surgical repair of coarctation of the aorta. Both procedures resulted in a significant reduction in the coarctation gradient. Both systolic and diastolic blood pressures increased in the surgical group after repair, whereas systolic pressures decreased and diastolic pressures remained unchanged after balloon angioplasty. In the surgical group, but not in the balloon angioplasty group, plasma catecholamines and plasma renin activity rose during the first 2 days after relief of the coarctation. The data presented in this report support the hypothesis that the sympathetic nervous system and the renin angiotensin system are important mediators of the paradoxical hypertension that occurs after surgical repair of coarctation. Furthermore, balloon angioplasty of coarctation of the aorta does not stimulate either system and thus paradoxical hypertension is not a complication of this procedure.

Quinidine syncope in children

Quinidine syncope and factors associated with it are well known among adult patients treated for cardiac arrhythmias. To define factors that may influence the occurrence of syncope in children taking quinidine, the clinical, anatomic, electrocardiographic, roentgenographic and pharmacologic data were compared in six patients with syncope (Group A) and 22 patients without syncope (Group B). There was a significant (chi-square = 10.2, p = 0.001) relation between heart disease and quinidine syncope: all six Group A (syncopal) patients had heart disease whereas 15 of the 22 Group B (non-syncopal) patients had no structural heart disease. In contrast, no significant difference was noted between Group A and Group B patients in mean age (11.4 versus 11.4 years), mean quinidine serum concentration (2.9 versus 2.3 micrograms/ml), mean corrected QT interval before quinidine (0.43 versus 0.40 second) or mean corrected QT interval during quinidine therapy (0.46 versus 0.46 second) or between those taking digitalis and those not. Two of the six Group A (syncopal) patients died during therapy, one 6 days after initiating therapy and one suddenly at home 6 months after beginning quinidine. Another two of the six Group A patients exhibited hypokalemia (both 2.9 mEq/liter) at the time of syncope, 2 weeks and 6 months, respectively, after initiation of quinidine therapy; both survived. Syncope occurred within 8 days of initiation of quinidine therapy in three of the six patients. Sustained ventricular tachycardia was observed during quinidine associated arrhythmia in three of six patients with syncope; nonsustained ventricular tachycardia or complex ventricular ectopic activity while on this therapy was observed before syncope in the other three patients in Group A.(ABSTRACT TRUNCATED AT 250 WORDS)

Transseptal left heart catheterization as an aid in the diagnosis of cor triatriatum

A case of cor triatriatum is described in which transseptal left heart catheterization was useful in making the diagnosis by allowing easy access to the accessory chamber for pressure measurements and angiography.

Arterial repair for simple and complex forms of transposition of the great arteries

Transposition of the great arteries (TGA) has traditionally been repaired by redirection of atrial flow. Concern over the late development of right ventricular and sinus node dysfunction has prompted increased use of the arterial repair. This approach was utilized in 11 patients ranging in age from 7 days to 22 months (mean 5.3 months) and in weight from 2.6 to 12.2 kg (mean 5.1 kg). Five patients had intact ventricular septum and underwent primary repair electively or after poor response to balloon atrial septostomy. A large ventricular septal defect (VSD) was present in 6 patients, one of whom had coarctation of the aorta and one with type B interrupted aortic arch. Pulmonary artery banding was done in 3 of these patients in addition to subclavian artery aortoplasty and primary arch repair. Spontaneous VSD closure occurred in 2 banded patients. All patients had normal coronary artery distribution. Conduits were not used in any repair. There were 2 operative deaths caused by injury to the right coronary artery prior to establishing bypass in one patient and to left ventricular (LV) failure in a patient operated on at 5 months of age with an LV pressure of only one-half systemic level. The 9 surviving patients are well from 4 to 38 months after operation (mean 15 months). No patient has congestive heart failure and 5 receive no medications. Catheterization in 4 patients revealed widely patent coronaries in each. Trivial aortic insufficiency was noted in 1 patient. Each had mild to moderate supravalvar pulmonary stenosis (12 to 51 mmHg). LV function was normal in each case.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term outcome after repair of coarctation in infancy: subclavian angioplasty does not reduce the need for reoperation

To assess the influence of surgical technique on the need for reoperation after coarctation repair in infancy, follow-up data were analyzed for 125 consecutive infants (less than 12 months) who underwent repair of coarctation of the aorta by subclavian angioplasty or resection and end to end anastomosis. Sixty-three infants underwent coarctation repair by resection between 1960 and 1980, and 62 underwent subclavian angioplasty between 1977 and 1985. The mean age (+/- SEM) at operation for infants with subclavian flap angioplasty was 1.54 +/- 0.93 months and for infants with resection was 2.70 +/- 0.93 months (p = 0.02). There was no difference between the groups in patient weight at initial repair or the proportion of patients with complex anatomy or aortic arch hypoplasia. Follow-up duration for the subclavian flap group was 2.55 +/- 0.51 years (range 0.3 to 8.2), and for the resection group was 7.97 +/- 3.61 years (range 0.6 to 21). Indication for reoperation was the presence of a coarctation gradient at rest of 40 mm Hg or greater and arm hypertension. Reoperation was required in 5 patients in the subclavian flap group and 12 patients in the resection group. The mean reoperation rate after subclavian flap repair was 0.0356 reoperations per patient-year, and after resection was 0.0342 reoperations per patient-year (p = 0.94). To determine an individual's risk of requiring reoperation from these group measures, a reoperation risk model was developed. The risk of reoperation by the fifth postoperative year was found to be 16.3% after subclavian flap repair and 15.7% after resection.(ABSTRACT TRUNCATED AT 250 WORDS)

The congenital long QT syndrome. An unusual cause of childhood seizures

The congenital long QT syndrome is an unusual disorder characterized by Q-T interval prolongation on electrocardiogram that predisposes the heart to ventricular tachycardia and fibrillation. We describe herein four patients with the congenital long QT syndrome who initially presented with generalized seizures. Three of these children were initially misdiagnosed as having a primary seizure disorder. The causal relationship of complex ventricular arrhythmias to seizure activity was documented in each child. This experience emphasizes the importance of obtaining an electrocardiogram in all children with a seizure disorder of unknown origin.

Comparison of high pulse repetition frequency and continuous wave Doppler echocardiography for velocity measurement and gradient prediction in children with valvular and congenital heart disease

To compare the ability of high pulse repetition frequency and continuous wave Doppler echocardiography to detect the peak velocity of a jet flow disturbance and to predict pressure gradients accurately, two groups of children with valvular or congenital heart disease were examined using both Doppler techniques. The use study group included 84 children or adolescents (aged 1 day to 19 years) who underwent examination in the echocardiography laboratory with both Doppler techniques in a randomized sequence. The peak velocity recorded with high pulse repetition frequency Doppler echocardiography was compared with the peak velocity recorded with the continuous wave technique. The accuracy study group included 41 children or adolescents (aged 1 day to 16 years) who underwent examination with both Doppler techniques at the time of cardiac catheterization. Doppler pressure gradients were calculated from the peak velocity using the simplified Bernoulli equation and were compared with peak instantaneous gradients and peak to peak gradients measured at catheterization. In the use study, a high correlation was found between peak velocities detected by high pulse repetition frequency and continuous wave Doppler echocardiography (r = 0.94, SEE = 0.28 m/s). In the accuracy study, close correlations were found between measured peak to peak pressure gradients and pressure gradients calculated from continuous wave (r = 0.95, SEE = 7.9 mm Hg) and high pulse repetition frequency Doppler echocardiography (r = 0.94, SEE = 8.7 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Transesophageal atrial pacing: importance of the atrial-esophageal relationship

To determine the thresholds for transesophageal atrial capture, as well as factors that might influence the thresholds, the authors measured the minimal current and pulse duration required to pace the atrium through transesophageal bipolar lead systems in 32 patients during 42 trials. Mathematical modeling suggested that the current density at the posterior atrial wall was dependent upon the current delivered, the electrode distance, and, most importantly, the esophageal-atrial geometry, expressed as the distance from the esophagus to the excitable tissue. To examine this esophageal-atrial distance, 17 different patients, aged 11 months to 44 years, were studied concurrently with either computerized tomography or magnetic resonance imaging of the chest. The thresholds needed to capture the atrium from the esophagus were 13.2 +/- 3.7 mA at a pulse duration of 5.8 +/- 3.1 msec. Further, the data demonstrated that the threshold for transesophageal atrial pacing was poorly related to the patient's age or size. The fit between these data and the mathematical model suggested that the distance between the left atrial posterior wall and the esophagus was approximately 5-6 mm. Likewise, the minimal esophageal-atrial distance as measured by the two imaging techniques was equal to or less than 3.3 mm. These observations suggest that the distance (anterior-posterior dimension) between left atrial posterior wall and the esophagus is small and remains constant despite obvious changes in somatic and linear growth.

Doppler evaluation of left ventricular diastolic filling in children with systemic hypertension

To assess left ventricular (LV) diastolic function in children with systemic hypertension, 11 patients with hypertension (mean blood pressure 99 mm Hg) and 7 normal patients (mean blood pressure 78 mm Hg) underwent M-mode echocardiography and pulsed Doppler examination of the LV inflow. From a digitized trace of the LV endocardium and a simultaneous phonocardiogram, echocardiographic diastolic time intervals, peak rate of increase in LV dimension (dD/dt), and dD/dt normalized for LV end-diastolic dimension (dD/dt/D) were measured. Doppler diastolic time intervals, peak velocities at rapid filling (E velocity) and atrial contraction (A velocity), and the ratio of E and A velocities were measured. The following areas under the Doppler curve and their percent of the total area were determined: first 33% of diastole (0.33 area), first 50% of diastole, triangle under the A velocity (A area), and the triangle under the E velocity (E area). The A velocity (patients with hypertension = 0.68 +/- 0.11 m/s, normal subjects = 0.49 +/- 0.08 m/s), the 0.33 area/total area (patients with hypertension = 0.49 +/- 0.09, normal subjects = 0.58 +/- 0.08), the A area (patients with hypertension = 0.17 +/- 0.05, normal subjects = 0.12 +/- 0.03), and the A area/total area (patients with hypertension = 0.30 +/- 0.11, normal subjects = 0.20 +/- 0.07) were significantly different between groups (p less than 0.05). M-mode and Doppler time intervals, (dD/dt)/D, E velocity, and the remaining Doppler areas were not significantly different between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Response to the Valsalva maneuver after the Fontan procedure for tricuspid valve atresia, single ventricle or pulmonic valve atresia

The Valsalva maneuver was performed during cardiac catheterization in 9 patients who had undergone a Fontan operation (Fontan group) and in 10 control subjects. The Fontan group had higher right atrial (RA) pressure (16 +/- 1 vs 4 +/- 0.5 mm Hg, p less than 0.001), lower cardiac index (2.5 +/- 0.1 vs 3.7 +/- 0.2 liters/min/m2, p less than 0.05), lower stroke index (32 +/- 2 vs 44 +/- 2 ml/beat/m2, p less than 0.05), and higher systemic vascular resistance (31 +/- 1 vs 24 +/- 1 units, p less than 0.05) than the control group. Four patients in the Fontan group had a normal 4-phase Valsalva response, and 5 did not (p less than 0.05). RA pressure was similar in those who responded normally and those who did not (16 +/- 0.5 vs 17 +/- 1 mm Hg), whereas in those who responded normally cardiac index was higher (2.9 +/- 0.2 vs 2.2 +/- 0.1 liters/min/m2, p less than 0.05), stroke index was higher (36 +/- 1 vs 28 +/- 1 ml/beat/m2, p less than 0.05), and systemic vascular resistance was lower (28 +/- 1 vs 31 +/- 1, p less than 0.05). It is concluded that cardiac output is a better predictor of a normal response to the Valsalva maneuver than RA pressure in patients after the Fontan procedure. A normal response to the supine Valsalva maneuver suggests a cardiac index greater than 2.4 liters/min/m2 and stroke index greater than 31 ml/beat/m2.

Results of balloon valvuloplasty in the treatment of congenital valvar pulmonary stenosis in children

Transluminal balloon valvuloplasty was used in the treatment of congenital valvar pulmonary stenosis in 19 children, aged 5 months to 18 years. The right ventricular (RV) systolic pressure and RV outflow tract gradient decreased significantly immediately after the procedure (95 +/- 29 vs 59 +/- 14 mm Hg, p less than 0.01, and 78 +/- 27 vs 38 +/- 13 mm Hg, p less than 0.01). Seven of these patients were evaluated at cardiac catheterization 1 year after balloon valvuloplasty. No significant change occurred in RV systolic pressure or RV outflow tract gradient at follow-up evaluation compared with measurements immediately after balloon valvuloplasty (60 +/- 5 mm Hg vs 56 +/- 12 mm Hg and 39 +/- 5 vs 38 +/- 10 mm Hg). In addition, follow-up evaluation was performed using noninvasive methods and included electrocardiography (n = 13), vectorcardiography (n = 11) and Doppler echocardiography (n = 11) Doppler echocardiography in 11 patients 15 +/- 9 months after balloon valvuloplasty showed a continued beneficial effect with a mild further decrease in RV outflow tract gradient. Thus, balloon valvuloplasty is effective in the relief of pulmonary stenosis.

Use of the pill electrode for transesophageal atrial pacing

The pill electrode, which was developed for esophageal electrocardiography, has found application in transesophageal atrial pacing during procedures such as conversion of tachycardia, electrophysiologic measurement, and acceleration of heart rate to produce stress during cardiac imaging studies. This paper presents theoretical studies that examine the relationship of interelectrode distance, current level, and pulse duration to the achievement of successful capture. Theoretical results agree with our clinical findings, i.e., current levels of 25 mA are effective to sustain capture; increased pulse duration reduces current requirements; and close bipolar spacing combines efficacy with safety. Results of animal studies performed to assess the extent of esophageal burn injury reveal that current levels in excess of 75 mA are required to produce lesions in short-term (under 30 minutes) pacing, and greater than 60 mA in long-term (4 hours) pacing. These results are based on experiments using a pulse duration of 2 ms, and the current levels that produce injury will be considerably lower if longer pulse durations are used. Typical current levels and pulse durations for successful capture are presented for 46 subjects in several new clinical applications. Termination of tachycardia, basic electrophysiologic measurements, and controlled acceleration of heart rate can be performed noninvasively with this technique.

Variant thyroxine-binding globulin in serum of Australian aborigines: its physical, chemical and biological properties

Low serum total thyroxine (TT4) and triiodothyronine (TT3) is found in approximately 40% of Australian Aborigines. Studies were carried out to characterize the properties of thyroxine-binding globulin (TBG) in these Australian Aborigines to explain the observed reduction of thyroid hormone concentration in their serum. TBG from Aborigines with low serum TT4 concentrations was compared to TBG from Aborigines with normal TT4 concentration and Caucasians and American Blacks with normal or reduced serum TBG levels due to familial partial TBG deficiency. TBG from Aborigines with low serum TT4 concentrations had a reduced affinity for thyroid hormone (Ka). The Ka for T4 was 54% and for T3 30% of the Ka values for TBG from Aborigines with normal TT4 concentration or non-Aborigines. Maximal binding values were in agreement with TBG measurements by RIA for Aborigines with low or normal serum TT4 and for non-Aborigines. An increase in the rate of heat denaturation of TBG at temperatures from 54 to 60 C was also observed in sera from Aborigines with low TT4. The heat lability was lowered by 2 C. The low concentration of TT4 in serum of these Aborigines could not explain this higher heat lability of TBG since only addition of greater than 80-fold the physiologic T4 concentration obliterated the difference of heat inactivation by denaturation.(ABSTRACT TRUNCATED AT 250 WORDS)

Variant thyroxine-binding globulin in serum of Australian aborigines: a comparison with familial TBG deficiency in Caucasians and American blacks

About 40% of clinically euthyroid Australian Aborigines have low concentrations of total thyroxine (TT4) and triiodothyronine (TT3) in serum. While the finding of normal concentrations of serum thyrotropin (TSH) in such individuals is compatible with their eumetabolic state, the reason for the finding of a low free T4 index (FT4I) has been unclear. A genetic variant of T4-binding globulin (TBG) with reduced affinity for T4 has been suggested but decrease in the absolute concentration of TBG has also been reported. In this study, we measured various parameters of thyroid function in 20 serum samples from euthyroid Australian Aborigines selected for their low TT4 levels. Results were compared to those obtained in serum samples from Caucasians and American Blacks with inherited partial TBG deficiency, 15 of which were matched to the Aborigines by their TBG and 20 by their TT4 concentrations. Results were also compared with those from another group of 20 samples from Caucasians and American Blacks with normal TBG concentration, matched to the Aborigines by their serum TT4 concentration. TBG in serum from these Australian Aborigines was immunologically identical to that in Caucasians and American Blacks in terms of parallelism of serially diluted samples in the TBG radioimmunoassay (RIA).(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic determinants of exercise-induced ST-segment depression in children with valvar aortic stenosis

To evaluate the hemodynamic factors associated with treadmill-induced ST-segment depression in children with valvar aortic stenosis, 12 patients (mean age 13 years) with ST-segment depression during treadmill exercise and 5 patients (mean age 13 years) without ST-segment depression during treadmill exercise underwent exercise testing during cardiac catheterization. The left ventricular (LV) systolic pressure and LV outflow tract gradient at rest (177 +/- 25 vs 138 +/- 8 mm Hg and 59 +/- 18 vs 23 +/- 7 mm Hg, respectively) and corresponding pressures during maximal supine exercise (248 +/- 37 vs 189 +/- 17 mm Hg and 112 +/- 34 vs 52 +/- 14 mm Hg) were significantly greater (p less than 0.01) in the patients with exercise-induced ST-segment depression, although overlap existed. The LV-O2 supply-demand ratio during maximal supine exercise was significantly less (6.4 +/- 2.7 vs 11.8 +/- 0.7; p less than 0.005) in patients with than in those without exercise-induced ST-segment depression. In fact, an LV-O2 supply-demand ratio less than 11.0 was 100% sensitive and specific in predicting treadmill-induced ST-segment depression. These results suggest that although the development of ST-segment depression during treadmill exercise is related to LV systolic pressure and LV outflow gradient, its major hemodynamic determinant is the LV-O2 supply-demand ratio.

Atrial overdrive pacing for conversion of atrial flutter in children

Twenty-three successive patients with 27 different episodes of sustained atrial flutter were treated with atrial pacing for conversion of the tachyarrhythmia; 15 patients with 16 episodes of atrial flutter underwent intracardiac right atrial pacing and eight patients with 11 episodes of atrial flutter were treated with transesophageal atrial pacing. Ten of sixteen episodes (63%) and eight of 11 episodes (73%) were successfully converted using intracardiac and transesophageal techniques, respectively. Mean flutter cycle length for all 27 episodes was 219 ms (mean heart rate 274 beats per minute); successful pacing conversion cycle length (n = 15) was 72% of the flutter cycle length. Hemodynamic, electrophysiologic, and roentgenographic data were not predictive of conversion by either technique. Induction of localized atrial fibrillation or failure to meet critical pacing criteria may explain pacing failures. Based on this experience, a trial of transesophageal atrial pacing for acute conversion of any episode of atrial flutter in children prior to direct current cardioversion is recommended.

Two-dimensional and M-mode echocardiographic evaluation of fetal arrhythmia

Cardiac anatomy and rhythm were evaluated in the fetuses of 18 pregnant women (between 20 and 42 weeks of gestation) referred because of abnormal fetal heart rate or rhythm. Utilizing a 3 MHz two-dimensional scan head with M-mode capability, M-mode recordings were obtained at paper speeds of 50 and 100 mm/s from 16 fetuses. The arrhythmia of two fetuses was diagnosed using two-dimensional echo alone. Semilunar and atrioventricular valve opening and closing points, A waves, plus ventricular wall motion were used for timing purposes; and heart rate and rhythm were determined. Diagnoses made were atrial premature beats n = 3, ventricular premature beats n = 3, congenital heart block n = 4, supraventricular tachycardia n = 3, sinus bradycardia n = 1, and blocked atrial beats n = 1. In three fetuses no arrhythmia was identified. Cardiac anatomy was normal in 16 fetuses, with two (congenital heart block) felt to have univentricular hearts. Fourteen pregnancies went to term, two were delivered prematurely, and two fetuses with congenital heart block were stillborn. In three fetuses arrhythmia was confirmed during labor by fetal scalp electrode. Arrhythmia was absent after birth in 11 of 16 infants, with congenital heart block persistent in two infants, and supraventricular tachycardia, atrial premature beats, and blocked atrial premature beats remaining in one each. Intervention with medical management was attempted in four pregnancies, with successful termination of arrhythmia supraventricular tachycardia) in two fetuses. We conclude that combined two-dimensional M-mode capability is useful in the diagnosis of fetal rhythm disturbances, and perhaps in the selection of timing, and mode of intervention.

Advances in the management of cardiac arrhythmias in children

The authors discuss several recent developments in the diagnosis and management of cardiac arrhythmias in the young, focusing on areas in which the greatest progress has been made so that the pediatrician can incorporate these developments into his practice and participate more fully in the management of the patient requiring tertiary care.

Use of balloon angioplasty to treat peripheral pulmonary stenosis

Balloon angioplasty was attempted in 13 children with peripheral pulmonary arterial (PA) stenosis. In 5 patients, angioplasty was successful in relieving the peripheral PA stenosis as judged by an increase in PA size of more than 75% over the predilatation size and a more than 50% reduction in the distal PA to main PA peak systolic pressure gradient. Each child has been followed for 6 to 30 months. All remain well, without signs of subsequent deterioration, and follow-up angiograms in 2 patients (at 10 and 12 months) showed persistence of anatomic and hemodynamic improvement. In 8 patients, angioplasty was unsuccessful: In 4 patients, stenosis at the site of a previous systemic-to-PA shunt could not be dilated and in 4 patients, angioplasty could not be performed because of technical difficulties. Thus, we could not dilate the stenosis in more than 60% of the patients; we also had a significant complication with the angioplasty procedure (perforation of a distal branch of the right pulmonary artery). Thus, although balloon angioplasty was not effective in all patients, it did provide significant improvement in some patients in whom traditional operative management is usually unsuccessful.