European Study on Maternal and Fetal Management of Fetal Supraventricular Tachyarrhythmia:Proposed Protocol for an International Project

> Objectives: This European protocol is designed to estimate the efficacy of transplacental digoxin administered intravenously to the mother in sustained fetal supraventricular tachyarrhythmias (FSVT) with or without cardiac failure and in intermittent runs of FSVT with cardiac failure. The natural history of FSVT is evaluated in self-limited runs of FSVT without cardiac failure. Study structure: The fetal criteria for inclusion in the study are: gestational age <35 weeks, a normal cardiac anatomy, no severe extracardiac anomalies and a heart rate of the FSVT >200 beats/min. The maternal criteria include no prior treatment with digoxin or drugs effecting fetal heart rate and hemodynamics, and no contraindication to digoxin. Doppler fetal echocardiography is utilized for the diagnosis of the type of FSVT, sequential evaluation, and assessment of fetal hemodynamics. Fetuses are assigned two groups: Group I includes all fetuses with sustained FSVT and those with intermittent runs and cardiac failure; Group II comprises fetuses with intermittent runs and no cardiac failure. Fetuses in Group I will be treated. Group II will receive no treatment initially and will be observed. Treatment is based on a acute loading phase with digoxin administered intravenously to the mother for a period of 7 days. Doses are adjusted to through levels of maternal digoxin, maternal clinical condition, and electrocardiogram. If sinus rhythm is obtained, a maintenance phase follows with oral digoxin. Another drug, according to local experience and preference, is added to oral digoxin if digoxin intravenously fails to restore sinus rhythm and gestational age is <36 weeks. Post natal outcome will be followed by sequential clinical and Holter examinations. The data collected will be reviewed in a blinded fashion. The collection of the data for the protocol requires extensive information on the maternal, fetal, and long-term follow-up studies. They are detailed in the Appendix section. Expected results: We propose to obstetricians and pediatric cardiologists involved in fetal cardiology a rationale for the management and treatment of FSVT. Our expectation is to obtain a controlled study on a large number of cases at an international scale and thus provide a homogeneous maternal and fetal therapeutic strategy for FSVT.

Value of Doppler ultrasound for the diagnosis of renal artery stenosis in children.

To evaluate the reliability of Doppler ultrasonography (US) in identifying children with renal artery stenosis (RAS) among those with hypertension, we compared Doppler US results in 22 hypertensive children (mean age 8.9 +/- 4.3 years), with (13 cases) and without RAS at angiography, and in 33 normotensive children (mean age 8.8 +/- 4.7 years). We observed 2 false-negatives and 2 false-positives with Doppler US. Of the 2 false-negative diagnoses, I had RAS on an accessory renal artery located behind a normal upper polar artery and the other was observed in a patient with bilateral multiple stenosis of the very distal segments of renal arteries. The 2 false-positive diagnoses were due to sinuous left renal artery and to technical reasons, respectively. In another patient, Doppler US showed a tight RAS, while arteriography was normal. RAS was subsequently confirmed by a second arteriography. Peak systolic velocity values of Doppler US were significantly higher in patients with proven angiographic RAS (3.44 +/- 0.66 m/s) than in hypertensive patients with normal renal arteries at angiography (0.99 +/- 0.35 m/s, P < 0.0001) and normotensive healthy children (1.04 +/- 0.23 m/s, P < 0.0001). With the use of multiple views, and the experience acquired with practice, false-negatives or false-positives due to the geometry of the renal artery can be avoided. Nevertheless, very distal stenosis can be missed by Doppler US.

Constriction of the fetal ductus arteriosus during prenatal betamethasone therapy.

BACKGROUND: Constriction of the fetal ductus arteriosus occurs with maternal indomethacin treatment and has been suggested with corticosteroid therapy as well. CASE: Fetal ductal constriction was diagnosed by Doppler echocardiography at 29 weeks' gestation after a third and fourth course of betamethasone was administered to a pregnant woman with placenta previa. Doppler echocardiography showed a patent ductus arteriosus 3 days after the treatment. CONCLUSION: The risk-benefit ratio of betamethasone should be assessed by large-scale studies when repeated courses or chronic maternal administration of betamethasone are required.

[Aptitude to physical effort in children with operated tetralogy of Fallot]. / Aptitude à l'effort physique des tétralogies de Fallot opérées.

BACKGROUND: Long-term follow-up of patients after total surgical correction of tetralogy of Fallot indicates that they have a smaller working capacity than controls, with an increased incidence of late onset complete heart block and sudden death. These abnormalities may be less frequent when surgery is undertaken at an early age. POPULATION AND METHODS: A cardio-pulmonary stress test was performed on 18 patients aged 8 to 20 years who had undergone correction of tetralogy of Fallot when they were 3 months to 7 years (mean age: 3 years). The basic ventilatory tests, exercise ventilatory tests and gas exchange were also performed. RESULTS: The cardiopulmonary stress test was maximal in 16 of the 18 cases. No stress-induced PVCs, or chronotropic insufficiency was found despite a basic long PR interval in 4 cases. A restrictive ventilatory syndrome was seen in 4 cases with low respiratory reserve at exercise (defined as the ratio between maximal observed ventilation and maximal theoretical ventilation, VEMS x 40). The respiratory function was normal in 14 cases with an aerobic capacity of over 40 ml/kg/min. CONCLUSION: Patients with a normal chronotropic function and preserved aerobic capacity show no post-operative restriction or cardiac of pulmonary exercise capacity.

Clinical and pharmacologic study of fetal supraventricular tachyarrhythmias.

The purpose of this study was to evaluate the efficacy of maternal digoxin administration in 16 cases of fetal supraventricular tachyarrhythmia diagnosed by fetal echocardiography; cardiac anatomy was normal in all cases. The retrospective analysis included nine mothers who received digoxin orally in most cases, with control of the arrhythmia in two fetuses. The addition of amiodarone (five cases) and propranolol (two cases) yielded two successes with amiodarone. The therapeutic regimen of digoxin was then modified on the basis of poor response to orally administered digoxin. In the prospective study, digoxin was administered intravenously to seven mothers according to a standard protocol; high doses (1 to 2 mg intravenously) were prescribed for the first 24 hours and intravenous digoxin therapy was maintained for at least 5 days, depending on the fetal response. Digoxin pharmacokinetic studies of four mothers showed an increased plasma clearance and reduced elimination half-life. Digoxin controlled the five supraventricular tachycardias (with hydrops in four cases). Maternal flecainide therapy restored sinus rhythm in two cases of atrial flutter. Our prospective study emphasizes the efficacy and safety for the fetus and the mother of intravenously administered digoxin as a first-choice drug in the treatment of supraventricular tachyarrhythmias. Flecainide may be a promising second-choice drug but requires further clinical investigation. Amiodarone and propranolol seem to be ineffective.

Mathematical modeling of the human fetal arterial blood circulation.

A mathematical model of the human fetal arterial circulation based on mass and momentum conservation for one-dimensional flow is presented. We simplified the fetal arterial vascular system from the heart to the placenta, defined 16 anatomical segments and studied the characteristics of the vascular system in relation to changes in morphology and hemodynamics. The two-step Lax-Wendroff finite difference scheme was used to solve the system of equations, after introducing the rheological constants, the diameter and length of the segments measured by two-dimensional imaging and the mean arterial velocity at the inlet segments obtained by pulsed Doppler. The model was validated by comparing the numerical results to our non-invasive ultrasound direct measurements and to previous published data.

[Ambulatory blood pressure measurement in children and adolescents with kidney transplants]. / Ambulante Blutdruckmessung bei nierentransplantierten Kindern und Jugendlichen.

Arterial hypertension (HT) is a common complication after renal transplantation. We evaluated ambulatory blood pressure profiles during 24 h in 30 pediatric patients (pts) aged 6-22 years who had been transplanted 2 months to 7 years previously. Creatinine clearance was 14-121 (median 57) ml/min/1.73 m2. Twenty-three pts were being treated with ciclosporin. Sixteen pts received antihypertensive drugs. Using the monitor Nippon Collins 630 (Baxter), blood-pressure (BP) values were taken every 20 min during the day and overnight (10 p.m.-7 a.m.). Five out of 10 pts with elevated office BP readings were normotensive by ambulatory blood pressure monitoring (ABPM). Ambulatory hypertension was discovered in one child with normal office BP. Echocardiography was performed in 23 pts. Five of six pts with significant left-ventricular hypertrophy (LVH), but none of the 17 pts without LVH had ambulatory HT (p less than 0.01). The physiological decline of BP during the night was significantly reduced when compared to 21 subjects of similar age with essential HT (-9.2% vs. -15.4%; p less than 0.02); no correlation was found with renal function or prednisone dose. Ciclosporin tended to reduce the day-night gradient (-14.5% vs. -9.2%; p = 0.11). One child showed a severe nocturnal BP rise of 25 mmHg. We conclude that abnormalities of nyctohemeral BP rhythm, as described in transplanted adults, can be observed to a lesser extent in children. ABPM allows a better evaluation of BP compared to office BP and, thus, may contribute to a better management of these patients.

M-mode and two-dimensional echocardiography in the routine follow-up of central venous catheters in children receiving total parenteral nutrition.

A retrospective study in 38 children (1 day to 7 years) on total parenteral nutrition (TPN) (1 month-24 months) with a central venous catheter (CVC) evaluated the contribution of two-dimensional echocardiography (2D) and M-mode in the follow-up of CVC location and early diagnosis of related complications. Fifty examinations were performed routinely in 21 patients (group I) and 40 in 17 patients for sepsis of the CVC or clinical suspicion of thrombosis (group II). The tip of the CVC was located in the upper right atrium in 17 cases (45%), superior vena cava in 14 cases (37%), jugular or subclavian vein in 5 cases (13%), and was not visualized in 2 cases (15%). In group I, 2D was normal in 19 cases, and catheter thrombosis suspected in 2 was not confirmed by digital angiography (DA). In group II, 2D was normal in 11 cases. In 6 patients, subxiphoid and suprasternal planes identified superior vena cava thrombus in the right atrium (DA confirmed the diagnosis in 2). In 2 pulmonary embolism occurred (1 case died); the remaining patients were successfully treated by medical therapy and removal of the catheter. Echocardiography is a useful noninvasive technique to control CVC tip location and follow-up. In this study, the sensitivity of cardiac thrombus detection by echocardiography was 100% and the specificity 93%; this method appeared, therefore, appropriate for early detection of cardiac thrombosis in pediatric patients on TPN.

[Value of ambulatory blood pressure monitoring in borderline hypertension in the child]. / Apport de la mesure de la pression artérielle ambulatoire dans l'hypertension artérielle limite de l'enfant.

This study was undertaken to evaluate the reliability of ambulatory blood pressure monitoring (ABPM) in children and its diagnostic value in teenagers with borderline hypertension. The apparatus used was a Nippon Colin (NC) ABPM 630 which simultaneously obtains BP levels by the auscultatory and oscillometric methods. Among 61 children (mean age 12 +/- 3 years), proportion of measurement failures was 14% (470/3399) for oscillometry, 26.5% (893/3360) for auscultation, and 2.7% for both methods together. Comparison of conventional auscultatory blood pressure measurements (mercury manometer) and simultaneous NC-auscultatory BP values (50 pairs) showed slightly lower diastolic blood pressure values with the NC monitor (-3.8 +/- 4.9 mmHg, p less than 0.01). Comparison of blood pressure values provided by the two NC methods (1580 pairs) demonstrated slightly higher systolic blood pressure values (+2.5 +/- 4 mmHg; p less than 0.001) and slightly lower diastolic blood pressure values (-5 +/- 4 mmHg; p less than 0.001) with the oscillometric method. Thirty-four ambulatory blood pressure recordings were obtained in 28 children (mean age 13.3: range 8-17) with outpatient clinic blood pressure values suggestive of borderline hypertension. Numbers of ambulatory blood pressure readings were 44 +/- 5 during the day and 9 +/- 1 during the night. The mean of daytime blood pressure values was compared with reference blood pressure values obtained at rest in normal French children.(ABSTRACT TRUNCATED AT 250 WORDS)