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Biomedical subjects

E Villain

Publications and source records attributed to E Villain.

At least 55 records · Page 3Linked to original sources
PubMed1998

Heart rate control of blood pressure variability in children: a study in subjects with fixed ventricular pacemaker rhythm.

1. To investigate the influence of heart rate variability on blood pressure variability, short-term variability in heart rate and blood pressure was studied in 10 children with fixed ventricular pacemaker rhythm (80 beats/min). Ten healthy children, in sinus rhythm, served as a reference population. 2. Arterial blood pressure and heart rate were measured continuously using a finger arterial device and an ECG respectively. Power spectra for heart rate and blood pressure (systolic and diastolic) were calculated in both supine and orthostatic positions. In addition, acute changes in blood pressure and heart rate during active standing were studied. 3. Healthy children exhibited considerable heart rate variability, which was slightly more pronounced in the supine position, while children with a fixed ventricular rate had no heart rate variability in either position. 4. Despite the differences in heart rate variability, mean systolic blood pressure and its variability profiles were poorly affected by the suppression of heart rate variability. The lack of autonomic control on the sinus node was associated with a reduction in magnitude of the changes in systolic blood pressure variability induced by orthostatic posture. 5. The suppression of heart rate fluctuations induced a noticeable decrease in diastolic blood pressure fluctuations, which was most conspicuous in the children with fixed cardiac rhythm when in the supine position. This may be explained by the lack of diastolic blood pressure fluctuations, physiologically due to heart rate fluctuations through the run-off effect: the longer the cardiac cycle, the greater the diastolic pressure decay. These results may challenge the classical theory of baroreflex-mediated diastolic blood pressure control described in adult patients. 6. During active standing, the early drop in systolic blood pressure was greater in subjects with fixed ventricular rhythm. A rise in heart rate of 36 beats/min was observed in the healthy subjects in response to active standing. 7. We conclude that in normal children, heart rate fluctuations increase the blood pressure variability rather than buffering it. However, during acute orthostatic stress, the abrupt baroreflex-mediated heart rate rise may partly compensate for the reduction in blood pressure.

Adolescent↗
PubMed1998

[Can partial cavo-pulmonary connection be considered an alternative to the Fontan procedure?].

The disappointing long-term results of the Fontan procedure led the authors to assess substitution with partial cavo-pulmonary connections for definitive palliative treatment of single ventricle malformations. One hundred and fifteen patients with a mean age of 4.3 +/- 4.5 years (1 month-22 years) were treated by termino-lateral anastomosis between the superior vena cava and corresponding pulmonary artery, either of necessity because of a contraindication to total cavo-pulmonary connections (31 cases) or electively (84 cases). Another source of pulmonary flow was preserved or added in 76% of children, the operative mortality was 4% and the secondary mortality 3.5%. Significant complications were observed in 15% of cases with a secondary morbidity of 13%. Reoperation was required in 18 cases (16%). In fact, the death rate was higher in indications of necessity (19 versus 3.6% in elective procedures). Similarly, the number of serious complications (veno-venous or pulmonary arterio-venous fistulae, ventricular dysfunction) was higher in this group than in patients undergoing an elective procedure (23 versus 2.4%). After 4.8 +/- 3.2 years' follow-up, 73% of children treated of necessity and 95% of children treated electively were well despite mild cyanosis (average saturation of 86 +/- 6%). On condition that these results are confirmed at long-term as present follow-up is relatively short, this strategy would seem to be justified, providing mild cyanosis with little functional impairment is accepted, so avoiding the serious complications of Fontan-like circulations.

Adolescent↗
PubMed1998

[Neonatal ventricular tachycardia].

Ventricular tachycardia is rare and poorly understood in the neonate. The authors undertook a retrospective study in 2 foetus and 8 neonates aged 1 to 20 days at the time of diagnosis. The tachycardia was permanent in 2 cases, observed in runs of variable variation in the other 8, incessant in 7 of these cases. Only two cases were symptomatic: cardiac failure with shock 16 hours after birth and hydramnios at 16 weeks gestation. The electrocardiographic criteria of ventricular tachycardia (wide QRS complexes of different morphology to the sinus QRS complexes, atrioventricular dissociation) were fulfilled in all patients. The arrhythmia was monomorphic 9 times out of 10 with a fixed (3 cases) or variable (7 cases) rate which was always > 150/min. Intravenous magnesium sulphate in the severe and permanent forms, oral betablockers in forms triggered by acceleration of the sinus rhythm, oral amiodarone alone or associated in one case with propranolol were prescribed but three neonates were not treated, either from the outset or after inefficacy of amiodarone: nine of the patients were cured and are treatment-free 12 to 24 months later: the other patient has a slow, well tolerated ventricular tachycardia. No aetiology was detected in 9 cases; the other had a metabolic disease of B-oxidation of long chain fatty acids. The authors conclude that isolated, idiopathic ventricular tachycardia of the neonate usually carry a good prognosis which is not dependent on the tachycardia of the permanence of the arrhythmia. Simple treatment (betablocker or amiodarone) is usually associate with restoration of sinus rhythm and definitive cure during the first year of life.

Adrenergic beta-Antagonists↗
PubMed1997

Progressive left main coronary artery obstruction leading to myocardial infarction in a child with Williams syndrome.

UNLABELLED: We report a 3-year-old child with Williams syndrome in whom the first vascular feature of the syndrome was a myocardial infarction related to the occlusion of the left main coronary artery trunk. This coronary artery occlusion was not associated with supravalvular aortic stenosis. CONCLUSION: This report emphazises that acute vascular events related to systemic artery anomalies may reveal Williams syndrome.

Child, Preschool↗
PubMed1997

Coronary artery obstruction after the arterial switch operation for transposition of the great arteries in newborns.

OBJECTIVES: We sought to describe a large series of coronary artery obstructions after the arterial switch operation for transposition of the great arteries and to discuss their clinical implications. BACKGROUND: Aortic root angiography and myocardial perfusion imaging yield ambiguous results regarding the fate of the coronary artery anastomoses after the arterial switch operation. Late death related to coronary artery obstruction and growth of the translocated coronary arteries are of major concern in these patients. METHODS: Selective coronary artery angiography was performed prospectively in a total of 165 children. RESULTS: A total of 12 coronary occlusions, 8 major stenoses, 6 minor stenoses of the left ostium and 4 stretchings of one coronary artery were identified. Obstructions were more frequent in types D and E (p < 0.001) of the Yacoub and Radley-Smith classification. Coronary obstruction was documented in all patients with electrocardiographic and ultrasound evidence of myocardial ischemia at time of study. Early postoperative ischemia did not predict coronary artery lesion if the patient had fully recovered. Persistent or delayed myocardial ischemia was highly predictive of coronary artery lesions. The incidence of coronary artery obstruction was very high (11 of 35) in patients operated on by a rapidly abandoned technique of single-orifice reimplantation of both coronary artery ostia. CONCLUSIONS: Selective coronary angiography is the most accurate means to assess coronary artery obstruction after the arterial switch operation. Precise diagnosis of coronary artery lesions after this operation will help to elucidate the pathogenesis, develop adequate therapeutic strategies and might indicate how to prevent coronary complications after operation.

Child, Preschool↗
PubMed1997

Amiodarone as treatment for atrial tachycardias after surgery.

Atrial flutter, including all types of postoperative atrial tachycardias, is the one with the highest risk of late sudden death. Thus, late postoperative atrial tachycardias must be suppressed and all patients should be permanently treated after a first episode of atrial flutter. Daily oral doses of 200-250 mg/m2 amiodarone were found to be highly effective and well tolerated in young patients. However, in older patients and after long-term therapy, its use is restricted by adverse side-effects. In these cases, association of lower doses of antiarrhythmic agents, including amiodarone, may be effective and well tolerated. The use of other therapeutic options such as radiofrequency ablation should also be considered in older patients having drug-refractory postoperative atrial flutter.

Administration, Oral↗
PubMed1997

[Double discordances with ventricular septal defect and pulmonary obstruction. A study of 72 cases].

Seventy-two patients with corrected transposition of the great arteries with ventricular septal defect and pulmonary obstruction were studied. Four deaths occurred in the neonatal period and two were lost to follow-up. The remaining 66 were divided into three groups: 1) Eight patients were not operated on because the lesions were well compensated; they are all alive and doing well eight years later. 2) Thirty-eight patients were treated with palliative surgery: one or more systemico-pulmonary shunts (33 cases), total cavo-pulmonary connection (1 case) and partial cavo-pulmonary connection complementary to a shunt (4 cases). There were 3 deaths and 17 patients were lost to follow-up. However, the 18 survivors are all well seven years later. 3) The other 20 patients underwent surgery for severe hypoxia, after previous shunt in 18 cases. A conventional surgical protocol was respected in 17 cases (closure of ventricular septal defect with pulmonary disobstruction by a direct pulmonary plasty or by ventriculo-pulmonary conduit). There were 4 deaths, 2 tricuspid valve replacements, 5 complete atrioventricular blocks requiring permanent pacing, 5 lost to follow-up and 8 good results after 4 years follow-up. In the last 3 cases, "anatomical" correction was attempted by tunnelling of the left ventricle to the aorta, conduit from the right ventricule to the pulmonary artery and intra-atrial Mustard procedure: these 3 children are doing well after 1 year though one of them required permanent pacing. Therefore, there is no place for elective surgery in this malformation: when necessary, the best option is to remain palliative as long as possible: when correction is required, an anatomical correction is the best procedure.

Cardiac Surgical Procedures↗
PubMed1997

[Prognosis and outcome of idiopathic dilatation of the right atrium in children. A cooperative study of 15 cases].

Idiopathic dilatation is a rare abnormality corresponding to isolated aneurysmal dilatation of the right atrium, the outcome of which is not well known. Therefore a multicentric retrospective study was set up by the paediatric working group of the French Society of Cardiology recensing 7 boys and 8 girls who were diagnosed with this condition between 1971 and 1993. Ten of the children were asymptomatic and the diagnosis was suggested by the chest X-ray: one neonate had cardiac failure secondary to atrial tachycardia. The diagnosis has been facilitated by echocardiography since 1980. In this series, since 1993, four diagnoses were made antenatally. The outcome was variable : eight children are alive and well with follow-up periods ranging from 2 to 15 years (average 6 years) : four children have had cardiac arrhythmias : benign atrial extrasystoles (1 case), junctional reentrant tachycardia (1 case). The other two had more severe arrhythmias with flutter in a 7 year-old and one neonatal atrial tachycardia. The outcome was favourable with medical treatment. Three children underwent surgical atrial resection : the outcome has been good in these 3 cases with follow-up periods of 4, 13 and 18 years. This series shows that idiopathic dilatation of the right atrium is usually a well tolerated abnormality but unexpected complications may arise which can be severe such as arrhythmias, or which may be potentially threatening such as interatrial thrombosis. Management consists of either follow-up to diagnose complications which require appropriate treatment of systematic surgical correction as some authors suggest.

Adolescent↗
PubMed1996

Phenotypic expression in double heterozygotes for familial hypercholesterolemia and familial defective apolipoprotein B-100.

Variability in the expression of monogenic lipid disorders may be observed in patients carrying the same DNA mutation, suggesting possible genetic or environmental interactions. Our objective was to investigate the genotype-phenotype relationships in two unrelated French patients with an aggravated expression of a dominantly inherited hypercholesterolemia. In probands, segregation analysis complemented by DNA sequencing identified heterozygous defective alleles and mutations on two nonallelic loci for two monogenic lipid disorders: familial hypercholesterolemia at the low density lipoprotein (LDL) receptor locus and familial defective apolipoprotein B-100 at the locus encoding its ligand, apolipoprotein B-100. The LDL-receptor missense mutations had been reported in French Canadians. The apolipoprotein B mutation was the Arg3500Gln founder mutation in Northern Europe. Probands had an unusual phenotype of aggravated hypercholesterolemia that was complicated with premature coronary arterial disease, although remaining responsive to lipid-lowering drugs. This phenotype was distinct from that observed in their heterozygous relatives and distinct from those observed in FH or FDB homozygotes. These cases refer to a new class of patients with digenic lipid disorders, defined by specific clinical features that result from the combined effects of two independent loci. Moreover, the observed phenotype of aggravated hypercholesterolemia gives further evidence that receptor and ligand play distinct roles in regulating LDL metabolism. Although uncommon, these cases give insight into the molecular mechanisms that underly the clinical variability of inherited hypercholesterolemia.

Adult↗
PubMed1996

[Late supraventricular arrhythmia complicating Fontan or cavopulmonary type procedures. Apropos of 7 cases].

The authors report 7 cases of late arrhythmias after atriopulmonary (5 cases) or total cavopulmonary (2 cases) bypass procedures. There were 6 cases of atrial flutter and one case of atrial tachycardia. The condition presented with cardiac failure in 5 cases. In 2 patients, atrial flutter caused syncope or dizziness. The arrhythmia was reduced by atrial stimulation (3 cases) or by cardioversion (1 case). Prevention of recurrence with oral amiodarone was effective in all cases but was responsible for secondary effects in 4 cases. In one patient, recurrence of atrial flutter was complicated by right atrial thrombosis with cerebral embolism. Five patients were reoperated after cardiac catheterisation and angiography. Surgery consisted of resection of a stenosis of the anastomosis in one case, and the transformation of atriopulmonary anastomosis into a total cavopulmonary bypass because of a very dilated right atrium without stenosis in 4 patients. The immediate postoperative period was complicated by a recurrence of the arrhythmia in 3 children not treated by antiarrhythmic therapy. At long-term, one patient died 6 months after withdrawal of amiodarone therapy of recurrence of atrial flutter. Five of the 6 survivors are treated with amiodarone or a betablocker; 3 have had pacemaker implantation for severe bradycardia. Late atrial arrhythmias complicating atrio- and cavopulmonary bypass procedures carry a risk of cardiac failure and sudden death. When diagnosed, the patient should be investigated for stenosis of the anastomosis but severe dilatation of the right atrium is often the only finding. After restoration of sinus rhythm, maintenance antiarrhythmic therapy should be continued indefinitely.

Amiodarone↗
PubMed1996

[Treatment and prognosis of tachyarrhythmia after atrial surgical repair of transposition of great vessels].

The Mustard and Senning procedures may be complicated by atrial tachyarrhythmias. In order to determine their prognosis, the authors undertook a review of the 288 patients operated and followed up in their department. Thirty-six (12.5%) had documented atrial tachycardias. In 13 cases, Holter monitoring showed bursts of atrial tachycardia. In the other 23 cases, the tachycardia was sustained and often caused severe symptoms (syncope). Reduction of the sustained forms was obtained by rapid atrial pacing, cardioversion or amiodarone therapy. After restoration of sinus rhythm, several therapeutic protocols were used, often in the same patient: abstention, leading to 5 recurrences in 6 cases; treatment with betablockers in 12 patients with well tolerated or exercise-induced atrial tachycardia with 11 successes; amiodarone, with 4 relapses out of 5 when the dosage was less than 200 mg/m2/day and 13 successes out of 18 when the dosage was 200-250 mg/m2/day. During a follow-up of 1 to 19 years, 6 severe complications (neurological sequellae, cardiac failure), and 6 deaths, were observed. All these patients were poorly controlled and continued to be have tachyarrhythmias. The authors conclude that tachyarrhythmias are neither rare nor always symptomatic, so justifying their systematic investigation. They should be reduced by oral amiodarone or rapid atrial pacing depending on the clinical urgency, never by intravenous antiarrhythmics which can be dangerous. The poor prognosis associated with tachyarrhythmias makes their control essential either with betablockers or good doses of amiodarone, eventually covered by permanent cardiac pacing.

Adolescent↗
PubMed1995

Spectral analysis of systolic blood pressure and heart rate after heart transplantation in children.

1. The aim of the study was to examine the short-term variability in blood pressure and heart rate in 19 children who had received heart transplants and in eight normal control children. 2. Blood pressure was determined by a finger arterial pressure device. We examined the power spectra for heart rate and systolic blood pressure in the supine and tilted positions. In addition, we studied the acute changes in blood pressure and heart rate during active standing. 3. In the transplanted children we could distinguish two groups (groups A and B) in whom heart rate variability differed, although in both it was greatly reduced compared with controls (group C). In group A there were no significant fluctuations in the mid-frequency range for heart rate. The gain of the relationship between systolic blood pressure and heart rate was very low and there were virtually no heart rate changes associated with passive tilting. 4. By contrast, in group B transplant patients the heart rate variability, as assessed by standard deviation, was about half that of normal controls. The power spectra attenuation was greater in the high-frequency than in the mid-frequency bands. On passive tilting the latter became enhanced, but not the high-frequency variability. On active standing the tachycardic response was about half that of controls. The findings suggest some reinnervation involving cardiac sympathetic fibres to a greater degree than the fast-responding vagal fibres. 5. In both groups A and B the drop in systolic blood pressure observed early in active standing was about 4-6 times as great as in controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1995

[Spectrum analysis of heart rate and arterial systolic pressure after heart transplantation in children].

The aim was to examine the short-term variability of blood pressure (BP) and heart rate (HR) in 19 children who had received heart transplants and in 8 normal control children. BP was determined by a finger arterial pressure device. We examined the power spectra for HR and systolic blood pressure (SBP) in the supine and standing posture. In the transplanted children we could distinguish two groups (groups A and B) in whom HR variability differed, though in both it was greatly reduced compared to controls (group C). In group A there were no significant fluctuations in the mid frequency (MF) range for HF. Gain of the relationship between SBP and HR was very low and there were virtually no HR changes associated with passive tilting. By contrast, in group B transplant patients the HR variability, as assessed by standard deviation was about half that of normal controls. The power spectra attenuation was greater in the high frequency (HF) than in the MF bands. On standing the latter became enhanced, but not the HF variability. The findings suggest some reinnervation involving cardiac sympathetic fibres to a greater degree than the fast-responding vagal fibres. Time since operation was a critical factor for reinnervation since all subjects from group B were transplanted more than 44 months prior to the recording. We conclude that in a proportion of children who have received heart transplantation there is a delayed reinnervation of the heart, which probably involves sympathetic effectors rather than the vagus.

Age Factors↗
PubMed1994

Pediatric arrhythmias.

As children with cardiac malformations grow older, it appears that although their hemodynamic abnormalities may have been corrected by surgery, an increasing number of these patients have severe and possibly lethal arrhythmias. Atrial surgery and Fontan-type operations are complicated by atrial tachyarrhythmias that are difficult to predict and control. The relation between sudden death and ventricular tachycardias in patients who have undergone tetralogy of Fallot repair is still controversial. Application of radiofrequency energy now offers an alternative to pharmacologic therapy and surgery for children who have symptomatic tachyarrhythmias and need life-long therapy. Initial results are encouraging, with a very low morbidity, especially for children who have supraventricular reentrant tachycardias due to accessory pathways. However, the place of ablation in children is not yet fully delineated, as long-term follow-up evaluations are still lacking at this time. For this reason, antiarrhythmic agents, including class Ic drugs and amiodarone, should be tried first, especially in very young children. Indications for antiarrhythmic surgery are becoming very rare, due to the introduction of ablation techniques. For children who have life-threatening ventricular arrhythmias, implantation of a cardioverter-defibrillator represents a new therapeutic option, one that may also be used as a bridge to heart transplantation.

Adolescent↗
PubMed1994

[Outcome of Wolff-Parkinson-White syndrome in children. Transesophageal study of anterograde permeability of the accessory pathway and of atrial vulnerability].

Twenty-nine children with the Wolff-Parkinson-White syndrome (WPW) were evaluated by transoesophageal electrophysiological studies to determine the quality of anterograde-conduction in the accessory pathway and the atrial vulnerability. The study group included 15 neonates, 1 to 30 days old, and 14 children from 5 to 15 years of age; Anterograde conduction through the bundle of Kent was tested by incremental transoesophageal atrial pacing and by the determination of the shortest conducted cycle with preexcited RR waves; bursts of atrial pacing were then used to try to trigger an atrial arrhythmia. In the group of the 15 neonates, 11 had accessory pathways capable of conduction to the ventricules at frequencies > 300/min (stimulation cycle < or = 2.00 ms) but no atrial arrhythmias could be induced. The older children had slower conduction in the accessory pathways with the shortest conducted cycle length > 200 ms in 11/14 cases; on the other hand, atrial fibrillation was easily induced in 4 children, all over 12 years of age. The risk of syncope by rapid conduction of an atrial arrhythmia through the accessory pathway is negligeable in young children, including those on digoxin. This study suggests that this low risk is explained more by the absence of atrial vulnerability than by the electrophysiological properties of the accessory pathways.

Arrhythmias, Cardiac↗
PubMed1993

[Disorders of supraventricular rhythm in children].

In children with otherwise normal heart, reentry is the most common cause of supraventricular tachycardia. The tachycardia is stopped by vagal stimulation, and digoxin is then given to prevent recurrences; in patients with Wolff-Parkinson-White syndrome, transeosophageal stimulation is performed to examine properties of anterograde condution across the accessory connection, and to select the most appropriate treatment. Radiofrequency ablation is selected only in children with refractory supraventricular tachycardia or who were admitted for syncope due to rapid conduction over an accessory pathway. Neonatal junctional ectopic tachycardia may be very severe and even results is death when the heart rate is not slowed down; amiodarone is the safest and the most effective drug. Atrial flutter is encountered in 2 groups of children: neonates, in whom it is converted by rapid transeosophageal pacing, with excellent prognosis, and children who have had atrial surgery (Mustard and Senning operations). These patients have sinus failure, with paroxysmal atrial flutter possibly responsible for sudden death when rapidly conducted to the ventricles. It is a new and concerning pathology, as these children have chronic arrhythmias requiring aggressive therapy such as amiodarone and cardiac stimulation.

Adolescent↗
PubMed1993

Drugs and ablation in the treatment of supraventricular tachyarrhythmias in children.

The vast majority of children who have symptoms (ie, cardiac failure, palpitations, dizziness) due to supraventricular tachycardias are successfully managed by medical treatment. Antiarrhythmic drug therapy may be complicated by side effects or become ineffective so that radiofrequency catheter ablation, which destroys the myocardial structure responsible for arrhythmias, can now offer an attractive option to lifelong drug therapy. Immediate results for supraventricular tachycardias due to a reentry mechanism or to an atrial ectopic focus are good, with a success rate over 80% and rare immediate complications. However, the long-term sequelae of the procedure on the growing heart have not been established and the risk of subsequent atrial and ventricular arrhythmias must be considered in young patients. For this reason, I believe that today, radiofrequency ablation should be reserved for young patients who have life-threatening symptoms or who have arrhythmias that are refractory to medical treatment, and for older patients who will need a lifelong drug therapy.

Catheter Ablation↗