Optimal high-pass filter settings of the signal-averaged electrocardiogram in patients with arrhythmogenic right ventricular dysplasia.
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Adult↗
Biomedical subjects
G Fontaine
Publications and source records attributed to G Fontaine.
Low density of neutral hydrogen and helium in the local interstellar medium: Extreme Ultraviolet Explorer photometry of the Lyman continuum of the hot white dwarfs MCT 0501-2858, MCT 0455-2812, HZ 43, and GD 153.
The first comprehensive sky survey of the extreme ultraviolet (EUV) spectral range performed by the Extreme Ultraviolet Explorer (EUVE) has uncovered a handful of very bright sources at wavelengths longer than the He I 504 angstroms photoionization edge. Among these objects are four white dwarfs with exceptionally low interstellar medium (ISM) column densities along the line of sight. Analysis of EUV photometry of the He-rich DO white dwarf MCT 0501-2858 and the H-rich DA white dwarf MCT 0455-2812 along one line of sight and of the DA white dwarfs HZ 43 and GD 153 near the north Galactic pole indicates that the overall minimum column density of the neutral material centered on the Sun is N(H I)= 0.5-1.0 x 10(18) cm-2. In the case of MCT 0501-2858, EUV photometric measurements provide a clear constraint to the effective temperature (60,000-70,000 K). Given these neutral hydrogen columns, the actual contribution to the density of neutral species from the immediate solar environment (the "local fluff") would only cover a distance of approximately 2-3 pc (assuming an average density n(H I) = 0.1 cm-3) leaving these lines of sight almost entirely within the hot phase of the ISM. A preliminary examination of the complete EUVE long-wavelength survey indicates that these lines of sight are exceptional and set a minimum column density in the solar environment.
Astronomy↗
Diagnosis of ventricular tachycardia using a pacemaker Holter function.
The diagnosis of ventricular tachycardia (VT) using the Holter function of an implanted pacemaker has not yet been reported. We present the case of a patient with episodes of slow VT, hemodynamically stable, but in whom long lasting attacks were not identified by the patient as VT recurrences, finally leading to progressive heart failure. Prospective analysis of the 24-hour ECG and comparison with the pacemaker Holter data allowed us to determine diagnostic criteria to recognize VT using the pacemaker Holter function. Using these criteria it was possible to retrospectively diagnose VT occurrence during the weeks when the patient was out-of-hospital.
Aged↗
Diagnosis of arrhythmogenic right ventricular dysplasia/cardiomyopathy. Task Force of the Working Group Myocardial and Pericardial Disease of the European Society of Cardiology and of the Scientific Council on Cardiomyopathies of the International Society and Federation of Cardiology.
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Arrhythmias, Cardiac↗
Presence seeking and sensation seeking as motives for international travel.
Although independent research has identified presence seeking and sensation seeking as important motives for a variety of activities, there is sufficient conceptual overlap to suggest the concepts describe in part the same motive or are related. The possible relationship was examined in motives of students for international travel. Nonsignificant correlations suggest that, at least for this activity, they are differentiable.
Adult↗
[Value and limitations of diagnostic function of bradycardia of a ventricular pacemaker].
The indication for permanent pacing may be confirmed by a bradycardia counter in patients without ECG or Holter recording of the causal bradycardia. The algorithm was assessed in a multicenter register with the SORIN Theorema model. The activation of the device was programmed on a double hysteresis of 2 seconds with a programmable histogramme of detections and sensing and pacing counters. One hundred and forty five patients were recruited in 50 centers over 2 years: 89 men and 56 women aged 33 to 96 years (average 72 years), 87 of whom had no other obvious cardiac disease. One hundred and ten had typical syncopal episodes, 19 had atypical or minor syncopal attacks and 16 were asymptomatic, one with sinus node dysfunction and the others with pathological prolongation of the HV interval (> or = 70 ms) during endocavitary electrophysiological investigation. The mechanism of the bradycardia was considered to be infra-hisian in 62 patients who had HV intervals > or = 70 ms. This was also the probable mechanism in 20 others who had bundle branch block and typical syncope despite a HV interval < 70 ms and in 6 patients with bundle branch block and typical syncope who did not undergo electrophysiological investigation before implantation. Twenty one patients had sinus node dysfunction during electrophysiological investigation and 8 had a carotid sinus syndrome. The remaining 28 cases had transient syncope but no ECG changes or abnormality on electrophysiological investigation. Permanent pacing was proposed when an extracardiac origin of the syncope was excluded.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
[Fulguration and radiofrequency in ventricular tachycardia].
Eighty-nine cases of ventricular tachycardia, resistant to antiarrhythmic therapy, were treated over a 10 year period by high energy D ablation (fulguration). This series included 37 cases of myocardial infarction with a mean ejection fraction of 30%. The mean follow-up period of the survivors was 61 months and clinical efficacy was 87.9%. Twenty-three cases of arrhythmogenic right ventricular dysplasia, aged 40 years, and with an ejection fraction of 57%, followed up for 71 months, had a clinical efficacy of 83%. Twelve patients had verapamil sensitive (fascicular) ventricular tachycardia. Their age was 30, their ejection fraction 65%, the follow-up period 55 months, and the clinical efficacy was 100%. Ten patients had primary dilated cardiomyopathy. Their age was 35, their ejection fraction 23%, the follow-up period of 38 months with a clinical efficacy of 80%. Four patients, aged 21, had operated congenital heart disease with an ejection fraction of 60%, a follow-up of 36 months and a clinical efficacy of 100%. Finally, 3 patients had idiopathic infundibular ventricular tachycardia. Their age was 36, the ejection fraction 62%, the follow-up period was 72 months and the clinical efficacy was 67%. Non lethal complications were observed in 16% of cases, mainly haemopericardium requiring pericardocentesis in 4.5% of cases. The operative mortality and in the month following ablation was 9.2%, observed mainly during the learning period. These results show that fulguration is not without risk, but in skilled hands, it gives remarkable results in the majority of cases.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
[Ablative methods, therapeutic alternative to medical treatment for junctional tachycardia].
The clinical syndrome corresponding to junctional tachycardia is generally known as Bouveret's disease, but actually corresponds to two quite separate entities: 1) tachycardia related to a secondary atrioventricular pathway or Kent bundle; 2) intranodal tachycardia arising in the atrio-ventricular node. Until recently, anti-arrhythmics were used to treat most of the cases of accessory pathways. If this was unsuccessful or if the anti-arrhythmics induced adverse effects and in life-threatening cases affecting Kent bundles, surgical section was sometimes proposed, carrying a non-negligible risk of morbidity and mortality. Intranodal arrhythmia is not a serious, but may call for prophylactic antiarrhythmic treatment if it becomes too frequent and disabling. Before the advent of ablative treatment, there was no satisfactory alternative to antiarrhythmic treatment. Ablation of the accessory pathways or selection ablation of the slow pathway of the atrio-ventricular node (sometimes of the rapid pathway) is not achieved by applying a high-frequency current (radiofrequency), which has virtually replaced fulguration (destruction using a modified electrical current). In both types of tachycardia, a cure is obtained in 90% of cases with a low incidence of complications and virtually no risk of mortality, which contrasts favorably with long-term antiarrhythmic treatment (or surgical section of Kent bundles), which justifies the large-scale development of radiofrequency ablation.
Catheter Ablation↗
[Bayesian approach to electrocardiographic criteria in arrhythmogenic right ventricular dysplasia].
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Arrhythmias, Cardiac↗
[Repolarization and intraventricular conduction disorders in arrhythmogenic right ventricular dysplasia].
Right ventricular dysplasia may lead to sudden cardiac death an adolescent or adult with little or no symptoms. Identification of this condition in the high-risk population appears to be an objective to be attained in the near future. Thorough ECG analysis seems to be a non-invasive and inexpensive technique which could be used as a first approach for screening of the disorder. In a series of 50 cases of arrhythmogenic right ventricular dysplasia compared with a control group, the diagnosis of ARVD could be determined by ECG with 84% sensitivity and 100% specificity if QRS duration in leads V1, V2 or V3 was longer than 110 ms, T wave was negative in V2 or if T wave was negative in V1, but in this latter case only provided incomplete right bundle branch block was present.
Adolescent↗
3-Hydroxy-3-methylglutaryl coenzyme A lyase (HL). Cloning of human and chicken liver HL cDNAs and characterization of a mutation causing human HL deficiency.
3-Hydroxy-3-methylglutaryl coenzyme A lyase (HL) catalyzes the final step of ketogenesis, an important pathway of mammalian energy metabolism. HL deficiency is an autosomal recessive inborn error in man leading to episodes of hypoglycemia and coma. Using the N-terminal peptide sequence of purified chicken liver HL, we designed degenerate sequence primers and amplified an 89-base pair (bp) chicken liver HL cDNA fragment. Longer cDNA clones for chicken (1384 bp) and human (1575 bp) HL were obtained by library screening. The peptide sequence predicted from the chicken clone contains two peptides from purified chicken HL. Mature human and chicken HL are 298-residue peptides. The sequence of the human clone predicts a 27-residue mitochondrial leader and a 31.6-kDa mature HL peptide. Human fibroblast and liver RNA contain a single 1.7-kilobase HL message. Two Acadian French-Canadian siblings with HL deficiency were homozygous for a 2-base pair deletion within the Ser-69 codon (S69fs(-2)), predicted to result in a truncated nonfunctional HL peptide lacking a complete active site. S69fs(-2) was not present in 12 other HL-deficient patients of 10 other ethnic origins, showing that HL deficiency is genetically heterogeneous.
Amino Acid Sequence↗
3-Hydroxy-3-methylglutaryl coenzyme A lyase (HL): cloning and characterization of a mouse liver HL cDNA and subchromosomal mapping of the human and mouse HL genes.
3-Hydroxy-3-methylglutaryl coenzyme A lyase (HL) is a homodimeric mitochondrial matrix enzyme that catalyzes the last step of ketogenesis. Using a human HL cDNA as a probe, we isolated a 1.4-kb mouse HL cDNA (HLM) from a mouse liver library and extended the sequence in the 5' direction, using RACE PCR to include the complete coding sequence. The nucleotide sequence of the mouse HL coding region is 85.7% identical to human HL, and 52.6% to Ps. mevalonii HL. Peptide identities of 87.4% and 54.3% respectively were observed. Southern analysis of 29 strains of laboratory mice and of Mus spretus revealed a total of about 25 kb of hybridizing fragments and three polymorphic fragments in both EcoRI and Hin-dIII digestions. The mouse HL locus (Hmgcl) was localized on Chromosome (Chr) 4: Pmv-19-12.6 +/- 3.6 cM-Hmgcl-7.3 +/- 2.3 cM-Xmv-8-1.5 +/- 1.0 cM-Gpd-1. The human HL locus (HMGCL) was mapped to distal Chr 1p by analysis of a human-hamster hybrid cell panel and by in situ hybridization.
Amino Acid Sequence↗
[Duration of QRS complexes in arrhythmogenic right ventricular dysplasia. A new non-invasive diagnostic marker].
Arrhythmogenic right ventricular dysplasia (ARVD) may result in sudden death of young and sometimes athletic individuals, while if properly treated it is associated with a good prognosis. It is probably more widespread than currently thought. Comparison of the electrocardiograms of 43 ARVD patients with those of 44 normal individuals provided a new criterion enabling identification of the disease. Measurement of a QRS interval longer than 110 ms in sinus rhythm in lead V1 in an individual with an apparently normal heart enabled identification of the disease with a sensitivity of 55 p. cent and specificity of 100 p. cent if used alone, and a sensitivity of 60 p. cent if used in combination with a prolongation of QRS in lead V3 to greater than 110 ms, but with a specificity of 82 p. cent. After elimination of appearances of right bundle branch block, sensitivity was 50 p. cent for V1. This parameter studied in a hospital population should be validated in minor forms before leading to compulsory ECGs for individuals in high-risk occupations (athletes, public vehicle drivers, etc.).
Adult↗
[Treatment of ventricular tachycardia by endocardial fulguration. Apropos of 86 cases].
Between 1983 and 1991, 86 cases of ventricular tachycardia (VT) resistant to antiarrhythmic therapy were treated by endocardious catheter fulguration: there were 21 cases of right ventricular dysplasia (RVD), 35 chronic myocardial infarctions (MI), 11 dilated cardiomyopathies (DCM), 10 bundle branch VT, 5 idiopathic septal VT, 3 operated Fallot procedures, 1 Ebstein's anomaly. There were 69 men and 17 women aged 14 to 76 years (average 45 +/- 18 years). The ejection fraction was under 30% in 37 cases. Forty-five VTs were permanent or recurred several times daily; 6 were inducible despite drug therapy and 35 patients had monthly recurrences. A total of 141 different forms of VT were treated in 133 procedures. One session was sufficient in 49 cases; 2 sessions were required in 29 cases; 3 sessions in 6 cases and 4 sessions in 2 cases. A total of 480 DC shocks were delivered with energies of 160 to 300 joules. The CPK-MB levels were 37 +/- 30 i.u./l. The following complications were observed: 7 perioperative deaths, 2 cardiac tamponades requiring surgical drainage, 1 permanent AV block, 5 reversible left ventricular failures. Follow up concerned 79 patients: 5 were followed up for less than 3 months with death occurring from cardiac failure which had been present before the ablation procedure without recurrence of VT. Seventy-four patients were followed up from 3 to 111 months (56 +/- 33 months). Thirty-two patients were without any antiarrhythmic therapy and had no recurrence of VT. Two of these patients developed a different form of VT 2 and 6 years after the catheter ablation.(ABSTRACT TRUNCATED AT 250 WORDS)
Actuarial Analysis↗
[Holter and sudden death: value in a case of arrhythmogenic right ventricular dysplasia].
The authors report the first case of arrhythmogenic right ventricular dysplasia presenting with a sudden death due to primary ventricular fibrillation (ventricular fibrillation not preceded by ventricular tachycardia) recorded by the Holter method. The patient was a 56 year old man whose only complaint was near syncopal case is the fact that it is the first documented case of ventricular fibrillation revealing arrhythmogenic right ventricular dysplasia, the diagnosis of which was made at autopsy. In addition, the Holter recording showed the factors which triggered the arrhythmia: the "trigger" of 4 monomorphic ventricular extrasystoles during the minute preceding the ventricular fibrillation; the arrhythmogenic substrate giving rise to late ventricular potentials and, finally, the analysis of the R-R intervals suggesting a role of the sympathetic and parasympathetic nervous systems. Holter recordings could help identify subjects at high risk of severe ventricular arrhythmias.
Adipose Tissue↗
[Sustained monomorphic ventricular tachycardia in non ischemic heart diseases].
Sustained ventricular tachycardia in the absence of coronary artery disease is mainly observed in diffuse left ventricular cardiomyopathy especially dilated but sometimes hypertrophic, and in right sided cardiomyopathies such as ventricular dysplasia, more difficult to diagnose. More rarely, other localised abnormalities, mitral valve prolapse, cardiac tumour and idiopathic aneurysm, may give rise to this arrhythmia. Irrespective of the case, sustained ventricular tachycardia carries a poor prognosis during the most advanced stages of a myocardial disease. The therapeutic strategy remains the same as that of other cases of sustained ventricular tachycardia, drug therapy generally orientated by the results of programmed ventricular stimulation with the exception of Class I antiarrhythmics when the ejection fraction is under 30%, and non-pharmacological methods when drug therapy fails.
Anti-Arrhythmia Agents↗
[Arrhythmogenic right ventricular dysplasia. A new clinical entity].
Arrhythmogenic right ventricular dysplasia has been identified in 1977. It affects the right ventricle and its etiology is unknown. It has been recently included in the group of cardiomyopathies since it affects mainly the right ventricular muscle. It is found in young adults, frequently sportsmen who have a nearly normal cardiac physical examination. Ventricular arrhythmias could lead to palpitations, syncopes or even sudden death. This accident could be the first presenting sign of the disease. Two physiopathogenic mechanisms have been considered: heredo-familial origin or the result of a burned out myocarditis which could be the result of an abnormal immunological response. Its treatment mainly involves antiarrhythmic drugs. In the resistant cases ablative techniques, implantable defibrillator or surgery and even cardiac transplantation could be considered. Correctly treated, ARVD has a good prognosis. More extensive studies are necessary both on the clinical as well as the basic science standpoints.
Adolescent↗
Ornithine delta-aminotransferase mutations in gyrate atrophy. Allelic heterogeneity and functional consequences.
Ornithine delta-aminotransferase is a nuclear-encoded mitochondrial matrix enzyme which catalyzes the reversible interconversion of ornithine and alpha-ketoglutarate to glutamate semialdehyde and glutamate. Inherited deficiency of ornithine delta-aminotransferase results in ornithine accumulation and a characteristic chorioretinal degeneration, gyrate atrophy of the choroid and retina. We have surveyed the ornithine delta-aminotransferase genes of gyrate atrophy patients for mutations. Using a variety of techniques, we discovered and molecularly characterized 21 newly recognized ornithine delta-aminotransferase alleles. We determined the consequences of these and three previously described mutations on ornithine delta-aminotransferase mRNA, antigen, and enzyme activity in cultured fibroblasts. The majority (20/24) of these alleles produce normal amounts of normally sized ornithine delta-aminotransferase mRNA. By contrast, only 2/24 had normal amounts of ornithine delta-aminotransferase antigen. Reproducing these mutations by site-directed mutagenesis and expressing the mutant ornithine delta-aminotransferase in Chinese hamster ovary cells confirms that several of these mutations inactivate ornithine delta-aminotransferase and cause gyrate atrophy in these patients.
Alleles↗