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Biomedical subjects

B Dodinot

Publications and source records attributed to B Dodinot.

At least 19 recordsLinked to original sources
PubMed1990

[Rate-responsive cardiac pacing].

The term "synchronous pacemaker (SPM)" is used to describe all pacemakers of which the frequency can be accelerated by means of a sensor other than the sinus node. The most commonly used system is the detection of changes in physical activity by means of a quartz crystal included in the casing. Changes in respiratory volume, the respiratory rate, the QT interval or central temperature have been less successfully used. Single and double-chamber (DC) synchronous pacemakers exist. Ventricular single-chamber synchronous pacemakers (VVIR) are primarily intended for active patients in a state of chronic atrial fibrillation or, secondarily, in cases in which the insertion of an atrial electrode raises difficulties. The single-chamber atrial synchronous pacemaker (AAIR), or preferably the double-chamber equivalent (DDDR) is intended for the correction of chronotropic failure, whether this is primary or induced by bradycardiac antiarrhythmic medication. AVB should be treated by double-chamber simulation designed to pick up P waves. The value of the synchronous pacemaker in these patients is that it makes it possible to partially offset the loss of atrial systole in cases of ventricular fibrillation by a synchronous pacemaker (pacemaker programmed to shift from DDD to VVIR). The setting of the SPM is fairly complex and calls for exercise tests. Iatrogenic acceleration is not unusual and must be identified by long-term recordings. All these pacemakers will here include a "synchronous" option, which may be of variable efficacy. It is up to the clinician to use them appropriately, and not automatically, remembering that the best sensor is the sinus node and that synchronous pacemakers are only second best.

Cardiac Pacing, Artificial↗
PubMed1988

[Cardiac stimulation in children. 20 years' experience].

Between July, 1967 and December, 1987, 71 children and adolescents (43 boys, 28 girls) aged from 9 days to 20 years (mean 7.8 years) underwent pacemaker implantation. In 91 p. 100 of the cases this treatment was performed for complete atrioventricular block (CAVB). Surgical CAVB was the reason for 59 p. 100 of implantations (correction of tetralogy of Fallot and, more recently, of complex cardiopathies), the second main reason (16.9 p. 100) being nonsurgical CAVB associated with heart disease; the children in this group were young (mean age 4.2 years), and the prognosis mainly depended on the heart disease. Isolated congenital CAVB accounted for only 8.5 p. 100 of pacemaker implantations; these were older children (mean age 13.7 years), and the decision to implant was often difficult to reach in the absence of major functional disorders; following implantation, it was frequently found that isolated congenital CAVBs regarded as being well tolerated in fact were unrecognized handicaps. Acquired CAVB (7 p. 100) mostly consisted of Kearns' syndrome (4/5 cases). In addition, 3 children with sinus node disease and 1 with Romano-Ward syndrome benefited from cardiac pacing. Seven children died; death was in no case due to pacing but to the heart disease associated with CAVB. Endocardial pacing (68.2 p. 100 of primary implantations during the last decade) was preferred to epicardial pacing. Since 1985 we have been using exclusively screwed endocardial monopolar electrodes. The pacemakers were usually of the single-chamber ventricular type (85.9 p. 100 of primary implantations), but since 1987 dual-chamber pacemakers have been increasingly preferred for children with permanent CAVB or for replacement of pacemaker cases. Single-chamber noncompetitive ("demand") pacemakers were implanted in only 2 children: one pacemaker was connected to a ventricular electrode (atrial paralysis), the other to an atrial electrode. Whatever the type of electrode used, the pacemakers were implanted in the abdominal region in very young infants and in the pectoral region in children older than 3 or 4 years. Breakage of the wire was the main complication. Rises in threshold are the major drawback of epicardial pacing, as they require reoperation when the energy delivered cannot be effectively programmed. Endocardial pacing, preferably with a dual-chamber instrument, seems to be the best method, being the least aggressive, with minimal complications in short and very long term; it is justified as first-line treatment of permanent or predominant CAVB.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1985

[Sudden death in patients wearing pacemakers].

10 to 30 p. cent of patients with cardiac pacemakers die suddenly. In most cases, the cause of death can not be established. Racing of the pacemaker is a rare but definite cause of sudden death. In contrast, failure of the stimulation, which occurs much more frequently, and which is due to failure of the pacemaker or the wire or to an elevation of the threshold of stimulation, rarely causes sudden death because of the development of an idioventricular rhythm, leading to detection of the fault. Competitive rhythms do not appear to be more dangerous than accidental inhibition in sentinel pacemakers; both of these mechanisms can lead to ventricular tachycardia which may degenerate to ventricular fibrillation. Programmable pacemakers have certain advantages and disadvantages, in that the programming may prove to be inappropriate. In most cases, the ventricular fibrillation is spontaneous, occurring in the context of myocardial failure. The extension of the indications for pacemakers is certainly responsible for the relatively high incidence of sudden death.

Death, Sudden↗
PubMed1983

[Tachycardia and ensuing electrosystole].

The benign or severe nature of a ventricular extrasystole depends on a number of parameters which involve the pathophysiological mechanism of the extrasystole: re-entry, exaggerated normal or abnormal automatism and therefore the presence or absence of an underlying cardiac disease. The prognosis depends directly on the morphology, the number and the characteristics of the arrhythmia. Various investigations are often necessary to evaluate this prognosis, including 24 hour Holter monitoring, stress test and electrophysiological investigations.

Cardiac Complexes, Premature↗
PubMed1979

[Harmful interference between preoperative prophylactic cardiac pacemaker and cutting diathermy. Case report].

The authors report the case of a patient suffering the consequences of harmful preoperative between a prophylactic cardiac pacemaker system and cutting diathermy, resulting in irreversible ventricular fibrillation. After reviewing the different mechanisms responsible for this accident, they attribute the blame to a phenomenon of capture of electromagnetic currents with the pacemaker catheter playing the role of an aerial. They reconsider the indications for the use of prophylactic pacing and recall the safety precautions which must be respected at the time of simultaneous use of an external pacemaker and cutting diathermy.

Diathermy↗
PubMed1977

[French evaluation of cardiac stimulation].

A national enquiry into the problems related to definitive cardiac pacemakers, carried out in 1975, has yielded certain essential findings: the number of first-time implantations of pacemakers has been increasing by about 20% per annum; 92% of electrodes are currently implanted by an endocavitary technique, thoracotomy having now practically been abandoned; 90% of pacemakers implanted in 1975 were threshold models, inhibited by a QRS complex; the indications have become progressively wider, and are essentially related with the various forms of bradycardia, most frequently those due to atrio--ventricular block. In 1976, we have now reached a figure of about 200 new implantations of pacemakers per million inhabitants; those using lithium are increasingly superceding the mercury and isotope models.

Aged↗
PubMed1976

[Pacemakers 16 years later].

In 1976, 10 years after the first successful implantations, the pacemaker technique is perfectly well accepted. Transvenous placement of the electrode is preferred in 95 % of the cases. Besides the 15 years nuclear power pacers (1970), conventional mercury pacemakers may reach a longevity of 4 to 5 years because of the reduction of the current drain. Lithium iodine seems a very promising source of energy. The mini-pacemakers with various iodine anodes are particularly attractive. The future is probably a well designed medium sized lithium pacemaker lasting more than 7 years. Patient follow-up is very much improved. All pacemakers exhibit an obvious rate reduction when their source of energy runs down. Therefore general practitioner and even the patients may detect this symptom. The main problem remains the lead resistance. The reduction of the frequency of pacemaker replacements and of the medical check-up makes life more simple for the pacemaker patient.

Aged↗