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Biomedical subjects

M Bolens

Publications and source records attributed to M Bolens.

At least 19 recordsLinked to original sources
PubMed1995

Recurrent infections in children observed throughout electronic medical record.

This paper shows the usefulness of routinely collected structured clinical findings in an computerized patient record. Medical observations are collected as detailed clinical findings, without any interpretation, according to a time structure, visit by visit. In the present example, the role of the microbial colonization is studied in relationship with infected organs and other processes which could facilitate the infection.

Child↗
PubMed1990

Electrophysiological studies after the Mustard and Senning operations for complete transposition. Do they have prognostic value?

Overall, long-term survival after the Mustard or Senning operation is good, but late arrhythmias remain a concern. Whether postoperative electrophysiological investigations can identify patients at risk of developing serious arrhythmias is unknown. In this study, 16 children who underwent electrophysiological study after the Mustard or Senning operation for complete transposition (the combination of a concordant atrioventricular and a discordant ventriculo-arterial connexion) were followed up for one month to 9 years (mean 4.33 years) after this investigation. At the electrophysiological study, sinus nodal dysfunction was diagnosed in 9/16 patients, and abnormalities of atrial conduction and refractoriness in 7/13. During follow-up, 7 children developed clinical evidence of the sick sinus syndrome. When considering corrected sinus node recovery time as the only electrophysiological parameter, the sensitivity of predicting sick sinus syndrome from the electrophysiological study was 42%, and specificity 66%. The sensitivity increased to 71% if additional electrophysiological criteria of sinus node dysfunction were included, such as sinuatrial conduction time or sinus node entrance block, but specificity dropped to 55%. Atrioventricular conduction disturbances were rare. Thus, abnormalities at electrophysiological studies after the Mustard or Senning operations are frequent, but identification of patients at risk of developing sick sinus syndrome remains difficult.

Arrhythmia, Sinus↗
PubMed1988

Conduction disturbances after correction of tetralogy of Fallot: are electrophysiologic studies of prognostic value?

Late complete heart block may occur after correction of tetralogy of Fallot. Whether postoperative electrophysiologic studies can identify patients at risk of developing this conduction disturbance is unknown. In this study, 57 children who underwent electrophysiologic investigation after correction of tetralogy of Fallot were followed up for 1 to 13 (mean 6.5) years after the investigation. One late death and two cases of late complete heart block occurred. The late death was due to ventricular arrhythmia and not to a conduction disturbance. The cases of late heart block occurred 2 and 5 years, respectively, after electrophysiologic study, and in both cases the patient had a prolonged HV interval; in one patient progressive lengthening of the HV interval could be demonstrated at two subsequent studies 1 year apart. Another five patients with a prolonged HV interval had normally conducted sinus rhythm up to 11 years after study. Atrial pacing at increasing rates (up to the occurrence of second degree atrioventricular block) during electrophysiologic study was the best means of predicting late heart block: of three patients with block below the bundle of His occurring at pacing rates less than 180/min, two developed late complete heart block. Thus, electrophysiologic testing of the conduction system after correction of tetralogy of Fallot is useful in predicting late complete heart block and should be performed in patients with a history of transient heart block after surgery and in those with a prolonged PR interval.

Cardiac Pacing, Artificial↗
PubMed1987

Electrophysiologic effects of intravenous verapamil in children after operations for congenital heart disease.

To assess the effect of verapamil in children with congenital heart disease after surgical correction, an electrophysiologic study was undertaken in 19 patients, 0.8 to 15 years old. Atrial pacing and programmed atrial extrastimulation were performed before and 5 mn after intravenous administration of verapamil. A significant increase in conduction time and refractory periods was observed at the atrioventricular node level. Dual or accessory atrioventricular pathways, present in 14 cases, appear to have been suppressed in 9. The effect on the sinus node was of particular interest: The corrected sinus node recovery time was strongly prolonged by verapamil in 6 patients, 5 of whom had undergone surgery with extensive atrial reconstruction (Senning 2, anomalous pulmonary venous return 3) and 1 of whom had undergone correction of tetralogy of Fallot. Additional effects of verapamil were the disappearance of a sinus node entrance block in 8 patients and emergence of an ectopic pacemaker in 6. Although verapamil has electrophysiologic properties that should make it a useful drug in the treatment of reentry tachycardia, caution is indicated after extensive atrial surgery because sinus node depression may occur.

Adolescent↗
PubMed1985

Intraventricular conduction disturbances after correction of tetralogy of Fallot: can bifascicular and trifascicular block be diagnosed from the surface ECG?

To determine the origin of conduction disturbances commonly seen in the ECG after correction of Fallot's tetralogy, 36 children underwent electrophysiologic studies; these included endocardial recordings of right ventricular (RV) and left ventricular (LV) apical activation and His-bundle recordings. The surface ECG showed a pattern of complete right bundle branch block (RBBB) in 22, and RBBB with left-axis deviation (LAD)--so-called bifascicular block--in nine; the remaining five had RBBB, LAD, and a long PR interval, often considered as indicating trifascicular block. Eight of 22 patients with RBBB and normal axis had delayed RV apical activation (36%), indicating a proximal lesion. Of nine patients with RBBB and LAD, four only had delayed RV apical activation (44%); in the other five, therefore, the RBBB pattern was due to a peripheral lesion (ventriculotomy); they cannot be considered as having true bifascicular block. LV activation was not delayed in any case. In five cases, the surface ECG suggested trifascicular block (long PR in the presence of RBBB and LAD). His-bundle recordings showed the HV interval to be prolonged in only two cases, at the upper limit of normal in two, and short in one. The AH interval was prolonged in all and was mainly responsible for the long PR interval. Thus, the surface ECG is not a reliable tool for making a diagnosis of true bifascicular block and trifascicular damage after correction of Fallot's tetralogy. This may explain controversies existing about the prognosis of such conduction abnormalities.

Adolescent↗
PubMed1984

Sinus node function and conduction system before and after surgery for secundum atrial septal defect: an electrophysiologic study.

Arrhythmias are common in the natural history as well as in the late postoperative course of patients with atrial septal defect (ASD); electrophysiologic disturbances may result from the ASD itself or from surgery. Electrophysiologic studies were performed in 18 children (mean age 10 years) both before and after surgical closure of the ASD. Sinus node (SN) function, conduction intervals and refractory periods (atrial and atrioventricular [AV] nodal) were determined. Before surgery, corrected SN recovery time was prolonged in 14 patients; the mean value for the group was 357 +/- 163 ms. The AH interval was slightly prolonged, as were AV nodal refractory periods. Postoperatively, SN recovery time decreased in all patients who remained in sinus rhythm (p less than 0.02), but 5 patients had atrial ectopic rhythm. The AH interval decreased significantly (p less than 0.02), as did the refractory periods, mainly for the AV node (p less than 0.01). The pacing rate at which second-degree AV block occurred increased. Thus, closure of ASD improves AV conduction, decreases AV nodal refractory periods and improves SN function, probably by suppressing rightsided heart volume overload. However, SN function may be lost, probably as a result of the operative procedure.

Adolescent↗
PubMed1982

Progressive atrioventricular block after total correction of Fallot's tetralogy, documented by repeat electrophysiological studies.

A case of progressive trifascicular block late after correction of Fallot's tetralogy is reported. Progressive damage to the His bundle and/or its branches over 18 months after surgery was suggested by sequential ECGs and confirmed by repeat electrophysiological studies done 3 and 18 months postoperatively: the H-V interval increased from 55 to 80 ms over this period. With atrial pacing at increasing rates, supra-His 2:1 atrioventricular (AV) block occurred at a rate of 158/min at the first study; at the second study, infra-His block occurred at an atrial pacing rate of only 128/min. A permanent pacemaker was implanted prophylactically. 5 years after surgery, complete heart block occurred without symptoms, the pacemaker having taken over ventricular stimulation.

Bundle of His↗
PubMed1979

[Conduction of disorders after total correction of Fallot's tetralogy. Electrocardiographic and electrophysiological study].

The conduction defects observed after total correction of Fallot's tetralogy in 133 children, and their association with the long term outcome were studied with comparison of pre and postoperative electrocardiograms and, in 26 cases, His bundle recording. 23 early complete heart blocks were recorded which were nearly always transient. Only 4 (3.6%) became permanent. 58 had a right bundle branch block (48.4%) and 19 a bifascicular block (15.8%). The early operative mortality (9.7%) appeared to be related to transient complete heart block with 26% deaths in this group. Late mortality was high in patients with permanent heart block (2 out of 4) and also with bifascicular block (3 out of 17). His Bundle recordings showed lengthened H-V intervals in 3 patients, all of whom had transient complete heart block early post-operatively. In conclusion, complete heart block, even when transient, and bifascicular blocks are related to early and late mortality. The indications of permanent pacing, formal for patients with permanent complete heart block, are arguable for patients with bifascicular blocks preceded by postoperative complete heart blocks with long H-V intervals.

Adolescent↗
PubMed1976

Tricuspid atresia, hypoplastic right ventricle, intact ventricular septum and congenital absence of the pulmonary valve.

A case of tricuspid atresia by sealing of the valves, associated with an intact ventricular septum, a hypoplastic right ventricle and the absence of the pulmonary valve, is described. The foramen ovale and the ductus arteriosus were widely patent but there was no interventricular communication. The pulmonary flow was assured by the ductus which had a saccular continuation in the pulmonary trunk. It is postulated that the lesions probably occurred during the period between the XIX and XXII horizons and that the malformed right coronary artery may have played an important role in producing the lesions of the right ventricle.

Abnormalities, Multiple↗