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Biomedical subjects

L Jacquemin

Publications and source records attributed to L Jacquemin.

44 records · Page 3Linked to original sources
PubMed1996

Significance and prevalence of inducible atrial tachyarrhythmias in patients undergoing electrophysiologic study for presyncope or syncope.

The purpose of the study was to report the prevalence of inducible supraventricular tachyarrhythmias (SVTA) in 827 consecutive patients aged 17 to 90 years who did not have spontaneous documented SVTA and who had unexplained presyncope and/or syncope. The electrophysiologic study (EPS) included programmed atrial and ventricular stimulation up to two extrastimuli at three cycle lengths, and the study of sino-atrial and AV conduction. The results were as follows. EPS was normal in 386 patients. Inducible junctional tachycardia or atrial flutter and fibrillation was the only finding in 187 patients (23%). In the remaining patients we found ventricular tachycardia in 103 (12%), heart block in 67 (8%), sick sinus syndrome in 56 (7%) and increased vagal tone in 28 (3%). The presence of an underlying heart disease (47%) and salvos of atrial premature beats on Holter monitoring (39%) were significantly correlated with the induction of SVTA. However, the comparison with similar groups without syncope indicates that only the induction of SVTA in patients with hypertrophic cardiomyopathy and mitral valve prolapse was significantly correlated with the history of syncope. In patients without heart disease or with prior myocardial infarction or decreased left ventricular function, the induction of SVTA, which is not associated with hypotension in the supine position, could require an induction after head-up tilting, because of the lack of specificity of programmed stimulation in these patients. Programmed atrial stimulation should be systematically performed in patients with unexplained syncope, in particular in those with hypertropic cardiomyopathy and mitral valve prolapse, who require a specific treatment, if a SVTA is induced. In other patients the results of programmed atrial stimulation should be interpreted cautiously.

Adolescent↗
PubMed1996

[Heart rate response to ventricular stimulation].

Analysis of heart rate variability (HRV) by Holter monitoring is the method of choice for assessing the cardiac autonomic regulation. Rapid ventricular stimulation also provokes changes in the autonomic nervous system tone. The aim of this study was to compare time and frequency domain analysis of HRV (Elatec version 3.02) with variations of HR observed after incremental ventricular stimulation to 200/min in 130 patients. In 80 patients, ventricular stimulation provoked an initial acceleration in HR followed by a slowing with a variation of over 10%. In the other 50 patients, these variations were not observed. Holter analysis of HRV showed concordance between the two methods. In time domain analysis, the standard deviation of normal R-R intervals, the coefficient of variability [(CV = SD/mean RR) and percentage of adjacent RR intervals with a difference of more than 50 msec (pNN 50) were significantly reduced in the abnormal group, the respective values in the normal and abnormal groups being: SD 122 vs 72 msec; CV 15 versus 9% and pNN50 9 versus 5%)]. In frequency domain analysis, there was a reduction of low and high frequency spectra and of the ratio of low/high frequencies in abnormal subjects. The authors conclude that the disappearance of HR changes after ventricular stimulation is correlated to the absence of HRV on Holter recording. This simple test may be performed systematically during electrophysiological investigations. The measurements are reproductible and the results are not affected by arrhythmias or technical problems of quality recording by the Holter method which may affect analysis of HRV.

Adult↗
PubMed1996

[Can signal-averaged electrocardiograms be interpreted in cases of complete bundle branch block?].

The aim of this study was to evaluate the results of signal-averaged (SA) ECG in cases of complete right (RBBB) or left bundle branch block (LBBB). One hundred and seven patients had RBBB; 42 without cardiac disease (0), 56 with chronic myocardial infarction (MI) and 9 with primary cardiomyopathy (CMP). Seventy-four patients had LBBB: 20 without cardiac disease, 26 with chronic myocardial infarction and 28 with primary cardiomyopathy. A SA ECG (Cardionics, Fidelity) was performed with a 40 Hz band pass and compared with the recordings of 72 healthy controls without bundle branch block. The duration of the averaged QRS (QRS dur), the voltage of the last 40 milliseconds (RMS40) and duration of terminal activity < 40 microV (LAS) were measured. The analysis of results showed that QRS dur was significantly longer in subjects with ventricular tachycardia (VT) (p < 0.05) and in those with advanced cardiac disease (p < 0.05), whatever the type of bundle branch block, and that only the RMS40 distinguished patients with VT from those without VT, irrespective of the underlying cardiac disease and the type of bundle branch block. However, the study of the diagnostic value of each parameter showed very mediocre results: RMS 40 < 20 microV in myocardial infarction and < 17 microV in cardiomyopathy had sensitivities and specificities in RBBB of 73% and 50% respectively, incalculable in CMP, in LBBB 70% and 33%, 77% and 60% respectively; the LAS was unusable. The authors conclude that it is hazardous to interprete SA ECG in bundle branch block, especially in advanced cardiac disease where the specificity of the criteria becomes very low (< 50%).

Bundle-Branch Block↗
PubMed1996

[Complete atrioventricular block, a possible complication of radiofrequency ablation of reciprocating nodal tachycardia].

Radiofrequency ablation of the slow pathway of the reentry circuit is the usual radical treatment of nodal tachycardia. It is, however, possible to create atrioventricular conduction defects, the significance of which is not known. The aim on this study was to report the history of these conduction defects created during ablation of the slow pathway of the intranodal reentry circuit. Four cases were observed in a series of 27 patients. In one female patient, complete atrioventricular block was observed for 5 minutes before conduction returned to normal followed by recurrence of the tachycardias. Three other women developed complete atrioventricular block one to four days after the ablation. The block regressed after a maximum delay of 7 days. Six months to one year after the procedure, these three patients remain free of tachycardia and have only first degree atrioventricular block on the surface ECG. These patients were not implanted with a pacemaker. The authors conclude that complete atrioventricular block after ablation of the slow pathway may be treated conservatively, providing it is well tolerated. It normally regresses within few days.

Adult↗
PubMed1996

[Syncopes associated with mitral valve prolapse. Mechanisms].

Prolapsed mitral valve prolapse (PMV) is classically associated with disorders of ventricular excitability whose significance is unclear. However, syncope can suggest the possibility of a serious ventricular arrhythmia. The objective of this study was to try to identify the mechanisms of dizziness and syncope associated with PMV. We report the results of programmed atrial and ventricular stimulation performed under baseline conditions and after administration of Isuprel in 56 patients with PMV: 27 patients had a history of presyncope or syncope (group I), 14 had spontaneous atrial or supraventricular tachycardias without dizziness or syncope (group II) and 15 were asymptomatic and investigated for VEBs or conduction disorders (group III). The following results were obtained: In group I, 6 patients experienced sustained inducible ventricular tachycardia (VT); an atrial tachycardia (atrial tachycardia and/or atrial fibrillation) (AT) was also induced in 5 of them. In another 19 patients, a supraventricular tachycardia (SVT) and/or AT was induced. A total of 24 atrial or junctional tachycardias were triggered in this group. In group II, AT and/or SVT were reproduced in 13 out of 14 cases (93%). In group III, AT was triggered in 3 patients (20%). SVT were induced by Isuprel while AT were triggered prior to administration of Isuprel, under baseline conditions, and 3 of them were reproduced during vagal manoeuvres. A ventricular arrhythmogenic effect was observed in two cases in group II while taking class I antiarrhythmics. In conclusion, spontaneous AT and SVT of PMV are easily inducible with a sensitivity of 93%, but are difficult to induce in asymptomatic subjects. The high incidence of TA and SVT in the case of unexplained presyncope in subjects without documented tachycardia therefore appears to be suggestive of a relationship between these presyncopes and AT or SVT. However, the search for VT should take precedence. SVT appear to be catecholaminergic while AT tend to be vagal.

Adolescent↗
PubMed1996

[Should protocol of programmed ventricular stimulation be adapted to each patient? ].

The authors report the case of a 56 year old patient in whom the mechanisms of a wide QRS complex tachycardia recorded on an intensive care monitor could not be determined. The patient also had episodes of atrial flutter with left bundle branch block. Programmed ventricular stimulation with 3 extrastimuli triggered a non-specific ventricular flutter. One week later, the patient was resuscitated from a cardiac arrest which was undocumented. It was therefore important to elucidate the mechanism of the initial tachycardia. A second session of programmed ventricular stimulation was undertaken. As the use of 2 extrastimuli triggered runs of unsustained polymorphic ventricular tachycardia, the classical protocol was stopped. An infusion of low-dose isoproterenol was used to repeat programmed stimulation with a single extrastimulus. This protocol triggered sustained monomorphic ventricular tachycardia at 240/min. The diagnosis of ventricular tachycardia could therefore be continued.

Cardiac Pacing, Artificial↗
PubMed1995

[Influence of the duration of myocardial infarction on QRS duration measured by signal averaged electrocardiography].

The aim of this study was to determine the influence of the chronicity of myocardial infarction on QRS duration. The signal-averaged electrocardiogram (SA ECG) was recorded with a 40 Hz filter in 239 patients with a history of myocardial infarction. The infarction was recent (up to 6 weeks) in 105 patients (group A) and chronic (> 1 year) in the other 134 cases (group B). In group A, 35 patients had inductible sustained ventricular tachycardia (VT) at less than 270/mn; 40 had negative electrophysiological investigations and 30 had inducible ventricular flutter or fibrillation (VF). In group B, 58 had inducible VT, 54 had negative investigations and 22 had inducible VF. The three SA ECG parameters (QRS duration, amplitude of RMS 40 and duration of LAS) differed significantly in subjects with VT with respect to those with negative investigations and inducible VF, irrespective of the chronicity of infarction. On the other hand, only QRS duration differentiated patients with recent infarction from those with chronic infarction, irrespective of the results of programmed pacing, QRS duration being longer in group B. The best diagnostic value of QRS duration for identifying subjects with VT < 270/mn and negative investigations was 110 ms in group A and 120 ms in group B (sensitivity 46% and 77.5% respectively). In chronic infarction, the increase in QRS duration was significantly correlated to the decrease in left ventricular ejection fraction. The authors conclude that the criteria of abnormality of QRS duration are dependent on the chronicity of myocardial infarction. Although a duration of 110 ms is abnormal in the early post-infarction period, after a period of one year, a value of 120 ms should be considered to be pathological, especially when the sequellae of infarction are important.

Adult↗