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S Kacet

Publications and source records attributed to S Kacet.

At least 19 recordsLinked to original sources
PubMed1992

Signal-averaged electrocardiography and detection of heart transplant rejection: comparison of time and frequency domain analyses.

To evaluate the role of the signal-averaged electrocardiogram (ECG) in the detection of heart transplant rejection, findings on 277 ECGs were compared with those in 218 endomyocardial biopsy specimens in 25 patients followed up for a median duration of 5.2 months (range 7 days to 17.5 months). Signal-averaged ECGs obtained at intervals of 16.4 +/- 22.3 days were analyzed in the time domain before and after high pass filtering at 25 and 70 Hz. Frequency domain analysis was performed with use of a fast Fourier transform algorithm. Sixteen severe rejection episodes requiring treatment were observed. These episodes induced significant decreases in peak and root-mean-square voltages of both filtered and unfiltered QRS complexes, as well as in the total spectral area. Conversely, QRS duration and 50- to 250-Hz or 70- to 110-Hz spectral areas were not significantly altered. In 14 cases mild rejection episodes were observed that did not significantly alter any of the variables studied. The root-mean-square voltage of the 70-Hz high pass filtered QRS complex was found to be the most accurate variable in detecting rejection. Moreover, this variable was also the most reproducible in 10 healthy control subjects. The optimal rejection criterion was defined as an 11% decrease in voltage between two consecutive recordings. It provided 87.5% sensitivity with 78.4% specificity. In conclusion, the signal-averaged ECG is helpful in the management of heart transplant rejection. Frequency domain analysis of the QRS complex does not increase the accuracy of the technique compared with the time domain approach.

Adult↗
PubMed1992

Evaluation of bepridil efficacy by electrophysiologic testing in patients with recurrent ventricular tachycardia: comparison of two regimens.

The purpose of the study was to evaluate this effect of different doses of intravenous and oral bepridil on the induction of ventricular tachycardia. Thirty-eight patients underwent electrophysiologic evaluation for recurrent ventricular tachycardia (VT). Sustained monomorphic VT was induced by programmed ventricular stimulation, using up to three extrastimuli in all patients. The effects of intravenous bepridil (2 mg/kg) were evaluated during the initial study. Intravenous bepridil prevented the induction of sustained VT in eight patients (21%). Electrophysiologic study was repeated after oral bepridil. In six patients the study was stopped because of adverse effects or VT recurrence. Thirty-two patients underwent repeat study 7 days later, taking oral bepridil, 500 mg/day (n = 16) or 900/day (n = 16). A dose of 500 mg/day of bepridil prevented the induction of sustained VT in only one patient. A dose of 900 mg/day of bepridil prevented the induction of sustained VT in eight patients. There were no significant clinical adverse effects, except in one patient receiving intravenous bepridil. The response to intravenous bepridil did not predict the response to oral bepridil. The response to intravenous or oral bepridil was not related to the plasma level of bepridil but was related to a higher left ventricular ejection fraction. Eight patients (21%) in whom VTs were noninducible on oral bepridil were discharged on 300 mg/day of bepridil if their initial loading dose was 500 mg/day or on 600 mg/day if their initial loading dose was 900 mg/day. They remained free of VT during a follow-up of at least 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

Effects of consecutive administration of central and peripheral anticholinergic agents on respiratory sinus arrhythmia in normal subjects.

Respiratory sinus arrhythmia is thought to be vagally mediated, since it disappears after atropine, but the site of action of the drug (central vs. peripheral) accounting for this effect has not been elucidated. To investigate the effects of anticholinergic agents on respiratory arrhythmia, ten healthy subjects received an intravenous bolus of tropatepine (a presumed central antagonist) at a dose of 0.08 mg per kg of body weight, then, 7 min later, prifinium (a peripheral antagonist) at a dose of 0.1 mg per kg of body weight. Respiratory sinus arrhythmia during controlled breathing was evaluated as the area under the high-frequency peak of the heart rate variability spectrum coinciding with the respiratory frequency +/- 0.02 Hz. The power of this high-frequency peak decreased by 55% after tropatepine (P less than 0.05) with a concomitant increase of the mean RR interval from 930 to 1072 ms (P less than 0.01). When prifinium was added, a further but non-significant decrease of respiratory arrhythmia was observed, while the mean RR interval decreased from 1072 to 714 ms (P less than 0.01). The low-frequency components (0.05 to 0.15 Hz) of the power spectrum, significantly decreased (P less than 0.05) after infusion of both drugs. In conclusion, tropatepine depresses respiratory sinus arrhythmia with a paradoxical concomitant bradycardia. This suggests that tropatepine acts like a pure central muscarinic antagonist, in support of the hypothesis that a central cholinergic receptor is involved in the respiratory modulation of heart rate.

Adult↗
PubMed1992

[Interference between cardiac pacemaker and electromagnetic anti-theft devices in stores].

Electromagnetic anti-theft devices in shops comprise large diameter magnetic induction coils between which the shoppers pass. This study was undertaken with a simulator to assess the behaviour of different models of single and double-chamber pacemakers when exposed to 6 stereotyped and repetitive situations of 4 different electromagnetic anti-theft devices. Of the 35 pacemakers tested, 25 developed serious dysfunctions: 14 long-lasting inhibitions (over 3 seconds), 2 stimulations at maximal frequency, 2 electrical bradycardias and 2 permanent reprogramming. These dysfunctions due to electromagnetic interference are observed in old or modern, monopolar or bipolar pacemakers, and seem to be influenced by the amplitude and complexity of the signals emitted by the detectors. These observations justify a clear signalization warning pacemaker patients of a potential danger.

Electromagnetic Fields↗
PubMed1992

[Influence of age and body surface on the signal averaged high amplification ECG after complete repair of tetralogy of Fallot].

The aim of this study was to assess the influence of age and body surface area on the signal averaged ECG after complete repair of Tetralogy of Fallot. Fifty eight patients operated for Tetralogy of Fallot in whom the postoperative ECG showed right bundle branch block without any significant arrhythmia on Holter monitoring or exercise stress testing underwent signal averaged electrocardiography. A very significant relationship was observed between age and body surface area and the duration of the filtered QRS (r = 0.45, p = 0.0004 and r = 0.49, p = 0.00009 respectively) or the average voltage of the last 40 milliseconds (r = -0.49, p less than 0.03 and r = -0.31, p less than 0.02 respectively). Therefore, signal averaged ECG in patients operated for Tetralogy of Fallot varies with age and morphology. An adjustment of the parameters of the signal averaged ECG with respect to clinical characteristics is necessary before assessing the value of this technique for identifying patients at risk of developing ventricular arrhythmias.

Adolescent↗
PubMed1991

Bipolar atrial triggered pacing to restore normal chronotropic responsiveness in an orthotopic cardiac transplant patient.

A not uncommon arrhythmia in cardiac orthotopic transplantation patients is sinus node dysfunction with chronotropic incompetence. This is a result of the surgical procedure that denervates the donor heart while the native sinus node may be normal but isolated in the remnant of the recipient atrial wall that serves as the anastomotic site. We were able to restore "normal sinus node function" in a heart transplant patient utilizing a bipolar single chamber pacemaker programmed to the triggered mode. A single unipolar active fixation lead was positioned in each atria. Both leads were connected to a bipolar AAT pulse generator utilizing a Y adaptator. The native atrium with its innervated intact sinus node effectively drove the donor atrium and thus the heart.

Arrhythmia, Sinus↗
PubMed1991

Wenckebach periods in sinoatrial block: experimental and clinical evidence.

The reality of sinoatrial Wenckebach periods (WP) has been suggested, but not proven, in the literature. We report experimental and clinical data showing WP in sinoatrial blocks. Experimental sinoatrial blocks were induced by superfusion of bepridil (10(-5) M) in 15 preparations of isolated rabbit right atria. Different types of block were observed, including Blumberger I block, i.e., sinoatrial WP. The recordings showed that the typical pattern of Blumberger type IA block and sinoatrial WP may be due to transient acceleration of the sinus rate, without change in the increment. We also observed sinoatrial WP in a 72-year-old patient on direct recordings of the sinus node (SN) electrical activity. In this case, transient acceleration of the sinus rate also seemed to be involved in the genesis of sinoatrial WP. Analysis of these clinical and experimental data showed similarities that may explain the mechanism of the WP. Usually type IA Blumberger block is said to involve a decrease in the sinoatrial increment to explain the atrial sequence (decrease in PP interval followed by a pause shorter than twice the value of the preceding cycle, then a cycle longer than the one preceding the pause). In fact, this pattern can be observed when the acceleration of the higher structure, the SN, induces block within the lower structure, i.e., the atrium.

Action Potentials↗
PubMed1991

[Prolongation of the CAST study.Is it justified to consider another trial?].

A possible prolongation of the CAST would be another trial of the same type, (CAST II), designed for high risk patients (1 year mortality over 20%). The aim of this study would be to confirm the hypothesis that the ratio efficacy/undesirable side effects of antiarrhythmic drugs is beneficial in this type of patient. The most important selection criteria would be an ejection fraction of less than 40%, the presence of repetitive arrhythmias, especially ventricular tachycardia on Holter monitoring and the recording of late ventricular potentials on surface averaging ECG. The patients would be included at about the 20th day after myocardial infarction in order to exclude as much as possible unstable coronary artery disease and ventricular arrhythmias on successive Holter recordings because this would make interpretation of the efficacy of antiarrhythmic drugs impossible. The ideal number of patients would be about 5,000 but this is unrealistic because the trial would only include high risk cases and there would be difficulties in recruiting this number even in a multicenter trial. During follow-up of 2 to 3 years, the surveillance of the therapeutic efficacy of the antiarrhythmics would have to be better than in the CAST. The most delicate methodological problem would be the randomization of patients as the formation of a placebo group is unethical in high risk coronary patients with severe or malignant ventricular arrhythmias. The use of the only proved cardioprotector drugs, the betablockers, in all these high risk patients would be one solution, even if it might introduce a bias in the results.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Arrhythmia Agents↗
PubMed1991

[Prognostic value and development of late potentials after aortocoronary bypass. A prospective study of 100 patients].

Ventricular late potentials are post-infarction markers of the risk of ventricular tachycardia and sudden death. In order to assess their prognostic value and evolution after coronary bypass surgery, 100 patients underwent signal-averaged electrocardiographic recordings 24 hours before and 9 days after surgery, and were then prospectively followed up for 40 +/- 8 months. Patients who displayed late ventricular potentials underwent an additional recording at 5 months with 24 hour Holter monitoring. The average age of the patients was 57.0 +/- 8.4 years; 55 had previous myocardial infarction; 32 had triple vessel disease; the mean left ventricular ejection fraction was 59.7 +/- 12.4%. Ventricular late potentials were recorded in 17 patients before surgery and their left ventricular ejection fraction was significantly lower (51.4 +/- 11.5% vs 61.4 +/- 11.9%: p less than 0.05). There was one operative death in a patient with late ventricular potentials. After surgery, late ventricular potentials were only recorded in 6 patients: at the 9th postoperative day in 3 cases and at the 5th postoperative day in 3 cases. Ventricular late potentials appeared postoperatively in 5 patients, 4 of whom had suffered perioperative myocardial infarction. The recordings became normal at the 5th month in 2 of these 5 patients. Holter monitoring at the 5th month compared with a control group, showed a significant correlation between left ventricular potentials and frequent repetitive or polymorphic ventricular extrasystoles. The 40 month survival rate was excellent: 2 patients were lost to follow-up; there were 3 cardiac deaths, one of which was sudden and 4 non-cardiac deaths. All patients with late ventricular potentials were still alive. These results show that late ventricular potentials persist after coronary bypass surgery in 2/3 of patients; their prognostic significance is not obvious. The low incidence of postoperative sudden death could be attributed to the favourable overall effects of revascularisation rather than on the arrhythmogenic substrate.

Adult↗
PubMed1991

[Holter monitoring, exercise test and atropine test in isolated congenital atrioventricular block in children].

Twenty-four patients with isolated congenital heart block were investigated by 24-hour Holter monitoring at an average age of 9.3 +/- 5.5 years. Six patients were symptomatic and 18 were asymptomatic. Eight asymptomatic patients underwent exercise stress tests and an atropine test was performed in 10 asymptomatic patients to evaluate the capacity to accelerate the heart rate. The symptomatic patients were older than the asymptomatic patients. None of the parameters which analyse ventricular rate were significantly different in the two groups of patients. Significant ventricular arrhythmias (Lown Grade 2 or over) were recorded in 1 symptomatic and 3 asymptomatic patients. The incidence of these ventricular arrhythmias increased with age and degree of bradycardia. The percentage increase in ventricular rate after atropine correlated with what was observed on effort (r = 0.95, p = 0.01) but there was no relationship between the ventricular rates during these two tests and those recorded on Holter monitoring. The results of this series of children with isolated congenital heart block show the Holter parameters cannot distinguish symptomatic from asymptomatic patients. The exercise stress and atropine tests gave very similar results but their prognostic value has not yet been established.

Adolescent↗
PubMed1991

[Circumferential laser thermo-exclusion of post-infarction ventricular tachycardia. Apropos of 11 cases].

Circumferential laser thermoexclusion was assessed in the treatment of postinfarction ventricular tachycardia resistant to drug therapy in 11 patients between December 1986 and April 1989. There were 10 men and 1 woman with an average age of 63.7 +/- 5.6 years whose ventricular tachycardia occurred 10.7 +/- 7.5 years after infarction. All had left ventricular aneurysm or an akinetic plaque. Circumferential thermoexclusion was carried out by Mesnildrey's method, systematically associated with resection of the aneurysm or, when this was not feasible, with coronary revascularisation. Programmed ventricular stimulation was performed before and after surgery in 8 patients. Sustained ventricular tachycardia remained inducible in 4 patients after surgery but the prescription of antiarrhythmic drugs in 2 of these cases resulted in tachycardia becoming non-inducible. The increase in the left ventricular ejection fraction after surgery was not statistically significant (36.9 +/- 9.4% to 44.4 +/- 12.8%). After an average follow-up of 16.7 +/- 10.6 months, there were 2 cardiac deaths not related to arrhythmias (18%), 1 early at the 20th postoperative day and 1 late, 10 months after surgery. There were 2 recurrences of tachycardia (18%) controlled by antiarrhythmic therapy. Late ventricular potentials were recorded in 9 out of the 11 patients before surgery but in only 3 of these cases (33%) after surgery. Circumferential laser thermoexclusion guided visually in the border zone of the infarct scar would seem to be a simple, safe, rapid and therefore attractive, surgical antiarrhythmic technique, the efficacy of which should be evaluated by programmed ventricular stimulation. This should be undertaken on a large scale in order to define the indications and results of this method.

Aged↗
PubMed1990

[Late potentials].

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Arrhythmias, Cardiac↗
PubMed1989

[Drug-induced major anomalies of ventricular repolarization masked by a left branch block].

The presence of a left bundle branch block (LBBB) may hamper the electrocardiographic diagnosis of diseases that involve the QRS complexes. That it may conceal, or even completely erase, major abnormalities of ventricular repolarization induced by certain drugs is not so well known. In this paper, two highly demonstrative examples of such abnormalities observed with bepridil (case 1) or with the amiodarone-aprindine combination (case 2) are reported. In both cases, the intermittent character of the LBBB revealed the phenomenon which deserves to be known as it is not without practical consequences: in patients under treatments likely to modify repolarization and induce severe dysrhythmias (notably torsades de pointes) the presence of a LBBB indicates that the QT and/or QU intervals must be very carefully measured. In case of phase 3 LBBB compression of the carotid sinus or intravenous ATP injection helps the diagnosis since in the presence of even moderately prolonged ventricular cycles such manoeuvres create a refinement of QRS complexes which then demonstrate the major alteration of the underlying repolarization.

Aged↗
PubMed1988

Comparative cardiac effects of intravenous bolus of ipratropium bromide (itrop) and atropine sulfate in 22 patients.

At the present time, there is no satisfactory pharmacological treatment for arrhythmia or conduction disorders induced by or aggravated by vagal hypertonia. The limited duration of action of the atropine derivatives currently available justifies the development of new compounds with expected longer acting duration. The aim of this study was to compare the effects of a single blind intravenous injection of ipratropium bromide to those of atropine sulfate in 22 patients. These patients were studied with continuous Holter recordings for three days. During the second and the third nights (patient sleeping), boluses of atropine (0.03 mg/kg) and of ipratropium bromide (0.03 mg/kg), respectively, were added to a continuous saline intravenous infusion. Accurate ECG analysis allowed determination of maximal heart rate peak, timing of maximal heart rate, variations in sinus cycle length, atrioventricular conduction, and durations of drug action. A nonsuggestive questionnaire was presented to patients to detect possible occurrence of side effects. The mean maximal heart rate rose significantly (p less than 0.001) for atropine (+46.2%) and for ipratropium bromide (+57.4%). The effects obtained with ipratropium bromide on the heart rate lasted nearly twice as long as those obtained with atropine (respectively, 120 +/- 38.4 min and 70 +/- 30 min- for the pharmacological half-life). Common minor muscarinic side effects (dryness of the mouth) were noted with the two drugs. In conclusion, this comparative intraindividual study confirmed the prolonged vagolytic effects of intravenous ipratropium bromide, which may be valuable in the treatment of patients with vagally mediated automaticity and conduction disturbances.

Adult↗
PubMed1988

Electrophysiological effects of intravenous nicaïnoprol, a new antiarrhythmic agent, in 11 patients.

Nicaïnoprol, a new class 1 antiarrhythmic drug was given intravenously in a dose of 2 mg kg-1 of body weight (two patients) and 3 mg kg-1 of body weight (nine patients), and the clinical, electrocardiographic and electrophysiological effects were studied. Fifteen minutes after the end of drug administration, the PR interval was prolonged by 24.4% (P less than 0.001), and the QTc by 3.9% (P less than 0.01). The prolongation of QRS duration (+6%) was not significant. There was a slight (-3.9%) but non-significant decrease of the heart rate, with no alteration in sinus node function. Alteration of atrial conduction and atrioventricular (AV) conduction were due to an increase in the PA interval (+57.4%, P less than 0.05), the AH interval (+10.9%, NS) and the HV interval (+43.8%, P less than 0.01). The anterograde Wenckebach cycle length increased by 11% (P less than 0.01). The effective and functional atrial refractory periods increased respectively by 4.5% and 11.4% (P less than 0.05), and the effective refractory period of the AV node increased by 11.2% (P less than 0.05). None of the other electrophysiological variables changed significantly. A non-significant drop in blood pressure was noted between the second minute following injection (-9.4%) and the 15th minute (-3.4%), and two patients complained of dizziness; one of these two patients reported a heat flush with an oral burning. In conclusion, nicaïnoprol seems to possess the electrophysiological properties of some other class I antiarrhythmic drugs, and is clinically well tolerated.

Adult↗
PubMed1988

[Late ventricular potentials. Clinical applications and relation to severe ventricular arrhythmias].

The recording of late ventricular potentials with high amplification cardiography (HAC) permits to identify patients presenting a risk of sudden death and ventricular tachycardia, especially in the later stage of myocardial infarction. Few authors have studied the prevalence of these potentials in other heart diseases presenting a risk of sudden death. Most series in the literature are too small to specify variations in the prevalence of these potentials according to the severity of the coronary disease. For this purpose, 835 patients including 535 coronary patients were evaluated with HAC compared to data from coronary angiography and Holter test. An automatic quantification method of the late potentials was used on 131 healthy subjects. The prevalence of late potentials is 32 p. cent after infarction, and 75 p. cent when a chronic ventricular tachycardia is present. These potentials retain their significance of tracers of ventricular arrhythmias in primary dilated myocardiopathies, with a prevalence of 25 p. cent reaching 50 p. cent in case of ventricular tachycardia. Their recording in the presence of idiopathic ventricular extrasystoles must be an indication to look for an underlying cardiopathy. It is possible to record them in other diseases especially in advanced valvular cardiopathies, as well as in right ventricular dysplasias with arrhythmia where their presence has a great diagnostic value.

Arrhythmias, Cardiac↗