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Biomedical subjects

S Kacet

Publications and source records attributed to S Kacet.

At least 73 records · Page 4Linked to original sources
PubMed1994

Vasospastic angina without flow-limiting coronary lesions as a cause for aborted sudden death.

Two patients resuscitated from out-of-hospital cardiac arrest were later found to have minor coronary atherosclerosis and no inducible ventricular arrhythmia. Coronary spasm was not elicited during provocative tests but occurred on introduction of the catheter in the right coronary artery and spontaneously recurred after resuscitation, leading to myocardial infarction in one patient. Both patients received an implantable cardioverter defibrillator and subsequent discharges, while receiving calcium antagonists.

Adult↗
PubMed1994

[Thromboembolic complications of arrhythmia due to atrial fibrillation].

Fifteen per cent of cerebrovascular accidents have a cardiac origin, two thirds of which are due to atrial fibrillation (AF). The Framingham study showed the risk of an ischaemic cerebral event to be increased by 5.6 in AF unrelated to rheumatic heart disease and by 17.5 when AF is associated with valvular heart disease. The risk of embolism is higher in elderly subjects and in those with underlying cardiac disease. Other high risk conditions include hypertension, diabetes, hyperthyroidism and cases with echocardiographic changes: left atrial dilatation, pre-thrombotic state or intra-atrial thrombus, atheroma of the ascending aorta. This stratification of risk should be taken into account when deciding on treatment. Conscious of the importance of the risk of embolism in AF, several authors have undertaken, over the last few years, randomised studies of the prevention of thromboembolic complications of AF: the AFASAK, BAATAF, SPAF and SPINAF trials. All showed the unquestionable efficacy of warfarin, even at low doses, at the price of a haemorrhagic risk of less than 2% per year for severe haemorrhages. A more recent study (SPAF II) confirmed the value of aspirin at the dosage of 325 mg/day which would seem to be a good alternative to anticoagulant therapy when this is contraindicated, although aspirin is less effective. The indications for anticoagulant therapy have become clearer since the publication of these results. Anticoagulant therapy is essential in permanent AF whether or not associated with rheumatic heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Influence of clinical and hemodynamic characteristics on signal-averaged electrocardiogram in postoperative tetralogy of Fallot.

This study examines the relation between signal-averaged electrocardiographic measurements and the occurrence of spontaneous ventricular arrhythmias in 86 patients with a postoperative right bundle branch block after repair of tetralogy of Fallot; special attention was given to the influence of age, body surface area and right ventricular systolic pressure on signal-averaged electrocardiograms. Twenty-eight of the 86 patients had significant ventricular arrhythmias on 24-hour ambulatory monitoring. A positive linear correlation was found between filtered QRS duration and age at evaluation or body surface area (r = 0.45, p = 0.00001; r = 0.54, p < 0.00001, respectively) and between amplitude of the last 40 ms of the filtered QRS and right ventricular systolic pressure (r = 0.48, p < 0.001). A negative linear correlation was found between amplitude of the last 40 ms of the filtered QRS and age at evaluation or body surface area (r = -0.27, p = 0.01; r = -0.34, p = 0.002, respectively). When the age of the patients or the body surface area was considered with an analysis of covariance, the presence of ventricular arrhythmias was associated with a higher amplitude of the last 40 ms of the filtered QRS. In addition, an amplitude of the last 40 ms of the filtered QRS > 170 microV had an excellent sensitivity (100%) and a good specificity (88%) for identifying patients with both right ventricular systolic hypertension and spontaneous ventricular arrhythmia. Thus, adjustment of signal-averaged parameters for age at evaluation and body size is mandatory when studying postoperative tetralogy of Fallot.

Adolescent↗
PubMed1993

Acute electrophysiological effects of intravenous milnacipran, a new antidepressant agent.

Milnacipran is a new antidepressant agent selected from a series of cycloproprane derivatives. The aim of this study was to investigate the acute electrophysiological effects and the tolerance of intravenous administration of this drug in 10 patients without any abnormality as shown in an electrophysiological study done for various complaints. Milnacipran was given over a 30-min period at doses of 0.2 mg/kg (2 patients), 0.4 mg/kg (2 patients) and 0.8 mg/kg (6 patients). The most significant alterations observed in this study were increases in heart rate (average of maximal increase: +19.5% at 50 min, P = 0.06) and systolic blood pressure (average of maximal increase: +21.5% at 10 min, P < 0.005), and decreases in the functional refractory period of the atrium (-3%, P < 0.05), the atrioventricular node (-9%, P < 0.005) and the effective refractory period of the right ventricle (-10.8%, P < 0.05) at 50 min. The sinus node function was improved in nine patients but depressed in one patient with previous slight baseline sinus node alterations. Milnacipran being devoid of both anticholinergic and monoamine oxidase inhibition activities, these alterations could be related to inhibition of noradrenaline uptake leading to an increase of adrenergic activities. No other ECG or electrophysiological parameters were significantly altered. Five of the 10 patients reported transient nausea, four of them for the highest dosage (0.8 mg/kg) and at the moment of peak of milnacipran plasma level. In conclusion, electrophysiological effects of intravenous milnacipran are negligible. These findings differ from those, well described in the literature, for imipramine-like antidepressant agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

[Efficacy and tolerability of sustained-release disopyramide in the treatment of cardiac arrhythmia. Results of a study with 593 patients].

In the context of an open multicentre study, 593 patients participated in the evaluation of sustained release disopyramide (*) in the treatment of cardiac arrhythmias. One hundred and seventy one (29%) had a ventricular arrhythmia, 382 (64%) a supraventricular arrhythmia and 40 (7%) an atrial and ventricular arrhythmia. Two hundred and seventy patients (46%) had underlying cardiac disease. Disopyramide was administered at the mean daily dose of 462 +/- 95 mg. The effectiveness of treatment was assessed after 3 and 6 months by Holter in the group treated for ventricular arrhythmias, the responder rate was 52.6% at three months and 58.1% at 6 months. It was significantly (p < 0.001) greater in the group treated for supraventricular arrhythmias (71.3% at 3 months and 82.1% at 6 months). The Holter responder rate in patients aged over 65 (70.5% at 6 months) was high and general and cardiac acceptability similar to that in younger patients. Adverse events led to the interruption of treatment in 8.2% of patients. Thus the effectiveness/acceptability ratio of SR disopyramide makes it entirely appropriate for the treatment of cardiac arrhythmias, even in the elderly.

Adult↗
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↗