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N Saoudi

Publications and source records attributed to N Saoudi.

At least 55 records · Page 3Linked to original sources
PubMed1995

Radiofrequency catheter ablation of type 1 atrial flutter. Prediction of late success by electrophysiological criteria.

BACKGROUND: Radiofrequency energy has demonstrated its efficacy in catheter ablation of atrial flutter (AFl). However, long-term recurrences of AFl have been reported frequently after initial, apparently successful ablation. To date, criteria for prediction of late recurrences are lacking. METHODS AND RESULTS: Twelve patients (10 men; mean age, 53.6 years; range, 26 to 69 years) were referred for AFl ablation. Duodecapolar and decapolar catheters were used for detailed mapping of the tricuspid ring, the inferior vena cavatricuspid annulus (IVC-TA) isthmus, and the coronary sinus ostium (CSOs) area. Additional multipolar catheters were used for recording activation of the coronary sinus and the CSOs-TA isthmus. AFl was present at baseline in 9 patients and was induced by proximal coronary sinus (PCS) pacing in 3. Counterclockwise right atrial activation was recorded in all patients. Primary success of ablation was defined as when AFl was no longer inducible even during isoproterenol infusion. AFl was successfully ablated in all 12 patients, with a median of 4 pulses delivered at the IVC-TA isthmus. In the 3 patients in whom AFl was induced, during PCS pacing in sinus rhythm before ablation, a collision of descending and ascending wave fronts was observed at the middle lateral right atrium (LRA). This activation pattern of the LRA also was noted after unsuccessful radiofrequency applications. Noninducibility of AFl after radiofrequency applications was associated with a change of activation pattern at the LRA and with an inversion of the activation sequence of the IVC-TA isthmus (from clockwise to counterclockwise) in 9 patients when pacing from the PCS. In 2 of 3 patients, despite noninducibility of atrial flutter, ablation was pursued to obtain evidence of permanent block of conduction at the IVC-TA isthmus. Finally, a completely descending LRA wave front was observed when pacing from the PCS in all patients except one. Low LRA pacing was also performed in 4 patients and showed evidence for block in the counterclockwise direction at the isthmus. During a follow-up of 9 +/- 3 months, AFl recurred in 1 patient; this was the only patient who showed no conduction block at the isthmus after the procedure. CONCLUSIONS: Direction of impulse propagation at LRA and block of propagation at the IVC-TA isthmus during PCS and low LRA pacing appear to be of interest in predicting long-term success of AFl ablation.

Adult↗
PubMed1995

Dynamics of, and alternating Wenckebach periods during, 4:1 and 6:1 atrioventricular block.

In summary, the irregular dynamics of progression of 4:1 AV block in atrial flutter, presumably different from those observed in similar degrees of rate-dependent block, most likely reflected the complex electrophysiologic mechanisms operating during the highest degrees of AV nodal block. Occurrence of previously undescribed arrhythmias, namely Wenckebach periods during 4:1 and 6:1 block, tends to support the multilevel block hypothesis.

Atrial Flutter↗
PubMed1995

Dobutamine stress echocardiography in orthotopic heart transplant recipients. VACOMED Research Group.

OBJECTIVES: This study sought to determine whether dobutamine stress echocardiography could accurately identify coronary artery disease after heart transplantation. BACKGROUND: After heart transplantation, coronary artery disease is related to either diffuse concentric intimal thickening or focal stenosis and may be underdiagnosed by coronary angiography. METHODS: We enrolled 41 patients, a mean (+/- SD) of 40 +/- 20 months after heart transplantation, at the time of their routine control coronary angiogram. Three patients were excluded because of poor echogenicity on the angiogram and one because of ventricular premature beats. Standard echocardiographic views were acquired at baseline and at incremental dobutamine infusion levels (from 5 to a maximal dose of 40 micrograms/kg body weight per min at 3-min intervals). Regional wall motion score was calculated from a 16-segment model, and each segment was graded from 1 (normal) to 4 (dyskinesia). Coronary angiography was performed 24 h after dobutamine stress echocardiography, and angiograms were analyzed in blinded manner. RESULTS: Twenty-three (62%) of 37 patients had normal coronary angiographic findings. Dobutamine stress echocardiography showed abnormalities in only 2 of 23 patients. Fourteen patients (38%) had abnormal angiographic findings, seven of whom had stenoses > 50%. Dobutamine stress echocardiography correctly identified the corresponding hypoperfused segments in these seven patients. More of interest were the other seven patients, of whom three had angiographic nonsignificant stenoses (< 50%), and four had minor diffuse coronary irregularities. Dobutamine stress echocardiography showed hypokinesia in five of these seven patients despite nonsignificant lesions at coronary angiography. The respective overall sensitivity and specificity of dobutamine stress echocardiography were 86% and 91%. At follow-up, 2 of the 37 patients had an acute myocardial infarction. Both had abnormal findings on dobutamine stress echocardiography: One had normal coronary angiographic results, and one had significant coronary lesions. CONCLUSIONS: Dobutamine stress echocardiography is a useful technique for the diagnosis of coronary artery disease after heart transplantation. These preliminary results indicate that dobutamine stress echocardiography may have a predictive value for further ischemic events in heart transplant recipients.

Cardiac Catheterization↗
PubMed1995

High incidence of left atrial thrombus detected by transoesophageal echocardiography in heart transplant recipients.

The aim of the study was the detection of spontaneous echo contrast (SEC) and left atrial thrombus by transoesophageal echocardiography (TEE) in patients who had undergone orthotopic heart transplantation. TEE was prospectively performed in 64 heart transplant recipients (53 males, 11 females, mean age 51 years). Since surgery (mean time: 31 months), all heart transplant recipients had received either aspirin (39), or dipyridamole (22), or both (3). Despite the antiplatelet treatment, an acute arterial embolism (two strokes, one popliteal and one mesenteric ischaemia) occurred in four patients who subsequently received an oral anticoagulant therapy. TEE was performed with a biplane high-frequency transducer after lidocaine pharyngeal anaesthesia, midazolam intravenous injection and antibiotic prophylaxis. Mean ejection fraction was 63 +/- 10%. None had evidence of rejection at endomyocardial biopsy performed on the same day as TEE and analysed in a blinded fashion. All were in sinus rhythm. Left atrial SEC was found in 35 patients (55%) and was associated with left atrial thrombus in 18 patients (28%). These thrombi were localized in the donor left atrial appendage in 10 cases, on the posterior wall of the left atrium in six cases, on the donor part of inter-atrial septum in one case and on the suture line in one case. They were not detected by transthoracic echocardiography (TTE). When compared with patients without thrombus, no difference was found concerning left atrial size, left ventricular ejection fraction, pulmonary artery pressure and number of previous episodes of rejection. However, cardiac index was significantly lower in patients with left atrial thrombus.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Function, Left↗
PubMed1994

Atrioatrial conduction after orthotopic heart transplantation.

OBJECTIVES: In two patients with orthotopic heart transplantation, the surface electrocardiogram suggested interaction between the donor right atrium and the recipient right atrium. An electrophysiologic investigation was performed to assess possible atrioatrial conduction. BACKGROUND: After orthotopic heart transplantation, both recipient and donor atrial activities are usually independent, but in humans they may synchronize for short periods during exercise. METHODS: Electrophysiologic recordings were made using standard techniques. The atrial electrode locations (anterior for the donor and posterior for the recipient right atria) were confirmed by fluoroscopy. Incremental and programmed donor and recipient right atrial pacing protocols were performed. RESULTS: Unidirectional conduction between native and graft atria occurred in both patients. This phenomenon was evident at rest, during normal sinus rhythm and at various pacing rates, resulting in frequent atrial bigeminy and trigeminy. CONCLUSIONS: Possible atrioatrial conduction after orthotopic heart transplantation may potentially be arrhythmogenic for the chamber where extrasystoles occur. This should be taken into account in attempting to devise new pacing modes if both atria are rendered electrically common.

Adult↗
PubMed1994

Role of catheter ablation for supraventricular tachyarrhythmias, with emphasis on atrial flutter and atrial tachycardia.

Catheter ablation techniques using radiofrequency current have become an accepted form of treatment for a variety of supraventricular tachycardias. The results are excellent in patients with preexcitation syndromes and as the complication rate is low, catheter ablation has become the first line of treatment for these disorders. In atrioventricular nodal reentry, a selective ablation of the fast or slow pathway is feasible. Ablation of the slow pathway guided by electrophysiologic markers appears to be safer with the use of a very low number of radiofrequency applications. Experience with atrial tachycardia remains limited but developments appear promising. Lastly, atrial flutter has become a growing indication for catheter ablation techniques using anatomical approaches. A high success rate can be achieved initially, but the technique is limited by a 20% recurrence rate and the late occurrence of atrial fibrillation.

Atrial Flutter↗
PubMed1994

[Prevalence of intra-auricular thrombi detected by transesophageal echocardiography in patients with cardiac transplants].

The aim of this study was to determine the prevalence of intra-atrial thrombi or spontaneous contrast by transoesophageal echocardiography in patients who underwent cardiac transplantation by Lower and Shumway's technique. Transoesophageal echocardiography was performed in 52 transplant patients (43 men, 9 women: average age 51 years) with a high frequency biplane transducer. After surgery, all patients received platelet antiaggregant therapy. Despite this treatment, 4 patients had a sudden systemic embolic episode and were then placed on oral anticoagulants. All patients were in sinus rhythm at the time of the examination and some had signs of acute rejection on endomyocardial biopsy performed the same day. Spontaneous contrast was observed in 27 patients (52%) and was associated with thrombosis in 15 patients (29%). These thrombi were located in the left atrial appendage in 8 cases, on the left atrial posterior wall in 5 cases and on the left atrial sutures in 2 cases. None of these thrombi had been detected by transthoracic echocardiography. No significant difference was observed between those with and those without thrombosis with respect to left atrial dimensions, left ventricular ejection fraction, cardiac index, pulmonary pressures and the number of episodes of acute rejection. The 4 patients with a history of arterial embolism all had an intra-atrial thrombus. This study demonstrates a high incidence of spontaneous contrast and intracardiac thrombi in the dilated left atrium of patients transplanted by Lower and Shumway's technique. It also underlines the value of transoesophageal echocardiography in the follow-up of transplant patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticoagulants↗
PubMed1994

[Treatment of supraventricular arrhythmia by permanent cardiac pacing].

Most pacemakers are used for the treatment of bradyarrhythmias. However, a small number of pacemakers has been implanted for the treatment of supraventricular tachycardia resistant to medical therapy. The results of small reported series show long-term pacing to be effective in terminating reentrant atrial and junctional tachycardia. This has led to an improved quality of life and fewer hospital admissions in the majority of patients. Although there are a number of limitations to the widespread use of this mode of treatment, the development of pacing techniques has improved our understanding of the mechanism of termination of tachycardia which has been fully used in ventricular tachyarrhythmias. In addition to the curative treatment of sustained junctional tachycardia, pacemakers have been implanted to prevent the occurrence of new episodes with seemingly equally satisfactory results. However, cardiac pacing for this indication is much less common now because of the very good results obtained recently by radiofrequency ablation techniques. The prevention of atrial arrhythmias, vagally-induced atrial tachyarrhythmias and the bradycardia-tachycardia syndrome are good indications for permanent pacing. The prevention of atrial fibrillation in sinus node dysfunction by pacing is becoming more popular with the emergence of new modes (DDI and rate-adjusted modes) and original arrhythmia preventing algorithms. The discussion about the real efficacy of atrial pacing in sinus node dysfunction is disappearing as results of prospective randomised trials confirming this efficacy become available, especially in preventing atrial fibrillation.

Arrhythmias, Cardiac↗
PubMed1994

[Ablation by radiofrequency in the treatment of atrial arrhythmia].

Atrial arrhythmias resistant to medical therapy are still a common indication for ablation of the normal atrioventricular conduction pathway (Tawara node and His Bundle). However, the development of catheter techniques of intra-atrial ablation to destroy arrhythmogenic myocardial zones enables radical cure of the arrhythmias with the respect of the nodo-hisian pathway. With respect to common flutter, a number of series, including our own, show a 50 to 75% long-term success rate. We believe that a very high success rate in the ablation of flutter will probably be achieved in a reproducible manner but this will require a more accurate understanding of the tachycardia circuit and technological developments allowing controlled radio-frequency destruction of bigger atrial myocardial zone. Experience of radio-frequency ablation atrial of atrial extrasystoles is more limited than that of flutter and there are fewer published series. Globally, catheter ablation of atrial tachycardia remains a more difficult and a less well codified procedure than that of accessory pathways or of intra-nodal reentry. Radio-frequency ablation in this indication is not without danger in view of the thinness of the atrial wall. We believe that radio-frequency catheter ablation for atrial arrhythmias should, for the moment, be reserved for centres specialised in the techniques of electro-physiological investigation and ablation.

Atrial Flutter↗
PubMed1993

Catheter ablation induced reversal of chronic left ventricular dysfunction in permanent junctional tachycardia.

Three patients with the permanent form of junctional tachycardia are reported. All had a normal cardiac function when the rhythm disorder was discovered. The basis for tachycardia in the three cases was atrioventricular junctional reentry whose retrograde limb was a concealed posteroseptal accessory pathway. Because of the development of heart failure over the years, one patient had His bundle ablation combined with pacemaker insertion, and the others underwent catheter ablation of the accessory pathway. Reversal of left ventricular involvement, as assessed by chest X ray and echocardiography was noted in every patient. Ejection fraction in one patient, measured by radionuclide angiography, returned to normal 3 months later. Thus catheter ablation of permanent junctional tachycardia can effectively suppress rhythmic cardiomyopathy.

Adult↗
PubMed1993

Results of balloon aortic valvuloplasty in patients with aortic stenosis associated with significant aortic regurgitation.

The influence of balloon aortic valvuloplasty (BAV) on aortic regurgitation (AR) in patients with severe aortic stenosis associated with greater than or equal to grade II AR was studied by supraaortic angiogram before and after BAV. The results of 50 patients aged 72 +/- 12 years with significant AR before BAV (group A) were compared to 297 patients (mean age 76 +/- 10 years) with no or mild AR (group B). In group A, the patients had a higher left ventricular end diastolic volume (96 +/- 19 mL/m 2 vs 81 +/- 32 mL/m 2, P less than 0.01) and left ventricular end diastolic pressure (23 +/- 9 mmHg vs 19 +/- 9 mmHg, P less than 0.01). The aortic valve area was similar in both groups. Following BAV, the improvement in aortic valve area and hemodynamics were similar in both groups. In group A, AR remained unchanged in 31 patients (62%), increased by 1 grade in 13 patients (26%), and decreased by 1 grade in 6 patients (12%). In group B, AR increased by greater than 1 grade in 34 patients (11%) and greater than 2 grades in 4 patients (1.3%) post-BAV. Two patients in group B underwent emergency aortic valve replacement following BAV because of severe acute AR. In conclusion, when it is indicated, BAV can be performed with similar risk in patients with significant AR.

Aged↗
PubMed1993

[Simplified continuity equation: absence of predictive value in assessing severity of mitral valve stenosis].

The object of this study was to assess the accuracy of the simplified continuity equation (SCE) defined as the ratio of velocity time integrals (VTI) of the aortic or pulmonary to mitral orifice in the evaluation of severe mitral stenosis. The results of the continuity equation and VTI ratios were compared with the Gorlin catheter valve area in 70 patients with pure mitral stenosis in sinus rhythm. The continuity equation (CE) and SCE were significantly correlated (p < 0.01) with the Gorlin surface area with a better coefficient with the CE (r = 0.86) than with the VTI ratio (r = 0.74). The patient population was divided into two groups depending on the severity of mitral stenosis; Group I had catheter valve areas of less than 1.5 cm2: 38 patients had mean value of the CE of 1.11 +/- 0.22 cm2 and of the SCE of 0.32 +/- 0.09. In Group II (mitral valve area > or = 1.5 cm2), 32 patients had a mean CE value of 1.92 +/- 0.29 cm2 and a SCE value of 0.56 +/- 0.14. Only two patients in Group I had SCE values greater than 0.5. Conversely, no patients in Group II had a SCE value of less than 0.3. For a range of SCE values of 0.3 to 0.5, there was an important overlap between the two groups (19 patients of Group I and 9 patients of Group II).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Electrophysiological evaluation of ventricular tachycardia].

The ability to induce and terminate ventricular tachycardia reproducibly by programmed stimulation has led to the development of electrophysiological investigations for the management of patients suffering from spontaneous arrhythmias. The investigation consists in introducing several multipolar catheter electrodes under local anaesthesia which are then positioned in contact with the endocardium in several regions of the heart. There is no consensus as to an ideal stimulation protocol for these patients but the basic principle is the introduction of one or several ventricular extrasystoles every 8 beats in sinus rhythm or during a controlled ventricular paced rhythm. At present, the major indication is rarely diagnostic in the presence of wide QRS complex tachycardias difficult to analyse by electrocardiography. On the other hand, electrophysiological investigations are highly recommended in cases of unexplained syncope in patients with documented or suspected heart disease, in symptomatic patients with intraventricular conduction defects in whom ventricular arrhythmias are suspected as the cause of symptoms or after cardiac arrest without transmural infarction or, for many teams, after the 48th hour of transmural infarction. Electrophysiological investigations are also justified in patients in whom surgical or catheter ablation of an arrhythmogenic focus is planned because of resistance to antiarrhythmic drug therapy. Evaluation of the efficacy of antiarrhythmic drugs by repeated investigations is common in the United States but is not so widely accepted in Europe.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Pacing, Artificial↗
PubMed1991

Prolonged QT, atrioventricular block, and sudden death in the newborn: an electrophysiologic evaluation.

An electrophysiologic study was performed in the first month of life in a patient with the congenital long QT syndrome and spontaneous episodes of 2/1 atrioventricular block. The block could be reproduced by incremental atrial pacing, and its infrahisian location was associated with a prolongation of the refractoriness in the ventricular muscle itself. Surprisingly, intravenous propranolol aggravated this phenomenon by further prolonging the QT interval. Sudden death occurred shortly thereafter during Holter monitoring and was due to a sudden resumption of normal AV conduction after an episode of 2:1 block, immediately followed by ventricular fibrillation.

Cardiac Pacing, Artificial↗
PubMed1991

The role of catheter ablation techniques in the treatment of classic (type 1) atrial flutter.

Several attempts at circuit interruption of type 1 atrial flutter by means of surgical or catheter techniques have been published. We recently reported the results of a series of patients who underwent catheter fulguration of the low septal right atrium, with a mean follow-up of almost 3 years. True electrophysiological success was observed in 7/14 patients (50%). Clinical success, defined as absence of symptoms, was observed in 8 was observed in 8/14 (57%) in this patient population. No serious complications were encountered, but the potential risks of DC shock, and the experience that we gained in right atrial mapping using this approach, led us to reconsider the role of atrial DC ablation in these patients. Additional studies assessing the meaning of fragmented electrograms, and identification of one (or of several) slow conduction areas of the reentrant circuit are ongoing.

Atrial Flutter↗