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Biomedical subjects

G Kirkorian

Publications and source records attributed to G Kirkorian.

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

Subdiaphragmatic implantation of implantable cardioverter defibrillator generator.

Despite several improvements in the surgical technique and in the technologic design of cardioverter defibrillators made over the past years, abdominal placement of the generator device, done as Mirowski did it in his first implantation performed in 1980, remains the widely used method. Although smaller defibrillators are available, they remain bulky and are a source of local complications. To prevent such complications and to enhance patient comfort, we performed a subdiaphragmatic implantation in 31 patients.

Defibrillators, Implantable↗
PubMed1995

[Radiofrequency ablation of intranodal tachycardia].

The first radical approach to the treatment of atrioventricular nodal reentrant tachycardia was surgical dissection of the perinodal region. This technique has been replaced by the delivery of radiofrequency energy by an ablation catheter to the region of the atrioventricular node. The aim of this report is to describe the authors' experience of atrioventricular nodal application of radiofrequency current. The study comprised 53 cases (32 women and 21 men, mean age 46 +/- 17 years) with frequent attacks of reciprocating tachycardia. Endocavitary electrophysiological investigation confirmed the intranodal reentrant mechanism. The region of application of the radiofrequency current was located radiologically and then the precise site determined by the recording of nodal electrical activity. The appearance of junctional rhythm during the procedure was also used as a means of identification of the zone of ablation. Dual conduction persisted after ablation in 35 patients. However, no episode of tachycardia could be induced after the procedure. The AH interval increased during application of radiofrequency current in 3 cases but this abnormality regressed in the 2 months following the procedure. Recurrences of nodal reentrant tachycardia were observed in 14 cases (26%), 24 hours to 2 months after ablation. The rate of recurrence was significantly higher in patients who did not have a junctional rhythm during application of the radiofrequency current (62% vs 4%, p < 0.05). The number of recurrences was also greater in the group of patients with persistence of slow intranodal conduction after the radiofrequency ablation (p < 0.04). A second session of radiofrequency ablation was undertaken in 14 patients and a third session was required for 2 of them.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Sustained ventricular tachycardia: an evaluation of long-term prognosis].

The authors analysed the clinical and paraclinical variables of 116 patients admitted to the Hôpital Cardiologique de Lyon between 1986 and 1990 with sustained ventricular tachycardia without cardiocirculatory arrest in order to determine the long-term outcome and the prognostic factors of death and recurrence. The average age of the patients was 56 +/- 15 years (mean +/- SD) and 83% were men. The mean ejection fraction was 39 +/- 15%. Sixty-five had previous myocardial infarction (group I); 30 (group II) had dilated cardiomyopathy (n = 21), right ventricular dysplasia (n = 4), hypertrophic cardiomyopathy (n = 2), congenital (n = 2) or valvular (n = 1) heart disease. Group III comprised 21 patients with no apparent cardiac disease or isolated mitral valve prolapse. Brief syncope was reported in 12 cases. The paraclinical investigations showed 46 patients (66%) with at least two criteria of positivity for ventricular late potentials; Holter recording showed doublets or runs of VES in 46% of cases and sustained or non-sustained VT was induced during exercise testing in 16 patients (22%). Programmed ventricular stimulation triggered VT in 85%, 79% and 61% of patients in groups I, II and III respectively. The patients were treated with amiodarone in 65 cases, a betablocker in 25 cases, catheter ablation of the origin of the tachycardia in 12 cases, antiarrhythmic surgery in 6 cases, coronary bypass grafting in 5 cases (with an associated antiarrhythmic procedure in 3 cases). An automatic defibrillator was implanted in 9 patients. The average follow-up period was 32 months (range: 17 days to 65 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Non-pharmacological treatment of atrial fibrillation].

Although often denigrated in recent years, antiarrhythmic drugs frequently enable control of atrial fibrillation in patients who are symptomatic or at high risk of complications. In patients resistant to therapy, a number of non-pharmacological options have become available. The choice is no longer limited to his bundle ablation, a method previously at the point of progress but which has gradually given way to more sophisticated and less definitively destructive techniques. Modulation of atrioventricular conduction is currently under development, the feasibility of which has not yet been completely evaluated, but whichmay provide a less radical alternative in selected patients. Restoration of sinus rhythm by electrical cardioversion has benefitted from the advances of cardiac defibrillation in general. The theoretical information which its use implies has improved its efficacy, especially in the case of endocavitary electrical shock. This method can also be employed with automatic implantable defibrillators but using specific algorithms. Atrial pacing is credited with a preventive efficacy but this has never been definitely demonstrated. Research is under way in this domain. Future hopes are also centered on atrial surgery, especially the operation described by Cox which is generally accepted to be effective and which may be adapted medically using endocavitary radiofrequency current. Most of these methods are insufficiently experimented but they should be considered reasonably in particularly symptomatic patients duely informed of the nature of the treatments which are proposed.

Atrial Fibrillation↗
PubMed1994

Radiofrequency ablation of atrial flutter. Efficacy of an anatomically guided approach.

BACKGROUND: Previous reports have shown that radiofrequency ablation can terminate atrial flutter and prevent recurrences. However, different methods have been used, and the current experience remains limited. The objective of the present study was to determine the efficacy of radiofrequency ablation of atrial tissue in patients with atrial flutter using an anatomically guided approach. METHODS AND RESULTS: We treated 22 patients aged 30 to 73 years. Atrial flutter was recurrent for a mean of 5 years despite the administration of multiple antiarrhythmic drugs. Radiofrequency current was directed to the atrial isthmus between the inferior vena cava and the tricuspid ring, regardless of the morphology of local electrograms. Radiofrequency energy was applied during typical atrial flutter in 12 patients, atypical atrial flutter in 2 patients, and successively both forms in 8 patients. In 19 patients, atrial flutter abruptly terminated. In 3 patients, atrial flutter persisted despite 37, 48, and 25 applications, respectively. Atrial recordings demonstrated that atrial flutter termination occurred as a consequence of conduction block at the site of radiofrequency energy application, regardless of the type of atrial flutter. The number of applications before termination ranged from 1 to 82 (mean, 32). Atrial flutter could no longer be induced in every case. There were no complications. During a 13-month mean follow-up, atrial flutter recurred in only 2 of the 19 patients who had a successful ablation. Four patients experienced chronic atrial fibrillation, and 2 of them returned to sinus rhythm with antiarrhythmic therapy. CONCLUSIONS: Radiofrequency ablation of atrial flutter using anatomic guidance is feasible and effective. Further experience is needed to delineate its role as an alternative approach to the management of refractory atrial flutter.

Adult↗
PubMed1994

[Diagnostic value of exercise test in the evaluation of sustained ventricular arrhythmia].

The authors undertook a prospective study comparing exercise testing and programmed ventricular stimulation in order to assess the diagnostic value and risks of exercise stress testing in patients with sustained ventricular arrhythmias. Fifty-five consecutive patients (47 men and 8 women) with an average age of 47 +/- 15 years were included. The initial condition requiring investigation was sustained ventricular tachycardia (47 cases) and ventricular fibrillation (8 cases). The patients had ischaemic heart disease (N = 18), dilated cardiomyopathy (N = 9), valvular heart disease (N = 4) and congenital heart disease (N = 3). Six patients presented with arrhythmogenic right ventricular dysplasia and 15 patients had apparently normal hearts. Four episodes of sustained ventricular tachycardia (7.3%) and 10 non-sustained ventricular tachycardia (18.2%) were induced by exercise testing. One poorly tolerated episode of ventricular tachycardia required cardioversion. No signs of myocardial ischaemia were observed in association with the induced ventricular tachycardia Patients with ventricular tachycardia induced by exercise were significantly younger (39.5 +/- 12.5 vs 49.5 +/- 15.4 years; p = 0.04) and attained a lower predicted maximal heart rate (82.2 +/- 14.6 vs 91.4 +/- 14.4%; p = 0.04), but the underlying pathologies were the same, as were the initial arrhythmias and the level of exercise attained. With respect to the clinical circumstances of induction of the initial ventricular arrhythmia, patients with ventricular tachycardia induced by exercise had an increased tendency to arrhythmias during effort or stress (7/14 vs 8/41; p = 0.06). Programmed ventricular stimulation induced more ventricular tachycardias than exercise testing (36/55 vs 14/55; p < 0.0001). The results of exercise testing were not correlated to those of programmed stimulation (p = 0.38).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Hemomediastinum caused by spontaneous rupture of the thoracic aorta].

The authors report the rare case of spontaneous rupture of the aortic isthmus in the absence of preexisting aortic aneurysm or dissection in a hypertensive woman presenting with chest pain and haemomediastinum. The history of trauma 30 years previously, could have been a predisposing factor. The diagnosis of this condition remains difficult and is often missed. The physiopathological, aetiological, clinical and diagnostic features are reviewed. Transoesophageal echocardiography showing an intraparietal haematoma confirmed the aortic origin of the haemomediastinum. Conventional angiography was of no value in the reported case because of the absence of rupture of continuity or of an intimal tear.

Aged↗
PubMed1994

[Automatic implantable defibrillators; subdiaphragmatic insertion].

Although the material and techniques of implantation of the electrodes of implantable defibrillators have been improved, the abdominal implantation of the generator remains widely used as described by Mirowski in 1980. Despite a progressive reduction in their size, the generators remain bulky and a source of local complications. The risks and discomfort of implantation in the abdominal wall led the authors to try subdiaphragmatic implantation in 22 patients. There was no morbidity with perfect healing in all 22 cases. The mean follow-up period was 11 months. The patients felt very comfortable, a significant advance with respect to abdominal implantations.

Adolescent↗
PubMed1994

[Long-term course after electric ablation of the bundle of His in the treatment of supraventricular tachycardia].

The authors report the long term results of His bundle ablation for supraventricular tachycardia in a series of 49 patients. This retrospective study was based on a patient population of 27 men and 22 women with an average age of 59 at the time of ablation, between 1984 and 1993. The indication for His bundle ablation was invalidating supraventricular tachycardia resistant to antiarrhythmic therapy in all cases. One group of patients (Group I, n = 31 patients) underwent high energy electrical shock and the second group (Group II, n = 18 patients) recruited after 1991, underwent radiofrequency catheter ablation. Complete atrioventricular block was obtained in the first group in 1 to 4 sessions whereas 17 patients of Group II were treated in a single session. During a follow-up period of an average of 40 months, 2 patients were lost to follow-up and 6 died, 3 of cardiac failure, 1 of a cerebrovascular accident, 1 of pulmonary carcinoma and 1 of unknown cause. In Group I, atrioventricular conduction persisted in 1 patient (primary failure) and reappeared in one other patient, but, in Group II, complete atrioventricular block persisted even in the patient in whom the interruption was not obtained with a single session of radiofrequency ablation. The patients were generally physically improved and satisfied not to have any palpitations. A decrease in exercise capacity estimated by the NYHA classification was observed in 38% of patients without apparent cardiac disease who developed dyspnea. On the other hand, 43% of patients with cardiac disease and in NYHA class > or = 2 were improved.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Surgery for atrial fibrillation by the Cox technique. Apropos of 2 cases].

The authors report the cases of two patients who underwent surgery of atrial fibrillation by Cox's technique. In one case, it was associated with mitral valvuloplasty for atrial fibrillation of 4 years' duration; sinus rhythm was restored on the 19th postoperative day; it persisted at 11 months without antiarrhythmic drugs. On the other case, it was associated with mitral valve replacement for atrial fibrillation of 7 years' duration in a patient with dilated cardiomyopathy and a poor left ventricle; sinus rhythm was restored by electrical cardioversion during the 4th postoperative month; it persisted at 9 months with antiarrhythmic therapy. Cox's technique allows: 1) definitive suppression of atrial fibrillation, 2) restoration of atrioventricular synchronisation, 3) preservation of atrial transport function. The indications are paroxysmal or permanent atrial fibrillation, invalidating and resistant to medical therapy; atrial fibrillation of over 3 years' duration associated with mitral regurgitation requiring valvular repair and atrial fibrillation of invalidating primary cardiomyopathy.

Aged↗
PubMed1994

[Intracardiac treatment of atrial flutter by radiofrequency currents].

Though not as common as atrial fibrillation, atrial flutter is frequently encountered in everyday cardiological practice. Though generally thought to be benign, it may be difficult to treat both in respect to its conversion to sinus rhythm and prevention of recurrences. It is often poorly tolerated. There are resistant, invalidating forms for which catheter ablation of the His bundle may be considered as a last resort. This is only a palliative measure even if effective from the functional point of view. A new technique for treating atrial flutter by a direct action on the atrial tissue has been recently introduced. The basis of this method is the concept of circus movement of the activation in the right atrium, the wave front circulating in an anti-clockwise direction in common atrial flutter. The postero-inferior region of the right atrium, at Koch's triangle, is the site of slow conduction and the target of choice for catheter ablation. The detection of this zone is determined by the endocavitary recording of fragmented, prolonged electrogrammes and by atrial stimulation techniques. The application of radiofrequency currents on these bases (high energy shocks are rarely used nowadays) results in interruption of atrial flutter. However, there are no data available concerning the long-term efficacy of this technique. Since 1992, our group has used an anatomical approach for catheter ablation. This aims to apply the radiofrequency current on the isthmus of atrial tissue between the orifice of the inferior vena cava and the tricuspid annulus through which the flutter wave front passes to reach the interatrial septum.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Flutter↗
PubMed1994

[New approach for implantation of automatic defibrillators using videothoracoscopy].

Nonthoracotomy lead systems are increasingly used in patients (pts) with implantable cardioverter defibrillator (ICD). In this setting, due to high energy requirements, a subcutaneous patch may be necessary in addition to endocardial leads. However in some patients, high defibrillation threshold (DT) may persist leading to thoracotomy for epicardial patch placement. In a preliminary experience, 3 patients with high DT (> 20 J) following endocardial lead system, underwent the insertion of a extrapericardial patch under video-thoracoscopic control. A left subcostal incision extended to the left pleural cavity was performed. Using thoracoscopy the patch was positioned on the pericardium, sutured and connected to the defibrillator. DTs were 10, 10 and 20 J respectively in our 3 patients. Postoperative course was uneventful. Thoracoscopy allows other techniques such as a stellectomy, which we performed in a 33 year old woman with long QT syndrome. Patients were reassessed after 8 days and 2 months. Termination of induced ventricular fibrillation was achieved with the same minimal energy levels used peroperatively. In conclusion, extrapericardial patch insertion using thoracoscopy may help reduce DT in ICD patients with a non thoracotomy lead system. Comparison with other lead configurations requires further investigation.

Adult↗
PubMed1994

[Implantation of automatic defibrillators by means of video-thoracoscopy. Authors' experience].

The implantable cardioverter-defibrillator represents an effective option for some potentially lethal ventricular arrhythmias. Nowadays defibrillation electrodes are often endoluminal only. In some patients, however, the presence of high defibrillation thresholds mandates the implantation of a subcutaneous patch. If the subcutaneous patch does not allow a sufficient decrease in defibrillation threshold, then two epicardial patches are generally implanted by different surgical approaches. Nevertheless surgical trauma could be a serious hazard in unstable patients. In 6 patients in whom endoluminal electrodes did not allow a safe defibrillation threshold, an extrapericardial patch has been implanted by means of a video-thoracoscopic approach: a left subcostal incision is performed and the subdiaphragmatic extraperitoneal space is reached; a patch electrode is then introduced into the left pleural cavity by blunt dissection of the diaphragm. This patch is positioned under thoracoscopic control in contact to the left pericardial surface and fixed by single stitches sutures. The impulse generator is finally implanted into the subdiaphragmatic pocket. In all the patients the patch electrode configuration sufficiently decreased defibrillation thresholds. In one of the patients a stellectomy was thoracoscopically performed to treat the long QT syndrome which was the cause of the ventricular fibrillation episodes. Defibrillation thresholds were confirmed after 8 day and 2 months postoperatively. In conclusion, the thoracoscopic implantation of an extrapericardial patch has allowed a significant reduction of defibrillation thresholds, without recurring to a major surgical procedure.

Defibrillators, Implantable↗
PubMed1993

Primary cardiogenic shock during acute myocardial infarction: results of emergency cardiac transplantation.

Fifteen patients with acute myocardial infarction and cardiogenic shock underwent emergency cardiac transplantation after medical treatment failed to improve their haemodynamic status. Their mean age was 49 +/- 7 years. The infarction was anterior in 12 cases, inferoposterior in two cases, and septal in one. Shock occurred within 3 days after the onset of chest pain in nine patients, and during the first day in six of them. Mechanical circulatory assistance was used in six patients as a bridge to transplantation when their haemodynamic status could not be stabilized pharmacologically. Orthotopic cardiac transplantation was performed an average of 15.6 +/- 14 days after onset of infarction. Three patients died during the early post-operative period. Another died 7 months after transplantation. During the mean follow-up period of 30.6 +/- 20.3 months, there were three acute rejections, all successfully treated, and one chronic rejection. The survival rate for this series is 70%. Thus, emergency cardiac transplantation may be the best option for selected patients with acute myocardial infarction and cardiogenic shock refractory to conventional therapy.

Adult↗
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

[Long-term results of implantable automatic defibrillator in 43 patients. Analysis of predictive factors of the first electric shock].

In order to identify patients who will receive an electric shock after implantation of an automatic fibrillator, the relationship between the time to the first shock and clinical and paraclinical characteristics were studied in 43 patients treated at the Lyon Cardiological Hospital between July 1987 and September 1991. The age of the patients was 49.5 +/- 16 years (mean + SD). Eighty two percent of patients were men and the average left ventricular ejection fraction was 38.5 +/- 16.8%. Four patients died in the peri-operative period. The average follow-up of the survivors was 22 months. During this period, 21 patients (53.8%) received an appropriate electric shock. Three patients died. The causal role of a malignant ventricular arrhythmia is discussed in one case. A second patient, who never had automatic fibrillation, died of cardiac failure. Finally, the third patient died of non-cardiac pathology. The 22 month actuarial survival rate was 86%. The probability of receiving an appropriate electric shock was 60%. Analysis of clinical and paraclinical features identified left ventricular dysfunction (ejection fraction less than 38%) and cardiac symptoms (Stage III dyspnoea of the NYHA classification) as being associated with earlier electric shocks. This association was even more clear cut in the group of patients with previous myocardial infarction. Therefore, patients with implantable automatic defibrillators for malignant ventricular arrhythmias receive appropriate electric shocks in over 50% of cases. Patients with symptoms of cardiac failure and low ejection fraction are particularly exposed especially when they have previous myocardial infarction.

Actuarial Analysis↗