Biomedical subjects
Publications and source records attributed to P Defaye.
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Percutaneous Pace-maker and ICD lead extraction techniques has been developped: by superior approach using locking stylet and more and more efficient outher sheats (laser assisted); and also by femoral approach using double lasso catheters (Needle's eye snare). Indication range has increased and is not only reserved for lead infection. Because of scar tissue holding the lead and also the impact of the distal tip, those techniques are not simples. Extraction recommandations do advise those procedures to be performed by expert physicians, in cardiac surgery centers, where complications can be managed and reduced. The use of laser assisted outher sheats will make lead extraction easier and will reduce complication rate. Alternative procedure in case of failure with superior approach remain femoral approach. All those techniques give a success rate of about 98 % for percutaneous lead extraction in an expert center.
The aim of this study was to assess the ability of overdrive atrial pacing to reduce sleep apnoea severity. A total of 17 unselected patients (12 males; mean+/-SD age 71+/-10 yrs; body mass index 27+/-3 kg x m(-2)) who had received permanent atrial-synchronous ventricular pacemakers for symptomatic bradyarrhythmias and not known to have central or obstructive sleep apnoea syndrome (OSAS) were studied. Using a crossover study design, patients were or were not in pacing mode with atrial overdrive (15 beats x min(-1) faster than mean baseline nocturnal cardiac frequency) for 1 month. Patients were paced only during sleep periods, identified by a specific algorithm included in the pacemaker. Patients underwent three overnight polysomnographic evaluations 1 month apart. The first was performed for baseline evaluation. The patients were then randomly assigned to either 1 night in spontaneous rhythm or to 1 night in pacing mode with atrial overdrive. Two patients refused to continue the study after the first polysomnographic evaluation. OSAS was highly prevalent in this population: 10 of the 15 (67%) patients exhibited an apnoea-hypopnoea index of >30 events x h(-1). The nocturnal spontaneous rhythm was 59+/-7 beats x min(-1) at baseline, compared to 75+/-10 beats x min(-1) with atrial overdrive pacing. The apnoea-hypopnoea index was 46+/-29 events x h(-1) in spontaneous rhythm, compared to 50+/-24 events x h(-1) with atrial overdrive pacing. Overdrive pacing changed none of the respiratory indices, or sleep fragmentation or sleep structure parameters. In conclusion, atrial overdrive pacing has no significant effect on obstructive sleep apnoea.
The development of memory functions with memorised electrogrammes is one of the most important technical advances in cardiac pacemakers and defibrillators. These memory functions are very useful in the management of patients with implanted prostheses. In the case of defibrillators, the memory allows evaluation and validation of appropriate treatments (shock or asymptomatic antitachycardia stimulation) or inappropriate function. The memory can also help assess the efficacy of complementary antiarrhythmic therapy or radiofrequency ablation. The incorporation of memory functions in pacemakers is more recent but no less useful. The latest generation of pacemakers have not only a therapeutic but also a diagnostic role with respect to atrial and ventricular arrhythmias. They can lead to the prescription of an antiarrhythmic or anticoagulant drug in cases of sustained atrial fibrillation confirmed by the memorised electrogrammes. The memory function is also a great aid in reprogramming stimulators in cases of overdetection (V-A cross talk). They may also be activated by the patient in cases of sporadic paroxysmal symptoms. The latest development is that of a purely diagnostic prosthesis: the implantable Holter, whose main indication is in the investigation of unexplained syncope.
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Preventive treatments for atrial fibrillation by stimulation have been developed for several years now, mainly due to the relative failure of anti-arrhythmic treatments. They are based on the hypothetical effects of stimulation by controlling cardiac frequency, abolishing bradycardia-dependent extrasystoles, by the inhibition of atrial automatic foci with "overdrive", and by the modification of intra- or inter-atrial conduction delays as well as by remodelling the arrhythmogenic substrate. It is clear that an undeniable effect exists for the prevention of atrial fibrillation, even for the risk of cerebral vascular accident, by physiological stimulation (DDD/DDDR) compared to pure ventricular stimulation (VVI/VVIR) in a heterogenous global population of stimulated patients. For the moment, there is not sufficient proof of a positive effect for the emerging sites of cardiac stimulation, either atrial mono-site or double site in the populations at high risk of atrial fibrillation, with or without associated bradycardia. Some new prevention algorithms by "overdrive" are under development but for the moment only a few preliminary studies seem to show a slight benefit. It is clear that at present stimulation should be reserved only for cases of atrial fibrillation associated with a classic indication for implantation. In these patients it is recommended to position the probes in an optimal manner in order to counteract conduction disorders, choosing an adapted double chamber stimulator with prevention algorithms. That said, the patient should be clearly warned that the long term success rate is no more than 50%.
PATIENTS AND METHODS: This prospective study analyzed the incidence of atrial arrhythmias in a population of 626 patients in 173 medical centers of eleven European countries and Japan with indication for a dual chamber pacemaker system. The accuracy of the new Automatic Interpretation for Diagnosis Assistance (AIDA) program which is included in Chorus pacemakers was evaluated and the AIDA analysis was compared to and proven with Holter monitoring. Data stored in the pacemakers' memories for the first 24 hours (D1) were compared with simultaneously recorded 24-hour surface electrocardiograms, and data stored over the following 28 days (D28) were examined against reported intercurrent symptoms. RESULTS: At D1, atrial arrhythmias were detected by AIDA in 60 of 626 patients (12%), consisting of atrial fibrillation (n = 29), atrial flutter (n = 4), and miscellaneous arrhythmias (n = 17), and closely corroborated by Holter monitoring (sensitivity 93.7%, specificity 94.9%). At D28, 149 of 386 patients (49%) had had episodes of automatic mode switch prompted by atrial arrhythmias. Symptoms were reported by 81 patients (54%), 92 (62%) had no histories of atrial arrhythmias, and 57 patients (38%) were neither symptomatic nor had histories of atrial arrhythmias. An inverse relationship was found between the number of atrial paced events and the occurrence of atrial arrhythmias (p < 0.001). A history of atrial arrhythmias and older age were associated with a higher risk of atrial arrhythmias (p < 0.05). In contrast, gender, hypertension, concomitant heart disease, or type of atrial lead fixation system were not related with the occurrence of atrial arrhythmias. CONCLUSION: AIDA allowed to confirm, or disprove, the occurrence of atrial arrhythmias as a source of symptoms reported during long-term follow-up. It could also be used to examine the efficacy of antiarrhythmic therapy, and be of assistance when weighing the needs for anticoagulation in patients experiencing asymptomatic atrial arrhythmias.
The authors report the case of a cardiac transplant patient with a recurrence of atrial flutter two months after electrical cardioversion and despite long-term preventive treatment with amiodarone. Early investigation for signs of rejection with 4 endomyocardial biopsies was negative. Aggravation of the haemodynamic status due to flutter with a rapid ventricular response led to an attempted radio-frequency ablation. Endocavitary mapping confirmed persistence of sinus activity in the native atrium and the presence of a circuit of type I isthmic flutter (anticlockwise circuit) in the donor atrium. Ablation by radio-frequency in the same procedure was successful. A fifth myocardial biopsy the same day finally confirmed stage 3A acute rejection. No signs of recurrent rejection or arrhythmia have been observed after 24 months' follow-up in this patient. This preliminary experience confirms the need to look for graft rejection by repeated myocardial biopsies in cardiac transplant, patients with atrial flutter and the efficacy of radio-frequency ablation in cases of resistance to conventional therapy.
A patient with Brugada syndrome experienced incessant ventricular fibrillation 7 years after implantation of an ICD. General anesthesia, fast ventricular pacing, bretylium, and atenolol infusion were ineffective; amiodarone infusion was started. After 190 defibrillation shocks over 36 hours, the electrical storm stopped. A multiorgan failure occurred as a complication of the electrical storm and necessitated prolonged reanimation. Thorough cardiac evaluation revealed no structural abnormality and the patient, now on chronic oral amiodarone therapy, remains free of arrhythmia 1 year after the event.
Ventricular tachycardia by branch to branch reentry is a rare arrhythmia. It occurs in cardiomyopathies associated with conduction defects. During tachycardia a His potential precedes each QRS complex which usually has a left bundle branch block appearance. The authors report two familial cases of ventricular branch to branch tachycardia (son and mother) without cardiomyopathy. The diagnosis of Steinert's disease was made post-mortem in these two patients. In cases of branch to branch ventricular tachycardia, the diagnosis of myotonic dystrophy should be excluded. Conversely, endocavitary electrophysiological investigation with ventricular stimulation should be proposed for symptomatic patients (dizzy spells, syncope) to diagnose branch to branch ventricular tachycardia, even in cases with conduction defects which could also explain the symptoms.
An international, prospective, multicentre trial (AIDA) was undertaken from October 1995 to March 1997. The object was to compare the diagnosis of atrial arrhythmias (AA) by the automatic interpretation of the memory functions of dual chamber pacemakers with that of 24 hour Holter monitoring at day 1. The second objective was to assess the incidence and symptomatology of the AA during follow-up at Day 28. In France, 226 patients implanted with Chorus, Chorus II and Chorus RM pacemakers were included in the study (148 men, 70.5 +/- 10.8 years) for the following indications: AVB (atrioventricular block)/bundle branch block (47.3%), sinus mode dysfunction (10.2%), bradycardia-tachycardia syndrome (10.2%), AVB + sinus node dysfunction + cardia-tachycardia syndrome (19.5%), other (2.2%). AA were documented in 34.5% of patients before implantation. Of the 226 patients analysed at Day 1, 23 (10.2%) had at least one episode of AA diagnosed simultaneously by Holter monitoring and the automatic interpretation (AIDA). These AA were atrial fibrillation (15 patients), atrial flutter (2 patients) and atrial tachycardia (6 patients). The sensitivity of the AIDA programme for detecting AA was 92% and the specificity 97%. Of the 156 patients evaluated at Day 28, the programme diagnosed AA in 78 patients (50%), 34 of which (21.8%) were asymptomatic and without previously documented AA. The results of the AIDA study confirmed the excellent sensitivity and specificity of the memory functions of these cardiac pacemakers for analysis of AA. They seem to be very common during the follow-up of pacemaker-equipped patients. This new diagnostic concept will facilitate the programming and study of the efficacy of anti-arrhythmic therapy prescribed during long-term follow-up.
OBJECTIVES: Our aim was to look at the clinical features and long-term follow-up of seven patients without coronary artery disease, who had a history of life-threatening ventricular arrhythmias due to coronary spasm. BACKGROUND: Arrhythmic cardiac arrest due to isolated coronary spasm is rare, and there is limited information on the patients affected by this entity alone. METHODS: The seven patients were recruited retrospectively from a cohort of survivors of cardiac arrest. None had a history of angina pectoris, structural heart disease or significantly narrowed coronary segments. All had a positive ergonovine provocation test result. RESULTS: The patients' mean age was 44 years; three were male and four female. All were habitual cigarette smokers. No arrhythmias were induced on programmed ventricular stimulation; corrected QT interval (QTc) and corrected JT interval (JTc) dispersion were within normal ranges. After the ergonovine provocation test, treatment with calcium channel blocking agents (diltiazem, verapamil, nifedipine or amlodipine) was initiated at a dose determined by titration until a negative test result was obtained. At a mean follow-up interval of 58 months for the total group, six patients remained free of symptoms, whereas the one patient who did not stop smoking had a new cardiac arrest despite treatment for coronary spasm. CONCLUSIONS: A favorable long-term outcome may be expected in survivors of cardiac arrest due to coronary spasm, in the absence of significant coronary artery disease. Calcium channel blockers are the most appropriate therapy in these patients. These observations provide further evidence for the role of silent ischemia in cardiovascular death.
The confirmation of the occurrence of supraventricular arrhythmias (SVAs) is possible only if a surface electrocardiogram (ECG) is recorded during an episode, or if SVAs occur during 24 h ambulatory monitoring (Holter). The automatic interpretation of memory functions in DDD pacemakers may be useful in this diagnostic task over longer periods of follow up. This hypothesis was tested in 384 men and 233 women (mean age = 70 +/- 11 years) who had received Chorus 6034/6035, 6234 or 7034 pacemakers (ELA Medical, Montrouge, France) with fall-back function in case of sustained SVAs. The Automatic Interpretation for Diagnostic Assistance (AIDA) algorithm included in these pacemakers was compared with 24 h Holters recorded simultaneously (D1) and with the clinical history of symptoms consistent with SVAs up to 28 days of follow up (D28). Indications for pacing were atrioventricular block (AVB) in 269 patients, sinus node dysfunction (SND) in 248, and AVB + SND in 100. SVAs were documented before implant in 199 patients (32%). Among the 617 patients included at D1, 76 (12.4%) developed at least one SVA episode, lasting between 1 min and 24 hours, simultaneously recorded on Holter and by AIDA with a 93.8% sensitivity and 94.2% specificity. Data from 354 patients were available for analysis at D28. AIDA diagnosed SVAs in 179 patients (50.6%), 104 of whom (65%) had remained asymptomatic and 117 of whom (65%) had had no SVA documented before implant. Among the 354 patients, AIDA diagnosed SVAs in 76 (21%) asymptomatic patients who had no known SVA before implant. The prevalence of SVA in our AVB population was higher than reported in previous studies: 89 patients (56.3%) with AVB had SVAs versus 90 patients (45.9%) with other diagnoses (p = 0.55). Furthermore atrial pacing was associated with fewer SVAs. These first clinical results of the AIDA study demonstrate that the memory functions of Chorus pacemakers and the AIDA software are reliable to analyze the prevalence of SVA at 1 month of follow-up. From a clinical point of view, AIDA is a valuable tool to evaluate the efficacy of antiarrhythmic therapy, particularly as it pertains to the prevention of stroke due to atrial fibrillation.
The authors report the case of a patient with an automatic defibrillator implanted by an endocavitary approach. The device emitted a series of inappropriate shocks. They were triggered by the detection of myopotentials resulting from lesions of the lead due to Twiddler's syndrome. This was reproduced by telemetry in real time and confirmed by chest and abdominal X-ray and the peroperative findings. Treatment consisted of ablation of all implanted material which was replaced by a new retropectoral model.
Takayasu's arteritis involves the pulmonary artery tree in more than 50% of the cases. Initial isolated involvement of the pulmonary artery by Takayasu's arteritis, however, is very rare. We report the case of a 34-year-old white woman who presented a clinical and radiographic pattern that mimicked an acute pulmonary embolism with pulmonary infarction. Pulmonary angiography showed stenosis lesions and occlusion of the right pulmonary artery tree. Magnetic resonance imaging demonstrated thickening of the pulmonary artery wall leading to the correct diagnosis.
The study of mitral flow and pulmonary venous flow by Doppler provides a non-invasive method of assessing diastolic function. But there are difficulties in differentiating normal pattern from "pseudo-normal" (Appleton Type II) (E/A Mitral > 1). Phonocardiography enables the recording of early (B3) and late (B4) diastolic gallops. The apexogramme enables calculation of the a/H and D/H ratios (amplitude of the "D" wave resulting from rapid early diastolic filling to the total amplitude of the apexogramme). These two techniques record pulsatile phenomena ("pulse waves") arising from variations in intra-left ventricular pressure. They may complete the interpretation of Doppler recordings of velocities of blood flow ("flow waves"). To evaluate the value of each technique, the authors studied left ventricular diastolic function by Doppler phonocardiography and apexography in 60 subjects (38 patients of which 30 with ischaemic heart disease, and 22 healthy subjects). The results showed that increase in velocity and deceleration slope of the Doppler mitral E wave was associated with the presence of a B3 and correlated (r = 0.60; p = 0.0001) with the D/H ratio of the apexogramme. On the other hand, the absence of correlation between the mitral A wave velocity and a B4 associated with an increased a/H ratio enables the differentiation of normal Doppler mitral flow (absence of B4, Doppler a/H ratio < 12%) from pseudo-normal appearances (B4, a/H ratio > 12%). Therefore, the evaluation of diastolic function by Doppler mitral and pulmonary venous flow analysis may be usefully completed by phonocardiography and apexography.
Takayasu's disease involves the pulmonary vessels in over 50% of cases. However, primary lesions of the pulmonary arteries are very rare. The authors report the cases of a 34 year-old Caucasian woman presenting with clinical and radiological signs of acute pulmonary embolism, but in whom the pulmonary angiography showed stenotic and occlusive lesions of the right pulmonary artery. MRI provided an accurate diagnosis by showing typical thickening of the pulmonary arterial walls.
Many doppler echocardiographic indices have been described for quantifying aortic regurgitation, posing the problem of the relative value of each. Therefore, the authors assessed the severity of aortic regurgitation in 60 consecutive patients (16 women and 44 men, mean age 56.7 years, range 7 to 84 years) by the four grades of Seller's classification with selective aortography. These results were compared with Doppler echocardiographic measurement of anterograde cardiac output (Qao), the pressure half time (PHT), diameter of the jet at its origin in M mode colour Doppler (DTM) and calculation of the regurgitant fraction (RF) by comparison of flow at the different cardiac orifices by a method previously described and validated in the author's laboratory with an interorifice correlation of 0.91 to 0.96 and confidence intervals at 95% of the order of 12%. The feasibility of doppler echocardiographic methods was good: 87.8% for PHT (58/66 patients), 90% for DTM (36/40 patients), 90.9% for Qao and RF (60/66 patients). The correlation with aortography was -0.65 (p < 0.01) for PHT; 0.91 (p < 0.01) for DTM, 0.80 (p < 0.01) for Qao and 0.92 (p < 0.005) for RF. However, there was a number of overlaps between Grades I and II and Grades III and IV.(ABSTRACT TRUNCATED AT 250 WORDS)