[Determinants of survival after implantation of an automatic defibrillator. Report of 127 patients]. / Déterminants de la survie après implantation d'un défibrillateur automatique implantable. A propos de 127 patients.

The authors present a retrospective and longitudinal study of the predictive factors of mortality in patients having an implanted automatic defibrillator. The population comprised 127 patients implanted between September 1988 and September 1997. There were 107 men with a mean age of 57.7 +/- 13 years. The left ventricular ejection fraction was 39.3%. The proportion of coronary patients was 68%; 20% of patients had atrial fibrillation and 5% were in Class III of the NYHA classification. The indications were: resuscitated cardiac arrest (N = 56) and poorly tolerated ventricular tachycardia (N = 71). The follow-up period was 30 +/- 25 months. There were 23 early and 10 late complications. Seventy-two patients had received an electric shock; 57 had an appropriate shock. There were 23 arrhythmic storms (ventricular arrhythmia requiring at least 2 shocks in less than 24 hours) in 17 patients. The operative mortality was 1.1%; at 1 year, the global survival was 93.9 +/- 2.2%; cardiac survival was 94.7 +/- 2.1%; survival without sudden death was 98.3 +/- 1.2%. Multivariate analysis isolated predictive factors for mortality; atrial fibrillation was predictive for global mortality; an ejection fraction < 30% and the fact of having received an appropriate shock were predictive of cardiac mortality; and an arrhythmic storm was predictive of sudden death.

Single center experience with femoral extraction of permanent endocardial pacing leads.

Between March 1995 and June 1997, 128 leads were extracted from the hearts of 28 women and 50 men, 69 +/- 15 years of age (mean +/- SD, range 22-92 years). The indications for the procedure were: Accufix leads in 18 patients (14%), dysfunction or incompatibility with ICD in 16 (12%), endocarditis on the lead in 41 (32%), pulse generator pocket infection in 28 (22%), and pulse generator and/or lead erosion in 25 patients (19%). The extraction was performed with a snare (lasso), via a femoral vein as a first approach in 116 leads, and as an alternate approach, after extraction from the original site of implantation had failed, in 12 leads. The leads had been implanted for 62 +/- 48 months (range 1-205 months). A Cook sheath was used in 7, and a femoral approach traction in 20 instances. Of the 128 leads, 122 (95%) were completely extracted, and 2 (2%) were partially extracted (the distal electrode remaining attached to the myocardium), and 4 (3%) could not be removed. Four complications occurred: 2 tears of the tricuspid valve without clinical consequences, one separation of the lead's distal electrode which migrated into the hypogastric vein, and one hemorrhage at the femoral puncture site. There was no death or serious complication caused by lead extraction in this series.

Inadequate sympathovagal balance in response to orthostatism in patients with unexplained syncope and a positive head up tilt test.

AIM: To analyse the immediate response of heart rate variability (HRV) in response to orthostatic stress in unexplained syncope. SUBJECTS: 69 subjects, mean (SD) age 42 (18) years, undergoing 60 degrees head up tilt to evaluate unexplained syncope. METHODS: Based on 256 second ECG samples obtained during supine and upright phases, spectral analyses of low (LF) and high frequency (HF) bands were calculated, as well as the LF/HF power ratio, reflecting the sympathovagal balance. All variables were measured just before tilt during the last five minutes of the supine position, during the first five minutes of head up tilt, and just before the end of passive tilt. RESULTS: Symptoms occurred in 42 subjects (vasovagal syncope in 37; psychogenic syncope in five). Resting haemodynamics and HRV indices were similar in subjects with and without syncope. Immediately after assuming the upright posture, adaptation to orthostatism differed between the two groups in that the LF/HF power ratio decreased by 11% from supine (from 2.7 (1.5) to 2.4 (1.2)) in the positive test group, while it increased by 11.5% (from 2.8 (1.5) to 3.1 (1.7)) in the negative test group (p = 0.02). This was because subjects with a positive test did not have the same increment in LF power with tilting as those with a negative test (11% v 28%, p = 0.04), while HF power did not alter. A decreased LF/HF power ratio persisted throughout head up tilt and was the only variable found to discriminate between subjects with positive and negative test results (p = 0.005, multivariate analysis). During the first five minutes of tilt, a decreased LF/HF power ratio occurred in 33 of 37 subjects in the positive group and three of 27 in the negative group. Thus a decreased LF/HF ratio had 89% sensitivity, 89% specificity, a 92% positive predictive value, and an 86% negative predictive value. CONCLUSIONS: Through the LF/HF power ratio, spectral analysis of HRV was highly correlated with head up tilt results. Subjects developing syncope late during continued head up tilt have a decrease in LF/HF ratio immediately after assuming the upright posture, implying that although symptoms have not developed the vasovagal reaction may already have begun. This emphasises the major role of the autonomic nervous system in the genesis of vasovagal (neurally mediated) syncope.

Extraction of endocardial implantable cardioverter-defibrillator leads.

Despite a growing number of implantable cardioverter-defibrillator (ICD) lead removal indications, there is no consensus about extraction techniques. We applied our experience of pacemaker lead removal to ICD leads using a superior approach with a standard extractor kit, and an inferior approach with a lasso, or a surgical extraction. Fifteen leads were removed in 11 patients during 12 procedures (1 patient was referred twice): 11 right ventricular defibrillation leads, 3 right atrial coils, and 1 atrial lead implanted with a DDD-ICD. The indication for lead extraction was insulation failure (n = 4), conductor fracture (n = 2), abdominal pocket infection (n = 4), lead endocarditis (n = 1), and replacement of an atrial coil by an atrial lead for DDD-R pacing (n = 1). One patient had surgical extraction of 2 leads because of an endocarditis with large vegetations on a DDD-ICD. In 11 other cases, 5 leads were removed using a superior approach with a standard extraction kit and 8 leads were removed by a femoral approach using a lasso alone or added to a pigtail catheter. There was no failure of explantation. One extraction attempt failed with the superior approach but was successful with a secondary inferior approach. The main difficulties encountered were due to tight adherence of the proximal coil to the venous wall and to dislodgment of passive fixation leads from their endocardial insertion. One patient had subclavian vein thrombosis after intervention; no major complication was noted. Ten patients immediately underwent reimplantation. Two patients (1 with an endocarditis and 1 free of ICD therapy for 5 years) did not have reimplantation. During a 4- to 44-month follow-up, no late complication appeared. Thus, ICD lead explantation can be performed with a good success rate, with extraction techniques similar to those used for pacemaker leads.

Extraction and reimplantation of defibrillation leads through a thrombotic subclavian vein.

Venous thrombosis is one of the most frequently encountered obstacles when reintervening on endocardial leads. We report on two patients with a ventricular defibrillator requiring lead replacement in whom a subclavian vein thrombosis was documented prior to the intervention. We recanalized the vein and replaced the lead through the same path to preserve the venous access.

[Complete atrioventricular block during temporal lobe epilepsy. Apropos of a case]. / Bloc auriculo-ventriculaire complet au cours d'une épilepsie temporale. A propos d'un cas.

The authors report the case of a 37 years old woman with no previous medical history, admitted to hospital for investigation of unexplained syncope, sometimes associated with generalised fits. After standard non-invasive cardiovascular investigations, no diagnosis could be made. The tilt test induced a minor syncopal episode without reproducing the clinical symptoms. In view of the discordance between the induced and spontaneous symptoms, a neurological opinion was requested. During the recording of an electroencephalogram, syncopal atrioventricular block was observed, preceded by auditory hallucinations, reproducing exactly the clinical symptoms. Analysis of the sequence of events showed the conduction defect to arise after the onset of the epileptic fit, indicating a diagnosis of syncopal complete atrioventricular block complicating cryptogenic temporal epilepsy, and requiring specific treatment. This case illustrates the importance of close collaboration between cardiologists and neurologists in the management of cases of unexplained syncope.

Single radiofrequency application to cure atrioventricular nodal reentry: arguments for the slow pathway origin of the high-low frequency slow potentials.

BACKGROUND: High-low frequency slow potentials are thought to be related to the slow AV pathway conduction. Their use was proposed to guide radiofrequency (RF) ablation of atrioventricular nodal reentrant tachycardia (AVNRT). The present study was designed to determine the prospective value of these high-low frequency slow potentials to guide AVNRT ablation using a single RF application. Single RF application could indeed reduce the size of the lesion created in the viciny of the specialized AV conduction system and shorten the radiation exposure and the overall duration of the procedure. RESULTS: Forty-one patients (14 men, 27 women, 45 +/- 16 years old) with AVNRT underwent slow pathway RF ablation guided by high-low frequency slow potentials. High-low frequency slow potentials were found in all patients along the tricuspid annulus and above the coronary sinus. Ablation was always performed in the posterior part of Koch's triangle. The mean A/V amplitude ratio of the successful site was 0.43 +/- 0.59. In 32 patients (78%) AVNRT was no longer inducible after a single RF application. Procedure and radiation times were 35 +/- 31 and 13 +/- 12 min respectively. Five patients required 2, 3 patients 3, and 1 patient 6 RF applications. The mean number of RF applications was 1.4 +/- 0.9 (median = 1). In the 32 patients who required only one RF application, 24 (75%) had an obvious dual AV nodal pathways with a jump before ablation, which completely disappeared in 18 of them (75%) after ablation. In the 6 remaining patients, who still had a jump after 1 RF application, there was no significant change in either conduction times or refractory periods concerning both the anterograde and retrograde AV conduction. No patient had PR interval purlongation. After a mean follow up of 11 +/- 5 months, recurrence was observed in a single patient who received 2 discontinued RF applications. CONCLUSION: Catheter-mediated ablation of AVNRT using high-low frequency slow potentials to localize the slow AV pathway is feasible and safe. Using this technique, a single RF application was successfull in 78% of patients, and slow pathway characteristics were completely eliminated in 75% of patients. The radiation time and the procedure duration were short. This suggest that, in patients with AVNRT, the choice of an appropriate RF target can reduce procedural duration.

Triple chamber pacemaker for end-stage heart failure in a patient with a previously implanted automatic defibrillator.

A 63-year-old man with an ischemic dilated cardiomyopathy previously implanted with an implantable cardioverter defibrillator (ICD) received a triple chamber pacemaker as an ultimate therapeutic resort for end-stage congestive heart failure. After implant, the tolerance to physical exercise increased and NYHA class decreased from III to II. Echocardiography assessed ventricular contraction resynchronization during DDD biventricular pacing as compared to VVI pacing. No major pacemaker-ICD interaction was noted during testing or follow-up. We conclude that sequential biventricular pacing is feasible in the presence of an ICD.

[Dual-chamber implantable automatic defibrillators. Experiences apropos of 16 cases]. / Le défibrillateur automatique implantable double chambre. Expérience à propos de 16 cas.

In view of the large number of inappropriate shocks observed in patients with implanted defibrillators, improved detection of ventricular arrhythmias has become a major objective. The addition of an atrial catheter has been proposed to improve discrimination between ventricular and non-ventricular arrhythmias. Besides this function, the additional catheter could be used for DDD pacing without risk of interaction between the pacemaker and defibrillator. The authors report their initial experience in 16 patients implanted with a DDD pacemaker. The indication was resuscitated sudden death (N = 5) or ventricular tachycardia (N = 11). The choice of a DDD defibrillator was justified by a bradycardia (N = 9), haemodynamic factors (N = 4) or supraventricular tachycardia (N = 3). The devices used were the Defender 9001 (ELA Medical SA, France, N = 3), the Ventak AV 1810 and the Ventak AV II DR 1821 (Guidant/CPI, Inc. USA, N = 11 and N = 2 respectively). There were three immediate complications. After 2 to 29 months' follow-up, 5 patients had received appropriate treatment by their devices. Five patients had inappropriate shocks : one patient received a shock triggered by electrical interference, two others had no active sensing algorithme when the shocks were delivered, and the other two had an activated algorithme with 1/1 conduction of a supraventricular arrhythmia. No recurrences were recorded after reprogramming the device. DDD or VDD pacing was permanent in 9 patients and intermittent in 3 others. Seven patients had dilated cardiomyopathy and severe cardiac failure and were clinically improved by dual chamber pacing. In many patients, candidates for a defibrillator, this new generation of devices has improved specificity of arrhythmia detection and cardiac pacing without risk of interaction. The authors propose a classification of the indications for a DDD defibrillator.

Effects of procainamide on the excitable gap composition in common human atrial flutter.

The composition of the excitable gap (EG) in common atrial flutter (AF1) was determined before and during infusion of procainamide (PA) in 9 patients (6 men and 3 women; age 70 +/- 7 years). The EG was determined by introducing a premature stimulus after every 20th AF1 complex detected using a quadripolar electrode catheter placed just above the tricuspid valve. Diastole was scanned in 2- to 4-ms decrements to the atrial effective refractory period (ERP). The relationship between the coupling interval and the return cycle length (CL) determined a reset-response curve (RRC), which described the EG. PA (15 mg/kg) was administered during AF1 over 30 minutes and RRC was repeated at maximum AF1 CL. PA prolonged AF1 CL from 227 +/- 29 to 296 +/- 62 ms (P < 0.01) but did not terminate AF1. ERP during AF1 prolonged from 169 +/- 24 to 219 +/- 41 ms (P < 0.01). Control EG was 57 +/- 16 ms or 25% +/- 6% of AF1 CL and on PA EG was 77 +/- 30 ms (P = 0.01), which was still 26% +/- 7% of the CL. Without drug, RRC was mixed in eight cases demonstrating an EG composed of fully excitable tissue (10 +/- 4 ms or 19% +/- 10% of the EG) and partially refractory tissue (48 +/- 18 ms). PA did not change the duration of the fully excitable region (13 +/- 10 ms or 19% +/- 15% of EG). Peak PA plasma concentration was 47 +/- 20 mumol/L. PA prolonged AF1 CL, ERP, and EG duration but did not change the proportion of AF1 CL occupied by the EG. The persistance of fully excitable tissue at the head of the wavefront in the presence of PA may largely explain its inefficacy in the acute termination of common AF1.

[Ventricular fibrillation after radiofrequency ablation of the atrioventricular node]. / Fibrillation ventriculaire dans les suites d'une ablation par radiofréquence du noeud auriculo-ventriculaire.

The authors report the case of a 77 year old patient who underwent radiofrequency ablation of the atrioventricular node for chronic. Invalidating atrial fibrillation, refractory to pharmacological therapy. A single chamber ventricular pacemaker was implanted one week before interruption of AV conduction. Eleven applications (7 on the right and 4 on the left side of the interventricular septum) were required for successful ablation. Four hours later, the patient developed episodes of non-sustained polymorphic ventricular tachycardia and torsades de pointe. These arrhythmias were initiated by long cycle-short cycle sequences and preceded by changes of ventricular repolarisation (prolongation of the spontaneous and paced QTc and JTc intervals). Eight days after ablation, the patient had an episode of ventricular fibrillation reduced by external DC shock. This arrhythmia was also preceded by changes in ventricular repolarisation. This case demonstrates the potential proarrhythmogenic effect of radiofrequency ablation of the AV node with changes in ventricular repolarisation which induces malignant ventricular arrhythmias. The authors suggest an appropriate preventive attitude. The progression in two distinct phases (immediate and late) imposes prolonged arrhythmia monitoring.

Underdetection of ventricular tachycardia using a 40 ms stability criterion: effect of antiarrhythmic therapy.

Inappropriate shocks can complicate cardioverter defibrillator therapy. Among solutions proposed to avoid oversensing are algorithms to reduce inappropriate detection of atrial fibrillation (AF) or sinus tachycardia. In patients not on antiarrythmic drugs, an interval stability criterion of 40 ms has been validated with the Medtronic PCD to discriminate ventricular tachycardia (VT) from AF. With this algorithm, VT is considered stable if no interval varies from one of the three preceding intervals by more than 40 ms. If an interval does not fulfill this criterion, the VT event counter is reset to zero. The aim of this study was to investigate the incidence of underdetection when this criterion is applied in patients treated with antiarrhythmic drugs. We studied 132 sustained monomorphic VTs induced in 42 patients during 101 electrophysiological studies (EPS). EPS were performed without treatment (group I, 24 patients, 44 VTs); on Class Ia drug (group II, 17 patients, 24 VTs); Class Ic drug (group III, 22 patients, 39 VTs); or sotalol (group IV, 17 patients, 25 VTs). The endocardial electrogram of all VT episodes was digitized and the stability algorithm was applied. The reset arrhythmias were distributed among no delay, small, moderate (< 10 s) and important (> 15 s) delay in VT detection. The relation between drug use and reset was analyzed. Reset was found in 86 (65%) of induced VTs. No difference in heart rate or induction mode was shown between reset and nonreset VTs. There was a significative association between drug use and reset probability (Chi2 significantly different, P < 0.05). In patients treated with Class Ic drugs, the probability of finding an important delay in VT detection was 12.5% versus 0% in nontreated patients or in patients treated with sotalol. We conclude that a stability criterion of 40 ms is probably safe in nontreated patients but should be used with caution in patients treated with antiarrhythmics, especially in the presence of Class Ic drugs.

[Automatic implantable defibrillators. Clinical experience apropos of 45 patients]. / Le défibrillateur automatique implantable. Expérience clinique á propos de 45 patients.

The aim of this study was to analyse the efficacy and survival after implantation of an automatic cardioverter-defibrillator.. Forty-five patients including 37 men were followed up for 0 to 51 months. The indications were ventricular fibrillation with no curable cause (n = 27) and sustained resistant or poorly tolerated ventricular tachycardia (n = 17) when programmed ventricular pacing with antiarrhythmic therapy was not applicable or gave poor results. One patient was implanted with this device for torsades de pointes. The underlying cardiac disease was ischaemic in 34 cases, non-ischaemic in 8 cases, and 3 patients had no apparent cardiac disease. Twenty patients were implanted with an epicardial system (group I) and 25 patients with endocardial system (group II). In group II, there was one complete failure of implantation requiring the use of an epicardial system and 2 partial failures requiring an additional epicardial patch electrode. The perioperative mortality was 2/45 (4.4%), both cases being due to permanent arrhythmias. In 5 patients, the minimal effective energy of defibrillation was over 25 Joules at implantation, without any untoward consequences on the clinical outcome. Ten non-fatal complications were observed including two major problems (haemopericardium); there were two cases of late increase of the minimal effective energy of defibrillation requiring the addition of a subcutaneous patch. Twenty-four patient (53%) received at least one appropriate therapy; 14 patients (36%) had at least one inappropriate shock during follow-up. During follow-up, 7 patients died, 6 of a cardiac cause and 3 of an arrhythmic problem.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pericarditis disclosing at adult age recurrent Still's disease in childhood]. / Péricardite révélatrice à l'âge adulte d'une récidive de maladie de Still de l'enfant.

A 29 year old patient with a history of juvenile rheumatoid arthritis had a recurrence 12 years later, presenting as pericardial effusion with cardiac tamponade. Cardiac tamponade is a rare complication of Still's disease. To the author's knowledge, it has never been described as the mode of presentation of adult Still's disease. The diagnostic difficulties and inefficacy of non-steroid anti-inflammatory agents are illustrated by this case.

Limited left ventricular inotropic response to exercise in early phase of pressure overload in dogs.

To study the mechanisms of myocardial adaptation to increased stress in the early phase of left ventricular (LV) pressure overload, 12 dogs were instrumented with LV micromanometer, LV dimensional ultrasonic crystals, aortic catheter, and aortic occluder cuff. After recovery, animals performed graded exercise with acute aortic stenosis (AS) or sustained (24 h) aortic stenosis (SS). At baseline, LV functional parameters with SS were not different from those obtained with AS. LV peak pressure increased similarly during exercise with AS or SS, but LV peak dP/dt was lower with SS than with AS (peak values, 6,292 +/- 525 vs. 7,570 +/- 432 mmHg/s; P < 0.05). LV end-diastolic pressure increased from 9.7 +/- 1.7 to 21.4 +/- 3.3 mmHg (P < 0.05) during exercise with SS, but was unchanged with AS. The decrease of the time constant of isovolumic pressure fall during exercise was significantly smaller after SS than during AS (P < 0.05). In addition, the percentage of subendocardial wall thickening did not increase during exercise with SS (30.3 +/- 3.6%), while it increased significantly with AS (from 29.3 +/- 3.3 to 39.4 +/- 4.5%; P < 0.01). Plasma catecholamine levels were similar at baseline and increased to similar levels during exercise with AS and SS. In the early phase of pressure overload, we conclude that exercise capacity is maintained but that the LV inotropic response to exercise is modified with an altered relaxation process and a lesser utilization of subendocardial inotropic reserve.

[Hepatic veno-occlusive disease caused by Deticene: a cause of acute hypovolemic shock]. / Maladie veinoocclusive hépatique du au Déticène: une cause de choc hypovolémique aigu.

A case is reported of severe hypovolaemic shock occurring in a 53-year-old female patient undergoing a second course of chemotherapy with intravenous DTIC for a malignant melanoma. A few hours after the injection of DTIC, she became shocked, with loss of peripheral pulses, polypnoea and cutaneous vasoconstriction. She also had pain and guarding of the right hypocondrium. She was given 4 litres of colloids within 2 hours, together with 10 micrograms.kg-1.min-1 dopamine. Abdominal echography showed hepatomegaly, with a permeable portal vein. However biological investigations revealed lactic acidosis with hepatic cytolysis and hepatic failure. Nuclear magnetic resonance imaging displayed a reduced portal venous flow, with abnormally small hepatic veins. Fluid replacement was continued, together with administration of small doses of heparin (1 mg.kg-1.day-1) and hydrocortisone hemisuccinate 5 mg.kg-1.day-1. The status of patient worsened over the next few hours, because of the development of a very large volume of exudative ascites and bilateral pleural effusions. Despite continuing fluid replacement (91), she became anuric at the 24th hour, requiring haemodialysis. However, her condition became stable, and then slowly improved. Fluid replacement was stopped after 72 h, steroids after a fortnight. Liver function tests returned to normal after the third week, together with diuresis. The patient was able to leave the ICU after 24 days. Physicians should be aware of this rare, often fatal side-effect, probably of immuno-allergic origin.